LT1761 Series 100mA, Low Noise, LDO Micropower Regulators in TSOT-23 FEATURES DESCRIPTION n Low Noise: 20μVRMS (10Hz to 100kHz) The LT®1761 series are micropower, low noise, low n Low Quiescent Current: 20μA dropout regulators. With an external 0.01μF bypass n Wide Input Voltage Range: 1.8V to 20V capacitor, output noise drops to 20μV over a 10Hz to RMS n Output Current: 100mA 100kHz bandwidth. Designed for use in battery-powered n Very Low Shutdown Current: <0.1μA systems, the low 20μA quiescent current makes them an n Low Dropout Voltage: 300mV at 100mA ideal choice. In shutdown, quiescent current drops to less n Fixed Output Voltages: 1.2V, 1.5V, 1.8V, 2V, 2.5V, than 0.1μA. The devices are capable of operating over an 2.8V, 3V, 3.3V, 5V input voltage from 1.8V to 20V, and can supply 100mA of n Adjustable Output from 1.22V to 20V output current with a dropout voltage of 300mV. Quiescent n Stable with 1μF Output Capacitor current is well controlled, not rising in dropout as it does n Stable with Aluminum, Tantalum or with many other regulators. Ceramic Capacitors The LT1761 regulators are stable with output capacitors as n Reverse-Battery Protected low as 1μF. Small ceramic capacitors can be used without n No Reverse Current the series resistance required by other regulators. n No Protection Diodes Needed n Overcurrent and Overtemperature Protected Internal protection circuitry includes reverse battery n Available in Tiny 5-Lead TSOT-23 Package protection, current limiting, thermal limiting and reverse current protection. The device is available in fi xed output APPLICATIONS voltages of 1.2V, 1.5V, 1.8V, 2V, 2.5V, 2.8V, 3V, 3.3V and 5V, and as an adjustable device with a 1.22V reference n Cellular Phones voltage. The LT1761 regulators are available in the 5-lead n Pagers TSOT-23 package. n Battery-Powered Systems n Frequency Synthesizers L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective n Wireless Modems owners. TYPICAL APPLICATION 10Hz to 100kHz Output Noise 5V Low Noise Regulator 5V AT100mA VIN IN OUT + 20μVRMS NOISE 5.4V2 T0OV 1μF LT1761-5 0.01μF 10μF 100μVV/ODUIVT 20μVRMS SHDN BYP 1761 TA01 GND 1761 TA01b 1761sff 1

LT1761 Series ABSOLUTE MAXIMUM RATINGS (Note 1) IN Pin Voltage .........................................................±20V Output Short-Circuit Duration ........................ Indefi nite OUT Pin Voltage ......................................................±20V Operating Junction Temperature Range Input to Output Differential Voltage .........................±20V E, I Grade (Note 2) .............................–40°C to 125°C ADJ Pin Voltage ...................................................... ±7V MP Grade (Note 2) .............................–55°C to 125°C BYP Pin Voltage .....................................................±0.6V Storage Temperature Range ...................–65°C to 150°C SHDN Pin Voltage ................................................. ±20V Lead Temperature (Soldering, 10 sec) ..................300°C PIN CONFIGURATION LT1761-BYP LT1761-SD LT1761-X TOP VIEW TOP VIEW TOP VIEW IN 1 5 OUT IN 1 5 OUT IN 1 5 OUT GND 2 GND 2 GND 2 BYP 3 4 ADJ SHDN 3 4 ADJ SHDN 3 4 BYP S5 PACKAGE S5 PACKAGE S5 PACKAGE 5-LEAD PLASTIC TSOT-23 5-LEAD PLASTIC TSOT-23 5-LEAD PLASTIC TSOT-23 TJMAX = 150°C, θJA = 250°C/W TJMAX = 150°C, θJA = 250°C/W TJMAX = 150°C, θJA = 250°C/W SEE APPLICATIONS INFORMATION SECTION SEE APPLICATIONS INFORMATION SECTION SEE APPLICATIONS INFORMATION SECTION ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING * PACKAGE DESCRIPTION TEMPERATURE RANGE LT1761ES5-BYP#PBF LT1761ES5-BYP#TRPBF LTGC 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-BYP#PBF LT1761IS5-BYP#TRPBF LTGC 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-SD#PBF LT1761ES5-SD#TRPBF LTGH 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-SD#PBF LT1761IS5-SD#TRPBF LTGH 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-1.2#PBF LT1761ES5-1.2#TRPBF LTCDS 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-1.2#PBF LT1761IS5-1.2#TRPBF LTCDS 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-1.5#PBF LT1761ES5-1.5#TRPBF LTMT 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-1.5#PBF LT1761IS5-1.5#TRPBF LTMT 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-1.8#PBF LT1761ES5-1.8#TRPBF LTJM 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-1.8#PBF LT1761IS5-1.8#TRPBF LTJM 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761MPS5-1.8#PBF LT1761MPS5-1.8#TRPBF LTDCH 5-Lead Plastic TSOT-23 –55°C to 125°C LT1761ES5-2#PBF LT1761ES5-2#TRPBF LTJE 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-2#PBF LT1761IS5-2#TRPBF LTJE 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-2.5#PBF LT1761ES5-2.5#TRPBF LTGD 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-2.5#PBF LT1761IS5-2.5#TRPBF LTGD 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-2.8#PBF LT1761ES5-2.8#TRPBF LTLB 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-2.8#PBF LT1761IS5-2.8#TRPBF LTLB 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-3#PBF LT1761ES5-3#TRPBF LTGE 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-3#PBF LT1761IS5-3#TRPBF LTGE 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-3.3#PBF LT1761ES5-3.3#TRPBF LTGF 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-3.3#PBF LT1761IS5-3.3#TRPBF LTGF 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761MPS5-3.3#PBF LT1761MPS5-3.3#TRPBF LTGF 5-Lead Plastic TSOT-23 –55°C to 125°C 1761sff 2

LT1761 Series ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING * PACKAGE DESCRIPTION TEMPERATURE RANGE LT1761ES5-5#PBF LT1761ES5-5#TRPBF LTGG 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-5#PBF LT1761IS5-5#TRPBF LTGG 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761MPS5-5#PBF LT1761MPS5-5#TRPBF LTGG 5-Lead Plastic TSOT-23 –55°C to 125°C LEAD BASED FINISH TAPE AND REEL PART MARKING * PACKAGE DESCRIPTION TEMPERATURE RANGE LT1761ES5-BYP LT1761ES5-BYP#TR LTGC 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-BYP LT1761IS5-BYP#TR LTGC 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-SD LT1761ES5-SD#TR LTGH 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-SD LT1761IS5-SD#TR LTGH 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-1.2 LT1761ES5-1.2#TR LTCDS 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-1.2 LT1761IS5-1.2#TR LTCDS 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-1.5 LT1761ES5-1.5#TR LTMT 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-1.5 LT1761IS5-1.5#TR LTMT 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-1.8 LT1761ES5-1.8#TR LTJM 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-1.8 LT1761IS5-1.8#TR LTJM 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761MPS5-1.8 LT1761MPS5-1.8#TR LTDCH 5-Lead Plastic TSOT-23 –55°C to 125°C LT1761ES5-2 LT1761ES5-2#TR LTJE 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-2 LT1761IS5-2#TR LTJE 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-2.5 LT1761ES5-2.5#TR LTGD 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-2.5 LT1761IS5-2.5#TR LTGD 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-2.8 LT1761ES5-2.8#TR LTLB 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-2.8 LT1761IS5-2.8#TR LTLB 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-3 LT1761ES5-3#TR LTGE 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-3 LT1761IS5-3#TR LTGE 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761ES5-3.3 LT1761ES5-3.3#TR LTGF 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-3.3 LT1761IS5-3.3#TR LTGF 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761MPS5-3.3 LT1761MPS5-3.3#TR LTGF 5-Lead Plastic TSOT-23 –55°C to 125°C LT1761ES5-5 LT1761ES5-5#TR LTGG 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761IS5-5 LT1761IS5-5#TR LTGG 5-Lead Plastic TSOT-23 –40°C to 125°C LT1761MPS5-5 LT1761MPS5-5#TR LTGG 5-Lead Plastic TSOT-23 –55°C to 125°C Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/ 1761sff 3

LT1761 Series ELECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T = 25°C. (Note 2) A PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Input Voltage (Notes 3, 11) I = 100mA l 1.8 2.3 V LOAD Regulated Output Voltage (Note 4) LT1761-1.2 V = 2V, I = 1mA 1.185 1.2 1.215 V IN LOAD 2.3V < V < 20V, 1mA < I < 50mA l 1.170 1.2 1.230 V IN LOAD 2.3V < V < 20V, 1mA < I < 100mA l 1.150 1.2 1.240 V IN LOAD LT1761-1.5 V = 2V, I = 1mA 1.478 1.5 1.522 V IN LOAD 2.5V < V < 20V, 1mA < I < 50mA l 1.457 1.5 1.538 V IN LOAD 2.5V < V < 20V, 1mA < I < 100mA l 1.436 1.5 1.555 V IN LOAD LT1761-1.8 V = 2.3V, I = 1mA 1.775 1.8 1.825 V IN LOAD 2.8V < V < 20V, 1mA < I < 50mA l 1.750 1.8 1.845 V IN LOAD 2.8V < V < 20V, 1mA < I < 100mA l 1.725 1.8 1.860 V IN LOAD LT1761-2 V = 2.5V, I = 1mA 1.970 2 2.030 V IN LOAD 3V < V < 20V, 1mA < I < 50mA l 1.945 2 2.045 V IN LOAD 3V < V < 20V, 1mA < I < 100mA l 1.920 2 2.060 V IN LOAD LT1761-2.5 V = 3V, I = 1mA 2.465 2.5 2.535 V IN LOAD 3.5V < V < 20V, 1mA < I < 50mA l 2.435 2.5 2.565 V IN LOAD 3.5V < V < 20V, 1mA < I < 100mA l 2.415 2.5 2.575 V IN LOAD LT1761-2.8 V = 3.3V, I = 1mA 2.762 2.8 2.838 V IN LOAD 3.8V < V < 20V, 1mA < I < 50mA l 2.732 2.8 2.868 V IN LOAD 3.8V < V < 20V, 1mA < I < 100mA l 2.706 2.8 2.884 V IN LOAD LT1761-3 V = 3.5V, I = 1mA 2.960 3 3.040 V IN LOAD 4V < V < 20V, 1mA < I < 50mA l 2.930 3 3.070 V IN LOAD 4V < V < 20V, 1mA < I < 100mA l 2.900 3 3.090 V IN LOAD LT1761-3.3 V = 3.8V, I = 1mA 3.250 3.3 3.350 V IN LOAD 4.3V < V < 20V, 1mA < I < 50mA l 3.230 3.3 3.370 V IN LOAD 4.3V < V < 20V, 1mA < I < 100mA l 3.190 3.3 3.400 V IN LOAD LT1761-5 V = 5.5V, I = 1mA 4.935 5 5.065 V IN LOAD 6V < V < 20V, 1mA < I < 50mA l 4.900 5 5.100 V IN LOAD 6V < V < 20V, 1mA < I < 100mA l 4.850 5 5.120 V IN LOAD ADJ Pin Voltage (Note 3, 4) LT1761 V = 2V, I = 1mA 1.205 1.220 1.235 V IN LOAD 2.3V < V < 20V, 1mA < I < 50mA l 1.190 1.220 1.250 V IN LOAD 2.3V < V < 20V, 1mA < I < 100mA l 1.170 1.220 1.260 V IN LOAD Line Regulation LT1761-1.2 ΔVIN = 2V to 20V, ILOAD = 1mA l 1 10 mV LT1761-1.5 ΔVIN = 2V to 20V, ILOAD = 1mA l 1 10 mV LT1761-1.8 ΔVIN = 2.3V to 20V, ILOAD = 1mA l 1 10 mV LT1761-2 ΔVIN = 2.5V to 20V, ILOAD = 1mA l 1 10 mV LT1761-2.5 ΔVIN = 3V to 20V, ILOAD = 1mA l 1 10 mV LT1761-2.8 ΔVIN = 3.3V to 20V, ILOAD = 1mA l 1 10 mV LT1761-3 ΔVIN = 3.5V to 20V, ILOAD = 1mA l 1 10 mV LT1761-3.3 ΔVIN = 3.8V to 20V, ILOAD = 1mA l 1 10 mV LT1761-5 ΔVIN = 5.5V to 20V, ILOAD = 1mA l 1 10 mV LT1761 (Note 3) ΔVIN = 2V to 20V, ILOAD = 1mA l 1 10 mV 1761sff 4

LT1761 Series ELECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T = 25°C. (Note 2) A PARAMETER CONDITIONS MIN TYP MAX UNITS Load Regulation LT1761-1.2 VIN = 2.3V, ΔILOAD = 1mA to 50mA 1 6 mV VIN = 2.3V, ΔILOAD = 1mA to 50mA l 12 mV VIN = 2.3V, ΔILOAD = 1mA to 100mA 1 12 mV VIN = 2.3V, ΔILOAD = 1mA to 100mA l 50 mV LT1761-1.5 VIN = 2.5V, ΔILOAD = 1mA to 50mA 10 20 mV VIN = 2.5V, ΔILOAD = 1mA to 50mA l 35 mV VIN = 2.5V, ΔILOAD = 1mA to 100mA 14 30 mV VIN = 2.5V, ΔILOAD = 1mA to 100mA l 55 mV LT1761-1.8 VIN = 2.8V, ΔILOAD = 1mA to 50mA 10 20 mV VIN = 2.8V, ΔILOAD = 1mA to 50mA l 35 mV VIN = 2.8V, ΔILOAD = 1mA to 100mA 15 30 mV VIN = 2.8V, ΔILOAD = 1mA to 100mA l 60 mV LT1761-2 VIN = 3V, ΔILOAD = 1mA to 50mA 10 20 mV VIN = 3V, ΔILOAD = 1mA to 50mA l 35 mV VIN = 3V, ΔILOAD = 1mA to 100mA 15 35 mV VIN = 3V, ΔILOAD = 1mA to 100mA l 65 mV LT1761-2.5 VIN = 3.5V, ΔILOAD = 1mA to 50mA 10 20 mV VIN = 3.5V, ΔILOAD = 1mA to 50mA l 35 mV VIN = 3.5V, ΔILOAD = 1mA to 100mA 20 40 mV VIN = 3.5V, ΔILOAD = 1mA to 100mA l 80 mV LT1761-2.8 VIN = 3.8V, ΔILOAD = 1mA to 50mA 10 20 mV VIN = 3.8V, ΔILOAD = 1mA to 50mA l 38 mV VIN = 3.8V, ΔILOAD = 1mA to 100mA 20 40 mV VIN = 3.8V, ΔILOAD = 1mA to 100mA l 86 mV LT1761-3 VIN = 4V, ΔILOAD = 1mA to 50mA 10 20 mV VIN = 4V, ΔILOAD = 1mA to 50mA l 40 mV VIN = 4V, ΔILOAD = 1mA to 100mA 20 40 mV VIN = 4V, ΔILOAD = 1mA to 100mA l 90 mV LT1761-3.3 VIN = 4.3V, ΔILOAD = 1mA to 50mA 10 20 mV VIN = 4.3V, ΔILOAD = 1mA to 50mA l 40 mV VIN = 4.3V, ΔILOAD = 1mA to 100mA 20 40 mV VIN = 4.3V, ΔILOAD = 1mA to 100mA l 100 mV LT1761-5 VIN = 6V, ΔILOAD = 1mA to 50mA 15 30 mV VIN = 6V, ΔILOAD = 1mA to 50mA l 60 mV VIN = 6V, ΔILOAD = 1mA to 100mA 25 65 mV VIN = 6V, ΔILOAD = 1mA to 100mA l 150 mV LT1761 (Note 3) VIN = 2.3V, ΔILOAD = 1mA to 50mA 1 6 mV VIN = 2.3V, ΔILOAD = 1mA to 50mA l 12 mV VIN = 2.3V, ΔILOAD = 1mA to 100mA 1 12 mV VIN = 2.3V, ΔILOAD = 1mA to 100mA l 50 mV Dropout Voltage I = 1mA 0.10 0.15 V LOAD V = V I = 1mA l 0.19 V IN OUT(NOMINAL) LOAD (Notes 5, 6, 11) I = 10mA 0.17 0.22 V LOAD I = 10mA l 0.29 V LOAD I = 50mA 0.24 0.28 V LOAD I = 50mA l 0.38 V LOAD I = 100mA 0.30 0.35 V LOAD I = 100mA 0.45 V LOAD 1761sff 5

LT1761 Series ELECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T = 25°C. (Note 2) A PARAMETER CONDITIONS MIN TYP MAX UNITS GND Pin Current I = 0mA l 20 45 μA LOAD V = V I = 1mA l 55 100 μA IN OUT(NOMINAL) LOAD (Notes 5, 7) I = 10mA l 230 400 μA LOAD I = 50mA l 1 2 mA LOAD I = 100mA l 2.2 4 mA LOAD Output Voltage Noise C = 10μF, C = 0.01μF, I = 100mA, BW = 10Hz to 100kHz 20 μV OUT BYP LOAD RMS ADJ Pin Bias Current (Notes 3, 8) 30 100 nA Shutdown Threshold V = Off to On l 0.8 2 V OUT V = On to Off l 0.25 0.65 V OUT SHDN Pin Current V = 0V l 0 0.5 μA SHDN (Note 9) V = 20V l 1 3 μA SHDN Quiescent Current in Shutdown V = 6V, V = 0V 0.01 0.1 μA IN SHDN Ripple Rejection (Note 3) V – V = 1.5V (Avg), V = 0.5V , f = 120Hz, 55 65 dB IN OUT RIPPLE P-P RIPPLE I = 50mA LOAD Current Limit V = 7V, V = 0V 200 mA IN OUT VIN = VOUT(NOMINAL) + 1V or 2.3V (Note 12), ΔVOUT = –5% l 110 mA Input Reverse Leakage Current V = –20V, V = 0V l 1 mA IN OUT Reverse Output Current LT1761-1.2 V = 1.2V, V < 1.2V 10 20 μA OUT IN (Note 10) LT1761-1.5 V = 1.5V, V < 1.5V 10 20 μA OUT IN LT1761-1.8 V = 1.8V, V < 1.8V 10 20 μA OUT IN LT1761-2 V = 2V, V < 2V 10 20 μA OUT IN LT1761-2.5 V = 2.5V, V < 2.5V 10 20 μA OUT IN LT1761-2.8 V = 2.8V, V < 2.8V 10 20 μA OUT IN LT1761-3 V = 3V, V < 3V 10 20 μA OUT IN LT1761-3.3 V = 3.3V, V < 3.3V 10 20 μA OUT IN LT1761-5 V = 5V, V < 5V 10 20 μA OUT IN LT1761 (Note 3) V = 1.22V, V < 1.22V 5 10 μA OUT IN Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 6: Dropout voltage is the minimum input to output voltage differential may cause permanent damage to the device. Exposure to any Absolute needed to maintain regulation at a specifi ed output current. In dropout, the Maximum Rating condition for extended periods may affect device output voltage will be equal to: V – V . IN DROPOUT reliability and lifetime. Note 7: GND pin current is tested with V = V or V = 2.3V IN OUT(NOMINAL) IN Note 2: The LT1761 regulators are tested and specifi ed under pulse load (whichever is greater) and a current source load. This means the device conditions such that T ≈ T . The LT1761E is 100% production tested is tested while operating in its dropout region or at the minimum input J A at T = 25°C. Performance at –40°C and 125°C is assured by design, voltage specifi cation. This is the worst-case GND pin current. The GND pin A characterization and correlation with statistical process controls. The current will decrease slightly at higher input voltages. LT1761I is guaranteed over the full –40°C to 125°C operating junction Note 8: ADJ pin bias current fl ows into the ADJ pin. temperature range. The LT1761MP is 100% tested and guaranteed over Note 9: SHDN pin current fl ows into the SHDN pin. the –55°C to 125°C operating junction temperature range. Note 10: Reverse output current is tested with the IN pin grounded and the Note 3: The LT1761 (adjustable versions) are tested and specifi ed for OUT pin forced to the rated output voltage. This current fl ows into the OUT these conditions with the ADJ pin connected to the OUT pin. pin and out the GND pin. Note 4: Operating conditions are limited by maximum junction Note 11: For the LT1761, LT1761-1.2, LT1761-1.5, LT1761-1.8 and temperature. The regulated output voltage specifi cation will not apply LT1761-2 dropout voltage will be limited by the minimum input voltage for all possible combinations of input voltage and output current. When specifi cation under some output voltage/load conditions. See the curve of operating at maximum input voltage, the output current range must be Minimum Input Voltage in the Typical Performance Characteristics. limited. When operating at maximum output current, the input voltage Note 12: To satisfy requirements for minimum input voltage, current limit range must be limited. is tested at V = V + 1V or V = 2.3V, whichever is greater. IN OUT(NOMINAL) IN Note 5: To satisfy requirements for minimum input voltage, the LT1761 (adjustable version) is tested and specifi ed for these conditions with an external resistor divider (two 250k resistors) for an output voltage of 2.44V. The external resistor divider will add a 5μA DC load on the output. 1761sff 6

LT1761 Series TYPICAL PERFORMANCE CHARACTERISTICS Typical Dropout Voltage Guaranteed Dropout Voltage Dropout Voltage 500 500 500 = TEST POINTS 450 450 450 400 400 400 V) V) V) AGE (m 335000 TJ = 125°C AGE (m 335000 TJ ≤ 125°C AGE (m335000 IL = 100mA OLT 250 OLT 250 TJ ≤ 25°C OLT250 UT V 200 TJ = 25°C UT V 200 UT V200 IL = 50mA O O O ROP 150 ROP 150 ROP150 IL = 10mA D D D 100 100 100 IL = 1mA 50 50 50 0 0 0 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 80 90 100 –50 –25 0 25 50 75 100 125 OUTPUT CURRENT (mA) OUTPUT CURRENT (mA) TEMPERATURE (°C) 1761 G00 1761 G01 1761 G01.1 LT1761-1.2 LT1761-1.5 Quiescent Current Output Voltage Output Voltage 40 1.220 1.528 VIN = 6V IL = 1mA IL = 1mA 35 RL = ∞ (250k FOR LT1761-BYP, -SD) 1.215 1.521 IL = 0 (5μA FOR LT1761-BYP, -SD) A) 30 1.210 1.514 UIESCENT CURRENT (μ 22115050 VSHDN = VIN OUTPUT VOLTAGE (V)1111....221100995050 OUTPUT VOLTAGE (V)1111....554400987036 Q 5 1.185 1.479 VSHDN = 0V 0 1.180 1.472 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 1761 G03 1761 G05 1761 G51 LT1761-1.8 LT1761-2 LT1761-2.5 Output Voltage Output Voltage Output Voltage 1.84 2.04 2.54 IL = 1mA IL = 1mA IL = 1mA 1.83 2.03 2.53 1.82 2.02 2.52 V) V) V) GE (1.81 GE (2.01 GE (2.51 A A A T T T L L L O1.80 O2.00 O2.50 V V V T T T PU1.79 PU1.99 PU2.49 T T T U U U O O O 1.78 1.98 2.48 1.77 1.97 2.47 1.76 1.96 2.46 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 1761 G06 1761 G07 1761 G08 1761sff 7

LT1761 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1761-2.8 LT1761-3 LT1761-3.3 Output Voltage Output Voltage Output Voltage 2.84 3.060 3.360 IL = 1mA IL = 1mA IL = 1mA 2.83 3.045 3.345 2.82 3.030 3.330 V) V) V) GE (2.81 GE (3.015 GE (3.315 A A A T T T L L L O2.80 O3.000 O3.300 V V V T T T PU2.79 PU2.985 PU3.285 T T T U U U O2.78 O2.970 O3.270 2.77 2.955 3.255 2.76 2.940 3.240 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 1761 G52 1761 G09 1761 G11 LT1761-5 LT1761-BYP, LT1761-SD LT1761-1.2 Output Voltage ADJ Pin Voltage Quiescent Current 5.08 1.240 250 IL = 1mA IL = 1mA TJ = 25°C 5.06 1.235 225 RL = ∞ 200 5.04 1.230 A) AGE (V)5.02 AGE (V)1.225 RENT (μ 117550 OUTPUT VOLT544...099086 ADJ PIN VOLT111...222211050 UIESCENT CUR 11207505 Q 50 4.94 1.205 25 VSHDN = VIN VSHDN = 0V 4.92 1.200 0 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 0 1 2 3 4 5 6 7 8 9 10 TEMPERATURE (°C) TEMPERATURE (°C) INPUT VOLTAGE (V) 1761 G12 1761 G10 1761 G10b LT1761-1.5 LT1761-1.8 LT1761-2 Quiescent Current Quiescent Current Quiescent Current 200 200 200 TJ = 25°C TJ = 25°C TJ = 25°C 175 RL = ∞ 175 RL = ∞ 175 RL = ∞ A) 150 A) 150 A) 150 μ μ μ T ( T ( T ( EN 125 EN 125 EN 125 R R R R R R CU 100 CU 100 CU 100 T T T N N N CE 75 CE 75 CE 75 S S S E E E UI 50 UI 50 UI 50 Q Q Q 25 VSHDN = VIN 25 VSHDN = VIN 25 VSHDN = VIN VSHDN = 0V VSHDN = 0V VSHDN = 0V 0 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 INPUT VOLTAGE (V) INPUT VOLTAGE (V) INPUT VOLTAGE (V) 1761 G53 1761 G18 1761 G19 1761sff 8

LT1761 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1761-2.5 LT1761-2.8 LT1761-3 Quiescent Current Quiescent Current Quiescent Current 200 200 200 TJ = 25°C TJ = 25°C TJ = 25°C 175 RL = ∞ 175 RL = ∞ 175 RL = ∞ A) 150 A) 150 A) 150 μ μ μ T ( T ( T ( EN 125 EN 125 EN 125 R R R R R R CU 100 CU 100 CU 100 T T T N N N CE 75 CE 75 CE 75 S S S E E E UI 50 UI 50 UI 50 Q Q Q 25 VSHDN = VIN 25 VSHDN = VIN 25 VSHDN = VIN VSHDN = 0V VSHDN = 0V VSHDN = 0V 0 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 INPUT VOLTAGE (V) INPUT VOLTAGE (V) INPUT VOLTAGE (V) 1761 G13 1761 G54 1761 G14 LT1761-3.3 LT1761-5 LT1761-BYP, LT1761-SD Quiescent Current Quiescent Current Quiescent Current 200 200 30 TJ = 25°C TJ = 25°C TJ = 25°C 175 RL = ∞ 175 RL = ∞ RL = 250k 25 IL = 5μA A) 150 A) 150 A) T (μ T (μ T (μ 20 VSHDN = VIN EN 125 EN 125 EN R R R R R R CU 100 CU 100 CU 15 T T T N N N CE 75 CE 75 CE S S S 10 E E E UI 50 UI 50 UI Q Q Q 25 VSHDN = VIN 25 VSHDN = VIN 5 VSHDN = 0V VSHDN = 0V VSHDN = 0V 0 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 0 2 4 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) INPUT VOLTAGE (V) INPUT VOLTAGE (V) 1761 G15 1761 G16 1761 G17 LT1761-1.2 LT1761-1.5 LT1761-1.8 GND Pin Current GND Pin Current GND Pin Current 2.50 2.50 2.50 TJ = 25°C TJ = 25°C TJ = 25°C 2.25 *FOR VOUT = 1.2V 2.25 *FOR VOUT = 1.5V 2.25 *FOR VOUT = 1.8V 2.00 2.00 2.00 A) A) A) NT (m11..7550 RILL = = 1 1020ΩmA* NT (m11..7550 RILL = = 1 1050ΩmA* NT (m11..7550 RILL = = 1 1080ΩmA* E E E R R R ND PIN CUR110...207505 RILL = = 5 204mΩA* ND PIN CUR110...207505 RILL = = 5 300mΩA* ND PIN CUR110...207505 RILL = = 5 306mΩA* G00..5205 RILL = = 1 1m.2Ak* RILL = = 1 102m0AΩ* G00..5205 RILL = = 1 1m.5Ak* RILL = = 1 105m0AΩ* G00..5205 RILL = = 1 1m.8Ak* RILL = = 1 108m0AΩ* 0 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 INPUT VOLTAGE (V) INPUT VOLTAGE (V) INPUT VOLTAGE (V) 1761 G17b 1761 G55 1761 G02 1761sff 9

LT1761 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1761-2 LT1761-2.5 LT1761-2.8 GND Pin Current GND Pin Current GND Pin Current 2.50 2.50 2.50 TJ = 25°C TJ = 25°C TJ = 25°C 2.25 *FOR VOUT = 2V 2.25 *FOR VOUT = 2.5V 2.25 *FOR VOUT = 2.8V mA)21..0705 RL = 20Ω mA)21..0705 RILL = = 1 2050ΩmA mA)21..0705 RILL = = 1 2080ΩmA T ( IL = 100mA* T ( T ( N1.50 N1.50 N1.50 E E E R R R UR1.25 UR1.25 UR1.25 PIN C1.00 RILL = = 5 400mΩA* PIN C1.00 RILL = = 5 500mΩA* PIN C1.00 RILL = = 5 506mΩA* ND 0.75 ND 0.75 ND 0.75 G G G 0.50 RL = 2k RL = 200Ω 0.50 RL = 2.5k RL = 250Ω 0.50 RL = 2.8k RL = 280Ω 0.25 IL = 1mA* IL = 10mA* 0.25 IL = 1mA* IL = 10mA* 0.25 IL = 1mA* IL = 10mA* 0 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 INPUT VOLTAGE (V) INPUT VOLTAGE (V) INPUT VOLTAGE (V) 1761 G04 1761 G20 1761 G56 LT1761-3 LT1761-3.3 LT1761-5 GND Pin Current GND Pin Current GND Pin Current 2.50 2.50 2.50 TJ = 25°C TJ = 25°C TJ = 25°C 2.25 *FOR VOUT = 3V 2.25 *FOR VOUT = 3.3V 2.25 *FOR VOUT = 5V 2.00 2.00 2.00 ENT (mA)11..7550 RILL = = 1 3000ΩmA* ENT (mA)11..7550 RILL = = 1 3030ΩmA* ENT (mA)11..7550 RILL = = 1 5000ΩmA R R R ND PIN CUR110...207505 RILL = = 5 600mΩA* ND PIN CUR110...207505 RILL = = 5 606mΩA* ND PIN CUR110...207505 RILL = = 5 100m0AΩ* G00..5205 RILL = = 1 3mkA* RILL = = 1 300m0AΩ* G00..5205 RILL = = 1 3m.3Ak* RILL = = 1 303m0AΩ* G00..5205 RILL = = 1 5mkA* RILL = = 1 500m0AΩ* 0 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 INPUT VOLTAGE (V) INPUT VOLTAGE (V) INPUT VOLTAGE (V) 1761 G21 1761 G22 1761 G23 LT1761-BYP, LT1761-SD SHDN Pin Threshold GND Pin Current GND Pin Current vs I (On to Off) LOAD 2.50 2.50 1.0 TJ = 25°C VIN = VOUT(NOMINAL) + 1V IL = 1mA 2.25 *FOR VOUT = 1.22V 2.25 0.9 mA)21..0705 RILL = = 1 1020.m2ΩA* mA)21..0705 D (V) 00..87 T ( T ( OL N1.50 N1.50 H 0.6 RE RE ES CUR1.25 RL = 24.4Ω CUR1.25 THR 0.5 N 1.00 IL = 50mA* N 1.00 N 0.4 PI PI PI ND 0.75 ND 0.75 DN 0.3 G G H 0.50 RL = 1.22k RL = 122Ω 0.50 S 0.2 0.25 IL = 1mA* IL = 10mA* 0.25 0.1 0 0 0 0 1 2 3 4 5 6 7 8 9 10 0 10 20 30 40 50 60 70 80 90 100 –50 –25 0 25 50 75 100 125 INPUT VOLTAGE (V) OUTPUT CURRENT (mA) TEMPERATURE (°C) 1761 G24 1761 G25 1761 G26 1761sff 10

LT1761 Series TYPICAL PERFORMANCE CHARACTERISTICS SHDN Pin Threshold (Off to On) SHDN Pin Input Current SHDN Pin Input Current 1.0 1.0 1.4 VSHDN = 20V 0.9 0.9 D (V) 00..87 IL = 100mA NT (μA) 00..87 NT (μA) 11..20 OL RE RE ESH 0.6 IL = 1mA CUR 0.6 CUR 0.8 HR 0.5 UT 0.5 UT HDN PIN T 00..43 N PIN INP 00..43 N PIN INP 00..64 S 0.2 HD 0.2 HD S S 0.2 0.1 0.1 0 0 0 –50 –25 0 25 50 75 100 125 0 1 2 3 4 5 6 7 8 9 10 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) SHDN PIN VOLTAGE (V) TEMPERATURE (°C) 1761 G27 1761 G28 1761 G29 ADJ Pin Bias Current Current Limit Current Limit 100 350 350 VOUT = 0V VIN = 7V 90 300 TJ = 25°C 300 VOUT = 0V A) 80 mA) J PIN BIAS CURRENT (n 7654300000 RT-CIRCUIT CURRENT (221150500000 CURRENT LIMIT (mA)221150500000 AD 20 HO S 50 50 10 0 0 0 –50 –25 0 25 50 75 100 125 0 1 2 3 4 5 6 7 –50 –25 0 25 50 75 100 125 TEMPERATURE ((cid:111)C) INPUT VOLTAGE (V) TEMPERATURE (°C) 1761 G30 1761 G31 1761 G32 Reverse Output Current Reverse Output Current Input Ripple Rejection ERSE OUTPUT CURRENT (μA) 10987654300000000 TVCIV(NLJIUOLNT TU=TRL 1O= T1TR72 7O0=165LE6V 17°UTNV1C-61TTAB-L17P DL3YFT-6UJTLP211L1TO.,7-8 T 7-WP26S16.I1S5D7N1-6-)2L11LLT.-TT811117.775666111-1--BS.2YDP ERSE OUTPUT CURRENT (μA)222111152075207........05050505 VVVVVVVVVVVIOOOOOOOOOONUUUUUUUUUU =TTTTTTTTTT ==========0 V1111222335....V..V.V2258583 2VVVVVV(((LLLV ((((((TTT LLLLLL(111LTTTTTT777T11111166617777771117666666---61111112351------)))111223-LB......258583TY))))))1P7,6-S1D-B)YP,-SD RIPPLE REJECTION (dB) 87654320000000 LTL1T716716-1B-5YP IV1CLVIB N= Y+ =P1 5 V0=00 Om0mUVTAC(RNOMOUSMT RI N=IA P1LP0) Lμ+EF REV 2100 LT1761-3.3 REV 52..05 L-2T.157,-621.8-1,-.32,,--31..35,,--51.8,-2, 10 COUT = 1μF LT1761-5 0 0 0 0 1 2 3 4 5 6 7 8 9 10 –50 –25 0 25 50 75 100 125 10 100 1k 10k 100k 1M OUTPUT VOLTAGE (V) TEMPERATURE (°C) FREQUENCY (Hz) 1761 G33 1761 G34 1761 G35 1761sff 11

LT1761 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1761-5 LT1761-BYP, LT1761-SD Input Ripple Rejection Input Ripple Rejection Minimum Input Voltage 80 80 2.5 70 CBYP = 0.01μF 70 CBYP = 1000pF V) 2.0 dB) 60 dB) 60 GE ( IL = 100mA EJECTION ( 5400 CBYP = 100pF EJECTION ( 5400 PUT VOLTA 1.5 IL = 50mA R R N LE 30 LE 30 M I 1.0 RIPP 20 IL = 100mA RIPP 20 VIN = VOUT (NOMINAL) + NIMU VIN = VOUT(NOMINAL) + 1V + 0.5VP-P RIPPLE MI 0.5 10 1V + 50mVRMS RIPPLE 10 AT f = 120Hz COUT = 10μF IL = 50mA 0 0 0 10 100 1k 10k 100k 1M –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 FREQUENCY (Hz) TEMPERATURE (°C) TEMPERATURE (°C) 1761 G36 1761 G37 1761 G38 Load Regulation Load Regulation ΔI = 1mA to 50mA ΔI = 1mA to 100mA L L 0 0 –5 LT1761-BYP, -SD, -1.2 –10 LT1761-BYP, -SD, -1.2 LT1761-1.5 LT1761-1.8 –20 LT1761-1.5 ON (mV) ––1105 LLLTTT111777666111---222..58 ON (mV) ––3400 LLLTTT111777666111---122..85 TI LT1761-3 TI LT1761-2.8 LA –20 LT1761-3.3 LA –50 LT1761-3 U U LT1761-3.3 G G RE –25 RE –60 D D A A –70 LO –30 LT1761-5 LO LT1761-5 –80 –35 –90 –40 –100 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) 1761 G39 1761 G40 RMS Output Noise vs Output Noise Spectral Density Output Noise Spectral Density Bypass Capacitor AL DENSITY (μV/√Hz) 101 LT1761L-T51761L-T31.3761L-2T.187,-631-2.5 AL DENSITY (μV/√Hz) 101 LT1761-5 CBYPC B=Y 1P0 =0 01p00FpF E (μV)RMS11142080000 LT1761L-T51L7T611L7-T361.137L-36T11-726CIfL .1=8O =- U12 T10. 50H=0 z1m T0AOμF 100kHz R R S OUTPUT NOISE SPECT 0.1 L-CCISLTOB D=1YU 7,PT1 61 0==1.0 2 01-mB0YAμFP,LT1761-L1LT.T511776611-1-2.8 OUTPUT NOISE SPECT 0.1 LCILCTO B=1UY 7T1P 60= =10 1 -m0B0.A0μY1FPμF OUTPUT NOI 642000 LT1761L-T11.87,6 -12-1.5LT1761-BYP, -1.2 0.01 0.01 0 10 100 1k 10k 100k 10 100 1k 10k 100k 10 100 1k 10k FREQUENCY (Hz) FREQUENCY (Hz) CBYP (pF) 1761 G43 1761 G41 1761 G42 1761sff 12

LT1761 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1761-5 LT1761-5 RMS Output Noise vs 10Hz to 100kHz Output Noise 10Hz to 100kHz Output Noise Load Current (10Hz to 100kHz) C = 0pF C = 100pF BYP BYP 160 COUT = 10μF 140 CBYP = 0 CBYP = 0.01μF LT1761-5 )S120 M μVR100 VOUT VOUT E ( 100μV/DIV 100μV/DIV OIS 80 N UT 60 LT1761-BYP P T U O 40 20 LT1761-5 COUT = 10μF 1ms/DIV 1761 G45 COUT = 10μF 1ms/DIV 1761 G46 LT1761-BYP IL = 100mA IL = 100mA 0 0.01 0.1 1 10 100 LOAD CURRENT (mA) 1761 G44 LT1761-5 LT1761-5 10Hz to 100kHz Output Noise 10Hz to 100kHz Output Noise C = 1000pF C = 0.01μF BYP BYP VOUT VOUT 100μV/DIV 100μV/DIV COUT = 10μF 1ms/DIV 1761 G46 COUT = 10μF 1ms/DIV 1761 G48 IL = 100mA IL = 100mA LT1761-5 Transient Response LT1761-5 Transient Response C = 0pF C = 0.01μF BYP BYP VIN = 6V VIN = 6V E 0.2 CIN = 10μF E 0.04 CIN = 10μF LTAGN (V) 0.1 COUT = 10μF LTAGN (V) 0.02 COUT = 10μF UTPUT VODEVIATIO–0.01 UTPUT VODEVIATIO–0.002 O –0.2 O –0.04 T T EN 100 EN 100 R R CURmA) 50 CURmA) 50 AD ( 0 AD ( 0 O O L L 0 400 800 1200 1600 2000 0 20 40 60 80 100120140160180 200 TIME (μs) TIME (μs) 1761 G49 1761 G50 1761sff 13

LT1761 Series PIN FUNCTIONS IN (Pin 1): Input. Power is supplied to the device through BYP (Pins 3/4, Fixed/-BYP Devices): Bypass. The BYP the IN pin. A bypass capacitor is required on this pin if pin is used to bypass the reference of the LT1761 regula- the device is more than six inches away from the main tors to achieve low noise performance from the regulator. input fi lter capacitor. In general, the output impedance The BYP pin is clamped internally to ±0.6V (one V ) from BE of a battery rises with frequency, so it is advisable to ground. A small capacitor from the output to this pin will include a bypass capacitor in battery-powered circuits. A bypass the reference to lower the output voltage noise. bypass capacitor in the range of 1μF to 10μF is suffi cient. A maximum value of 0.01μF can be used for reducing The LT1761 regulators are designed to withstand reverse output voltage noise to a typical 20μV over a 10Hz RMS voltages on the IN pin with respect to ground and the OUT to 100kHz bandwidth. If not used, this pin must be left pin. In the case of a reverse input, which can happen if unconnected. a battery is plugged in backwards, the device will act as ADJ (Pin 4, Adjustable Devices Only): Adjust Pin. For the if there is a diode in series with its input. There will be adjustable LT1761, this is the input to the error amplifi er. no reverse current fl ow into the regulator and no reverse This pin is internally clamped to ±7V. It has a bias current voltage will appear at the load. The device will protect both of 30nA which fl ows into the pin (see curve of ADJ Pin itself and the load. Bias Current vs Temperature in the Typical Performance GND (Pin 2): Ground. Characteristics section). The ADJ pin voltage is 1.22V referenced to ground and the output voltage range is SHDN (Pin 3, Fixed/-SD Devices): Shutdown. The SHDN 1.22V to 20V. pin is used to put the LT1761 regulators into a low power shutdown state. The output will be off when the SHDN pin OUT (Pin 5): Output. The output supplies power to the load. is pulled low. The SHDN pin can be driven either by 5V logic A minimum output capacitor of 1μF is required to prevent or open-collector logic with a pull-up resistor. The pull-up oscillations. Larger output capacitors will be required for resistor is required to supply the pull-up current of the applications with large transient loads to limit peak volt- open-collector gate, normally several microamperes, and age transients. See the Applications Information section the SHDN pin current, typically 1μA. If unused, the SHDN for more information on output capacitance and reverse pin must be connected to V . The device will not function output characteristics. IN if the SHDN pin is not connected. For the LT1761-BYP, the SHDN pin is internally connected to V . IN 1761sff 14

LT1761 Series APPLICATIONS INFORMATION The LT1761 series are 100mA low dropout regulators with ADJ pin bias current. Note that in shutdown the output is micropower quiescent current and shutdown. The devices turned off and the divider current will be zero. Curves of are capable of supplying 100mA at a dropout voltage of ADJ Pin Voltage vs Temperature and ADJ Pin Bias Cur- 300mV. Output voltage noise can be lowered to 20μV rent vs Temperature appear in the Typical Performance RMS over a 10Hz to 100kHz bandwidth with the addition of a Characteristics. 0.01μF reference bypass capacitor. Additionally, the refer- The adjustable device is tested and specifi ed with the ADJ ence bypass capacitor will improve transient response of pin tied to the OUT pin for an output voltage of 1.22V. the regulator, lowering the settling time for transient load Specifi cations for output voltages greater than 1.22V will conditions. The low operating quiescent current (20μA) be proportional to the ratio of the desired output voltage drops to less than 1μA in shutdown. In addition to the to 1.22V: V /1.22V. For example, load regulation for an OUT low quiescent current, the LT1761 regulators incorporate output current change of 1mA to 100mA is –1mV typical several protection features which make them ideal for use at V = 1.22V. At V = 12V, load regulation is: OUT OUT in battery-powered systems. The devices are protected against both reverse input and reverse output voltages. (12V/1.22V)(–1mV) = –9.8mV In battery backup applications where the output can be Bypass Capacitance and Low Noise Performance held up by a backup battery when the input is pulled to ground, the LT1761-X acts like it has a diode in series with The LT1761 regulators may be used with the addition of a its output and prevents reverse current fl ow. Additionally, bypass capacitor from OUT to the BYP pin to lower output in dual supply applications where the regulator load is voltage noise. A good quality low leakage capacitor is rec- returned to a negative supply, the output can be pulled ommended. This capacitor will bypass the reference of the below ground by as much as 20V and still allow the device regulator, providing a low frequency noise pole. The noise to start and operate. pole provided by this bypass capacitor will lower the output voltage noise to as low as 20μV with the addition of a RMS Adjustable Operation 0.01μF bypass capacitor. Using a bypass capacitor has the The adjustable version of the LT1761 has an output voltage added benefi t of improving transient response. With no range of 1.22V to 20V. The output voltage is set by the bypass capacitor and a 10μF output capacitor, a 10mA to ratio of two external resistors as shown in Figure 1. The 100mA load step will settle to within 1% of its fi nal value device servos the output to maintain the ADJ pin voltage in less than 100μs. With the addition of a 0.01μF bypass at 1.22V referenced to ground. The current in R1 is then capacitor, the output will stay within 1% for a 10mA to equal to 1.22V/R1 and the current in R2 is the current in 100mA load step (see LT1761-5 Transient Response in R1 plus the ADJ pin bias current. The ADJ pin bias cur- Typical Performance Characteristics section). However, rent, 30nA at 25°C, fl ows through R2 into the ADJ pin. regulator start-up time is proportional to the size of the The output voltage can be calculated using the formula in bypass capacitor, slowing to 15ms with a 0.01μF bypass Figure 1. The value of R1 should be no greater than 250k capacitor and 10μF output capacitor. to minimize errors in the output voltage caused by the VIN IN OUT + VOUT VOUT(cid:29)1(cid:14)22V(cid:165)(cid:166)1(cid:11)R2(cid:180)(cid:181)(cid:11)(cid:8)IADJ(cid:9)(cid:8)R2(cid:9) LT1761 R2 (cid:167) R1(cid:182) VADJ(cid:29)1(cid:14)22V ADJ GND IADJ(cid:29)30nA AT 25(cid:111)C R1 OUTPUT RANGE = 1.22V TO 20V 1761 F01 Figure 1. Adjustable Operation 1761sff 15

LT1761 Series APPLICATIONS INFORMATION Output Capacitance and Transient Response and temperature coeffi cients as shown in Figures 3 and 4. When used with a 5V regulator, a 16V 10μF Y5V capacitor The LT1761 regulators are designed to be stable with a can exhibit an effective value as low as 1μF to 2μF for the wide range of output capacitors. The ESR of the output DC bias voltage applied and over the operating tempera- capacitor affects stability, most notably with small capaci- ture range. The X5R and X7R dielectrics result in more tors. A minimum output capacitor of 1μF with an ESR of stable characteristics and are more suitable for use as the 3Ω or less is recommended to prevent oscillations. The output capacitor. The X7R type has better stability across LT1761-X is a micropower device and output transient temperature, while the X5R is less expensive and is avail- response will be a function of output capacitance. Larger able in higher values. Care still must be exercised when values of output capacitance decrease the peak deviations using X5R and X7R capacitors; the X5R and X7R codes and provide improved transient response for larger load only specify operating temperature range and maximum current changes. Bypass capacitors, used to decouple capacitance change over temperature. Capacitance change individual components powered by the LT1761-X, will due to DC bias with X5R and X7R capacitors is better than increase the effective output capacitor value. With larger Y5V and Z5U capacitors, but can still be signifi cant enough capacitors used to bypass the reference (for low noise to drop capacitor values below appropriate levels. Capaci- operation), larger values of output capacitors are needed. tor DC bias characteristics tend to improve as component For 100pF of bypass capacitance, 2.2μF of output capaci- case size increases, but expected capacitance at operating tor is recommended. With a 330pF bypass capacitor or voltage should be verifi ed. larger, a 3.3μF output capacitor is recommended. The shaded region of Figure 2 defi nes the region over which 20 BOTH CAPACITORS ARE 16V, the LT1761 regulators are stable. The minimum ESR 1210 CASE SIZE, 10μF 0 needed is defi ned by the amount of bypass capacitance used, while the maximum ESR is 3Ω. %) X5R E (–20 U L Extra consideration must be given to the use of ceramic A V N –40 capacitors. Ceramic capacitors are manufactured with a E I G N variety of dielectrics, each with different behavior across A–60 H C Y5V temperature and applied voltage. The most common –80 dielectrics used are specifi ed with EIA temperature char- acteristic codes of Z5U, Y5V, X5R and X7R. The Z5U and –100 0 2 4 6 8 10 12 14 16 Y5V dielectrics are good for providing high capacitances DC BIAS VOLTAGE (V) 1761 F03 in a small package, but they tend to have strong voltage Figure 3. Ceramic Capacitor DC Bias Characteristics 4.0 40 3.5 20 3.0 STABLE REGION %) 0 X5R 2.5 E ( Ω) LU –20 R ( 2.0 VA S N E 1.5 CBYP = 0 GE I –40 Y5V CBYP = 100pF AN 1.0 CBYP = 330pF CH –60 CBYP > 3300pF 0.5 –80 BOTH CAPACITORS ARE 16V, 0 1210 CASE SIZE, 10μF 1 2 3 4 5 6 7 8 910 –100 –50 –25 0 25 50 75 100 125 OUTPUT CAPACITANCE (μF) 1761 F02 TEMPERATURE (°C) 1761 F04 Figure 2. Stability Figure 4. Ceramic Capacitor Temperature Characteristics 1761sff 16

LT1761 Series APPLICATIONS INFORMATION Voltage and temperature coeffi cients are not the only The ground pin current can be found by examining the sources of problems. Some ceramic capacitors have a GND Pin Current curves in the Typical Performance Char- piezoelectric response. A piezoelectric device generates acteristics section. Power dissipation will be equal to the voltage across its terminals due to mechanical stress, sum of the two components listed above. similar to the way a piezoelectric accelerometer or micro- The LT1761 series regulators have internal thermal limiting phone works. For a ceramic capacitor the stress can be designed to protect the device during overload conditions. induced by vibrations in the system or thermal transients. For continuous normal conditions, the maximum junction The resulting voltages produced can cause appreciable temperature rating of 125°C must not be exceeded. It is amounts of noise, especially when a ceramic capacitor is important to give careful consideration to all sources of used for noise bypassing. A ceramic capacitor produced thermal resistance from junction to ambient. Additional Figure 5’s trace in response to light tapping from a pencil. heat sources mounted nearby must also be considered. Similar vibration induced behavior can masquerade as increased output voltage noise. For surface mount devices, heat sinking is accomplished by using the heat spreading capabilities of the PC board and its copper traces. Copper board stiffeners and plated through-holes can also be used to spread the heat gener- ated by power devices. The following table lists thermal resistance for several VOUT 500μV/DIV different board sizes and copper areas. All measurements were taken in still air on 3/32" FR-4 board with one ounce copper. Table 1. Measured Thermal Resistance LT1761-5 100ms/DIV 1761 F05 COPPER AREA COUT = 10μF THERMAL RESISTANCE CBYP = 0.01μF TOPSIDE* BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT) ILOAD = 100mA 2500mm2 2500mm2 2500mm2 125°C/W Figure 5. Noise Resulting from Tapping on a Ceramic Capacitor 1000mm2 2500mm2 2500mm2 125°C/W 225mm2 2500mm2 2500mm2 130°C/W Thermal Considerations 100mm2 2500mm2 2500mm2 135°C/W The power handling capability of the device will be limited 50mm2 2500mm2 2500mm2 150°C/W by the maximum rated junction temperature (125°C). The *Device is mounted on topside. power dissipated by the device will be made up of two Calculating Junction Temperature components: Example: Given an output voltage of 3.3V, an input voltage 1. Output current multiplied by the input/output voltage range of 4V to 6V, an output current range of 0mA to 50mA differential: (I )(V – V ), and OUT IN OUT 2. GND pin current multiplied by the input voltage: (I )(V ). GND IN 1761sff 17

LT1761 Series APPLICATIONS INFORMATION and a maximum ambient temperature of 50°C, what will Current limit protection and thermal overload protection the maximum junction temperature be? are intended to protect the device against current overload conditions at the output of the device. For normal operation, The power dissipated by the device will be equal to: the junction temperature should not exceed 125°C. I (V – V ) + I (V ) OUT(MAX) IN(MAX) OUT GND IN(MAX) The input of the device will withstand reverse voltages where, of 20V. Current fl ow into the device will be limited to less than 1mA (typically less than 100μA) and no negative I = 50mA OUT(MAX) voltage will appear at the output. The device will protect V = 6V IN(MAX) both itself and the load. This provides protection against I at (I = 50mA, V = 6V) = 1mA GND OUT IN batteries which can be plugged in backward. So, The output of the LT1761-X can be pulled below ground P = 50mA(6V – 3.3V) + 1mA(6V) = 0.14W without damaging the device. If the input is left open circuit The thermal resistance will be in the range of 125°C/W to or grounded, the output can be pulled below ground by 150°C/W depending on the copper area. So the junction 20V. For fi xed voltage versions, the output will act like a temperature rise above ambient will be approximately large resistor, typically 500k or higher, limiting current fl ow equal to: to typically less than 100μA. For adjustable versions, the 0.14W(150°C/W) = 21.2°C output will act like an open circuit; no current will fl ow out of the pin. If the input is powered by a voltage source, the The maximum junction temperature will then be equal to output will source the short-circuit current of the device the maximum junction temperature rise above ambient and will protect itself by thermal limiting. In this case, plus the maximum ambient temperature or: grounding the SHDN pin will turn off the device and stop T = 50°C + 21.2°C = 71.2°C the output from sourcing the short-circuit current. JMAX The ADJ pin of the adjustable device can be pulled above Protection Features or below ground by as much as 7V without damaging the The LT1761 regulators incorporate several protection device. If the input is left open circuit or grounded, the features which make them ideal for use in battery-pow- ADJ pin will act like an open circuit when pulled below ered circuits. In addition to the normal protection features ground and like a large resistor (typically 100k) in series associated with monolithic regulators, such as current with a diode when pulled above ground. limiting and thermal limiting, the devices are protected against reverse input voltages, reverse output voltages and reverse voltages from output to input. 1761sff 18

LT1761 Series APPLICATIONS INFORMATION In situations where the ADJ pin is connected to a resistor voltage may be held up while the input is either pulled divider that would pull the ADJ pin above its 7V clamp volt- to ground, pulled to some intermediate voltage or is left age if the output is pulled high, the ADJ pin input current open circuit. Current fl ow back into the output will follow must be limited to less than 5mA. For example, a resistor the curve shown in Figure 6. divider is used to provide a regulated 1.5V output from the When the IN pin of the LT1761-X is forced below the OUT 1.22V reference when the output is forced to 20V. The top pin or the OUT pin is pulled above the IN pin, input cur- resistor of the resistor divider must be chosen to limit the rent will typically drop to less than 2μA. This can happen current into the ADJ pin to less than 5mA when the ADJ if the input of the device is connected to a discharged pin is at 7V. The 13V difference between output and ADJ (low voltage) battery and the output is held up by either pin divided by the 5mA maximum current into the ADJ pin a backup battery or a second regulator circuit. The state yields a minimum top resistor value of 2.6k. of the SHDN pin will have no effect on the reverse output In circuits where a backup battery is required, several current when the output is pulled above the input. different input/output conditions can occur. The output 100 TJ = 25°C LT1761-BYP 90 VIN = 0V LT1761-SD A) CURRENT FLOWS ENT (μ 8700 IVNOTUOT O= UVTAPDUJT PINLT1761-1.2 R (LT1761-BYP, -SD) R U 60 LT1761-1.5 C PUT 50 LLTT11776611--21.8 UT 40 LT1761-2.5 O SE 30 LT1761-2.8 R LT1761-3 E V 20 E R 10 LT1761-3.3 LT1761-5 0 0 1 2 3 4 5 6 7 8 9 10 OUTPUT VOLTAGE (V) 1761 F06 Figure 6. Reverse Output Current 1761sff 19

LT1761 Series PACKAGE DESCRIPTION S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 0.62 0.95 2.90 BSC MAX REF (NOTE 4) 1.22 REF 1.50 – 1.75 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC (NOTE 4) PIN ONE RECOMMENDED SOLDER PAD LAYOUT 0.30 – 0.45 TYP 0.95 BSC PER IPC CALCULATOR 5 PLCS (NOTE 3) 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 1.90 BSC NOTE: (NOTE 3) S5 TSOT-23 0302 REV B 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 1761sff 20

LT1761 Series REVISION HISTORY (Revision history begins at Rev F) REV DATE DESCRIPTION PAGE NUMBER F 5/10 Added MP-grade 2, 3 Added Typical Application 22 1761sff 21 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

LT1761 Series TYPICAL APPLICATION Noise Bypassing Provides Soft-Start Startup Time 100 5V IN OUT VIN AT 100mA 5.4V TO 20V 1μF LT1761-5 CBYP 10μF BYP ms) 10 E ( OFF ON SHDN M TI GND P U 1761 TA02a T R TA 1 S 0.1 10 100 1000 10000 CBYP (pF) 1761 TA02b RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1120 125mA Low Dropout Regulator with 20μA I Includes 2.5V Reference and Comparator Q LT1121 150mA Micropower Low Dropout Regulator 30μA I , SOT-223 Package Q LT1129 700mA Micropower Low Dropout Regulator 50μA Quiescent Current LT1175 500mA Negative Low Dropout Micropower Regulator 45μA I , 0.26V Dropout Voltage, SOT-223 Package Q LT1521 300mA Low Dropout Micropower Regulator with Shutdown 15μA I , Reverse-Battery Protection Q LT1529 3A Low Dropout Regulator with 50μA I 500mV Dropout Voltage Q LT1762 Series 150mA, Low Noise, LDO Micropower Regulator 25μA Quiescent Current, 20μV Noise RMS LT1763 Series 500mA, Low Noise, LDO Micropower Regulator 30μA Quiescent Current, 20μV Noise RMS LTC1928 Doubler Charge Pump with Low Noise Linear Regulator Low Output Noise: 60μV (100kHz BW) RMS LT1962 Series 300mA, Low Noise, LDO Micropower Regulator 30μA Quiescent Current, 20μV Noise RMS LT1963 1.5A, Low Noise, Fast Transient Response LDO 40μV , SOT-223 Package RMS LT1764 3A, Low Noise, Fast Transient Response LDO 40μV , 340mV Dropout Voltage RMS LTC3404 High Effi ciency Synchronous Step-Down Switching Regulator Burst Mode® Operation, Monolithic, 100% Duty Cycle 1761sff 22 Linear Technology Corporation LT 0510 REV F • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2005

Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: A nalog Devices Inc.: LT1761ES5-1.5 LT1761ES5-2#TR LT1761ES5-3#PBF LT1761IS5-1.2#TRMPBF LT1761ES5-3.3#TR LT1761ES5- BYP#TR LT1761ES5-3#TRMPBF LT1761ES5-1.2#TRPBF LT1761IS5-2.8#TRPBF LT1761ES5-SD LT1761MPS5- 3.3 LT1761IS5-1.5#TRPBF LT1761IS5-5#TRPBF LT1761ES5-2.8#TR LT1761ES5-2#TRPBF LT1761ES5- 1.5#TRMPBF LT1761IS5-BYP#TRMPBF LT1761ES5-5#TRM LT1761IS5-2.8#PBF LT1761ES5-3.3#TRPBF LT1761MPS5-3.3#TRM LT1761IS5-3#TRPBF LT1761IS5-BYP#PBF LT1761ES5-2.8#TRPBF LT1761ES5-2.5 LT1761ES5-1.5#TR LT1761MPS5-5#PBF LT1761IS5-1.5#PBF LT1761ES5-5#PBF LT1761ES5-1.5#PBF LT1761ES5-SD#PBF LT1761ES5-2.5#PBF LT1761ES5-3#TR LT1761IS5-3#PBF LT1761ES5-2#TRM LT1761ES5- 1.5#TRPBF LT1761IS5-3.3#TRPBF LT1761IS5-3.3#TRM LT1761IS5-2#PBF LT1761ES5-5#TRMPBF LT1761IS5- BYP#TRPBF LT1761IS5-2.5#TRMPBF LT1761ES5-SD#TRMPBF LT1761IS5-3.3#PBF LT1761IS5-SD#TRPBF LT1761ES5-2.8 LT1761ES5-3#TRPBF LT1761MPS5-5#TRM LT1761ES5-2 LT1761IS5-SD#PBF LT1761MPS5- 5#TRPBF LT1761ES5-SD#TRPBF LT1761IS5-2#TRMPBF LT1761ES5-5#TR LT1761ES5-1.8#PBF LT1761ES5- 3#TRM LT1761ES5-SD#TR LT1761ES5-2#PBF LT1761ES5-3.3 LT1761ES5-1.2 LT1761ES5-5 LT1761ES5- 2.5#TRPBF LT1761IS5-2.5#TRPBF LT1761ES5-5#TRPBF LT1761IS5-1.8#TRPBF LT1761IS5-5#TRM LT1761MPS5-1.8#TRPBF LT1761IS5-SD#TRMPBF LT1761MPS5-5#TRMPBF LT1761ES5-2.8#TRM LT1761ES5- 3.3#PBF LT1761ES5-3 LT1761IS5-3.3#TRMPBF LT1761ES5-2.8#PBF LT1761ES5-BYP#PBF LT1761IS5-5#PBF LT1761IS5-1.2#TRPBF LT1761ES5-2.5#TRM LT1761IS5-1.5#TRMPBF LT1761ES5-1.2#TRMPBF LT1761ES5- 1.8#TR LT1761ES5-1.8#TRMPBF LT1761ES5-3.3#TRM LT1761ES5-BYP LT1761MPS5-3.3#TRMPBF LT1761IS5- 3#TRMPBF LT1761ES5-2#TRMPBF LT1761IS5-2.8#TRMPBF LT1761ES5-1.5#TRM LT1761IS5-5#TRMPBF LT1761IS5-2#TRPBF LT1761IS5-1.8#PBF LT1761ES5-2.8#TRMPBF LT1761ES5-3.3#TRMPBF LT1761ES5- BYP#TRMPBF LT1761MPS5-3.3#TR LT1761ES5-BYP#TRPBF LT1761ES5-SD#TRM LT1761IS5-1.8#TRMPBF LT1761ES5-2.5#TRMPBF