LT6656 1µA Precision Series Voltage Reference FEATURES DESCRIPTION n Ultralow Supply Current: 850nA The LT®6656 is a tiny precision voltage reference that n Low Drift draws less than 1µA of supply current and can operate A Grade: 10 ppm/°C Max with a supply voltage within 10mV of the output voltage. B Grade: 20 ppm/°C Max The LT6656 offers an initial accuracy of 0.05% and tem- n High Accuracy perature drift of 10ppm/°C. The combined low power and A Grade: 0.05% Max precision characteristics are ideal for portable and battery B Grade: 0.1% Max powered instrumentation. n Long-Term Drift: 15ppm/√kHr (LS8 Package) The LT6656 can supply up to 5mA of output drive with n No Humidity Sensitivity (LS8 Package) 65ppm/mA of load regulation, allowing it to be used as n High Output Drive Current: 5mA Min the supply voltage and the reference input to a low power n Low Dropout Voltage: 10mV Max ADC. The LT6656 can accept a supply voltage up to 18V n Fully Specified from –40°C to 85°C and withstand the reversal of the input connections. n Operational from –55°C to 125°C n Wide Supply Range to 18V The LT6656 output is stable with 1µF or larger output n Reverse Input/Output Protection capacitance and operates with a wide range of output n Available Output Voltage Options: capacitor ESR. 1.25V, 2.048V, 2.5V, 3V, 3.3V, 4.096V and 5V This reference is fully specified for operation from –40°C n Available in Low Profile (1mm) ThinSOT™, to 85°C, and is functional over the extreme temperature (2mm × 2mm) DFN and High Stability Hermetic range of –55°C to 125°C. Low hysteresis and a consistent (5mm × 5mm) LS8 Packages temperature drift are obtained through advanced design, APPLICATIONS processing and packaging techniques. The LT6656 is offered in the 6-lead SOT-23, (2mm × n Precision A/D and D/A Converters 2mm) DFN, and 8-lead LS8 Packages. The LS8 is a 5mm n Portable Gas Monitors × 5mm surface mount hermetic package that provides n Battery- or Solar-Powered Systems outstanding stability. n Precision Regulators L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and n Low Voltage Signal Processing ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property n Micropower Remote Sensing of their respective owners. TYPICAL APPLICATION Output Voltage Temperature Drift 2.503 38 TYPICAL UNITS LT6656-2.5 Basic Connection 2.502 LT6656-2.5 2.51V ≤ VIN ≤ 18V VIN VOUT 2V.O5UVT 2.501 GND V) 0.1µF 1µF (UT O V 2.500 6656 TA01a 2.499 2.498 –40 –20 0 20 40 60 80 TEMPERATURE (°C) 6652 TA01b 6656fc 1 For more information www.linear.com/LT6656

LT6656 ABSOLUTE MAXIMUM RATINGS (Note 1) Input Voltage ...........................................................±20V Operating Temperature Range (Note 2)..–55°C to 125°C Output Voltage ...........................................–0.3V to 20V Output Short Circuit Duration .........................Indefinite Output Voltage Above Input Voltage .........................20V Junction Temperature ..........................................150°C Specified Temperature Range (Note 2) Storage Temperature Range (Note 3) .....–65°C to 150°C Commercial .............................................0°C to 70°C Lead Temperature (Soldering, 10 sec.) Industrial .............................................–40°C to 85°C TSOT-23 (Note 4) ..............................................300°C PIN CONFIGURATION TOP VIEW TOP VIEW VIN TOP VIEW 8 GND* 1 6 VOUT NC 1 6 VIN NC 1 7 NC 7 GND 2 5 NC GND 2 GND* 5 NC NC 2 6 VOUT NC 3 4 VIN GND* 3 4 VOUT GND* 3 5 VOUT 4 S6 PACKAGE 6-LEAD PLASTIC TSOT-23 DC PACKAGE GND TJMAX = 150°C, θJA = 230°C/W 6-LEAD (2mm × 2mm) PLASTIC DFN LS8 PACKAGE *CONNECT PIN TO DEVICE GND (PIN 2) TJMAX = 125°C, θJA = 102°C/W 8-PIN LEADLESS CHIP CARRIER (5mm × 5mm) EXPOSED PAD (PIN 7) MUST BE CONNECTED TO GND TJMAX = 150°C, θJA = 125°C/W *CONNECT PIN TO DEVICE GND (PIN 4) ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL (MINI) TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LT6656ACS6-1.25#TRMPBF LT6656ACS6-1.25#TRPBF LTFNK 6-Lead Plastic TSOT-23 0°C to 70°C LT6656BCS6-1.25#TRMPBF LT6656BCS6-1.25#TRPBF LTFNK 6-Lead Plastic TSOT-23 0°C to 70°C LT6656AIS6-1.25#TRMPBF LT6656AIS6-1.25#TRPBF LTFNK 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656BIS6-1.25#TRMPBF LT6656BIS6-1.25#TRPBF LTFNK 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656ACS6-2.048#TRMPBF LT6656ACS6-2.048#TRPBF LTFNN 6-Lead Plastic TSOT-23 0°C to 70°C LT6656BCS6-2.048#TRMPBF LT6656BCS6-2.048#TRPBF LTFNN 6-Lead Plastic TSOT-23 0°C to 70°C LT6656AIS6-2.048#TRMPBF LT6656AIS6-2.048#TRPBF LTFNN 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656BIS6-2.048#TRMPBF LT6656BIS6-2.048#TRPBF LTFNN 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656ACS6-2.5#TRMPBF LT6656ACS6-2.5#TRPBF LTFGW 6-Lead Plastic TSOT-23 0°C to 70°C LT6656BCS6-2.5#TRMPBF LT6656BCS6-2.5#TRPBF LTFGW 6-Lead Plastic TSOT-23 0°C to 70°C LT6656AIS6-2.5#TRMPBF LT6656AIS6-2.5#TRPBF LTFGW 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656BIS6-2.5#TRMPBF LT6656BIS6-2.5#TRPBF LTFGW 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656ACS6-3#TRMPBF LT6656ACS6-3#TRPBF LTFNQ 6-Lead Plastic TSOT-23 0°C to 70°C LT6656BCS6-3#TRMPBF LT6656BCS6-3#TRPBF LTFNQ 6-Lead Plastic TSOT-23 0°C to 70°C LT6656AIS6-3#TRMPBF LT6656AIS6-3#TRPBF LTFNQ 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656BIS6-3#TRMPBF LT6656BIS6-3#TRPBF LTFNQ 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656ACS6-3.3#TRMPBF LT6656ACS6-3.3#TRPBF LTFNS 6-Lead Plastic TSOT-23 0°C to 70°C LT6656BCS6-3.3#TRMPBF LT6656BCS6-3.3#TRPBF LTFNS 6-Lead Plastic TSOT-23 0°C to 70°C LT6656AIS6-3.3#TRMPBF LT6656AIS6-3.3#TRPBF LTFNS 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656BIS6-3.3#TRMPBF LT6656BIS6-3.3#TRPBF LTFNS 6-Lead Plastic TSOT-23 –40°C to 85°C 6656fc 2 For more information www.linear.com/LT6656

LT6656 ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL (MINI) TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LT6656ACS6-4.096#TRMPBF LT6656ACS6-4.096#TRPBF LTFNV 6-Lead Plastic TSOT-23 0°C to 70°C LT6656BCS6-4.096#TRMPBF LT6656BCS6-4.096#TRPBF LTFNV 6-Lead Plastic TSOT-23 0°C to 70°C LT6656AIS6-4.096#TRMPBF LT6656AIS6-4.096#TRPBF LTFNV 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656BIS6-4.096#TRMPBF LT6656BIS6-4.096#TRPBF LTFNV 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656ACS6-5#TRMPBF LT6656ACS6-5#TRPBF LTFNX 6-Lead Plastic TSOT-23 0°C to 70°C LT6656BCS6-5#TRMPBF LT6656BCS6-5#TRPBF LTFNX 6-Lead Plastic TSOT-23 0°C to 70°C LT6656AIS6-5#TRMPBF LT6656AIS6-5#TRPBF LTFNX 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656BIS6-5#TRMPBF LT6656BIS6-5#TRPBF LTFNX 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656ACDC-1.25#TRMPBF LT6656ACDC-1.25#TRPBF LFNM 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656BCDC-1.25#TRMPBF LT6656BCDC-1.25#TRPBF LFNM 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656AIDC-1.25#TRMPBF LT6656AIDC-1.25#TRPBF LFNM 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656BIDC-1.25#TRMPBF LT6656BIDC-1.25#TRPBF LFNM 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656ACDC-2.048#TRMPBF LT6656ACDC-2.048#TRPBF LFNP 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656BCDC-2.048#TRMPBF LT6656BCDC-2.048#TRPBF LFNP 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656AIDC-2.048#TRMPBF LT6656AIDC-2.048#TRPBF LFNP 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656BIDC-2.048#TRMPBF LT6656BIDC-2.048#TRPBF LFNP 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656ACDC-2.5#TRMPBF LT6656ACDC-2.5#TRPBF LFGX 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656BCDC-2.5#TRMPBF LT6656BCDC-2.5#TRPBF LFGX 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656AIDC-2.5#TRMPBF LT6656AIDC-2.5#TRPBF LFGX 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656BIDC-2.5#TRMPBF LT6656BIDC-2.5#TRPBF LFGX 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656ACDC-3#TRMPBF LT6656ACDC-3#TRPBF LFNR 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656BCDC-3#TRMPBF LT6656BCDC-3#TRPBF LFNR 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656AIDC-3#TRMPBF LT6656AIDC-3#TRPBF LFNR 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656BIDC-3#TRMPBF LT6656BIDC-3#TRPBF LFNR 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656ACDC-3.3#TRMPBF LT6656ACDC-3.3#TRPBF LFNT 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656BCDC-3.3#TRMPBF LT6656BCDC-3.3#TRPBF LFNT 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656AIDC-3.3#TRMPBF LT6656AIDC-3.3#TRPBF LFNT 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656BIDC-3.3#TRMPBF LT6656BIDC-3.3#TRPBF LFNT 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656ACDC-4.096#TRMPBF LT6656ACDC-4.096#TRPBF LFNW 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656BCDC-4.096#TRMPBF LT6656BCDC-4.096#TRPBF LFNW 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656AIDC-4.096#TRMPBF LT6656AIDC-4.096#TRPBF LFNW 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656BIDC-4.096#TRMPBF LT6656BIDC-4.096#TRPBF LFNW 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656ACDC-5#TRMPBF LT6656ACDC-5#TRPBF LFNY 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656BCDC-5#TRMPBF LT6656BCDC-5#TRPBF LFNY 6-Lead (2mm × 2mm) Plastic DFN 0°C to 70°C LT6656AIDC-5#TRMPBF LT6656AIDC-5#TRPBF LFNY 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LT6656BIDC-5#TRMPBF LT6656BIDC-5#TRPBF LFNY 6-Lead (2mm × 2mm) Plastic DFN –40°C to 85°C LEAD FREE FINISH PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LT6656AILS8-1.25#PBF† 656125 8-Lead (5mm × 5mm) Ceramic LCC –40°C to 85°C LT6656BILS8-1.25#PBF† 656125 8-Lead (5mm × 5mm) Ceramic LCC –40°C to 85°C TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container. Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ †This product is only offered in trays. For more information go to: http://www.linear.com/packaging/ 6656fc 3 For more information www.linear.com/LT6656

LT6656 AVAILABLE OPTIONS SPECIFIED TEMPERATURE RANGE 0°C TO 70°C –40°C TO 85°C TEMPERATURE OUTPUT VOLTAGE INITIAL ACCURACY COEFFICIENT ORDER PART NUMBER* ORDER PART NUMBER* 1.250V 0.05% 10ppm/°C LT6656ACS6-1.25 LT6656AIS6-1.25 0.05% 10ppm/°C N/A LT6656AILS8-1.25 0.10% 20ppm/°C LT6656BCS6-1.25 LT6656BIS6-1.25 0.10% 10ppm/°C LT6656ACDC-1.25 LT6656AIDC-1.25 0.10% 15ppm/°C N/A LT6656BILS8-1.25 0.20% 20ppm/°C LT6656BCDC-1.25 LT6656BIDC-1.25 2.048V 0.05% 10ppm/°C LT6656ACS6-2.048 LT6656AIS6-2.048 0.10% 20ppm/°C LT6656BCS6-2.048 LT6656BIS6-2.048 0.10% 10ppm/°C LT6656ACDC-2.048 LT6656AIDC-2.048 0.20% 20ppm/°C LT6656BCDC-2.048 LT6656BIDC-2.048 2.500V 0.05% 10ppm/°C LT6656ACS6-2.5 LT6656AIS6-2.5 0.10% 20ppm/°C LT6656BCS6-2.5 LT6656BIS6-2.5 0.10% 10ppm/°C LT6656ACDC-2.5 LT6656AIDC-2.5 0.20% 20ppm/°C LT6656BCDC-2.5 LT6656BIDC-2.5 3.000V 0.05% 10ppm/°C LT6656ACS6-3 LT6656AIS6-3 0.10% 20ppm/°C LT6656BCS6-3 LT6656BIS6-3 0.10% 10ppm/°C LT6656ACDC-3 LT6656AIDC-3 0.20% 20ppm/°C LT6656BCDC-3 LT6656BIDC-3 3.300V 0.05% 10ppm/°C LT6656ACS6-3.3 LT6656AIS6-3.3 0.10% 20ppm/°C LT6656BCS6-3.3 LT6656BIS6-3.3 0.10% 10ppm/°C LT6656ACDC-3.3 LT6656AIDC-3.3 0.20% 20ppm/°C LT6656BCDC-3.3 LT6656BIDC-3.3 4.096V 0.05% 10ppm/°C LT6656ACS6-4.096 LT6656AIS6-4.096 0.10% 20ppm/°C LT6656BCS6-4.096 LT6656BIS6-4.096 0.10% 10ppm/°C LT6656ACDC-4.096 LT6656AIDC-4.096 0.20% 20ppm/°C LT6656BCDC-4.096 LT6656BIDC-4.096 5.000V 0.05% 10ppm/°C LT6656ACS6-5 LT6656AIS6-5 0.10% 20ppm/°C LT6656BCS6-5 LT6656BIS6-5 0.10% 10ppm/°C LT6656ACDC-5 LT6656AIDC-5 0.20% 20ppm/°C LT6656BCDC-5 LT6656BIDC-5 *See Order Information section for complete part number listing. 6656fc 4 For more information www.linear.com/LT6656

LT6656 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the specified temperature range, otherwise specifications are at T = 25°C. V = V + 0.5V (for LT6656-1.25, V = 2.2V), C = 1μF, I = 0,unless A IN OUT IN L L otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Output Voltage Error LT6656ACS6, LT6656AIS6, LT6656AILS8 –0.05 0.05 % LT6656BCS6, LT6656BIS6, LT6656BILS8 –0.1 0.1 % LT6656ACDC, LT6656AIDC –0.1 0.1 % LT6656BCDC, LT6656BIDC –0.2 0.2 % Output Voltage Temperature Coefficient (Note 5) LT6656A l 5 10 ppm/°C LT6656B l 12 20 ppm/°C Line Regulation V = (V + 0.5V) to 18V 2 25 ppm/V IN OUT LT6656-2.048, LT6656-2.5, LT6656-3, l 40 ppm/V LT6656-3.3, LT6656-4.096, LT6656-5 V = 2.2V to 18V 2 25 ppm/V IN LT6656-1.25 l 40 ppm/V Load Regulation (Note 6) I = 5mA, Sourcing 65 150 ppm/mA L LT6656-2.048, LT6656-2.5, LT6656-3, l 375 ppm/mA LT6656-3.3, LT6656-4.096, LT6656-5 I = 5mA, Sourcing 80 175 ppm/mA L LT6656S6-1.25, LT6656DC-1.25 l 425 ppm/mA I = 5mA, Sourcing 135 250 ppm/mA L LT6656LS8-1.25 l 500 ppm/mA Dropout Voltage (Note 7) V – V , ∆V Error ≤ 0.1% IN OUT OUT I = 0 3 10 mV L LT6656-2.048, LT6656-2.5, LT6656-3, l 40 mV LT6656-3.3, LT6656-4.096, LT6656-5 I = 5mA, Sourcing 250 370 mV L LT6656-2.048, LT6656-2.5, LT6656-3, l 500 mV LT6656-3.3, LT6656-4.096, LT6656-5 Minimum Input Voltage I = 0, ∆V Error ≤ 0.1% L OUT LT6656-1.25 1.35 1.5 V 0°C ≤ T ≤ 70°C l 1.6 V A –40°C ≤ T ≤ 85°C l 1.8 V A Supply Current 0.85 1.0 µA l 1.5 µA Output Short Circuit Current Short V to GND 18 mA OUT Short V to V 4 mA OUT IN Input Reverse Leakage Current V = –18V, V = GND 80 µA IN OUT Reverse Output Current V = GND, V = 18V 30 µA IN OUT Output Voltage Noise (Note 8) 0.1Hz to 10Hz 30 ppm P-P 10Hz to 1kHz, LT6656-1.25 50 µV RMS 10Hz to 1kHz, LT6656-2.5 80 µV RMS 10Hz to 1kHz, LT6656-5 140 µV RMS Turn-On Time LT6656-1.25, 0.1% Settling 15 ms LT6656-2.5, 0.1% Settling 30 ms LT6656-5, 0.1% Settling 60 ms Long Term Drift of Output Voltage (Note 9) LT6656S6, LT6656DC 50 ppm/√kHr LT6656LS8 15 ppm/√kHr Hysteresis (Note 10) LT6656S6, LT6656DC ∆T = 0°C to 70°C 25 ppm ∆T = –40°C to 85°C 70 ppm LT6656LS8 ∆T = 0°C to 70°C 15 ppm ∆T = –40°C to 85°C 55 ppm 6656fc 5 For more information www.linear.com/LT6656

LT6656 ELECTRICAL CHARACTERISTICS Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 7: Excludes load regulation errors. may cause permanent damage to the device. Exposure to any Absolute Note 8: Peak-to-peak noise is measured with a 3-pole highpass filter at Maximum Rating condition for extended periods may affect device 0.1Hz and a 4-pole lowpass filter at 10Hz. The unit is enclosed in a still-air reliability and lifetime. environment to eliminate thermocouple effects on the leads. The test Note 2: The LT6656C is guaranteed to meet specified performance from time is 10 seconds. RMS noise is measured on a spectrum analyzer in a 0°C to 70°C. The LT6656C is designed, characterized and expected to shielded environment. meet specified performance from –40°C to 85°C but is not tested or Note 9: Long term stability typically has a logarithmic characteristic and QA sampled at these temperatures. The LT6656I is guaranteed to meet therefore, changes after 1000 hours tend to be much smaller than before specified performance from –40°C to 85°C. By design, the LT6656 is that time. Total drift in the second thousand hours is normally less than guaranteed functional over the operating temperature range of –55°C to one third that of the first thousand hours with a continuing trend toward 125°C. reduced drift with time. Long-term stability will also be affected by Note 3: If the LT6656 is stored outside of the specified temperature range, differential stresses between the IC and the board material created during the output may shift due to hysteresis. board assembly. Note 4: The stated temperature is typical for soldering of the leads during Note 10: Hysteresis in output voltage is created by mechanical stress manual rework. For detailed IR reflow recommendations, refer to the that differs depending on whether the IC was previously at a higher or Applications section. lower temperature. Output voltage is always measured at 25°C, but Note 5: Temperature coefficient is measured by dividing the maximum the IC is cycled to the hot or cold temperature limit before successive change in output voltage by the specified temperature range. measurements. For instruments that are stored at well controlled temperatures (within 20 or 30 degrees of operational temperature) Note 6: Load regulation is measured with a pulse from no load to the hysteresis is usually not a dominant error source. Typical hysteresis is the specified load current. Output changes due to die temperature change worst-case of 25°C to cold to 25°C or 25°C to hot to 25°C, preconditioned must be taken into account separately. by one thermal cycle. TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage Temperature Drift Typical V Distribution Supply Current vs Input Voltage OUT 10000 200 100 ALL OPTIONS ALL OPTIONS 1.25V OPTION TA = 125°C GE IN OUTPUT VOLTAGE (ppm) 35678942000000000000000000000000 I2NCL5LO = R=T Y0 M1PµAIFCLAIZLE DU NAITT S25°C NUMBER OF UNITS 1111184066280000000 ITCLAL = == 0 21µ5F°C SUPPLY CURRENT (µA) 101 TTTTAAAA ==== 82––5545°°05CC°°CC AN 1000 40 H C 0 20 –1000 0 0.1 –60 –40 –20 0 20 40 60 80 100 120 –0.10 –0.06 –0.02 0 0.02 0.06 0.10 0 2 4 6 8 10 12 14 16 18 20 TEMPERATURE (°C) OUTPUT VOLTAGE ERROR (%) INPUT VOLTAGE (V) 6652 G01 6656 G02 6656 G17 6656fc 6 For more information www.linear.com/LT6656

LT6656 TYPICAL PERFORMANCE CHARACTERISTICS Minimum Supply Voltage Supply Current vs Input Voltage vs Load Current Dropout Voltage vs Load Current 100 2.0 1000 2.048V TO 5V OPTIONS TA = 125°C 1.25V OPTION 2.048V TO 5V OPTIONS TA = 85°C INITIAL VIN = 2.2V VIN – VOUT TA = 25°C V) 1.8 ∆VOUT = 0.1% INITIAL VIN = VOUT + 0.5V SUPPLY CURRENT (µA) 101 2.5VVO ONPTION SHOWN TA = –55°C MINIMUM SUPPLY VOLTAGE ( 1111....6420 TTTAAA === 1822555°°CC°C DROPOUT VOLTAGE (mV) 10100 ∆VOUT = 0.1% TTAA == 18255°C°C VON MOVES WITH VOLTAGE OPTION TA = –40°C TA = 25°C TA = –55°C TA = –55°C 0.1 0.8 1 0 2 4 6 8 10 12 14 16 18 20 0.1µ 1µ 10µ 100µ 1m 10m 0.1µ 1µ 10µ 100µ 1m 10m INPUT VOLTAGE (V) LOAD CURRENT (A) LOAD CURRENT (A) 6656 G03 6656 G18 6656 G04 Load Regulation (Sourcing) Load Regulation (Sourcing) Load Regulation (Sinking) 500 750 5.0 1.25V OPTION 2.048V TO 5V OPTIONS ALL OPTIONS VIN = 1.75V VIN = VOUT + 0.5V 4.5 VIN = VOUT + 0.5V pm) 250 CL = 1µF pm) 500 CL = 1µF %) 4.0 CL = 1µF E (p E (p GE ( 3.5 G 0 G 250 N N N A 3.0 HA HA CH TA = 85°C, 125°C LTAGE C–250 LTAGE C 0 OLTAGE 22..05 TTTAAA === 2––545°05C°°CC UT VO–500 TA = 125°C UT VO–250 PUT V 11..50 TP TA = 85°C TP TA = 125°C UT OU–750 TA = 25°C OU–500 TA = 85°C O 0.5 TA = –40°C TA = 25°C 0 TA = –55°C TA = –55°C –1000 –750 –0.5 0.1µ 1µ 10µ 100µ 1m 10m 0.1µ 1µ 10µ 100µ 1m 10m 10µ 100µ 1m LOAD CURRENT (A) LOAD CURRENT (A) LOAD CURRENT (A) 6656 G19 6656 G05 6656 G06 Power Supply Rejection Ratio Power Supply Rejection Ratio Line Regulation vs Frequency vs Frequency 1000 90 90 ALL OPTIONS TA = 125°C VIN = VOUT + 0.5V 2.5V OPTION CHANGE (ppm) 987650000000000 2VVCIL.OOL 5= NL=V T 0 MA1OµGOPFETV IEOOSPN TW SIOIHTNOHW N TTTAAA === 82–555°°5CC°C CTION RATIO (dB) 87650000 ICLL = = 0 1µF CTION RATIO (dB) 87650000 VIN = 3V GE 400 EJE EJE 40 OUTPUT VOLTA 3210000000 VON WER SUPPLY R 432000 1.25V OPTION WER SUPPLY R 312000 IILL == 00,, CCLL == 11µ0FµF –100 PO 10 2.5V OPTION PO 0 IL = 1mA, CL = 1µF 5V OPTION IL = 1mA, CL = 10µF –200 0 –10 0 2 4 6 8 10 12 14 16 18 20 10 100 1k 10k 10 100 1k 10k INPUT VOLTAGE (V) FREQUENCY (Hz) FREQUENCY (Hz) 6656 G08 6656 G09 6656 G20 6656fc 7 For more information www.linear.com/LT6656

LT6656 TYPICAL PERFORMANCE CHARACTERISTICS Output Impedance vs Frequency Output Impedance vs Frequency Ground Current vs Load Current 10k 10k 1000 VIN = VOUT + 0.5V 2.5V OPTION ALL OPTIONS CL = 1µF VIN = 3V VIN = VOUT + 0.5V IL = 0 CL = 1µF Ω) 1k Ω) 1k A) CE ( CE ( T (µ 100 N N N A A E D D R PE100 PE100 UR M M C OUTPUT I 10 OUTPUT I 10 IL = 0, CL = 1µF GROUND 10 TA = 125°C 1.25V OPTION IL = 0, CL = 10µF TA = 85°C 2.5V OPTION IL = 100µA, CL = 1µF TA = 25°C 5V OPTION IL = 100µA, CL = 10µF TA = –55°C 1 1 1 10 100 1k 10k 10 100 1k 10k 10µ 100µ 1m 10m FREQUENCY (Hz) FREQUENCY (Hz) LOAD CURRENT (A) 6656 G21 6656 G22 6656 G07 Reverse Input Current Reverse Output Current Output Noise 0.1Hz to 10Hz 1000 100 ALL OPTIONS ALL OPTIONS ALL OPTIONS VOUT = GND VIN = GND VIN = VOUT + 0.5V NPUT CURRENT (µA)10100 UTPUT CURRENT (µA) 10 NOISE (20ppm/DIV) ICLL = = 0 1µF REVERSE I 1 TTAA == 18255°C°C REVERSE O TTAA == 18255°C°C OUTPUT TA = 25°C TA = 25°C TA = –55°C TA = –55°C 0 1 0 –2 –4 –6 –8 –10–12–14–16–18–20 0 5 10 15 20 TIME (1s/DIV) INPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 6656 G13 6656 G11 6656 G12 Output Voltage Noise Spectrum Output Noise Voltage Spectrum Output Voltage Noise Spectrum vs Load Current vs Load Capacitance 30 16 40 VIN = VOUT + 5V 2.5V OPTION IL = 0 2.5V OPTION CL = 1µF 14 VIN = 3V IL = 10µA 35 VIN = 3V 25 IL = 0 CL = 1µF IL = 250µA IL = 0 CL = 47µF OISE VOLTAGE (µV/√Hz)RMS211050 5V 2O.5PVT IOOPNTION NOISE VOLTAGE (µV/√Hz) 1120864 IL = 1mA NOISE VOLTAGE (µV/√Hz) 3221105050 CL = 4.7µCFL = 0.47µF N 5 2 5 1.25V OPTION 0 0 0 10 100 1k 10k 10 100 1k 10k 1 10 100 1k FREQUENCY (Hz) FREQUENCY (Hz) FREQUENCY (Hz) 6656 G24 6656 G14 6656 G15 6656fc 8 For more information www.linear.com/LT6656

LT6656 TYPICAL PERFORMANCE CHARACTERISTICS Integrated 10Hz to 1kHz Noise Integrated 10Hz to 1kHz Noise vs Load Current vs Load Current 500 250 VIN = VOUT + 0.5V 2.5V OPTION CL = 1µF )S400 )S200 M M R R V V µ µ E ( 300 E ( 150 S S OI OI N N D 5V OPTION D TE 200 TE 100 RA 2.5V OPTION RA G G E E INT 100 INT 50 CCLL == 01µ.4F7µF 1.25V OPTION CL = 10µF CL = 47µF 0 0 0.1µ 1µ 10µ 100µ 1m 10m 0.1µ 1µ 10µ 100µ 1m 10m LOAD CURRENT (A) LOAD CURRENT (A) 6656 G25 6656 G23 Long-Term Drift Long-Term Drift (LS8) 200 200 ALL OPTIONS 1.25V OPTION 35 TYPICAL PARTS FT (ppm) 11550000 ICLL = = 0 1µF HANGE (ppm) 11505000 IVCLILONOA A=DD 2= =V 01µF SOLDERED ONTO PCB M DRI 0 AGE C 0 R T TE –50 OL –50 NG T V LO–100 TPU–100 U O –150 5 TYPICAL PARTS –150 SOLDERED ONTO PCB –200 –200 0 1002003004005006007008009001000 0 1002003004005006007008009001000 HOURS TIME (HOURS) 6656 G16 6656 G26 6656fc 9 For more information www.linear.com/LT6656

LT6656 PIN FUNCTIONS (TSOT-23/DFN) (LS8) GND* (Pin 1/Pin 3): Internal Function. This pin must be NC (Pins 1, 2, 7): Not Internally Connected. May be tied tied to ground. to V , V , GND or floated. IN OUT GND (Pin 2/Pin 2): Device Ground. GND* (Pin 3): Internal Function. This pin must be tied to ground. NC (Pins 3, 5/Pins 1, 5): Not Internally Connected. May be tied to V , V , GND or floated. GND (Pin 4): Device Ground. IN OUT V (Pin 4/Pin 6): Power Supply. The minimum supply V (Pin 5): Output Voltage. A minimum output capacitor IN OUT varies with output load and voltage option, see the Dropout of 1µF is required for stable operation. Voltage specification in the Electrical Characteristics table V (Pin 6): Output Voltage. Tie to pin 5 for best load OUT for further details. The maximum input voltage is 18V. regulation. Bypass V with a 0.1µF capacitor to ground. IN V (Pin 8): Power Supply. Bypass V with a 0.1µF IN IN V (Pin 6/Pin 4): Output Voltage. A minimum output OUT capacitor to ground. capacitor of 1µF is required for stable operation. GND*(Exposed Pad Pin 7, DFN Only): This pin must be tied to ground. BLOCK DIAGRAM 8 TSOT-23/DFN VIN LS8 VIN NC 1 NC NC 7 VOUT 2 NC 6 VOUT VOUT 5 ERROR ERROR BANDGAP BANDGAP AMP AMP NC GND* GND GND* GND 3 4 6656 BD 6656 BD (LS8) 6656fc 10 For more information www.linear.com/LT6656

LT6656 APPLICATIONS INFORMATION Long Battery Life Output Voltage Options Series references have a large advantage over shunt style The performance of the LT6656 is consistent for the 2.048V references. Shunt references require a resistor from the to 5V options. The 1.25V option has slightly reduced load power supply to operate. This resistor must be chosen regulation, and unlike the higher voltage options, the to supply the maximum current that can be demanded by minimum operating supply voltage is limited by internal the load. When the load is not operating at this maximum circuitry rather than the output voltage. current, the shunt reference must always sink this current, Parameters that are based on changes in the output voltage, resulting in high dissipation and shortened battery life. such as load regulation and hysteresis, remain proportional The LT6656 series reference does not require a current to the output voltage and are specified in relative units, setting resistor and is specified to operate with any supply for example, parts per million (ppm). Parameters that from 1.5V to 18V, depending on the output voltage option, are not based on changes in the output voltage, such as load current and operating temperature (see Dropout supply current and reverse input current, are the same Voltage and Minimum Input Voltage in the Typical Perfor- for all options. mance Characteristics). When the load does not demand The bandwidth of the LT6656 decreases with higher output current, the LT6656 reduces its dissipation and battery life voltage. This causes parameters that are affected by both is extended. If the reference is not delivering load current, bandwidth and output voltage, such as wideband noise it dissipates only a few µW, yet the same connection can and output impedance, to increase less with higher output deliver 5mA of load current when required. voltage. Start-Up Bypass and Load Capacitance To ensure proper start-up, the output voltage should be The LT6656 voltage reference needs a 0.1μF input bypass between –0.3V and the rated output voltage. If the output capacitor placed within an inch of the input pin. An ad- load may be driven more than 0.3V below ground, a low ditional 2.2μF capacitor should be used when the source forward voltage schottky diode from the output to ground impedance of the input supply is high or when driving is required. The turn-on characteristics can be seen in heavy loads. The bypassing of other local devices may Figure 1. serve as the required components. The output of the LT6656 requires a capacitance of 1µF or larger. The LT6656 is stable with a wide variety of capacitor types including ceramic, tantalum and electrolytic due to its low sensitivity VIN to ESR (5Ω or less). 1V/DIV The test circuit in Figure 2 was used to test the response and stability of the LT6656 to various load currents. The VOUT resultant transient responses can be seen in Figure 3 and Figure 4. The large scale output response to a 500mV input step is shown in Figure 5 with a more detailed photo and 1ms/DIV 6656 F01 description in the Output Settling section. Figure 1. LT6656-2.5 Turn-On Characteristics, C = 1µF L R2 V3IVN LT6656-2.5 VGEN 3V 0.1CµINF 1CµLF R1 2N7000 6656 F02 Figure 2. Transient Load Test Circuit 6656fc 11 For more information www.linear.com/LT6656

LT6656 APPLICATIONS INFORMATION The settling time is typically less than 8ms for output loads 0µA up to 5mA, however the time required to settle when the IOUT 100µA load is turned off or in response to an input transient can be significantly longer due to the dead band (shown in Figure 7). During this interval the output stage is neither sourcing nor sinking current so the settling time is dominated by 2.52V the ability of the application circuit to discharge the output VOUT 2.50V capacitor to the voltage at which the sourcing circuitry 2.48V in the output stage reactivates. Larger load currents will 5ms/DIV 6656 F03 decrease the settling time and higher output capacitance will increase the settling time. Figure 3. Transient Response, 0µA to 100µA Load Step (R2 = 24.9k, R1 = Open) In application circuits where the LT6656 is experiencing a load step greater than 5µA, such as an ADC reference 1mA and supply implementation, the settling time will typically IOUT remain less than 8ms, regardless of the output settling 2mA from a previous load step. The settling time can be estimated by the following equation: 2.52V VOUT 2.50V Settling time≈2(Deadband)(CL)+(V )(0.8ms/V) OUT I 2.48V L 5ms/DIV 6656 F04 The deadband is ≈7mV for the 2.5V option, is proportional Figure 4. Transient Response, 1mA to 2mA Load Step to the voltage option (i.e., ≈14mV for the 5V option) and (R1 = R2 = 2.49k) can double due to variations in processing. The graph in Figure 6 shows the settling time versus load step with no load and with a constant 2µA load applied. 3.25V VIN Note the settling time can be longer with load steps that 2.75V are not large enough to activate the sinking side of the output stage. 2.7V 30 VOUT 2.5V 2.5V OPTION VIN = 3V 2.3V s) 25 CL = 1µF 5ms/DIV 6656 F05 ME (m 20 S∆TILE =P LTOOA ZDERO TI Figure 5. Output Response to 0.5VP-P Step on VIN, CL = 1µF, IL = 0 NG LI 15 T T Output Settling UT SE 10 S∆TILE =P LTOOA 2DµA P The output of the LT6656 is primarily designed to source UT O 5 current into a load, but is capable of sinking current to ∆IL = ZERO TO LOAD STEP aid in output transient recovery. The output stage uses a 0 0.001 0.01 0.1 1 10 class B architecture to minimize quiescent current and LOAD STEP (mA) has a crossover dead band as the output transitions from 6656 F06 sourcing to sinking current. Figure 6. Output Settling Time to 0.05% vs Load Step 6656fc 12 For more information www.linear.com/LT6656

LT6656 APPLICATIONS INFORMATION the output can be held up by a backup battery with the 3.25V input pulled to ground, the reverse output protection of VIN 2.75V the LT6656 limits the output current to typically less than 30µA. The current versus reverse voltage is shown in the Typical Performance Characteristics section. IL = 0 VOUT 10mV/DIV Long-Term Drift IL = 5µA Long-term drift cannot be extrapolated from accelerated high temperature testing. This erroneous technique gives 5ms/DIV 6656 F07 drift numbers that are wildly optimistic. A more realistic Figure 7. Detailed Output Response to a 0.5V Input Step, way to determine long-term drift is to measure it over the CIN = CL = 1µF time interval of interest. The LT6656 drift data was taken over 100 parts that were soldered onto PC boards in a The photo in Figure 7 shows the output response to a 0.5V typical application configuration. The boards were then input step in both a no-load and 5µA load condition. In placed into a constant temperature oven with T = 30°C, A the no-load condition only the bias current of the internal their outputs scanned regularly and measured with an bandgap reference (about 400nA) is available to discharge 8.5 digit DVM. The parts chosen in the Long Term Drift the output capacitor. curves in the Typical Performance Characteristics section represent high, low and typical units. Output Noise Hysteresis Low frequency noise is proportional to the output voltage and is insensitive to output current and moderate levels Hysteresis on the LT6656 is measured in two steps, for of output capacitance. example, from 25°C to –40°C to 25°C, then from 25°C to 85°C to 25°C, for the industrial temperature range. After Wideband noise increases less with higher output voltage preconditioning by one thermal cycle, this two-step cycle and is proportional to the bandwidth of the output stage, is repeated several times and the maximum hysteresis increasing with higher load current and lower output from all the partial cycles is noted. capacitance. Results over both commercial and industrial temperature Peaking in the noise response is another factor contribut- ranges are shown in Figure 8 and Figure 9. The parts cycled ing to the output noise level for a given frequency range. over the higher temperature range have a higher hysteresis Noise peaking can be reduced by increasing the size of the than those cycled over the lower range. output capacitor when driving heavier loads, or conversely, reducing the size of the output capacitor when driving Power Dissipation lighter loads. Noise plots in the Typical Performance Curves section show noise spectrum with various load currents The LT6656 will not exceed the maximum junction tem- and output capacitances. perature when operating within its specified temperature range of –40°C to 85°C, maximum input voltage of 18V Internal Protection and specified load current of 5mA. The LT6656 incorporates several internal protection IR Reflow Shift features that make it ideal for use in battery powered systems. Reverse input protection limits the input cur- The different expansion and contraction rates of the mate- rent to typically less than 40µA when either the LT6656 rials that make up the LT6656 package may induce small or the battery is installed backwards. In systems where stresses on the die that can cause the output to shift during 6656fc 13 For more information www.linear.com/LT6656

LT6656 APPLICATIONS INFORMATION 30 20 2.5V OPTION 0°C TO 25°C –40°C TO 25°C 1.25V OPTION VIN = 3V 70°C TO 25°C 85°C TO 25°C VIN = 2V 25 CL = 1µF CL = 1µF IL = 0 15 IL = 0 NITS 20 NITS U U R OF 15 R OF 10 MBE MBE U 10 U N N 5 5 0 0 –60 –40 –20 0 20 40 60 –160–120 –80 –40 0 40 80 120 160 HYSTERESIS (ppm) HYSTERESIS (ppm) 6656 F08 6656 F11 Figure 8. LT6656 S6, DC 0°C to 70°C Hysteresis Figure 11. LT6656 LS8 –40°C to 85°C Hysteresis 20 –40°C TO 25°C 2.5V OPTION IR reflow. Common lead free IR reflow profiles reach over 18 85°C TO 25°C VIN = 3V 250°C, considerably more than lead solder profiles. The 16 ICLL = = 0 1µF higher reflow temperature of the lead free parts exacerbates S14 T the issue of thermal expansion and contraction causing UNI12 F the output shift to generally be greater than with a leaded R O10 E reflow process. MB 8 U N 6 The lead free IR reflow profile used to experimentally 4 measure the output voltage shift in the LT6656-2.5 is 2 shown in Figure 12. Similar results can be expected us- 0 –160–120 –80 –40 0 40 80 120 160 ing a convection reflow oven. Figures 13 and 14 show the HYSTERESIS (ppm) change in output voltage that was measured for parts that 6656 F09 Figure 9. LT6656 S6, DC –40°C to 85°C Hysteresis were run through the reflow process for 1 cycle and also 3 cycles. Additional drift of the LT6656 after IR reflow does not vary significantly. 20 1.25V OPTION VIN = 2V CL = 1µF 15 IL = 0 300 380s S 0°C TO 25°C TP = 260°C NIT 70°C TO 25°C RAMP R OF U 10 225 TS(MAX) = 2T0L 0=° C217°C DOWN MBE TS = 190°C 3t0Ps U N 150 T = 150°C 5 RAMP TO tL 130s 150°C 75 0 40s –60 –40 –20 0 20 40 60 HYSTERESIS (ppm) 120s 6656 F10 0 0 2 4 6 8 10 Figure 10. LT6656 LS8 0°C to 70°C Hysteresis MINUTES 6656 F12 Figure 12. Lead Free Reflow Profile Due to IR Reflow 6656fc 14 For more information www.linear.com/LT6656

LT6656 APPLICATIONS INFORMATION short as possible to minimize the voltage drops caused 7 2.5V OPTION SOT-23 VIN = 3V 3 CYCLES by load and ground currents. Excessive trace resistance 6 CL = 1µF 1 CYCLE directly impacts load regulation. IL = 0 5 S T NI Humidity Sensitivity F U 4 O R Plastic mold compounds absorb water. With changes in BE 3 UM relative humidity, plastic packaging materials change the N 2 amount of pressure they apply to the die inside, which 1 can cause slight changes in the output of a voltage refer- ence, usually on the order of 100ppm. The LS8 package is 0 0 20 60 100 140 180 220 hermetic, so it is not affected by humidity, and is therefore CHANGE IN OUTPUT VOLTAGE (ppm) 6656 F13 more stable in environments where humidity may be a Figure 13. ∆V Due to IR Reflow, concern. However, PC board material may absorb water OUT Peak Temperature = 260°C, SOT-23 and apply mechanical stress to the LT6656LS8. Proper board materials and layout are essential. 10 2.5V OPTION DFN 9 VIN = 3V 3 CYCLES For best stability, the PC board layout is critical. Change 8 CL = 1µF 1 CYCLE in temperature and position of the PC board, as well as IL = 0 S 7 aging, can alter the mechanical stress applied to compo- T UNI 6 nents soldered to the board. FR4 and similar materials also F R O 5 absorb water, causing the board to swell. Even conformal E MB 4 coating or potting of the board does not always eliminate U N 3 this effect, though it may delay the symptoms by reduc- 2 ing the rate of absorption. Removing power and ground 1 planes in the PC board under the voltage reference can 0 –160 –80 0 80 160 240 improve the stability significantly. CHANGE IN OUTPUT VOLTAGE (ppm) Figure 15a shows a tab cut through the PC board on three 6656 F14 sides of an LT6656, which significantly reduces stress Figure 14. ∆V Due to IR Reflow, OUT Peak Temperature = 260°C, DFN on the IC, as described in Application Note 82. For even better performance, Figure 15b shows slots cut through PC Board Layout the PC board on all four sides. The slots should be as long as possible, and the corners just large enough to The mechanical stress of soldering a surface mount volt- accommodate routing of traces. It has been shown that age reference to a PC board can cause the output voltage for PC boards designed in this way, humidity sensitivity to shift and temperature coefficient to change. can be reduced to less than 35ppm for a change in relative To reduce the effects of stress-related shifts, position humidity of approximately 60%. Mounting the reference the reference near the short edge of the PC board or in a near the center of the board, with slots on four sides, can corner. In addition, slots can be cut into the board on two further reduce the sensitivity to less than 10ppm. sides of the device. See Application Note AN82 for more An additional advantage of slotting the PC board is that the information. http://www.linear.com LT6656 is thermally isolated from surrounding circuitry. The input and output capacitors should be mounted close This can help reduce thermocouple effects and improve to the package. The GND and V traces should be as accuracy. OUT 6656fc 15 For more information www.linear.com/LT6656

LT6656 APPLICATIONS INFORMATION LS8 6656 F15a Figure 15a. 3-Sided PCB Cutout LS8 6656 F12b Figure 15b. 4-Sided PCB Cutout 6656fc 16 For more information www.linear.com/LT6656

LT6656 TYPICAL APPLICATIONS Regulator Reference only 27.4µA. This system is greatly simplified because the precision reference does not need to be cycled on and The robust input and output of the LT6656 along with its off to save power. Furthermore, leaving the reference on high output current make it an excellent precision low continuously eliminates concern for turn-on settling time. power regulator as well as a reference. The LT6656 would be a good match with a small, low power microcontroller. LT6656-2.5 Using the LT6656 as a regulator reduces power consump- 3V ≤ VIN ≤ 18V IN OUT tion, decreases solution size and increases the accuracy MCU of the microcontroller’s on board ADC. 0.1µF 10µF VCC/VREF 5 PB0/AIN0/AREF/MOSI 6 Low Power ADC Reference PB1/INT0/AIN1/MISO/OC1A 7 PB2/ADC1/SCK/T0/INT0 Low power ADCs draw only a few µAs during their idle 2 PB3/ADC2 period and well over 100µA during conversions. Despite 3 PB4/ADC3 these surges of current, the ADC in reality can have very PB5/RESET/ADC0 1 low power consumption. Figure 17 shows the LTC2480, GND a low power delta sigma ADC. When the ADC is disabled 6656 F16 its quiescent current (I ) is roughly 1µA, during conver- Q Figure 16. Microcontroller Reference and Regulator sion the I jumps up to 160µA. In reality, the power con- Q sumption is not only based on the I during conversion, Q but the real power consumption of the ADC is set by the LT6656-5 conversion time and the sample rate. The LTC2480 shown 5.1V ≤ VIN ≤ 18V IN OUT 0.1µF 4.7µF in Figure 17 has a conversion time of 160ms which sets the maximum sample rate of 6 samples per second. The IN+ REF VCC CS maximum sample rate also sets the maximum current DIFFERENTIAL INPUT LTC2480 SCK consumption to 160µA, but at slower sample rates the ±VREF (cid:127) 0.5 (±2.5V) IN– SDO ADC will have significantly lower average current draw. 6656 F17 If the ADC is sampled at 1 sample per second the aver- AT 1sps, IQ = 27.4µA age current drawn by the ADC during a 1 second interval Figure 17. Low Power ADC Reference would only be 26.4µA. When taking into consideration the current drawn by the reference, the total current draw is 6656fc 17 For more information www.linear.com/LT6656

LT6656 TYPICAL APPLICATIONS Extended Supply Range Reference VCC UP TO 160V 330k MMBT5551 BZX584C12 0.1µF IN OUT VOUT 2.2µF LT6656-2.5 1µF 6656 TA03 Boosted Output Current Reference 3.6V ≤ VCC ≤ 18V + 220Ω 10µF 2N2905 0.1µF IN OUT VOUT 40mA MAX LT6656-2.5 1µF 6656 TA04 Micropower Regulator, I = 2µA, Sink Up to 8mA Q 3V ≤ VCC ≤ 18V LT6656-2.5 IN OUT + 0.1µF 1µF LT6003 2.5V – 6656 TA06 ADC Reference and Bridge Excitation Supply LT6656-3.3 3.3V ≤ VCC ≤ 5.5V 3.8V ≤ VIN ≤ 18V IN OUT 0.1µF 1µF 10k 10k 0.1µF 10µF VREF VCC IN– CS 0.1µF LTC2452 SCK IN+ SDO 10k 0.1µF 6656fc 18 For more information www.linear.com/LT6656

LT6656 TYPICAL APPLICATIONS Low Power Precision High Voltage Supply Monitor, I = 1.4µA, High Voltage Supply Load = 10µA Q 100V 105V OVERVOLTAGE THRESHOLD VCC 9.53M 3 + 7 6.5V ≤ VCC ≤ 10V LTC1540 OVERVOLTAGE FLAG IN LT6656-5 OUT 4 – 5 6 0.1µF 1µF 475k 1, 2 6656 TA08 2-Terminal Current Source + + LT6003 LT6656-1.25 VREF R1 IN OUT – GND 0.1µF 1µF R2 R3 – 6656 TA09 IOUT=VRRE1FRR23+1 Precision Current and Boosted Reference, I = 5.5µA Q 249k VCC + + 1k 2N5086 LT6004 LT6004 2.75V – – 200k 1µA OUT 3V ≤ VCC ≤ 16V LT6656-2.5 2M IN OUT 2.5V 0.1µF 1µF 6656 TA10 6656fc 19 For more information www.linear.com/LT6656

LT6656 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 2.90 BSC 0.62 0.95 (NOTE 4) MAX REF 1.22 REF 1.50 – 1.75 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT 0.30 – 0.45 0.95 BSC PER IPC CALCULATOR 6 PLCS (NOTE 3) 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 1.90 BSC 0.09 – 0.20 (NOTE 3) S6 TSOT-23 0302 NOTE: 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 6656fc 20 For more information www.linear.com/LT6656

LT6656 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. DC6 Package 6-Lead Plastic DFN (2mm × 2mm) (Reference LTC DWG # 05-08-1703 Rev B) 0.70 ±0.05 2.55 ±0.05 1.15 ±0.050.61 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 1.42 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS R = 0.125 0.40 ±0.10 TYP 0.56 ±0.05 4 6 (2 SIDES) 2.00 ±0.10 PIN 1 NOTCH PIN 1 BAR (4 SIDES) R = 0.20 OR TOP MARK 0.25 × 45° (SEE NOTE 6) CHAMFER R = 0.05 (DC6) DFN REV B 1309 TYP 3 1 0.25 ±0.05 0.200 REF 0.75 ±0.05 0.50 BSC 1.37 ±0.05 (2 SIDES) 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WCCD-2) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 6656fc 21 For more information www.linear.com/LT6656

LT6656 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. LS8 Package 8-Pin Leadless Chip Carrier (5mm × 5mm) (Reference LTC DWG # 05-08-1852 Rev B) 8 2.50 ±0.15 PACKAGE OUTLINE 7 1 2 0.5 6 2.54 ±0.15 1.4 3 1.50 ±0.15 XYY ZZ 4 ABCDEF Q12345e4 0.70 ±0.05 × 8 COMPONENT PIN “A1” 5.00 SQ ±0.15 5.80 SQ ±0.15 TRAY PIN 1 APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED BEVEL PACKAGE IN TRAY LOADING ORIENTATION 5.00 SQ ±0.15 1.45 ±0.10 4.20 SQ ±0.10 5.00 SQ ±0.15 0.95 ±0.10 8 8 R0.20 REF 2.00 REF PIN 1 1 1 TOP MARK 7 7 (SEE NOTE 5) 2 6 6 0.5 2 4.20 ±0.10 2.54 ±0.15 1.4 5 3 3 5 R0.20 REF 1.00 × 7 TYP LS8 0113 REV B 4 4 NOTE: 0.70 TYP 0.10 TYP 0.64 × 8 TYP 1. ALL DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS PACKAGE DO NOT INCLUDE PLATING BURRS PLATING BURRS, IF PRESENT, SHALL NOT EXCEED 0.30mm ON ANY SIDE 4. PLATING—ELECTO NICKEL MIN 1.25UM, ELECTRO GOLD MIN 0.30UM 5. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 6656fc 22 For more information www.linear.com/LT6656

LT6656 REVISION HISTORY REV DATE DESCRIPTION PAGE NUMBER A 7/10 Voltage options added (1.25, 2.048, 3, 3.3), reflected throughout the data sheet 1 to 18 B 5/11 Added 6-lead DFN package reflected throughout the data sheet 1 to 20 C 11/13 Addition of 1.25V option in the LS8 package 1 to 4 Note 10 updated with additional explanation of hysteresis 6 Pin Functions updated to show pin numbers and LS8 package 10 Block Diagram updated to show pin numbers and LS8 package 10 Hysteresis section updated with additional explanation 13 Hysteresis graphs updated for SOT23 and LS8 packages 14 New section added for Humidity Sensitivity 15, 16 6656fc Information furnished by Linear Technology Corporation is believed to be accurate and reliable. 23 However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnecFtioorn mof oitrse c iirncfuoitrsm asa dtieosncr wibewdw h.elrineiena wr.icll onmot /inLTfr6in6g5e 6on existing patent rights.

LT6656 TYPICAL APPLICATION Reference Regulator for Micropower DAC, Total I = 4.8µA Q LT6656-5 5V 5.1V ≤ VIN ≤ 18V IN OUT 0.1µF 10µF VREF VCC DAC A 0V TO 5V OUTPUT CS SCK LTC1662 SDI DAC B 0V TO 5V OUTPUT GND 6656 TA07 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1389 Nanopower Precision Shunt Voltage Reference 0.05% Max 10ppm/°C Max, 800nA Supply LTC1440 Micropower Comparator with Reference 3.7µA Max Supply Current, 1% 1.182V Reference, MSOP, PDIP and SO-8 Packages LT1460 Micropower Series Reference 0.075% Max, 10ppm/°C Max Drift, 2.5V, 5V and 10V Versions,MSOP, PDIP, SO-8, SOT-23 and TO-92 Packages LT1461 Micropower Precision LDO Series Reference 3ppm/°C Max Drift, 0°C to 70°C, –40°C to 85°C, –40°C to 125°C Options in SO-8 LT1495 1.5µA Precision Rail-to-Rail Dual Op Amp 1.5µA Max Supply Current, 100pA Max IOS LTC1540 Nanopower Comparator with Reference 600nA Max Supply Current, 2% 1.182V Reference, MSOP and SO-8 Packages LT1634 Micropower Precision Shunt Voltage 0.05% Max, 10ppm/°C Max Drift, 1.25V, 2.5V, 4.096V, 5V, 10µA Maximum Supply Reference Current LT1790 Micropower Precision Series Reference 0.05% Max, 10ppm/°C Max, 60µA Supply, SOT23 Package LTC1798 6µA Low Dropout Series Reference Available in Adjustable, 2.5V, 3V, 4.096V and 5V LT6003 1.6V, 1µA Precision Rail-to-Rail Op Amp 1µA Max Supply Current, 1.6V Minimum Operating Voltage, SOT-23 and DFN Packages LT6650 Micropower Reference with Buffer Amplifier 0.05% Max, 5.6µA Supply, SOT-23 Package LT6660 Tiny Micropower Series Reference 0.2% Max, 20ppm/°C Max, 20mA Output Current, 2mm × 2mm DFN LT6700 Micropower, Low Voltage Dual Comparator 6.5µA Supply Current, 1.4V Minimum Operating Voltage with 40mV Reference 6656fc 24 Linear Technology Corporation LT 1113 REV C • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LT6656 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LT6656  LINEAR TECHNOLOGY CORPORATION 2010