LT6660 Tiny Micropower Precision Series References in 2mm × 2mm DFN FEATURES DESCRIPTIOU ■ No Output Capacitor Required The LT®6660 is a family of micropower series references ■ Low Drift: 20ppm/°C Max that combine high accuracy and low drift with low power ■ High Accuracy: 0.2% Max dissipation and extremely small package size. These se- ■ Low Supply Current ries references use curvature compensation to obtain ■ 20mA Output Current Guaranteed low temperature coefficient, and laser trimmed precision ■ Reverse-Battery Protection thin-film resistors to achieve high output accuracy. The ■ Low IR Reflow Induced Stress: 0.02% Typ LT6660 will supply up to 20mA with excellent line regula- ■ Voltage Options: 2.5V, 3V, 3.3V, 5V and 10V tion characteristics, making it ideal for precision regulator ■ Space-Saving Alternative to the LT1460 applications. ■ 3-Lead 2mm × 2mm × 0.75mm DFN Package The LT6660 family of series references provide supply current and power dissipation advantages over shunt APPLICATIOUS references that must idle the entire load current to oper- ate. Additionally, the LT6660 does not require an output ■ Handheld Instruments compensation capacitor. This feature is important in ■ Precision Regulators applications where PC board space is a premium, fast set- ■ A/D and D/A Converters tling is demanded, or total capacitance must be kept to a ■ Power Supplies minimum, as in intrinsic safety applications. Reverse-bat- ■ Hard Disk Drives tery protection keeps these references from conducting ■ Sensor Modules reverse current. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATIOU LT6660H V Shift Due to IR Reflow OUT 32 28 Basic Connection 24 %) LT6660 N ( 20 O VOUT + 0.9V ≤ VIN ≤ 20V IN OUT VOUT UTI 16 B C1 GND RI 0.1µF DIST 12 6660 TA01 8 4 0 –0.09 –0.05 –0.01 0.01 0.05 0.09 CHANGE IN VOUT (%) 6660 TA01b 6660fa 1

LT6660 ABSOLUTE WAXIWUW RATIUGS (Note 1) Input Voltage .............................................................30V Operating Temperature Range Reverse Voltage ......................................................–15V (Note 2) ...............................................–40°C to 85°C Output Short-Circuit Duration, T = 25°C ................5 sec Storage Temperature Range (Note 3) .....–65°C to 150°C A Specified Temperature Range ......................0°C to 70°C Lead Temperature (Soldering, 10 sec) ..................300°C PACKAGE/ORDER IUFORWATIOU ORDER PART NUMBER DFN PART MARKING* LT6660HCDC-2.5 LBXN LT6660JCDC-2.5 LBXN LT6660KCDC-2.5 LBXN TOP VIEW LT6660HCDC-3 LBYV LT6660JCDC-3 LBYV 4 LT6660KCDC-3 LBYV LT6660HCDC-3.3 LBYW 1 2 3 LT6660JCDC-3.3 LBYW T D N U N I O G LT6660KCDC-3.3 LBYW DC PACKAGE LT6660HCDC-5 LBYT 3-LEAD (2mm × 2mm) PLASTIC DFN TJMAX = 125°C, θJA = 102°C/W LT6660JCDC-5 LBYT EXPOSED PAD IS GND, MUST BE SOLDERED TO PCB LT6660KCDC-5 LBYT LT6660HCDC-10 LBYX LT6660JCDC-10 LBYX LT6660KCDC-10 LBYX Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. AVAILABLE OPTIONS OUTPUT VOLTAGE SPECIFIED TEMPERATURE ACCURACY TEMPERATURE PART ORDER (V) RANGE (%) COEFFICIENT (ppm/°C) NUMBER 2.5 0°C to 70°C 0.2 20 LT6660HCDC-2.5 2.5 0°C to 70°C 0.4 20 LT6660JCDC-2.5 2.5 0°C to 70°C 0.5 50 LT6660KCDC-2.5 3 0°C to 70°C 0.2 20 LT6660HCDC-3 3 0°C to 70°C 0.4 20 LT6660JCDC-3 3 0°C to 70°C 0.5 50 LT6660KCDC-3 3.3 0°C to 70°C 0.2 20 LT6660HCDC-3.3 3.3 0°C to 70°C 0.4 20 LT6660JCDC-3.3 3.3 0°C to 70°C 0.5 50 LT6660KCDC-3.3 6660fa 2

LT6660 AVAILABLE OPTIONS OUTPUT VOLTAGE SPECIFIED TEMPERATURE ACCURACY TEMPERATURE PART ORDER (V) RANGE (%) COEFFICIENT (ppm/°C) NUMBER 5 0°C to 70°C 0.2 20 LT6660HCDC-5 5 0°C to 70°C 0.4 20 LT6660JCDC-5 5 0°C to 70°C 0.5 50 LT6660KCDC-5 10 0°C to 70°C 0.2 20 LT6660HCDC-10 10 0°C to 70°C 0.4 20 LT6660JCDC-10 10 0°C to 70°C 0.5 50 LT6660KCDC-10 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25°C. V = V + 2.5V, I = 0 unless otherwise specified. A IN OUT OUT PARAMETER CONDITIONS MIN TYP MAX UNITS Output Voltage Tolerance LT6660HCDC –0.2 0.2 % LT6660JCDC –0.4 0.4 % LT6660KCDC –0.5 0.5 % Output Voltage Temperature Coefficient (Note 4) LT6660HCDC ● 10 20 ppm/°C LT6660JCDC ● 10 20 ppm/°C LT6660KCDC ● 25 50 ppm/°C Line Regulation V + 0.9V ≤ V ≤ V + 2.5V 150 800 ppm/V OUT IN OUT ● 1000 ppm/V V + 2.5V ≤ V ≤ 20V 50 100 ppm/V OUT IN ● 130 ppm/V Load Regulation Sourcing (Note 5) I = 100µA 1000 3000 ppm/mA OUT ● 4000 ppm/mA I = 10mA 50 200 ppm/mA OUT ● 300 ppm/mA I = 20mA 20 70 ppm/mA OUT ● 100 ppm/mA Thermal Regulation (Note 6) ΔP = 200mW 2.5 10 ppm/mW Dropout Voltage (Note 7) VIN – VOUT, ΔVOUT ≤ 0.2%, IOUT = 0 ● 0.9 V VIN – VOUT, ΔVOUT ≤ 0.2%, IOUT = 10mA 1.3 V ● 1.4 V Output Current Short V to GND 40 mA OUT Reverse Leakage V = –15V ● 0.5 10 µA IN Output Voltage Noise (Note 8) 0.1Hz ≤ f ≤ 10Hz 4 ppm (P-P) 10Hz ≤ f ≤ 1kHz 4 ppm (RMS) Long-Term Stability of Output Voltage (Note 9) 100 ppm/√kHr Hysteresis (Note 10) ΔT = 0°C to 70°C ● 50 ppm ΔT = –40°C to 85°C ● 250 ppm Supply Current LT6660-2.5 115 145 µA ● 175 µA LT6660-3 145 180 µA ● 220 µA LT6660-3.3 145 180 µA ● 220 µA LT6660-5 160 200 µA ● 240 µA LT6660-10 215 270 µA ● 350 µA 6660fa 3

LT6660 ELECTRICAL CHARACTERISTICS Note 1: Stresses beyond those listed under Absolute Maximum Ratings is 10 sec. RMS noise is measured with a single pole highpass filter at may cause permanent damage to the device. Exposure to any Absolute 10Hz and a 2-pole lowpass filter at 1kHz. The resulting output is full wave Maximum Rating condition for extended periods may affect device rectified and then integrated for a fixed period, making the final reading an reliability and lifetime. average as opposed to RMS. A correction factor of 1.1 is used to convert Note 2: The LT6660 is guaranteed functional over the operating from average to RMS and a second correction of 0.88 is used to correct temperature range of –40°C to 85°C. for the nonideal bandpass of the filters. Note 3: If the parts are stored outside of the specified temperature range, Note 9: Long-term stability typically has a logarithmic characteristic the output may shift due to hysteresis. and therefore, changes after 1000 hours tend to be much smaller than before that time. Total drift in the second thousand hours is normally less Note 4: Temperature coefficient is measured by dividing the change in than one third that of the first thousand hours with a continuing trend output voltage by the specified temperature range. Incremental slope is toward reduced drift with time. Long-term stability will also be affected by also measured at 25°C. differential stresses between the IC and the board material created during Note 5: Load regulation is measured on a pulse basis from no load to the board assembly. specified load current. Output changes due to die temperature change Note 10: Hysteresis in output voltage is created by package stress that must be taken into account separately. differs depending on whether the IC was previously at a higher or lower Note 6: Thermal regulation is caused by die temperature gradients created temperature. Output voltage is always measured at 25°C, but the IC by load current or input voltage changes. This effect must be added to is cycled to 70°C or 0°C before successive measurements. Hysteresis normal line or load regulation. This parameter is not 100% tested. is roughly proportional to the square of the temperature change. For Note 7: Excludes load regulation errors. instruments that are stored at well-controlled temperatures (within 20 or Note 8: Peak-to-peak noise is measured with a single pole highpass filter 30 degrees of operational temperature) hysteresis is not a problem. at 0.1Hz and 2-pole lowpass filter at 10Hz. The unit is enclosed in a still-air environment to eliminate thermocouple effects on the leads. The test time TYPICAL PERFORW AU CE CHARACTERISTICS Characteristic curves are similar for all voltage options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic curves for other output voltages fall between these curves, and can be estimated based on their voltage output. 2.5V Minimum Input-Output Voltage Differential 2.5V Load Regulation, Sourcing 2.5V Load Regulation, Sinking 100 0 120 –0.5 V) V)100 m m NT (mA) 10 125°C HANGE (––11..05 –55°C HANGE ( 80 UT CURRE –5255°°CC OLTAGE C––22..05 25°C OLTAGE C 60 25°C 125°C –55°C OUTP 1 PUT V–3.0 125°C PUT V 40 OUT OUT 20 –3.5 0.1 –4.0 0 0 0.5 1.0 1.5 2.0 2.5 0.1 1 10 100 0 1 2 3 4 5 INPUT-OUTPUT VOLTAGE (V) OUTPUT CURRENT (mA) OUTPUT CURRENT (mA) 6660 G01 6660 G02 6660 G03 6660fa 4

LT6660 TYPICAL PERFORW AU CE CHARACTERISTICS Characteristic curves are similar for all voltage options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic curves for other output voltages fall between these curves, and can be estimated based on their voltage output. 2.5V Output Voltage 2.5V Supply Current Temperature Drift vs Input Voltage 2.5V Line Regulation 2.503 250 2.502 THREE TYPICAL PARTS 2.501 2.502 25°C 25°C 200 GE (V) 2.501 T (A)µ 125°C –55°C GE (V) 22..540909 –55°C A N 150 A LT RE LT O 2.500 R O 2.498 PUT V LY CU 100 PUT V 2.497 125°C UT 2.499 PP UT O U O S 2.496 2.498 50 2.495 2.497 0 2.494 –50 –25 0 25 50 75 100 125 0 5 10 15 20 0 2 4 6 8 10 12 14 16 18 20 TEMPERATURE (°C) INPUT VOLTAGE (V) INPUT VOLTAGE (V) 6660 G04 6660 G05 6660 G06 2.5V Power Supply Rejection 2.5V Output Impedance Ratio vs Frequency vs Frequency 2.5V Transient Response 80 1000 dB) 70 CL = 0µF 20 O ( A) REJECTION RATI 456000 MPEDANCE ()Ω11000 CL = 0.1µF AD CURRENT (m 101 R SUPPLY 2300 OUTPUT I 1 CL = 1µF LO 0.1 WE 200µs/DIV 6660 G09 O 10 P CLOAD = 0µF 0 0.1 0.1 1 10 100 1000 0.01 0.1 1 10 100 1000 FREQUENCY (kHz) FREQUENCY (kHz) 6660 G07 6660 G08 2.5V Output Voltage Noise Spectrum 2.5V Output Noise 0.1Hz to 10Hz 1000 Hz) DIV) V/√ V/µ TAGE (n OISE (20 OISE VOL UTPUT N N O 100 10 100 1k 10k 100k TIME (2 SEC/DIV) FREQUENCY (Hz) 6660 G10 6660 G11 6660fa 5

LT6660 TYPICAL PERFORW AU CE CHARACTERISTICS Characteristic curves are similar for all voltage options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic curves for other output voltages fall between these curves, and can be estimated based on their voltage output. 10V Minimum Input-Output Voltage Differential 10V Load Regulation, Sourcing 10V Load Regulation, Sinking 100 35 250 30 mV) 25 mV) 200 T (mA) 10 125°C ANGE ( 20 ANGE ( 125°C N H H 150 UTPUT CURRE 1 –552°5C°C UT VOLTAGE C 11505 UT VOLTAGE C 100 25°C –55°C O UTP 0 –55°C UTP 50 O O –5 125°C 25°C 0.1 –10 0 0 0.5 1.0 1.5 2.0 2.5 0.1 1 10 100 0 1 2 3 4 5 INPUT-OUTPUT VOLTAGE (V) OUTPUT CURRENT (mA) OUTPUT CURRENT (mA) 6660 G12 6660 G13 6660 G14 10V Output Voltage 10V Supply Current Temperature Drift vs Input Voltage 10V Line Regulation 10.006 350 10.010 THREE TYPICAL PARTS 10.004 300 10.002 10.005 25°C OUTPUT VOLTAGE (V)19099999.......909999990999988064208 SUPPLY CURRENT (A)µ211200550000 125°C –55°C OUTPUT VOLTAGE (V)1990...990990050 –1225555°°°CCC 9.986 50 9.985 9.984 9.982 0 9.980 –50 –25 0 25 50 75 100 125 0 2 4 6 8 10 12 14 16 18 20 6 8 10 12 14 16 18 20 TEMPERATURE (°C) INPUT VOLTAGE (V) INPUT VOLTAGE (V) 6660 G15 6660 G16 6660 G17 6660fa 6

LT6660 TYPICAL PERFORW AU CE CHARACTERISTICS Characteristic curves are similar for all voltage options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic curves for other output voltages fall between these curves, and can be estimated based on their voltage output. 10V Power Supply Rejection 10V Output Impedance Ratio vs Frequency vs Frequency 10V Transient Response 100 1000 B) 90 20 O (d 80 CL = 0µF A) REJECTION RATI 576000 MPEDANCE ()Ω11000 CL = 0.1µF AD CURRENT (m 101 R SUPPLY 324000 OUTPUT I 1 CL = 1µF LO 0.1 E W 200µs/DIV 6660 G20 O 10 P CLOAD = 0µF 0 0.1 0.1 1 10 100 1000 0.01 0.1 1 10 100 1000 FREQUENCY (kHz) FREQUENCY (kHz) 6660 G18 6660 G19 10V Output Voltage Noise Spectrum 10V Output Noise 0.1Hz to 10Hz 10 Hz) DIV) AGE (V/µ√ 1 SE (20V/µ OLT NOI E V UT S P OI UT N O 0.1 0.01 0.1 1 10 100 TIME (2 SEC/DIV) FREQUENCY (kHz) 6660 G21 6660 G22 6660fa 7

LT6660 APPLICATIOUS IUFORWATIOU Longer Battery Life Series references have a large advantage over older shunt VGEN 2.5V style references. Shunt references require a resistor 1.5V from the power supply to operate. This resistor must be chosen to supply the maximum current that can ever be VOUT 1mA demanded by the circuit being regulated. When the circuit being controlled is not operating at this maximum current, VOUT 10mA the shunt reference must always sink this current, resulting in high dissipation and short battery life. 1µs/DIV 6660 F02 The LT6660 series references do not require a current Figure 2. C = 0µF setting resistor and can operate with any supply voltage L from V + 0.9V to 20V. When the circuitry being regu- OUT lated does not demand current, the LT6660s reduce their dissipation and battery life is extended. If the references are not delivering load current, they dissipate only several VGEN 2.5V mW, yet the same connection can deliver 20mA of load 1.5V current when demanded. VOUT 1mA Capacitive Loads VOUT 10mA The LT6660 family of references are designed to be stable with a large range of capacitive loads. With no capacitive load, these references are ideal for fast settling or applica- 100µs/DIV 6660 F03 tions where PC board space is a premium. The test circuit Figure 3. C = 0.1µF shown in Figure 1 is used to measure the response time L and stability of various load currents and load capacitors. This circuit is set for the 2.5V option. For other voltage options, the input voltage must be scaled up and the output voltage generator offset voltage must be adjusted. VGEN 2.5V The 1V step from 2.5V to 1.5V produces a current step of 1.5V 10mA or 1mA for R = 100Ω or R = 1k. Figure 2 shows L L the response of the reference to these 1mA and 10mA VOUT 1µF load steps with no load capacitance, and Figure 3 shows a 1mA and 10mA load step with a 0.1µF output capaci- VOUT 4.7µF tor. Figure 4 shows the response to a 1mA load step with C = 1µF and 4.7µF. L 100µs/DIV 6660 F04 Figure 4. I = 1mA OUT VOUT RL VIN = 2.5V LT6660-2.5 VGEN 0.1CµINF CL 21..55VV 6660 F01 Figure 1. Response Time Test Circuit 6660fa 8

LT6660 APPLICATIOUS IUFORWATIOU Table 1 gives the maximum output capacitance for vari- Hysteresis ous load currents and output voltages to avoid instability. Hysteresis data shown in Figure 6 and Figure 7 represents Load capacitors with low ESR (effective series resistance) the worst-case data taken on parts from 0°C to 70°C and cause more ringing than capacitors with higher ESR such from –40°C to 85°C. The output is capable of dissipat- as polarized aluminum or tantalum capacitors. ing relatively high power, i.e., for the LT6660-2.5, P = D Table 1. Maximum Output Capacitance 17.5V • 20mA = 350mW. The thermal resistance of the DFN package is 102°C/W and this dissipation causes a VOLTAGE OPTION I = 100µA I = 1mA I = 10mA I = 20mA 36°C internal rise. This elevated temperature may cause OUT OUT OUT OUT 2.5V >10µF >10µF 2µF 0.68µF the output to shift due to thermal hysteresis. For highest 3V >10µF >10µF 2µF 0.68µF performance in precision applications, do not let the 3.3V >10µF >10µF 1µF 0.68µF LT6660’s junction temperature exceed 85°C. 5V >10µF >10µF 1µF 0.68µF Input Capacitance 10V >10µF 1µF 0.15µF 0.1µF It is recommended that a 0.1µF or larger capacitor be Long-Term Drift added to the input pin of the LT6660. This can help with stability when large load currents are demanded. Long-term drift cannot be extrapolated from accelerated high temperature testing. This erroneous technique 18 WORST-CASE HYSTERESIS gives drift numbers that are wildly optimistic. The only 16 ON 40 UNITS way long-term drift can be determined is to measure it 14 over the time interval of interest. The LT6660 long-term TS12 NI drift data was taken on over 100 parts that were soldered U F 10 into PC boards similar to a “real world” application. The R O 70°C TO 25°C 0°C TO 25°C E 8 B boards were then placed into a constant temperature oven M U 6 N with T = 30°C, their outputs were scanned regularly and A 4 measured with an 8.5 digit DVM. Figure 5 shows typical 2 long-term drift of the LT6660s. 0 –240–200–160–120 –80 –40 0 40 80 120 160 200 240 150 HYSTERESIS (ppm) 6660 F06 100 Figure 6. 0°C to 70°C Hysteresis 50 9 WORST-CASE HYSTERESIS m 8 ON 34 UNITS p 0 p 7 85°C TO 25°C –40°C TO 25°C –50 TS 6 NI U –100 OF 5 R E 4 B M –150 U 3 0 100200 300400500600700800 9001000 N HOURS 2 6660 F05 1 Figure 5. Typical Long-Term Drift 0 –600–500–400–300–200–100 0 100 200 300 400 500 600 HYSTERESIS (ppm) 6660 F07 Figure 7. –40°C to 85°C Hysteresis 6660fa 9

LT6660 APPLICATIOUS IUFORWATIOU Output Accuracy Total worst-case output error is: Like all references, either series or shunt, the error budget 0.2% + 0.04% + 0.14% = 0.380% of the LT6660s is made up of primarily three components: Table 2 gives the worst-case accuracy for LT6660HC, initial accuracy, temperature coefficient and load regulation. LT6660JC and LT6660KC from 0°C to 70°C, and shows Line regulation is neglected because it typically contributes that if the LT6660HC is used as a reference instead of a only 150ppm/V. The LT6660s typically shift 0.02% when regulator, it is capable of 8 bits of absolute accuracy over soldered into a PCB, so this is also neglected. The output temperature without a system calibration. errors are calculated as follows for a 100µA load and 0°C to 70°C temperature range: Table 2. Worst-Case Output Accuracy over Temperature I LT6660HCDC LT6660JCDC LT6660KCDC LT6660HCDC OUT 0µA 0.340% 0.540% 0.850% Initial Accuracy = 0.2% 100µA 0.380% 0.580% 0.890% For I = 100µA 10mA 0.640% 0.840% 1.15% OUT 20mA 0.540% 0.740% 1.05% ΔV = (4000ppm/mA)(0.1mA) = 0.04% OUT For Temperature 0°C to 70°C the maximum ΔT = 70°C ΔV = (20ppm/°C)(70°C) = 0.14% OUT 6660fa 10

LT6660 PACKAGE DESCRIPTIOU DC Package 3-Lead Plastic DFN (2mm × 2mm) (Reference LTC DWG # 05-08-1717 Rev Ø) 1.35 ±0.05 (2 SIDES) 1.00 ±0.05 1.30 ±0.05 (2 SIDES) 2.00 ±0.05 PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 1.35 ± 0.05 (2 SIDES) R = 0.05 TYP 1.00 ± 0.05 2.00 ±0.10 (2 SIDES) PIN 1 NOTCH (4 SIDES) R = 0.20 OR PIN 1 BAR TOP MARK 0.25 × 45° CHAMFER (SEE NOTE 6) R = 0.115 TYP 0.40 ±0.05 3 1 0.25 ± 0.05 0.70 ±0.05 0.200 REF 0.75 ±0.05 0.50 BSC BOTTOM VIEW—EXPOSED PAD (DC3) DFN 1205 REV Ø 0.00 – 0.05 NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (W-TBD) 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 6660fa Information furnished by Linear Technology Corporation is believed to be accurate and reliable. 11 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.

LT6660 TYPICAL APPLICATIOU Handling Higher Load Currents V+ 40mA + 3 47µF IN R1* LT6660 10mA 1 OUT VOUT GND 2 RL TCYUPRIRCEANLT L =O A5D0mA *SELECT R1 TO DELIVER 80% OF TYPICAL LOAD CURRENT. LT6660 WILL THEN SOURCE AS NECESSARY TO MAINTAIN R1 = V+ – VOUT PROPER OUTPUT. DO NOT REMOVE LOAD AS OUTPUT WILL 40mA BE DRIVEN UNREGULATED HIGH. LINE REGULATION IS DEGRADED IN THIS APPLICATION 6660 TA02 Boosted Output Current with No Current Limit Boosted Output Current with Current Limit V+ ≥ (VOUT + 1.8V) + V+ ≥ VOUT + 2.8V + R1 47µF D1* R1 8.2Ω 47µF 220Ω LED 220Ω 2N2905 2N2905 3 3 IN IN LT6660 GND OUT 1 + 2SµOFLID V10O0UmTA LGT6N6D60OUT 1 + 2µF V10O0UmTA 2 SOLID TANT 2 TANT *GLOWS IN CURRENT LIMIT, 6660 TA03 DO NOT OMIT 6660 TA04 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1019 Precision Bandgap Reference 0.05% Max, 5ppm/°C Max LT1027 Precision 5V Reference 0.02%, 2ppm/°C Max LT1236 Precision Low Noise Reference 0.05% Max, 5ppm/°C Max, SO Package LT1460 Micropower Series References 0.075% Max, 10ppm/°C Max, 20mA Output Current LT1461 Micropower Precision Low Dropout 0.04% Max, 3ppm/°C Max, 50mA Output Current LT1634 Micropower Precision Shunt Reference 1.25V, 2.5V Output 0.05%, 25ppm/°C Max LT1790 Micropower Precision Series References 0.05% Max, 10ppm/°C Max, 60µA Supply, SOT23 Package LTC®1798 Micropower Low Dropout Reference, Fixed or Adjustable 0.15% Max, 40ppm/°C, 6.5µA Max Supply Current 6660fa 12 Linear Technology Corporation LT 0406 REV A PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com  LINEAR TECHNOLOGY CORPORATION 2006