LT6656 1µA Precision Series Voltage Reference Features Description Low Drift A Grade: 10 ppm/°C Max B Grade: 20 ppm/°C Max n High Accuracy A Grade: 0.05% Max B Grade: 0.1% Max n Ultralow Supply Current: 850nA n High Output Drive Current: 5mA Min n Low Dropout Voltage: 10mV Max n Fully Specified from –40°C to 85°C n Operational from –55°C to 125°C n Wide Supply Range to 18V n Reverse Input/Output Protection n Available Output Voltage Options: 2.5V For 1.25V, 2.048V, 3V, 3.3V, 4.096V and 5V Options, Consult LTC Marketing n Thermal Hysteresis: 25ppm n Low Profile (1mm) ThinSOT™ Package The LT®6656 is a small precision voltage reference that draws less than 1µA of supply current and can operate with a supply voltage within 10mV of the output voltage. The LT6656 offers an initial accuracy of 0.05% and temperature drift of 10ppm/°C. The combined low power and precision characteristics are ideal for portable and battery powered instrumentation. n Applications Precision A/D and D/A Converters Portable Gas Monitors n Battery- or Solar-Powered Systems n Precision Regulators n Low Voltage Signal Processing n Micropower Remote Sensing n The LT6656 can supply up to 5mA of output drive with 65ppm/mA of load regulation, allowing it to be used as the supply voltage and the reference input to a low power ADC. The LT6656 can accept a supply voltage up to 18V and withstand the reversal of the input connections. The LT6656 output is stable with 1µF or larger output capacitance and operates with a wide range of output capacitor ESR, ensuring that the LT6656 is simple to use. This reference is fully specified for operation from –40°C to 85°C, and is functional over the extreme temperature range of –55°C to 125°C. Low hysteresis and a consistent temperature drift are obtained through advanced design, processing and packaging techniques. The LT6656 is offered in the 6-lead SOT-23 package. n L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical Application Output Voltage Temperature Drift 2.503 Basic Connection 38 TYPICAL UNITS 2.510V b VIN b 18V 0.1MF VOUT 2.5V LT6656-2.5 1MF 6656 TA01a VOUT (V) 2.502 2.501 2.500 2.499 2.498 –40 –20 0 20 40 TEMPERATURE (°C) 60 80 6652 TA01b 6656f LT6656 Absolute Maximum Ratings Pin Configuration (Note 1) TOP VIEW Input Voltage..............................................................20V Output Voltage............................................ –0.3V to 20V Output Voltage Above Input Voltage........................±20V Specified Temperature Range Commercial.............................................. 0°C to 70°C Industrial..............................................–40°C to 85°C Operating Temperature Range................ –55°C to 125°C Output Short Circuit Duration .......................... Indefinite Junction Temperature ........................................... 150°C Storage Temperature Range (Note 2)...... –65°C to 150°C Lead Temperature (Soldering, 10 sec.) (Note 3).................................................................. 300°C GND* 1 6 VOUT GND 2 5 NC NC 3 4 VIN S6 PACKAGE 6-LEAD PLASTIC TSOT-23 TJMAX = 150°C, θJA = 230°C/W *CONNECT PIN TO DEVICE GND (PIN 2) Order Information LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LT6656ACS6-2.5#PBF LT6656ACS6-2.5#TRPBF LTFGW 6-Lead Plastic TSOT-23 0°C to 70°C LT6656BCS6-2.5#PBF LT6656BCS6-2.5#TRPBF LTFGW 6-Lead Plastic TSOT-23 0°C to 70°C LT6656AIS6-2.5#PBF LT6656AIS6-2.5#TRPBF LTFGW 6-Lead Plastic TSOT-23 –40°C to 85°C LT6656BIS6-2.5#PBF LT6656BIS6-2.5#TRPBF LTFGW 6-Lead Plastic TSOT-23 –40°C to 85°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature and performance grades are identified by a label on the shipping container. Consult LTC Marketing for information on non-standard 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/ Available Options SPECIFIED TEMPERATURE RANGE –40°C to 85°C INITIAL ACCURACY TEMPERATURE COEFFICIENT 0°C to 70°C OUTPUT VOLTAGE ORDER PART NUMBER** ORDER PART NUMBER** 2.5V 0.05% 0.1% 10ppm/°C 20ppm/°C LT6656ACS6-2.5 LT6656BCS6-2.5 LT6656AIS6-2.5 LT6656BIS6-2.5 **See Order Information section for complete part number listing. 6656f LT6656 Electrical Characteristics The l denotes the specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C. VIN = VOUT + 500mV, CL = 1µF, IL = 0, unless otherwise noted. (Note 9) PARAMETER CONDITIONS MIN Output Voltage Error LT6656A LT6656B –0.05 –0.10 Output Voltage Temperature Coefficient (Note 4) LT6656A LT6656B Line Regulation VIN = (VOUT + 0.5V) to 18V l l TYP ISOURCE = 5mA VOUT Error ≤ 0.1% ISOURCE = 0µA ISOURCE = 5mA ppm/°C ppm/°C 2 25 40 ppm/V ppm/V 65 150 375 ppm/mA ppm/mA 3 10 40 500 mV mV mV 0.85 1.0 1.5 µA µA l l Supply Current % % 10 20 l Dropout Voltage (Note 6) UNITS 0.05 0.10 5 12 l Load Regulation (Note 5) MAX l Output Short Circuit Current Sourcing, Short VOUT to GND Sinking, Short VOUT to VIN 18 4 mA mA Input Reverse Leakage Current VIN = -18V, VOUT = GND 35 µA Reverse Output Current VIN = GND, VOUT = 18V 30 µA Output Voltage Noise (Note 7) 0.1Hz to 10Hz 10Hz to 1kHz 60 80 µVP-P µVRMS Turn-On Time 0.1% Settling 25 ms 50 ppm/√kHr 25 70 ppm ppm Long Term Drift of Output Voltage (Note 8) Hysteresis (Note 9) ∆T = 0°C to 70°C ∆T = –40°C to 85°C Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: If the parts are stored outside of the specified temperature range, the output may shift due to hysteresis. Note 3: The stated temperature is typical for soldering of the leads during manual rework. For detailed IR reflow recommendations, refer to the Applications section. Note 4: Temperature coefficient is measured by dividing the maximum change in output voltage by the specified temperature range. Note 5: Load regulation is measured with a pulse from no load to the specified load current. Output changes due to die temperature change must be taken into account separately. Note 6: Excludes load regulation errors. Note 7: Peak-to-peak noise is measured with a 3-pole highpass filter at 0.1Hz and a 4-pole lowpass filter at 10Hz. The unit is enclosed in a still-air environment to eliminate thermocouple effects on the leads. The test time is 10 seconds. RMS noise is measured on a spectrum analyzer in a shielded environment. Note 8: Long term stability typically has a logarithmic characteristic 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 than one third that of the first thousand hours with a continuing trend toward reduced drift with time. Long-term stability will also be affected by differential stresses between the IC and the board material created during board assembly. Note 9: Hysteresis in output voltage is created by mechanical stress that differs depending on whether the IC was previously at a higher or lower temperature. Output voltage is always measured at 25°C, but the IC is cycled to the hot or cold temperature limit before successive measurements. For instruments that are stored at well controlled temperatures (within 20 or 30 degrees of operational temperature) hysteresis is usually not a dominant error source. 6656f LT6656 Typical Performance Characteristics Output Voltage Temperature Drift 200 NUMBER OF UNITS 38 TYPICAL UNITS 2.512 VIN = 3V CL = 1µF 2.510 IL = 0 SPECIFIED TEMPERATURE RANGES INDUSTRIAL COMMERCIAL 2.504 2.502 VIN = 3V 180 CL = 1µF I =0 160 TL = 25°C A 140 120 100 80 60 2.500 40 2.498 20 0 2.496 –60 –40 –20 0 20 40 60 80 100 120 TEMPERATURE (°C) 2.4975 6652 G01 10 TA = 125°C TA = 85°C TA = 25°C TA = –40°C 1µ 10µ 100µ 1m LOAD CURRENT (A) OUTPUT VOLTAGE CHANGE (ppm) DROPOUT VOLTAGE (mV) 100 VIN = 3V CL = 1µF 750 500 250 0 TA = 125°C TA = 85°C TA = 25°C TA = –40°C –250 –500 0.1µ 10m 1µ 10µ 100µ 1m LOAD CURRENT (A) 0 VIN = 3V CL = 1µF –0.5 10µ 100µ 1m LOAD CURRENT (A) 10m 6656 G07 100µ LOAD CURRENT (A) 2.504 TA = 125°C TA = 85°C TA = 25°C TA = –40°C 2.503 2.502 2.501 2.500 2.499 2.498 0 2 4 1m 6656 G06 90 2.505 1 10µ 0.5 Power Supply Rejection Ratio vs Frequency IL = 0 2.506 CL = 1µF OUTPUT VOLTAGE (V) GROUND CURRENT (µA) 10m 1.0 2.507 VIN = 3V CL = 1µF TA = 125°C TA = 85°C TA = 25°C TA = –40°C 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) TA = 85°C, 125°C TA = 25°C TA = 0°C TA = –40°C 1.5 Line Regulation 10 4 6656 G05 Ground Current vs Load Current 100 2 Load Regulation (Sinking) 2.0 6656 G04 1000 0 6656 G03 Load Regulation(Sourcing) 1000 VIN = 3V VIN = VOUT ∆VOUT = 0.1% 1 0.1µ 1 6656 G02 Dropout Voltage 1000 TA = 125°C TA = 85°C TA = 25°C TA = –40°C 10 0.1 2.4985 2.4995 2.5005 2.5015 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE CHANGE (%) 2.506 Supply Current vs Input Voltage 100 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 6656 G08 POWER SUPPLY REJECTION RATIO (dB) VOUT (V) 2.508 Typical VOUT Distribution SUPPLY CURRENT (µA) 2.514 VIN = 3V CL = 1µF IL = 0 80 70 60 50 40 30 20 10 0 10 100 1k FREQUENCY (Hz) 10k 6656 G09 6656f LT6656 Typical Performance Characteristics IL = 10µA 100 IL = 100µA 100 1k FREQUENCY (Hz) 10 1 0 10k TA = 125°C TA = 85°C TA = 25°C TA = –40°C 0 6656 G10 VIN = GND 10 1 –2 –4 –6 –8 –10 –12 –14 –16 –18 –20 INPUT VOLTAGE (V) TA = 125°C TA = 85°C TA = 25°C TA = –40°C 0 5 10 15 OUTPUT VOLTAGE (V) 20 6656 G12 6656 G11 Output Voltage Noise Spectrum vs Load Current Output Noise 0.1Hz to 10Hz 16 VS = 3V CL = 1µF IL = 0 VS = 3V 14 CL = 1µF NOISE VOLTAGE (µV/√Hz) IL = 0 IL = 10µA IL = 250µA IL = 1mA 12 10 8 6 4 2 0 TIME (1s/DIV) 10 6656 G13 100 1k FREQUENCY (Hz) 10k 6656 G14 Output Noise Voltage Spectrum vs Load Capacitance Long-Term Drift 40 VIN = 3V 35 IL = 0 200 VIN = 3V 150 CL = 1µF IL = 0 CL = 47µF 30 LONG TERM DRIFT (ppm) 10 100 VOUT = GND OUTPUT NOISE (20µV/DIV) 10 NOISE VOLTAGE (µV/√Hz) OUTPUT IMPEDANCE (Ω) REVERSE INPUT CURRENT (µA) VIN = 3V CL = 1µF IL = 0 Reverse Output Current Reverse Input Current 100 REVERSE OUTPUT CURRENT (µA) Output Impedance vs Frequency 1k 25 20 CL = 4.7µF 15 CL = 0.47µF 10 5 0 1 10 100 FREQUENCY (Hz) 1k 6656 G15 100 50 0 –50 –100 –150 5 TYPICAL PARTS SOLDERED ONTO PCB –200 0 100 200 300 400 500 600 700 800 900 1000 HOURS 6656 G16 6656f LT6656 Pin Functions GND* (Pin 1): Internal Function. This pin must be tied to ground. GND (Pin 2): Device Ground. NC (Pin 3): Not internally connected. May be tied to VIN, VOUT, GND or floated. VIN (Pin 4): Power Supply. The minimum supply varies with output load and voltage option, see the Dropout Voltage specification in the Electrical Characteristics table. The maximum input voltage is 18V. Bypass VIN with a 0.1µF capacitor to ground. NC (Pin 5): Not internally connected. May be tied to VIN, VOUT, GND or floated. VOUT (Pin 6): Output Voltage. A minimum output capacitor of 1µF is required for stable operation. Block Diagram 4 VIN NC 5 VOUT 6 ERROR AMP BANDGAP NC 3 GND GND 1 2 6656 BD 6656f LT6656 Applications Information Long Battery Life Series references have a large advantage over shunt style references. Shunt references require a resistor from the power supply to operate. This resistor must be chosen to supply the maximum current that can be demanded by the load. When the load is not operating at this maximum current, the shunt reference must always sink this current, resulting in high dissipation and shortened battery life. The LT6656 series reference does not require a current setting resistor and is specified to operate with any supply from VOUT + 10mV to 18V, depending on the load current and operating temperature (see Dropout Voltage in the Typical Performance Characteristics). When the load does not demand current, the LT6656 reduces its dissipation and battery life is extended. If the reference is not delivering load current, it dissipates only a few µW, yet the same connection can deliver 5mA of load current when required. The output of the device requires a capacitance of 1µF or larger. With its low sensitivity to ESR, the LT6656 is stable with a wide variety of capacitor types including ceramic, tantalum and electrolytic. The test circuit in Figure 2 was used to test the response and stability of the LT6656 to various load currents. The 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 description in the Output Settling section. 4 VIN 3V CIN 0.1µF LT6656-2.5 1, 2 R2 6 3V VGEN CL 1µF R1 2N7000 6656 F02 Figure 2. Transient Load Test Circuit 0µA Start-Up IOUT To ensure proper start-up, the output voltage should be between –0.3V and 2.5V. If the output load may be driven more than 0.3V below ground, a low forward voltage schottky diode from the output to ground is required. The turn-on characteristics can be seen in Figure 1. 100µA 2.52V VOUT 2.50V 2.48V Bypass and Load Capacitance The LT6656 voltage reference needs an input bypass capacitor of 0.1µF or larger, however, the bypassing of other local devices may serve as the required component. 5ms/DIV 6656 F03 Figure 3. Transient Response, 0µA to 100µA Load Step (R2 = 24.9k, R1 = Open) 1mA IOUT 2mA VIN 1V/DIV 2.52V VOUT VOUT 2.50V 2.48V 1ms/DIV 6656 F01 Figure 1. Turn-On Characteristics, CL = 1µF 5ms/DIV 6656 F04 Figure 4. Transient Response, 1mA to 2mA Load Step (R1 = R2 = 2.49k) 6656f LT6656 Applications Information 30 OUTPUT SETTLING TIME (ms) VIN 3.25V 2.75V 2.7V VOUT 2.5V 2.3V 5ms/DIV 6656 F05 25 VIN = 3V CL = 1µF 15 ∆IL = LOAD STEP TO 2µA 10 5 0 0.001 Figure 5. Output Response to 0.5VP-P Step on VIN, CL = 1µF, IL = 0 ∆IL = LOAD STEP TO ZERO 20 ∆IL = ZERO TO LOAD STEP 0.01 0.1 LOAD STEP (mA) 1 10 6656 F06 Output Settling Figure 6. Output Settling Time to 0.05% vs Load Step The output of the LT6656 is primarily designed to source current, but is capable of sinking current to aid in output transient recovery. The output stage uses a class B architecture to minimize quiescent current, and has a typical crossover dead band of 6mV as the output transitions from sourcing to sinking current, and twice the deadband as the output transitions from sinking back to sourcing current. The settling time is typically less than 8ms for output loads up to 5mA, however the time required to settle when the load is turned off or in response to an input transient can be significantly longer. Settling time is dominated by the ability of the application circuit to discharge the output capacitor. Larger load currents decrease settling time. The settling time can be estimated by the following equation: Settling time ≈ 2(Deadband)(CL ) + 2ms IL The graph in Figure 6 shows the settling time versus load step with no load and with a constant 2µA load applied. Note the settling time can be longer with load steps that are not large enough to activate the sinking side of the output stage. The photo in Figure 7 shows the output response to a 0.5V input step in both a no-load and 5µA load condition. In the no-load condition only the bias current of the internal bandgap reference (about 400nA) is available to discharge the output capacitor. VIN 3.25V 2.75V IL = 0 VOUT 10mV/DIV IL = 5µA 5ms/DIV 6656 F07 Figure 7. Detailed Output Response to a 0.5V Input Step, CIN = CL = 1µF Output Noise In general, output noise in the LT6656 is proportional to the bandwidth of the output stage and therefore increases with higher load current and lower output capacitance. However, peaking in the noise response may be the dominant factor in determining the output noise level. Noise peaking can be reduced by increasing the size of the output capacitor when driving heavier loads, or conversely, reducing the size of the output capacitor when driving lighter loads. Noise plots may be found in the Typical Performance Characteristics section. Internal Protection The LT6656 incorporates several internal protection features that make it ideal for use in battery powered systems. Reverse input protection limits the input current to typically less than 40µA when either the LT6656 6656f LT6656 Applications Information 30 Hysteresis Hysteresis on the LT6656 is measured in two steps, for 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. This two-step cycle is repeated several times and the maximum hysteresis from all the partial cycles is noted. Unlike other commonly used methods for specifying hysteresis, this ensures the worst-case hysteresis is included, whether it occurs in the first temperature excursion or the last. Results over both commercial and industrial temperature ranges are shown in Figure 8 and Figure 9. As expected, the parts cycled over the higher temperature range have a higher hysteresis than those cycled over the lower range. Power Dissipation The LT6656 will not exceed the maximum junction temperature when operating within its specified temperature range of –40°C to 85°C, maximum input voltage of 18V and specified load current of 5mA. 20 15 10 5 Long-Term Drift 0 –60 –40 –20 0 20 HYSTERESIS (ppm) 40 60 6656 F08 Figure 8. 0°C to 70°C Hysteresis 20 –40°C TO 25°C 85°C TO 25°C 18 16 NUMBER OF UNITS Long-term drift cannot be extrapolated from accelerated high temperature testing. This erroneous technique gives drift numbers that are wildly optimistic. A more realistic way to determine long-term drift is to measure it over the time interval of interest. The LT6656 drift data was taken over 100 parts that were soldered into PC boards similar to a real world application. The boards were then placed into a constant temperature oven with TA = 30°C, their outputs scanned regularly and measured with an 8.5 digit DVM. The parts chosen in the Long Term Drift curves in the Typical Performance Characteristics section represent high, low and typical units. 0°C TO 25°C 70°C TO 25°C VIN = 3V CL = 1µF 25 IL = 0 NUMBER OF UNITS or the battery is installed backwards. In systems where the output can be held up by a backup battery with the input pulled to ground, the reverse output protection of the LT6656 limits the output current to typically less than 30µA. Should the output be pulled above the input when the LT6656 is biased, the output will typically sink 4mA. The current versus reverse voltage is shown in the Typical Performance Characteristics section. VIN = 3V CL = 1µF IL = 0 14 12 10 8 6 4 2 0 –160 –120 –80 –40 0 40 80 120 160 HYSTERESIS (ppm) 6656 F09 Figure 9. –40°C to 85°C Hysteresis IR Reflow Shift The different expansion and contraction rates of the materials that make up the LT6656 package induce small stresses on the die that can cause the output to shift during IR reflow. Common lead free IR reflow profiles reach over 250°C, considerably more than lead solder profiles. The higher reflow temperature of the lead free parts exacerbates the issue of thermal expansion and contraction causing the output shift to generally be greater than with a leaded reflow process. The lead free IR reflow profile used to experimentally measure the output voltage shift in the LT6656-2.5 is shown in Figure 10. Similar results can be expected using a convection reflow oven. Figure 11 shows the change in output voltage that was measured for parts that were 6656f LT6656 Applications Information 300 380s TP = 260°C TL = 217°C TS(MAX) = 200°C 225 TS = 190°C run through the reflow process for 1 cycle and also 3 cycles. The results indicate that the standard deviation of the output voltage increases with a positive mean shift of 120ppm. While there can be up to 220ppm of output voltage shift, additional drift of the LT6656 after IR reflow does not vary significantly. RAMP DOWN tP 30s T = 150°C 150 tL 130s RAMP TO 150°C 75 PC Board Layout 40s 120s 0 0 2 4 6 MINUTES 8 The mechanical stress of soldering a surface mount voltage reference to a PC board can cause the output voltage to shift and temperature coefficient to change. 10 6656 F10 Figure 10. Lead Free Reflow Profile Due to IR Reflow 7 NUMBER OF UNITS To reduce the effects of stress-related shifts, position the reference near the short edge of the PC board or in a corner. In addition, slots can be cut into the board on two sides of the device. See Application Note AN82 for more information. http://www.linear.com 3 CYCLES 1 CYCLE VIN = 3V CL = 1µF 6 I =0 L 5 4 The input and output capacitors should be mounted close to the package. The GND and VOUT traces should be as short as possible to minimize the voltage drops caused by load and ground currents. Excessive trace resistance directly impacts load regulation. 3 2 1 0 0 20 60 100 140 180 220 CHANGE IN OUTPUT VOLTAGE (ppm) 6656 F11 Figure 11. Output Voltage Shift Due to IR Reflow, Peak Temperature = 260°C Typical Applications Regulator Reference The robust input and output of the LT6656 along with its high output current make it an excellent precision low power regulator as well as a reference. The LT6656 would be a good match with a small, low power microcontroller. Using the LT6656 as a regulator reduces power consumption, decreases solution size and increases the accuracy of the microcontroller’s on board ADC. Microcontroller Reference and Regulator IN 3V TO 18V C13 0.1µF OUT LT6656 C12 10µF MCU VCC/VREF PB0/AIN0/AREF/MOSI PB1/INT0/AIN1/MISO/OC1A PB2/ADC1/SCK/T0/INT0 PB3/ADC2 PB4/ADC3 PB5/RESET/ADC0 5 6 7 2 3 1 GND 6656 TA02 6656f 10 LT6656 Typical Applications Boosted Output Current Reference Extended Supply Range Reference VIN UP TO 160V 3.6V TO 18V R3 330k R5 2207 R4 4.7k D1 BZX584C12 + 10µF Q2 MMBT5551 LT6656 C4 0.1µF LT6656 6656 TA03 C3 1µF Q3 2N2905 C5 1µF VOUT VOUT 40mA MAX 6656 TA04 Package Description S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 0.62 MAX 2.90 BSC (NOTE 4) 0.95 REF 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 6 PLCS (NOTE 3) 0.95 BSC 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 (NOTE 3) 1.90 BSC 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 S6 TSOT-23 0302 REV B 6656f 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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 11 LT6656 Typical Application ADC Reference IN 3V TO 18V LT6656 OUT C1 1µF C2 0.1µF TO MCU CS SCK SDO VREF VCC IN– LTC2452 R16 10k R17 10k RT7 10k –tc° R19 10k C10 0.1µF IN+ C11 0.1µF 6656 TA05 Related Parts PART NUMBER DESCRIPTION LT1389 Nanopower Precision Shunt Voltage Reference 0.05% Max 10ppm/°C Max, 800nA Supply COMMENTS 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 Reference 0.05% Max, 10ppm/°C Max Drift, 1.25V, 2.5V, 4.096V, 5V, 10µA Maximum Supply 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 Package 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 with 40mV Reference 6.5µA Supply Current, 1.4V Minimum Operating Voltage 6656f 12 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LT 0210 • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2010