Datasheet

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LT6656

6656fc

For more information www.linear.com/LT6656

TYPICAL APPLICATION

Output Voltage Temperature Drift

TEMPERATURE (°C)

–40

2.498

2.499

OUT

(V)

2.500

2.501

2.502

2.503

–20 0 20 40

6652 TA01b

60 80

38 TYPICAL UNITS

LT6656-2.5

Basic Connection

DESCRIPTION

1µA Precision Series

Voltage Reference

The LT

6656 is a tiny 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 tem

perature drift of 10ppm/°C. The combined low power and

precision characteristics are ideal for portable and battery

powered instrumentation.

The L

T6656 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.

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, (2mm ×

2mm) DFN, and 8-lead LS8 Packages. The LS8 is a 5mm

× 5mm surface mount hermetic package that provides

outstanding stability.

FEATURES

APPLICATIONS

Ultralow Supply Current: 850nA

Low Drift

A Grade: 10 ppm/°C Max

B Grade: 20 ppm/°C Max

High Accuracy

A Grade: 0.05% Max

B Grade: 0.1% Max

Long-Term Drift: 15ppm/√kHr (LS8 Package)

No Humidity Sensitivity (LS8 Package)

High Output Drive Current: 5mA Min

Low Dropout Voltage: 10mV Max

Fully Speciﬁed from –40°C to 85°C

Operational from –55°C to 125°C

Wide Supply Range to 18V

Reverse Input/Output Protection

Available Output Voltage Options:

1.25V, 2.048V, 2.5V, 3V, 3.3V, 4.096V and 5V

Available in Low Proﬁle (1mm) ThinSOT™,

(2mm × 2mm) DFN and High Stability Hermetic

(5mm ×

5mm) LS8 Packages

Precision A/D and D/A Converters

Portable Gas Monitors

Battery- or Solar-Powered Systems

Precision Regulators

Low Voltage Signal Processing

Micropower Remote Sensing

2.51V ≤ V

≤ 18V

0.1µF 1µF

OUT

2.5V

6656 TA01a

LT6656-2.5

OUT

GND

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property

of their respective owners.

Summary of content (24 pages)

PAGE 1
LT6656 1µA Precision Series Voltage Reference DESCRIPTION FEATURES n n n n n n n n n n n n n Ultralow Supply Current: 850nA Low Drift A Grade: 10 ppm/°C Max B Grade: 20 ppm/°C Max High Accuracy A Grade: 0.05% Max B Grade: 0.
PAGE 2
LT6656 ABSOLUTE MAXIMUM RATINGS (Note 1) Input Voltage............................................................±20V Output Voltage............................................ –0.3V to 20V Output Voltage Above Input Voltage..........................20V Specified Temperature Range (Note 2) Commercial.............................................. 0°C to 70°C Industrial..............................................–40°C to 85°C Operating Temperature Range (Note 2)..
PAGE 3
LT6656 ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL (MINI) TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION LT6656ACS6-4.096#TRMPBF LT6656ACS6-4.096#TRPBF LTFNV 6-Lead Plastic TSOT-23 LT6656BCS6-4.096#TRMPBF LT6656BCS6-4.096#TRPBF LTFNV 6-Lead Plastic TSOT-23 LT6656AIS6-4.096#TRMPBF LT6656AIS6-4.096#TRPBF LTFNV 6-Lead Plastic TSOT-23 LT6656BIS6-4.096#TRMPBF LT6656BIS6-4.
PAGE 4
LT6656 AVAILABLE OPTIONS SPECIFIED TEMPERATURE RANGE OUTPUT VOLTAGE 1.250V 2.048V 2.500V 3.000V 3.300V 4.096V 5.000V INITIAL ACCURACY TEMPERATURE COEFFICIENT 0°C TO 70°C –40°C TO 85°C ORDER PART NUMBER* ORDER PART NUMBER* 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.
PAGE 5
LT6656 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C. VIN = VOUT + 0.5V (for LT6656-1.25, VIN = 2.2V), CL = 1μF, IL = 0,unless otherwise noted. PARAMETER CONDITIONS MIN Output Voltage Error LT6656ACS6, LT6656AIS6, LT6656AILS8 LT6656BCS6, LT6656BIS6, LT6656BILS8 LT6656ACDC, LT6656AIDC LT6656BCDC, LT6656BIDC –0.05 –0.1 –0.1 –0.
PAGE 6
LT6656 ELECTRICAL CHARACTERISTICS 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: The LT6656C is guaranteed to meet specified performance from 0°C to 70°C. The LT6656C is designed, characterized and expected to meet specified performance from –40°C to 85°C but is not tested or QA sampled at these temperatures.
PAGE 7
LT6656 TYPICAL PERFORMANCE CHARACTERISTICS Minimum Supply Voltage vs Load Current Supply Current vs Input Voltage VON 1 2.5V OPTION SHOWN VON MOVES WITH VOLTAGE OPTION 0.1 0 2 4 1.25V OPTION INITIAL VIN = 2.2V 1.8 ∆VOUT = 0.1% 1.6 1.4 1.2 TA = 125°C TA = 85°C TA = 25°C TA = –40°C TA = –55°C 1.0 0.8 0.
PAGE 8
LT6656 TYPICAL PERFORMANCE CHARACTERISTICS Output Impedance vs Frequency 100 10 1.25V OPTION 2.5V OPTION 5V OPTION 1k 100 FREQUENCY (Hz) 1k 100 10 1 10k IL = 0, CL = 1µF IL = 0, CL = 10µF IL = 100µA, CL = 1µF IL = 100µA, CL = 10µF 10 1k 100 FREQUENCY (Hz) 6656 G21 TA = 125°C TA = 85°C TA = 25°C TA = –55°C 0 1 ALL OPTIONS VIN = GND TA = 125°C TA = 85°C TA = 25°C TA = –55°C 0 5 10 15 OUTPUT VOLTAGE (V) 15 10 2.
PAGE 9
LT6656 TYPICAL PERFORMANCE CHARACTERISTICS Integrated 10Hz to 1kHz Noise vs Load Current 250 VIN = VOUT + 0.5V CL = 1µF 400 300 5V OPTION 200 2.5V OPTION 100 INTEGRATED NOISE (µVRMS) INTEGRATED NOISE (µVRMS) 500 Integrated 10Hz to 1kHz Noise vs Load Current 2.5V OPTION 200 150 100 CL = 0.47µF CL = 1µF CL = 10µF CL = 47µF 50 1.25V OPTION 0 0.1µ 1µ 10µ 100µ LOAD CURRENT (A) 1m 0 0.
PAGE 10
LT6656 PIN FUNCTIONS (TSOT-23/DFN) (LS8) GND* (Pin 1/Pin 3): Internal Function. This pin must be tied to ground. NC (Pins 1, 2, 7): Not Internally Connected. May be tied to VIN, VOUT, GND or floated. 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 VIN, VOUT, GND or floated. VIN (Pin 4/Pin 6): Power Supply.
PAGE 11
LT6656 APPLICATIONS INFORMATION Long Battery Life Output Voltage Options 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.
PAGE 12
LT6656 APPLICATIONS INFORMATION 0µA IOUT 100µA 2.52V VOUT 2.50V 2.48V 5ms/DIV 6656 F03 Figure 3. Transient Response, 0µA to 100µA Load Step (R2 = 24.9k, R1 = Open) 1mA IOUT 2mA In application circuits where the LT6656 is experiencing a load step greater than 5µA, such as an ADC reference and supply implementation, the settling time will typically remain less than 8ms, regardless of the output settling from a previous load step. The settling time can be estimated by the following equation: 2.52V VOUT 2.
PAGE 13
LT6656 APPLICATIONS INFORMATION VIN 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. The current versus reverse voltage is shown in the Typical Performance Characteristics section. 3.25V 2.75V IL = 0 VOUT 10mV/DIV Long-Term Drift IL = 5µA 5ms/DIV 6656 F07 Figure 7. Detailed Output Response to a 0.
PAGE 14
LT6656 APPLICATIONS INFORMATION 30 20 0°C TO 25°C 70°C TO 25°C 1.25V OPTION VIN = 2V CL = 1µF IL = 0 –40°C TO 25°C 85°C TO 25°C 15 20 NUMBER OF UNITS NUMBER OF UNITS 2.5V OPTION VIN = 3V 25 CL = 1µF IL = 0 15 10 10 5 5 0 –60 –40 –20 0 20 HYSTERESIS (ppm) 40 0 60 6656 F08 Figure 8. LT6656 S6, DC 0°C to 70°C Hysteresis 20 –40°C TO 25°C 85°C TO 25°C 18 NUMBER OF UNITS 16 12 10 8 6 4 2 –160 –120 –80 –40 0 40 80 120 160 HYSTERESIS (ppm) 6656 F09 Figure 9.
PAGE 15
LT6656 APPLICATIONS INFORMATION NUMBER OF UNITS 7 2.5V OPTION VIN = 3V 6 C = 1µF L IL = 0 5 short as possible to minimize the voltage drops caused by load and ground currents. Excessive trace resistance directly impacts load regulation. SOT-23 3 CYCLES 1 CYCLE Humidity Sensitivity 4 3 2 1 0 0 20 60 100 140 180 220 CHANGE IN OUTPUT VOLTAGE (ppm) 6656 F13 Figure 13. ∆VOUT Due to IR Reflow, Peak Temperature = 260°C, SOT-23 NUMBER OF UNITS 10 2.
PAGE 16
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.
PAGE 17
LT6656 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. only 27.4µA.
PAGE 18
LT6656 TYPICAL APPLICATIONS Extended Supply Range Reference VCC UP TO 160V 330k MMBT5551 BZX584C12 0.1µF 2.2µF IN VOUT OUT LT6656-2.5 1µF 6656 TA03 Boosted Output Current Reference 3.6V ≤ VCC ≤ 18V 220Ω + 10µF 2N2905 0.1µF IN VOUT 40mA MAX OUT LT6656-2.5 1µF 6656 TA04 Micropower Regulator, IQ = 2µA, Sink Up to 8mA 3V ≤ VCC ≤ 18V IN LT6656-2.5 + OUT 0.1µF 1µF 2.5V LT6003 – 6656 TA06 ADC Reference and Bridge Excitation Supply 3.8V ≤ VIN ≤ 18V IN 0.1µF LT6656-3.3 3.3V ≤ VCC ≤ 5.
PAGE 19
LT6656 TYPICAL APPLICATIONS Low Power Precision High Voltage Supply Monitor, IQ = 1.4µA, High Voltage Supply Load = 10µA 100V 105V OVERVOLTAGE THRESHOLD VCC 9.53M 3 + 4 – 6.5V ≤ VCC ≤ 10V IN LT6656-5 OUT 0.1µF 1µF 475k 7 OVERVOLTAGE FLAG LTC1540 5 6 1, 2 6656 TA08 2-Terminal Current Source + + IN LT6656-1.25 GND 0.1µF OUT VREF LT6003 R1 – 1µF R2 R3 – IOUT = 6656 TA09 VREF  R2  +1 R1  R3  Precision Current and Boosted Reference, IQ = 5.
PAGE 20
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) 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) NOTE: 1.
PAGE 21
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 ±0.05 0.61 ±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 TYP 0.56 ±0.05 (2 SIDES) 0.40 ±0.10 4 6 2.00 ±0.10 (4 SIDES) PIN 1 BAR TOP MARK (SEE NOTE 6) PIN 1 NOTCH R = 0.20 OR 0.
PAGE 22
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 0.5 2 6 2.54 ±0.15 1.4 3 1.50 ±0.15 0.70 ±0.05 × 8 e4 XYY ZZ ABCDEF Q12345 4 COMPONENT PIN “A1” 5.00 SQ ±0.15 5.80 SQ ±0.15 TRAY PIN 1 BEVEL APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 5.00 SQ ±0.15 1.45 ±0.10 0.95 ±0.10 4.20 SQ ±0.
PAGE 23
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.
PAGE 24
LT6656 TYPICAL APPLICATION Reference Regulator for Micropower DAC, Total IQ = 4.8µA 5.1V ≤ VIN ≤ 18V IN LT6656-5 OUT 5V 0.1µF 10µF VREF VCC CS SCK SDI DAC A 0V TO 5V OUTPUT DAC B 0V TO 5V OUTPUT LTC1662 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.