LT6656
1µA Precision Series
Voltage Reference
FeaTures
n
DescripTion
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 tem-
perature drift of 10ppm/°C. The combined low power and
precision characteristics are ideal for portable and battery
powered instrumentation.
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.
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.
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.
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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
Ultralow Supply Current: 850nA
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
Thermal Hysteresis: 25ppm
Low Profile (1mm) ThinSOT™ Package
applicaTions
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Precision A/D and D/A Converters
Portable Gas Monitors
Battery- or Solar-Powered Systems
Precision Regulators
Low Voltage Signal Processing
Micropower Remote Sensing
Typical applicaTion
2.503
Output Voltage Temperature Drift
LT6656-2.5
38 TYPICAL UNITS
Basic Connection
2.51V ≤ V
IN
≤ 18V
0.1µF
V
IN
LT6656-2.5
V
OUT
GND
V
OUT
2.5V
1µF
6656 TA01a
2.502
V
OUT
(V)
2.501
2.500
2.499
2.498
–40
–20
0
20
40
TEMPERATURE (°C)
60
80
6652 TA01b
6656fa
LT6656
absoluTe MaxiMuM raTings
(Note 1)
pin conFiguraTion
TOP VIEW
GND* 1
GND 2
NC 3
6 V
OUT
5 NC
4 V
IN
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
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
T
JMAX
= 150°C,
θ
JA
= 230°C/W
*CONNECT PIN TO DEVICE GND (PIN 2)
orDer inForMaTion
LEAD FREE FINISH
LT6656ACS6-1.25#PBF
LT6656BCS6-1.25#PBF
LT6656AIS6-1.25#PBF
LT6656BIS6-1.25#PBF
LT6656ACS6-2.048#PBF
LT6656BCS6-2.048#PBF
LT6656AIS6-2.048#PBF
LT6656BIS6-2.048#PBF
LT6656ACS6-2.5#PBF
LT6656BCS6-2.5#PBF
LT6656AIS6-2.5#PBF
LT6656BIS6-2.5#PBF
LT6656ACS6-3#PBF
LT6656BCS6-3#PBF
LT6656AIS6-3#PBF
LT6656BIS6-3#PBF
LT6656ACS6-3.3#PBF
LT6656BCS6-3.3#PBF
LT6656AIS6-3.3#PBF
LT6656BIS6-3.3#PBF
TAPE AND REEL
LT6656ACS6-1.25#TRPBF
LT6656BCS6-1.25#TRPBF
LT6656AIS6-1.25#TRPBF
LT6656BIS6-1.25#TRPBF
LT6656ACS6-2.048#TRPBF
LT6656BCS6-2.048#TRPBF
LT6656AIS6-2.048#TRPBF
LT6656BIS6-2.048#TRPBF
LT6656ACS6-2.5#TRPBF
LT6656BCS6-2.5#TRPBF
LT6656AIS6-2.5#TRPBF
LT6656BIS6-2.5#TRPBF
LT6656ACS6-3#TRPBF
LT6656BCS6-3#TRPBF
LT6656AIS6-3#TRPBF
LT6656BIS6-3#TRPBF
LT6656ACS6-3.3#TRPBF
LT6656BCS6-3.3#TRPBF
LT6656AIS6-3.3#TRPBF
LT6656BIS6-3.3#TRPBF
PART MARKING*
LTFNK
LTFNK
LTFNK
LTFNK
LTFNN
LTFNN
LTFNN
LTFNN
LTFGW
LTFGW
LTFGW
LTFGW
LTFNQ
LTFNQ
LTFNQ
LTFNQ
LTFNS
LTFNS
LTFNS
LTFNS
PACKAGE DESCRIPTION
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
SPECIFIED TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
6656fa
LT6656
orDer inForMaTion
LEAD FREE FINISH
LT6656ACS6-4.096#PBF
LT6656BCS6-4.096#PBF
LT6656AIS6-4.096#PBF
LT6656BIS6-4.096#PBF
LT6656ACS6-5#PBF
LT6656BCS6-5#PBF
LT6656AIS6-5#PBF
LT6656BIS6-5#PBF
TAPE AND REEL
LT6656ACS6-4.096#TRPBF
LT6656BCS6-4.096#TRPBF
LT6656AIS6-4.096#TRPBF
LT6656BIS6-4.096#TRPBF
LT6656ACS6-5#TRPBF
LT6656BCS6-5#TRPBF
LT6656AIS6-5#TRPBF
LT6656BIS6-5#TRPBF
PART MARKING*
LTFNV
LTFNV
LTFNV
LTFNV
LTFNX
LTFNX
LTFNX
LTFNX
PACKAGE DESCRIPTION
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
SPECIFIED TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–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
OUTPUT VOLTAGE
1.250V
2.048V
2.500V
3.000V
3.300V
4.096V
5.000V
INITIAL ACCURACY
0.05%
0.1%
0.05%
0.1%
0.05%
0.1%
0.05%
0.1%
0.05%
0.1%
0.05%
0.1%
0.05%
0.1%
TEMPERATURE
COEFFICIENT
10ppm/°C
20ppm/°C
10ppm/°C
20ppm/°C
10ppm/°C
20ppm/°C
10ppm/°C
20ppm/°C
10ppm/°C
20ppm/°C
10ppm/°C
20ppm/°C
10ppm/°C
20ppm/°C
0°C to 70°C
ORDER PART NUMBER**
LT6656ACS6-1.25
LT6656BCS6-1.25
LT6656ACS6-2.048
LT6656BCS6-2.048
LT6656ACS6-2.5
LT6656BCS6-2.5
LT6656ACS6-3
LT6656BCS6-3
LT6656ACS6-3.3
LT6656BCS6-3.3
LT6656ACS6-4.096
LT6656BCS6-4.096
LT6656ACS6-5
LT6656BCS6-5
–40°C to 85°C
ORDER PART NUMBER**
LT6656AIS6-1.25
LT6656BIS6-1.25
LT6656AIS6-2.048
LT6656BIS6-2.048
LT6656AIS6-2.5
LT6656BIS6-2.5
LT6656AIS6-3
LT6656BIS6-3
LT6656AIS6-3.3
LT6656BIS6-3.3
LT6656AIS6-4.096
LT6656BIS6-4.096
LT6656AIS6-5
LT6656BIS6-5
**See Order Information section for complete part number listing.
6656fa
LT6656
elecTrical characTerisTics
PARAMETER
Output Voltage Error
Output Voltage Temperature Coefficient (Note 4)
Line Regulation
LT6656A
LT6656B
LT6656A
LT6656B
V
IN
= (V
OUT
+ 0.5V) to 18V
LT6656-2.048, LT6656-2.5, LT6656-3,
LT6656-3.3, LT6656-4.096, LT6656-5
V
IN
= 2.2V to 18V
LT6656-1.25
Load Regulation (Note 5)
I
L
= 5mA, Sourcing
LT6656-2.048, LT6656-2.5, LT6656-3,
LT6656-3.3, LT6656-4.096, LT6656-5
I
L
= 5mA, Sourcing
LT6656-1.25
Dropout Voltage (Note 6)
V
IN
– V
OUT
, ∆V
OUT
Error ≤ 0.1%
I
L
= 0
LT6656-2.048, LT6656-2.5, LT6656-3,
LT6656-3.3, LT6656-4.096, LT6656-5
I
L
= 5mA, Sourcing
LT6656-2.048, LT6656-2.5, LT6656-3,
LT6656-3.3, LT6656-4.096, LT6656-5
Minimum Input Voltage
I
L
= 0, ∆V
OUT
Error ≤ 0.1%
LT6656-1.25
0°C ≤ T
A
≤ 70°C
–40°C ≤ T
A
≤ 85°C
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The
l
denotes the specifications which apply over the specified
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= V
OUT
+ 0.5V (for LT6656-1.25, V
IN
= 2.2V), C
L
= 1μF I
L
= 0,unless
,
otherwise noted.
CONDITIONS
MIN
–0.05
–0.10
5
12
2
TYP
MAX
0.05
0.10
10
20
25
40
25
40
150
375
175
425
10
40
370
500
UNITS
%
%
ppm/°C
ppm/°C
ppm/V
ppm/V
ppm/V
ppm/V
ppm/mA
ppm/mA
ppm/mA
ppm/mA
mV
mV
mV
mV
2
l
65
l
80
l
3
l
250
l
1.35
l
l
1.5
1.6
1.8
1.0
1.5
V
V
V
µA
µA
mA
mA
µA
µA
ppm
P-P
µV
RMS
µV
RMS
µV
RMS
ms
ms
ms
ppm/√kHr
ppm
ppm
Supply Current
l
0.85
Short V
OUT
to GND
Short V
OUT
to V
IN
V
IN
= –18V, V
OUT
= GND
V
IN
= GND, V
OUT
= 18V
0.1Hz to 10Hz
10Hz to 1kHz, LT6656-1.25
10Hz to 1kHz, LT6656-2.5
10Hz to 1kHz, LT6656-5
LT6656-1.25, 0.1% Settling
LT6656-2.5, 0.1% Settling
LT6656-5, 0.1% Settling
∆T = 0°C to 70°C
∆T = –40°C to 85°C
18
4
80
30
30
50
80
140
15
30
60
50
25
70
Output Short Circuit Current
Input Reverse Leakage Current
Reverse Output Current
Output Voltage Noise (Note 7)
Turn-On Time
Long Term Drift of Output Voltage (Note 8)
Hysteresis (Note 9)
6656fa
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:
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.
Typical perForMance characTerisTics
Output Voltage Temperature Drift
10000
CHANGE IN OUTPUT VOLTAGE (ppm)
ALL OPTIONS
9000 25 TYPICAL UNITS
8000 NORMALIZED AT 25°C
C
L
= 1µF
7000 I
L
= 0
6000
5000
4000
3000
2000
1000
0
–1000
–60 –40 –20 0 20 40 60 80 100 120
TEMPERATURE (°C)
200
Typical V
OUT
Distribution
Supply Current vs Input Voltage
100
1.25V OPTION
T
A
= 125°C
T
A
= 85°C
T
A
= 25°C
T
A
= –40°C
T
A
= –55°C
SUPPLY CURRENT (µA)
NUMBER OF UNITS
ALL OPTIONS
180 C
L
= 1µF
I
L
= 0
160 T = 25°C
A
140
120
100
80
60
40
20
0
–0.10
–0.06
–0.02 0 0.02
0.06
OUTPUT VOLTAGE ERROR (%)
0.10
6656 G02
10
1
0.1
0
2
4
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
6656 G17
6652 G01
6656fa
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