LINER LT6656AIS6-2.5TRPBF 1î¼a precision series voltage reference Datasheet

LT6656
1µA Precision Series
Voltage Reference
Features
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Description
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: 2.5V
For 1.25V, 2.048V, 3V, 3.3V, 4.096V and 5V Options,
Consult LTC Marketing
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
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.
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.
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
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
ISOURCE = 5mA
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
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Current
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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
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