LT1431
Programmable Reference
Features
Description
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The LT®1431 is an adjustable shunt voltage regulator
with 100mA sink capability, 0.4% initial reference voltage
tolerance and 0.3% typical temperature stability. On-chip
divider resistors allow the LT1431 to be configured as a
5V shunt regulator, with 1% initial voltage tolerance and
requiring no additional external components. By adding
two external resistors, the output voltage may be set to
any value between 2.5V and 36V. The nominal internal
current limit of 100mA may be decreased by including
one external resistor.
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Guaranteed 0.4% Initial Voltage Tolerance
0.1Ω Typical Dynamic Output Impedance
Fast Turn-On
Sink Current Capability, 1mA to 100mA
Low Reference Pin Current
Available in J8, N8, S8 or 3-Lead TO-92 Z Packages
Applications
Linear Regulators
Adjustable Power Supplies
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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.
A simplified 3-pin version, the LT1431CZ/LT1431IZ, is
available for applications as an adjustable reference and
is pin compatible with the TL431.
Typical Application
Isolated 5V Regulator
+
5V
+
VIN
SWITCHING
REGULATOR
VREF vs Temperature
2.5025
2.5000
–
2.4975
RTOP
V+
COMP
VREF (V)
5V
COLL
2.4950
2.4925
REF
+
2.4900
gm =
4mA/V
2.4875
–50 –25
–
RMID
50
25
75
0
TEMPERATURE (°C)
100
125
LT1431 TA01b
2.5V
LT1431
GND-S
GND-F
LT1431 TA01
1431fe
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