Diodes ZR431L User Manual
ZR431L
Adjustable precision shunt regulator
Summary
Description
The ZR431L is a three terminal adjustable shunt regulator offering excellent
temperature stability and output current handling capability up to 25mA.
The output voltage may be set to any chosen voltage between 1.24 and
10 volts by selection of two external divider resistors.
The devices can be used as a replacement for zener diodes in many
applications requiring an improvement in zener performance.
The ZR431L is particularly used in the feedback control loop of switch mode
power supplies. In this application the device 1.24 volt reference enables
the generation of low voltage supplies, typically 3.3 volts or 3 volts.
Features
• 2.5% and 1% tolerance
• Max. temperature coefficient 50 ppm/°C
• Temperature compensated for operation over -40 to 85°C
• 100mA to 25mA current sink capability
• Surface mount SOT23 package
Applications
• Switch mode power supplies
• Shunt regulator
• Series regulator
• Voltage monitor
• Over voltage / under voltage protection
Ordering information
Device Pack Part mark Status Quantity
per reel
ZR431LF01TA SOT23 43M Active 3000 7 1
ZR431LF02TA SOT23 43L Active 3000 7 2.5
ZR431LC01STOB TO92 ZR431L01 Obsolete 1500 1
ZR431LC02STOB TO92 ZR431L02 Obsolete 1500 2.5
ZR431LC01L TO92 ZR431L01 Obsolete Loose 1
ZR431LC02L TO92 ZR431L02 Obsolete Loose 2.5
Reel size
(inches)
TOL %
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ZR431L
Absolute maximum ratings
Parameter Symbol Limit Unit
Cathode voltage V
Cathode current 50 mA
Storage temperature T
Junction temperature T
Z
STG
J
10 V
-55 to 105 °C
-40 to 125 °C
Power dissipation (at T
Package Value Unit
SOT23 330 mW
= 25°C unless otherwise stated)
amb
Recommended operating conditions
Parameter Min. Max.
Cathode voltage V
Cathode current 100A25mA
Operating temperature -40°C 85°C
REF
10V
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Block diagram
)21(
0
)(
TTV
xV
ppmICVref
ref
dev
−
=
Z
Z
Z
I
V
R
Δ
Δ
=
)
1
1('
R
R
RR
Z
+=
ZR431L
Deviation of reference input voltage, V
the maximum variation of the reference input voltage
over the full temperature range.
The average temperature coefficient of the reference
input voltage, V
is defined as:
ref
, is defined as
dev
100000
The dynamic output impedance, R
When the device is programmed with two external
resistors, R1 and R2, (fig 2), the dynamic output
impedance of the overall circuit, R’, is defined as:
, is defined as:
z
2
Issue 3 - April 2008 3 www.zetex.com
© Zetex Semiconductors plc 2008
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