Zetex (Now Diodes) ZR431LC01L, ZR431LC02L, ZR431LF01TA, ZR431LF02TA Schematic [ru]

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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

Reel size

TOL %

 

 

 

 

per reel

(inches)

 

 

 

 

 

 

 

 

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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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ZR431L

Absolute maximum ratings

 

 

 

Parameter

Symbol

Limit

Unit

Cathode voltage

VZ

10

V

Cathode current

 

50

mA

Storage temperature

TSTG

-55 to 105

°C

Junction temperature

TJ

-40 to 125

°C

Power dissipation (at Tamb = 25°C unless otherwise stated)

 

Package

 

Value

Unit

SOT23

 

330

mW

Recommended operating conditions

 

 

 

Parameter

 

Min.

Max.

Cathode voltage

 

VREF

10V

Cathode current

 

100 A

25mA

Operating temperature

 

-40°C

85°C

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ZR431L

Block diagram

Deviation of reference input voltage, Vdev, is defined as the maximum variation of the reference input voltage over the full temperature range.

The average temperature coefficient of the reference input voltage, Vref is defined as:

Vref( ppmIC) = Vdevx1000000

Vref (T1 T2)

The dynamic output impedance, Rz, is defined as:

RZ

=

VZ

IZ

 

 

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:

R'= RZ (1+ RR12)

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ZR431L

Electrical characteristics (at Tamb = 25°C unless otherwise stated)

Parameter

Symbol

Min.

Typ.

Max.

Unit

Conditions

 

 

 

 

 

 

 

 

 

Reference Voltage 2.5%

Vref

1.209

1.24

1.271

V

IL = 10mA (Fig1), VZ = Vref

1.0%

V

1.228

1.24

1.252

V

 

 

 

ref

 

 

 

 

 

Deviation of Reference

Vdev

 

4.0

8.0

mV

IL = 10mA, VZ = Vref

Input Voltage over

 

 

 

 

 

 

 

Ta = full range (Fig 1)

Temperature

 

 

 

 

 

 

 

 

Ratio of the change in

 

Vref

 

 

0.5

2.0

mV/V

VZ from Vref to 10V

Reference Voltage to the

 

 

 

 

 

IZ = 10mA (Fig2)

change in Cathode

 

VZ

 

 

 

 

 

 

 

 

 

 

Voltage)

 

 

 

 

 

 

 

 

Reference Input Current

Iref

0.02

0.11

0.4

A

R1 = 10k, R2 = O/C,

 

 

 

 

 

 

 

 

lL = 10mA (fig2)

Deviation of Reference

Iref

 

0.02

0.2

A

R1 = 10k, R2 = O/C,

Input Current over

 

 

 

 

 

 

 

IL = 10mA Ta = full

Temperature

 

 

 

 

 

 

 

range (Fig2)

 

 

 

 

 

 

 

 

 

Minimum Cathode

IZmin

 

30

100

A

 

Current for Regulation

 

 

 

 

 

 

 

 

Off-state Current

IZoff

 

10

30

A

VZ = 10V, Vref = 0V

 

 

 

 

 

 

 

 

(Fig3)

Dynamic Output

RZ

 

0.25

2

Ω

VZ = Vref(Fig1), f = 0Hz,

Impedance

 

 

 

 

 

 

 

IL = 10mA

DC Test circuits

Fig 1 - Test Circuit for VZ = Vref Fig 2 - Test Circuit for VZ > Vref Fig 3 - Test Circuit for Off State current

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