Diodes ZR431 User Manual

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Description

The ZR431 is a three terminal adjustable shunt regulator
offering excellent temperature stability and output current
handling capability up to 100mA. T he output voltage may be
set to any chosen voltage between 2.5 and 20 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.

ADJUSTABLE PRECISION ZENER SHUNT REGULATOR

Pin Assignments

V

REF

V

Z

Features

• Surface mount SOT223 and SOT23 packages

• 2%, 1 % and 0.5% tolerance

• Max. temperature coefficient 55 ppm/°C

• Temperature compensated for operation

• over the full temperature range

• Programmable output voltage

• 50μA to 100mA current sink capability

• Low output noise

• All package options available in “Green” Molding

ADVANCE INFORMATION

Compound (No Br, Sb) and Lead Free Finish/ RoHS
Compliant (Note 1)

Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at

http://www.diodes.com/products/lead_free.html.

Applications

• Shunt regulator

• Series regulator

• Voltage monitor

• Over voltage/ under voltage protection

• Switch mode power supplies

(Top View)

3

2

SOT23

1

GND

(Top View

V

1

Z

GND

2

V

3

REF

SOT223

Pin 4 floating or

connected to pin 2

ZR431

4

GND

Typical Application Circuit

V

ZR431

Document number: DS33255 Rev. 6 - 2



REF

+

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V

Z

GND

October 2011

© Diodes Incorporated

ADJUSTABLE PRECISION ZENER SHUNT REGULATOR

Absolute Maximum Ratings (Note 2)

Symbol Parameter Rating Unit

VZ

IZ

TA

TST

PD

Notes: 2. Operation above the absolute maximum rating may cause device failure. Operation at the absolute maximum ratings, for extended periods, may
reduce device reliability. Unless otherwise stated voltages specified are relative to the ANODE pin.

3. T

4. Ratings apply to ambient temperature at 25°C.

Cathode Voltage 20 V

Cathode Current 150 mA
Operating Temperature -40 to +85
Storage Temperature -55 to +125

Power Dissipation (Notes 3, 4)

, max =150°C.

J

SOT23 330 mW
SOT223 2 W

Recommended Operating Conditions (T

= 25°C)

A

Symbol Parameter Min Max Unit

VZ

IZ

ADVANCE INFORMATION

Cathode Voltage
Cathode Current 0.05 100 mA

V

REF

20 V

Electrical Characteristics (T

= 25°C unless otherwise specified)

A

Symbol Parameter Test Conditions Min Typ. Max Unit

Reference voltage (Note 5) 2%

V

1 %

REF

= 10mA (Fig 1), VZ = V

I

L

REF

0.5%

V

ΔV

ΔV

I

REF

ΔI

I

Z(MIN)

I

Z(OFF)

RZ

Note 5: 0.5% and 1% SOT23 only
For definitions of reference voltage temperature coefficient and dynamic output impedance see NOTES following DC TEST CIRCUITS

Deviation of reference input voltage

DEV

over temperature

Ratio of the change in reference

REF

voltage to the change in cathode

Z

voltage

Reference input current
Deviation of reference input current

REF

over temperature
Minimum cathode current for

regulation
Off-state current
Dynamic output impedance

IL = 10mA, VZ = V
TA = Full range (Fig 1)
V

from V

Z

I

= 10mA (fig 2)

Z

REF

to 10V

VZ from 10V to 20V
I

= 10mA (Fig 2)

Z

R1 = 10k, R2 = O/C, IL = 10mA (Fig 2)
R1 = 10k, R2 = O/C, I

= Full range (Fig 2)

T

A

= V

V

Z

VZ = 20V, V
VZ = V

(Fig 1)

REF

REF

(Fig 1), f = 0Hz

REF

REF

= 10mA

L

= 0V (Fig 3)

2.45

2.475

2.487

2.50

2.50

2.50

2.55

2.525

2.513

8.0 17 mV

-1.85 -2.7

-1.0 -2.0

0.12 1.0 μA

0.04 0.2 μA

35 50 µA

0.1 μA

0.75

ZR431

Document number: DS33255 Rev. 6 - 2

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ZR431

°

C

°

C

V

mV/V

Ω

October 2011

DC Test Circuits

Input

I

L

I

REF

V

REF

ZR431

ADJUSTABLE PRECISION ZENER SHUNT REGULATOR

I

I

REF

V

L

REF

V

Z

I

Z

V

Z

I

Z

Input

R1

R2

Input

I

ZOFF

V

Z

Fig. 1 Test Circuit for V

Z

= V

REF

Fig. 2 Test Circuit for VZ > V

Deviation of reference input voltage, V
temperature range.

ADVANCE INFORMATION

The average temperature coefficient of the reference input voltage, V

V

MAX

V = V - V

V

MIN

DEV MAX MIN

, is defined as the maximum variation of the reference input voltage over the full

DEV

REF

is defined as:

REF

Fig.3 Test Circuit for Off State Current

1000000V

ref

o

)C/ppm(V

=

dev

ref

×

−

)2T1T(V

The dynamic output impedance, RZ is defined as:

V

Δ

R

z

z

=

I

Δ

z

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:

′

1R

)

1(RR

+=

z

2R

T1 T2Temperature

ZR431

Document number: DS33255 Rev. 6 - 2

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October 2011

© Diodes Incorporated