Diodes AS431 User Manual

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Description

The AS431 is a three-terminal adjustable shunt regulator with guaranteed thermal stability over a full operation range. It features sharp turn-on characteristics, low temperature coefficient and low output impedance, which make it ideal substitute for Zener diode in applications such as switching power supply, charger and other adjustable regulators.

The output voltage of AS431 can be set to any value between VREF (2.5V) and the corresponding maximum cathode voltage (36V).

The AS431 precision reference is offered in two voltage tolerance:

0.5% and 1.0%.

This IC is available in 4 packages: TO-92 (bulk or ammo packing), SOT-23, SOT-23-5 and SOT-89.

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ADJUSTABLE PRECISION SHUNT REGULATORS

Features

 Programmable Precise Output Voltage from 2.5V to 36V  High Stability under Capacitive Load  Low Temperature Deviation: 4.5mV Typical  Low Equivalent Full-range Temperature Coefficient with

20PPM/°C Typical

 Sink Current Capacity from 1mA to 100mA  Low Output Noise  Wide Operating Range of -40 to +125°C  Lead-Free Packages: SOT-23, SOT-23-5, TO-92, SOT-89

 Totally Lead-Free; RoHS Compliant (Notes 1 & 2)

 Lead-Free Packages, Available in “Green” Molding Compound:

SOT-23, SOT-23-5, TO-92, SOT-89

 Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)  Halogen and Antimony Free. “Green” Device (Note 3)

S431

Applications

 Charger  Voltage Adapter  Switching Power Supply  Graphic Card  Precision Voltage Reference

Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.

2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free.

3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds.

Pin Assignments

N Package R Package R Package

(SOT-23) (SOT-89 Option 1) (SOT-89 Option 2)

123

REF CATHODEANODE

1

REF CATHODEANODE

2

3

K Package Z Package Z Package

(SOT-23-5) (TO-92 (Bulk Packing)) (TO-92 (Ammo Packing

3

CATHODE

2

ANODE

1

REF

Note: 4. * Pin 2 is attached to substrate and must be connected to ANODE or open.

AS431

Document number: DS36599 Rev. 3 - 2

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S431

Typical Applications Circuit

Shunt Regulator

AS431

Document number: DS36599 Rev. 3 - 2

High Current Shunt Regulator

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S431

Typical Applications Circuit

(Cont.)

Current Source or Current Limit

AS431

Document number: DS36599 Rev. 3 - 2

Precision 5V 1A Regulator

PWM Converter with Reference

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S431

Functional Block Diagram

Absolute Maximum Ratings

(Note 5)

Symbol Parameter

V

KA

I

KA

I

REF

PD

TJ

T

STG

ESD ESD (Human Body Model) 2000 V

Note 5: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and

functional operation of the device at these or any other conditions beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability.

Cathode Voltage 40 V

Cathode Current Range (Continuous) -100 to 150 mA

Reference Input Current Range 10 mA

Power Dissipation

Junction Temperature +150 °C

Storage Temperature Range -65 to +150 °C

Z, R Package 770

N, K Package 370

Rating

Recommended Operating Conditions

Unit

mW

Symbol Parameter

V

I

TA

KA

Cathode Voltage

Cathode Current 1.0 100

Operating Ambient Temperature Range -40 +125

Min Max

V

REF

36

Unit

V

mA

°C

AS431

Document number: DS36599 Rev. 3 - 2

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S431

Electrical Characteristics

(Operating Conditions: TA = +25°C, unless otherwise specified.)

Symbol Parameter

V

REF

∆V

REF

∆V

REF

∆VKA

I

REF

∆I

REF

I

KA

(Min)

I

KA

(Off)

Z

KA

θ

JC

Reference Voltage

Deviation of Reference Voltage Over Full Temperature Range

Ratio of Change in Reference Voltage to the Change in Cathode Voltage

Reference Current 5

Deviation of Reference Current Over Full Temperature Range

Minimum Cathode Current for Regulation

Off-state Cathode Current 6

Dynamic Impedance 4

Thermal Resistance –

0.5%

1.0% 2.475 2.500 2.525

Test

Circuit

4

5

4

Conditions Min Typ Max Unit

= V

, I

REF

= 10mA

KA

V

KA

0 to +70°C – 4.5 8

V

= V

REF

= 10mA

,

-40 to +85°C – 4.5 10

KA

I

KA

-40 to +125°C – 4.5 16

= 10V to V

∆V

REF

∆V

= 0

KA

= 36V to 10V

I

= 10mA

KA

I

= 10mA, R1 = 10KΩ, R2 = ∞

KA

= 10mA, R1 = 10KΩ, R2 = ∞,

I

KA

T

= -40 to +125°C

A

V

= V

KA

V

KA

V

KA

REF

= 36V, V

= V

, IKA = 1 to 100mA,

REF

f ≤ 1.0KHz

SOT-23

SOT-23-5

TO-92

SOT-89

REF

2.487 2.500 2.512

– -1.0 -2.7

– -0.5 -2.0

–

0.7 4

0.4 1.2

0.4 1.0

0.05 1.0

0.15 0.5

135.9

81.9

29.8

V

mV

mV/V

µA

mA

µA

Ω

–

°C/W

–

AS431

Document number: DS36599 Rev. 3 - 2

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S431

Electrical Characteristics

(Cont.)

Test Circuit 4 for V

= V

KA

REF

AS431

Document number: DS36599 Rev. 3 - 2

Test Circuit 5 for V

KA

> V

REF

Test Circuit 6 for I

OFF

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