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Exp.3Voltage Reference

How to get the info you need from a data sheet?

1. Device name (part no.), features and descriptions2. Internal block diagram and pin configuration3. Absolute maximum ratings, recommended operating

conditions

4. Electrical characteristics, typical test circuits5. Performance characteristics6. Typical applications7.

Mechanical dimensions of case

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Voltage Reference TL431 Data sheet p.1

A three-terminal (R, A

and K) adjustable

voltage reference IC

Vo or VKA can be

adjusted to any value betweenVref(2.5 V)

and 36 V

Sink current capability

and TC

Three available cases

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Voltage Reference TL431 Data sheet p.2 - Internal block diagram and equiv. ckt

VREF is about 2.5 V

w.r.t. Anode

VKA can be set to be

equal to or larger than VREF

by external connections.

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Voltage Reference TL431 Data sheet p.2

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Voltage Reference TL431 Data sheet p.3

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Voltage Reference TL431 Data sheet p.4 - Test circuits

For VKA = VREF For VKA VREF

VKA = VREF(1 + R1/R2) + IREFR1

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Voltage Reference TL431 Data sheet p.4 - Test circuits

For IKA(OFF)

The current-limiting R must be designed so thatIKA(MIN) IKA IKA(MAX)

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Voltage Reference TL431 Data sheet p.5 - Performance characteristics

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Voltage Reference TL431 Data sheet p.5 - Performance characteristics

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Voltage Reference TL431 Data sheet p.5 - Performance characteristics

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Voltage Reference TL431 Data sheet p.6 - Typical applications

Shunt regulator

VO =

2R

1R

1 VREF

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Voltage Reference TL431 Data sheet p.6 - Typical applications

Output control for 3-terminal fixed regulator

VO =

2R

1R1 VREF

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Voltage Reference TL431 Data sheet p.6 - Typical applications

High current shunt regulator

VO =

2R

1R1 VREF

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Voltage Reference TL431 Data sheet p.6 - Typical applications

Current source or current limit

IO =CL

REF

R

V

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Voltage Reference TL431 Data sheet p.6 - Typical applications

Constant-current sink

IO =S

REF

R

V

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Experiment 3

1. Use TL431 and design R1, R2 to obtain Vo = 5 V.

RC