AIM AT431Z, AT431X, AT431UT, AT431UN, AT431C Datasheet

AT431

Low-Voltage Adjustable Precision

Shunt Regulator

Features

˙Low-Voltage Operation: Down to 1.24V
˙1% Reference-Voltage Tolerance
˙Adjustable Output Voltage, Vo=V
˙Low Operational Cathode Current….50μA
˙0.25Ω Typical Output Impedance
˙SOT-23-3 , SOT-23-5 and TO-92 Packages

ref to 12V

Application

˙Linear Regulators
˙Voltage Reference for Power Circuit

Block Diagram and Symbol

Description

The AT431 is low-voltage three-terminal
adjustable voltage reference with specified
thermal stability over applicable commercial
temperature ranges. Output voltage may be set to
any value between V

two external resistors (see Figure 2).

When used with an optocoupler, the AT431 is
ideal voltage reference in isolated feedback
circuits for 1.8V to 12 V switching-mode power
supplies. This device has typical output
impedance of 0.20Ω. Active output circuitry
provides a very sharp turn-on characteristic,
making the AT431 excellent replacements for
low-voltage zener diodes in many applications,
including onboard regulation and adjustable
power supplies.

(1.24V) and 12V with

ref

2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: [phone] WWW: http://www.aimtron.com.tw
Fax: [phone] Email: [e-mail]

1

AT431

Low-Voltage Adjustable Precision

Shunt Regulator

Equivalent Schematic

Pin Assignments

Ordering Information

Part number Package Marking

AT431Z TO-92

AT431X SOT-25
AT431UN SOT-23
AT431UT SOT-23

AT431C SOT-89

: Data Code

*

Z
X
N
T
C

2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: [phone] WWW: http://www.aimtron.com.tw
Fax: [phone] Email: [e-mail]

2

AT431

Low-Voltage Adjustable Precision

Shunt Regulator

Absolute maximum ratings (TA = 25oC)

Parameter Symbol Limits unit

Cathode voltage

V
Continuous cathode current range

Reference Current

I

Operating temperature T
Storage temperature T
Package thermal impedance θ

JA

SOT-23-5
SOT-23-3

TO-92 156

KA

I

K

REF

OPR

STG

12 V

-20~20 mA

-0.05~3 mA

-30~+85

-55~+150
347

o

C / W

o

C

o

C

Power Dissipation PD

Stresses beyond those listed under “ absolute maximum ratings” may cause permanent damage to the
device. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

(TJ(max)-TA)/ θ

Recommend operating condtion

Parameter min Max unit
Cathode voltage V

Continuous cathode current range I
Operating free-air temperature range T

Electrical characteristics (

KA

K

A

unless otherwise noted

Parameter Symbol Min. Typ. Max. Unit Conditions

TA = 2 5oC

V

V

deviation over full

ref

(

ref

TA = f ull

V

(

ref

range 0~70

V

ref(dev)

) 1.228 1.24 1.252 VReference Voltage

1.221 - 1.259 V

o

C)

temperature range

Ratio of V

change in

ref

∆ V

ref

/∆ V

KA

cathode voltage change

Reference terminal

I

ref

current

I

deviation over full

ref

I

ref(dev)

temperature range
Minimum cathode current

I

K(min)

for regulation
Off-state cathode current

Dynamic impedance

* The dynamic impedance is defined as : |ZKA| = ∆ VKA /∆ I

I

K(off)

| Z

KA

|

Vref 12 V

0.05 15 mA

070oC

)

VKA= V
IK=10mA

-420mVVKA= V
IK=10mA

- -1.5 -2.7 mV/V VKA= V
IK=10mA

- 0.15 0.5

- 0.05 0.3

-4050

-0.0010.1

- 0.20 0.4

KA

IK=10mA

µA

R1=10KΩ

µAIK=10mA R1=10KΩ

R2=open
VKA= V

µA

VKA=12V

µA

V

=0V

ref

VKA= V

Ω

IK=0.1mA to 15mA

(Figure 1)

JA

ref

(Figure 1)

ref

(Figure 1)

ref to 12V

(Figure 2)

(Figure 2)

(Figure 2)

(Figure 1)

ref

(Figure 3)

ref f≤1KHz

2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: [phone] WWW: http://www.aimtron.com.tw
Fax: [phone] Email: [e-mail]

3

AT431

Low-Voltage Adjustable Precision

Shunt Regulator

Parameter Measurement Information

Figure 1. Test Circuit for VKA=V

VO= VKA=V

ref

Figure 3. Test Circuit for I

ref

Figure 2. Test Circuit for VKA>V

VO= VKA=V

K(off)

*(1+R1/R2)+I

ref

ref *

ref

R1

2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: [phone] WWW: http://www.aimtron.com.tw
Fax: [phone] Email: [e-mail]

4

AT431

Low-Voltage Adjustable Precision

Shunt Regulator

Figure 4. Figure 5.

Figure 6. Figure 7.

2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: [phone] WWW: http://www.aimtron.com.tw
Fax: [phone] Email: [e-mail]

5