POWER MANAGEMENT

1

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SC431L

Low Voltage Adjustable

Shunt Regulator

Description

Features

Revision: May 16, 2008

The SC431L is a three terminal adjustable shunt

regulator with thermal stability guaranteed over

temperature. The output voltage can be adjusted to any

value from 1.24V (V

resistors. The SC431L has a typical dynamic output

impedance of 0.05

Ω. Active output circuitry provides a

very sharp turn on characteristic, making the SC431L an

excellent replacement for zener diodes.

The SC431L shunt regulator is available with four volt-

age tolerances (0.25%, 0.5%, 1.0% and 2.0%), two

operating temperature ranges (commercial and indus-

trial) and two package options (SOT-23-3 and SOT-23-

5). This allows the designer the opportunity to select the

optimum combination of cost and performance for their

application.

Linear Regulators

Adjustable Supplies

Switching Power Supplies

Battery Operated Computers

Instrumentation

Computer Disk Drives

Low voltage operation (down to 1.24V)

Wide operating current range 100µA to 100mA

Low dynamic output impedance 0.05

Ω typ.

Trimmed bandgap design ± 0.25%

Upgrade for TLV431A

SOT-23-3 and SOT-23-5 packages. Also available in

Lead-free package, fully WEEE and RoHS compliant

Notes:

1) Set V

1

R

I

2

R

1

R

1

V

V

REF

REF

OUT

+











 +

=

2) Choose the value for R as follows:

cathode current, I

operating current (100µA) at V

not exceed 100mA under all load conditions, and the

instantaneous turn-on value for I

150mA. Both of the following conditions must be met:

mA

150

V

R

(max)

IN

(to limit instantaneous turn-on I

mA

100

I

V

V

R

(min)

OUT

OUT

(max)

IN

min

+

−

≥

(to limit I

operating conditions)

Applications