1

Rev. B Date:01/20/04

SPX2945 400mA Low Dropout Voltage Regulator with Shutdown

©Copyright 2004 Sipex Corporation

SPX2945

DESCRIPTION

FEATURES

■ Output 3.3V, 5.0V at 400mA Output

■ Very Low Quiescent Current, 100µA

■ Low Dropout Voltage, 420mV at 400mA

■ Extremely Tight Load and Line Regulation

■ Very Low Temperature Coefficient

■ Current & Thermal Limiting

■ Error Flag Warns Of Output Dropout

■ Logic-Controlled Electronic Shutdown

■ Output Programmable From 1.24V to 20V

(for SO-8)

®

The SPX2945 is a low power voltage regulator. This device is an excellent choice for use in battery-powered

applications such as cordless telephones, radio control systems, and portable computers. The SPX2945

features very low quiescent current (100µA Typ.) and very low dropout voltage. This includes a tight initial

tolerance of 1% max and very low output temperature coefficient, making the SPX2945 useful as a low-

power voltage reference.

The error flag output feature is used as power-on reset for warning of a low output voltage, due to a falling

voltage input of batteries. Another feature is the logic-compatible shutdown input which enables the

regulator to be switched on and off. The SPX2945 is offered in 3-pin TO-220 package, SO-8 (same pin

out as SPX2951), SOT-223, surface mount 3-Pin TO-252, 3-Pin TO-263 packages and 5-Pin TO-263.

The regulator output voltage (of the 8-pin SO-8) may be pin-strapped for a 3.3V and 5.0V or programmed

from 1.24V to 20V with an external pair of resistors. Look for SPX2951 for 150mA and SPX2954 for 250mA

applications.

400mA Low Dropout Voltage Regulator with Shutdown

TO-220-3 (U)

123

V

IN

V

OU

GN

SPX2945

13

25

4

SPX2945

5 Pin TO-263

13

2

SOT-223 (M3)

V

IN

GN

V

OU

SPX2945

2

1

3

4

8

7

6

5

8-Pin Surface Mount

V

OU

SENS

SHUTDOWN

GN

V

IN

FEEDBACK

5V/ 3.3V TAP

ERRO

SPX2945

TO-252 (R)

1

23

V

IN

V

OU

GN

SPX2945

TO-263-5

V

IN

TO-263-3 (T)

V

OU

GN

SPX2945

3

2

1

(S)

(T5)

100K

ERROR

______

SD

V

OUT

GND

FB

+V

IN

0.01µF

3

8

1

4

7

SHUTDOWN

INPUT

SPX2945

OFF

ON

+V

IN

5

10µF

V

REF

R

2

R

1

+

ERROR

OUTPUT

1.2V to 20V

+

2.2 µF

+

SPX2945

V

IN

5V

IN

GND

OUT

0.1 µF

Adjustable Regulator

5V Regulator Circuit