Elektronische Bauelemente

01-Jun-2002 Rev. A

Page 1 of

4

http://www.SeCoSGmbH.com/

Any changing of specification will not be informed individual

RoHS Compliant Product

Typical Circuit

S5U1284

4

A Ultra Low Dropout

Positive Adjustable or Fixed-Mode Regulator

Description

The S5U1284 is 4A regulator with extremely low dropout voltage.

This product is specifically designed to provide well regulated

supply for applications requiring 2.8V or lower voltages from 3.3V

ATX power supplies where high efficiency of the switch can be

achieved without the cost and compliexity associated with

switching regulator. One such application is the new graphic

chipsets that requires anywhere from 2.4V to 2.7V supply.

* Adjustable or Fixed Output Voltage 1.5V,1.8V,2.5V,3.3V,5.0V

Features

*

0.7V Max. Dropout Voltage At 4A Load Current

* Output Current Limiting

* Good Noise Rejection

* Fast Transient Response

* Built-in Thermal Shutdown

Pin Descriptions

Block Diagram

Name

I/O

Description

Adj (Gnd)

A resistor divider from this pin to the Vout pin and ground sets the output voltage. (Gnd only for fixed mode)

Vsense

I

The pin is the positive side of the reference that allows remote load sensing to achieve excellent load

regulation. A minimum of 10uF capacitor must be connected from this pin to ground to insure stability.

Vin

I

The input pin of regulator. Typically a large storage capacitor is connected from this pin to ground to insure

that the input voltage does not sag below the minimum dropout voltage during the load transient response.

This pin must always be higher than Vout in order for the device to regulate.

Vctrl

I

This pin is the supply pin for the internal control circuit as well as the base drive for the pass transistor. This

pin must always by higher than the Vout pin in order the device to regulate. A minimum of 100uF capacitor

must be connected from this pin to ground to insure stability.

Vout

O

The output of the regulator. A minimum of 100uF capacitor must be connected from this pin to ground to

insure stability.

S5U1284-25

Millimeter

REF.

Min.

Max.

REF.

Min.

Max.

A

4.40

4.80

c2

1.25

1.45

b

0.66

0.91

L2

1.27 REF.

L4

0.00

0.30 B D

8.6

9.0

c

0.36

0.5

e

1.70 REF.

L1

2.29

2.79

L

14.6

15.8

E

9.80

10.4

0˚

8˚

Millimeter