3A, 52kHz, Step-Down Switching Regulator

LM2576

Dec 2011 – Rev. 1.3

- 3

-

HTC

PIN CONFIGURATION

SOP8-PP

TO220-5L

TO263-5L

PIN DESCRIPTION

Package

Symbol

Description

TO-220 5L

TO-263 5L

SOP8-PP

1

1

VIN

This pin is the positive input supply for the LM2576 step–down

switching regulator.

In order to minimize voltage transients and to supply the switching

currents needed by the regulator, a suitable input bypass capacitor

must be present. (Cin in Figure 1).

2

2

VOUT

This is the emitter of the internal switch. The saturation voltage

that the PCB area connected to this pin should be kept to a

minimum in order to minimize coupling to sensitive circuitry.

3

6

GND

Circuit ground pin. See the information about the printed circuit

board layout.

4

3

FEEDBACK

This pin senses regulated output voltage to complete the feedback

loop.

The signal is divided by the internal resistor divider network R2, R1

and applied to the non–inverting input of the internal error amplifier.

In the adjustable version of the LM2576 switching regulator this pin

is the direct input of the error amplifier and the resistor network R2,

R1 is connected externally to allow programming of the output

voltage.

5

4

ON/OFF

It allows the switching regulator circuit to be shutdown using logic

level signals, thus dropping the total input supply current to

approximately 80uA.

The threshold voltage is typically 1.4V. Applying a voltage above

this value (up to +Vin) shuts the regulator off. If the voltage applied

to this pin is lower than 1.4V or if this pin is left open, the regulator

will be in the "on" condition

-

5, 7, 8

N.C.

No Connect.

* Exposed Pad of SOP8-PP package should be externally connected to GND.

Exposed

PAD

VIN 1

VOUT 2

FEEDBACK 3

ON/OFF 4

8 N.C

7 N.C

6 GND

5 N.C.