LM2576BM

6/9

APPLI CATION CI RCUI T

Ty p i c a l

Low Noise

APPLI CATION INFORMATION

Careful layout is important with any switching regulator. Rapidly switching currents

associated with wiring inductance generate voltage transients which can cause problems. To

minimize inductance and ground loops, the lengths of the leads indicated by heavy lines in

Figure 1 below should be kept as short as possible. Single point grounding or ground plane

construction should be used for best results. When using the Adjustable version, place the

programming resistors as close as possible to

LM2576BM, to keep the sensitive feedback

wiring short.

A low ESR aluminum or tantalum bypass capacitor is needed between the input pin and

ground pin. It must be located near the regulator using short leads. This capacitor prevents

large voltage transients from appearing at the input, and provides the instantaneous current

needed each time the switch turns on. Selecting an input capacitor requires consulting the

manufacturers data sheet for maximum allowable RMS ripple current. For a maximum

ambient temperature of 40°C, a general guideline would be to select a capacitor with a

ripple current rating of approximately 50% of the DC load current. For ambient

LM2576BM

LM 2576BM