LM1771SSDX datasheet(14/18 Pages) NSC

Part #	LM1771SSDX

Description	Low-Voltage Synchronous Buck Controller with Precision Enable and No External Compensation

PDF	18 Pages

Scroll/Zoom	100%

Manufacturer	NSC [National Semiconductor (TI)]

Direct Link	http://www.national.com

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14 / 18 page

Layout

The LM1771, like all switching regulators, requires careful

attention to layout to ensure optimal performance. The fol-

lowing steps should be taken to aid in the layout. For more

information refer to Application Note AN-1299.

Ensure that the ground connections of the input capaci-

tor, output capacitor and NMOS are as close as pos-

sible. Ideally these should all be grounded together in

close proximity on the component side of the board.

Keep the switch node small to minimize EMI without

degrading thermal cooling of the FETs.

Locate the feedback resistors close to the IC and keep

the feedback trace as short as possible. Do not run any

feedback traces near the switch node.

Keep the gate traces short and keep them away from the

switch node as much as possible.

If a small bypass capacitor is used on V

IN (0.1µF) place

it as close to the pin, with the ground connection as

close to the chip ground as possible.

LM1771SSDX Datasheet(PDF) 14 Page - National Semiconductor (TI)