10

LTC1872

Figure 5. LTC1872 Layout Diagram (See PC Board Layout Checklist)

PC Board Layout Checklist

When laying out the printed circuit board, the following

checklist should be used to ensure proper operation of the

LTC1872. These items are illustrated graphically in the

layout diagram in Figure 5. Check the following in your

layout:

1. The Schottky diode should be closely connected

between the output capacitor and the drain of the

external MOSFET.

resistor as closely as possible. This capacitor provides

AC current to the inductor.

3. The input decoupling capacitor (0.1

µF) should be

(Pin 2).

comparator.

should be kept short. The trace should connect close

6. Keep the switching node NGATE away from sensitive

small signal nodes.

resistors. The resistive divider R1 and R2 must be

ground.

L1

M1

BOLD LINES INDICATE HIGH CURRENT PATHS

D1

1872 F05

0.1

µF

R2

R1

+

LTC1872

GND

6

5

4

1

2

3

NGATE

+