L6997S

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Table 8. PCB Layout guidelines

Goal

Suggestion

To minimize radiation and magnetic

coupling with the adjacent circuitry.

and Low side MOSFETS, Shottky diode as close as possible).

2) Place controller placed as close as possible to the power MOSFETs.

3) Group the gate drive components (Boot cap and diode) near the IC.

To maximize the efficiency.

Keep power traces and load connections short and wide.

To ensure high accuracy in the

current sense system.

Make Kelvin connection for Phase pin and PGND pin and keep them as close

as possible to the Low Side MOSFETS.

To reduce the noise effect on the IC.

1) Put the feedback component (like output divider, integrator network, etc) as

close as possible to the IC.

2) Keep the feedback traces parallel and as close as possible. Moreover they

must be routed as far as possible from the switching current loops.

3) Make the controller ground connection like the figure 8.

Table 9. Component list

The component list is shared in two sections: the first for the general-purpose component, the second for

power section:

Part name

Value

Dimension

Notes

GENERAL-PURPOSE SECTION

RESISTOR

R1, R5, R9, R10

33k

Ω

0603

Pull-up resistor

R2

1k

Ω

0603

Output resistor divider (To set output voltage)

R3

1.1k

Ω

0603

R4

0603

Input resistor divider (To set switching frequency)

R6

470k

Ω

0603

R7

0

Ω

0603

R8

0603

Current limit resistor

CAPACITOR

C1

330pF

0603

First integrator capacitor

C2

N.M.

0603

Second integrator capacitor

C3

1nF

0603

C4

100nF

0603

C5

1

µFTantalum

C6

10nF

0603

C9

10nF

0603

Softstart capacitor

C10

100nF

0603

C11

100nF

0603

C8, C12

47pF

0603

DIODE

D1

BAR18

POWER SECTION

INPUT CAPACITORS

C7, C13

47

µF

ECJ4XF0J476Z

PANASONIC