AP6503

340kHz 23V 3A SYNCHRONOUS DC/DC BUCK CONVERTER

AP6503

Document number: DS35077 Rev. 1 - 2

10 of 13

www.diodes.com

September 2011

© Diodes Incorporated

PC Board Layout

This is a high switching frequency converter. Hence

attention

must

be

paid

to

the

switching

currents

interference in the layout. Switching current from one

power device to another can generate voltage transients

across the impedances of the interconnecting bond wires

and circuit traces. These interconnecting impedances

should be minimized by using wide, short printed circuit

traces.

AP6503 is exposed at the bottom of the package

and must be soldered directly to a well designed

thermal pad on the PCB. This will help to increase

the power dissipation.

External Bootstrap Diode

It is recommended that an external bootstrap diode be

added when the input voltage is no greater than 5V or the

5V rail is available in the system. This helps to improve the

efficiency of the regulator. This solution is also applicable

for D > 65%. The bootstrap diode can be a low cost one

such as BAT54 or a schottky that has a low Vf.

AP6503

BST

SW

10nF

BOOST

DIODE

5V

4

3

Figure 7—External Bootstrap

Compensation Components

Recommended Diodes:

Part Number

Voltage/Current

Rating

Vendor

B130

30V, 1A

Diodes Inc

SK13

30V, 1A

Diodes Inc

Input capacitor C1

must be placed as

close as possible

to the IC and to L1.

34mm

52mm

External feedback

resistor dividers

must be placed

close to the FB pin.