PAM2841 datasheet(11/14 Pages) PAM

11 / 14 page

PAM2841

1.5A SW Current, 40V Precision WLED Driver

Power Analog Microelectronics Inc

www.poweranalog.com

Layout Considerations

Layout Example

Top Layer

Bottom Layer

As for all switching power supplies, especially

those in high frequency and high current ones,

layout is an important design step. If layout is not

carefully done, the regulator could suffer from

instability as well as noise problems.

(1) Use separate traces for power ground and

signal ground. Power ground and signal ground

are connected together to a quite ground (input

connector)

(2) To prevent radiation of high frequency

resonance, proper layout of the high frequency

switching path is essential. Minimize the length

and area of all traces connecting to the SW pin.

The loop including the PWM switch, schottky

diode and output capacitor, contains high current

rising and falling in nanosecond and thus it

should be kept as short as possible.

(3) The input capacitor should be close to both

the VIN pin and the GND pin in order to reduce

the IC supply ripple.

(4) Keep the signal ground traces short and as

close to the IC as possible. Small signal

components should be placed as close as

possible to the IC, thus minimizing control signal

noise interference.

08/2008 Rev 1.3

PAM2841 Datasheet(PDF) 11 Page - Power Analog Micoelectronics