MP3305 –36V, 1.3A, STEP-UP WHITE LED DRIVER WITH HIGH FREQUENCY TRUE PWM DIMMING & ADJUST OVP

MP3305 Rev. 1.0

www.MonolithicPower.com

8

4/10/2013

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Layout Considerations

Careful attention must be paid to the PCB board

layout and components placement. Proper layout

of the high frequency switching path is critical to

prevent noise and electromagnetic interference

problems. The loop of MP3305 SW to GND pin,

output diode, and output capacitor is flowing with

high frequency ripple current, it must be as short

as possible. And connect the GND (2 pin) and

PGND (8 pin) together thru thermal pad, as

showed in Figure 3.

Figure 3—Layout consideration

The IN pin of the IC must be locally bypassed. A

RC filter is highly recommended for eliminating

the noise on IN pin. It could be implemented as

shown in Figure 4.

MP3305

SW

GND

IN

Input

Figure 4—Input Bias Filtering