MP157 –SMALLEST ENERGY EFFICIENT OFF-LINE REGULATOR WITH EXTENDED POWER RANGE

MP157 Rev. 1.04

www.MonolithicPower.com

17

6/27/2016

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L

N

10uF/400V

C4

10uF/400V

C5

L1

D3

D6

39

R8

D4

D7

33nF

CX1

F1

SS-5-2A

RV1

TVR14431

Figure 10: Solution to Pass 2kV Surge Test

Layout Guide

PCB layout is very important for reliable

operation, good EMI and thermal performance.

Please follow these guidelines to optimize

performance.

1) Minimize the loop area formed by the input

capacitor, IC, freewheeling diode, inductor

and output capacitor.

2) Place the power inductor far away from the

input filter.

3) Place a capacitor valued at several nF

between the FB pin and SOURCE as close

to the IC as possible.

4) Connect the exposed pad with the DRAIN

pin to a larger copper area to improve

thermal performance.

a) Top layer

b) Bottom layer

Figure 11: PCB layout

Design Example

Below is a design example following the

application guidelines for the specifications:

Table 3: Design Example

85VAC to 265VAC

12V

350mA

The detailed application schematic is shown in

Figure 12. The typical performance and circuit

waveforms have been shown in the Typical

Performance Characteristics section. For more

device applications, please refer to the related

Evaluation Board Datasheets -- EV157-J-

00A_r1.0 or EV157-S-00A_r1.0.