MP100L EASYPOWER

transformer (usually in the mH’s), high voltage

spikes occur when MP100L turns off the internal

switch connected between VIN and VB, which

may damage the IC.

An X- capacitor must be

installed before the rectifier to guarantee the

reliability of the system.

EMI

To meet the relevant conducted emissions

standard, the internal switch connected between

VIN and VB is designed to turn on and off slowly.

By

adopting

this

method,

a

small

X

cap

connected between the input ports will pass EMI

with enough margins. For general application,

220nF X-capacitor between the input ports is

enough to pass EMI, which will make the whole

system compact.

Surge

From its working principle, mP100L is working

just when VIN falls into its charging window, so

when surges happen at this moment, then a lot of

energy will be by MP100L due to the slow turn off

process. To protect it from damage, a fast turn off

threshold (typically it is 86V) of VIN is set

specially to shut down the switch connected

between VIN and VB quickly.

Since there is no bulk capacitor to absorb AC line

transients, MOV should be used to protect the IC

to survive the transient test. Besides the value of

fuse resistor will also affect the surge result, the

larger value used, the better to facilitate to pass

the surge test, but the more power consumption

will be caused, in the meanwhile, the larger value

used, the easier to trigger its fast turn off

threshold, 20 ohm fuse resistor is recommended

in real application.

Besides, the thermal pad must be connected to

the GND for better surge performance.

PCB Layout Guide

PCB layout is very important to achieve good

regulation, ripple rejection, transient response

and thermal performance. It is highly

recommended to duplicate EVB layout for

optimum performance.

If change is necessary, please follow these

guidelines and take Figure 3 for reference.

1) Minimize the loop area formed by positive

output of rectifier, VIN,VB and GND.

2) Ensure all feedback connections are short

and direct. Place the feedback resistors and

compensation components as close to the

chip as possible.

3) Output capacitor should be put close to the

output terminal.

4) Connect the exposed pad with GND to a

large

copper

area

to

improve

thermal

performance and long-term reliability

GND

GND

RV

MP100L

VD

5

NC

7

FB

3

VB

6

PG

1

VIN

8

GND

2

VOUT

4

U1

BD1

C1

C3

R3

R1

R2

C2

C4

RF

L

N

VOUT

GND

CX1

R4

R5

R6

Top Layer

Bottom Layer

Figure 2: PCB Layout

MP100L Rev. 1.0

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11/3/2014

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