2013/5/2

Rev.A.1

11

EM5301F/G

Power MOSFET Selection

The EM5301F/G requires two N-Channel power

MOSFETs. These should be selected based upon

on-resistance, breakdown voltage, gate supply

requirement,

and

thermal

management

requirements.

In high current applications, the MOSFET power

dissipation, package selection and heat sink are the

dominate design factor. The power dissipation

includes two loss components: conduction loss and

switching loss. The conduction losses are the

largest component of power dissipation for both

the upper and lower MOSFETs. These losses are

distributed between the two MOSFETs according

to duty factor.

The power dissipations in the two MOSFETs are

approximately the following equation:

SW

SW

IN

OUT

DS(ON)

OUT

2

UPPER

t

F

V

I

D

*

R

*

I

PD

*

*

*

*

5

.

0

+

=

D)

-

(1

*

R

*

I

PD

DS(ON)

OUT

2

LOWER

=

switch ON and OFF time.