R 2

220

Vi n

V o u t

Q1

P N P

NP N

LO A D

R1

10K

MMST3904

MMST3906

BQ2

Control

CQ1

CQ2

BQ1

EQ2

EQ1

Q2

Application Details

•

PNP Transistor (MMST3906) and NPN Transistor (MMST3904)

integrated as one in LBN150B01 can be used as a discrete entity

for general purpose applications or as a part of a circuit to function

as a Load Switch. When it is used as the latter as shown in Fig 16,

various input voltage sources can be used as long as they do not

exceed the maximum rating of the device. These devices are

designed to deliver continuous output load current up to maximum

of 150 mA. The use of the NPN as a switch eliminates the need

for higher current required to overcome the gate charge in the

event an N-MOSFET is used. Care must be taken for higher levels

of dissipation while designing for higher load conditions. These

devices provides power on demand and also consume less space.

It mainly helps in optimizing power usage, thereby conserving

battery life in a controlled load system like portable battery

powered applications. (Please see Fig. 17 for one example of

typical application circuit used in conjunction with a voltage

regulator as a part of power management system).

Fig. 16: Example Circuit Schematic

Typical Application Circuit

U1

Vi n

OU T 1

GN D

Vo u t

U2

1

3

2

4

5

6

E_ Q 1

B_ Q 2

B_ Q 1

C_ Q 2

E_ Q 2

C_ Q 1

C ontr o l

U3

IN

O U T

Vi n

5V S uppl y

GN D

Load Switch

Voltage Regulator

LBN150B01

Diodes, Inc.

Point of

Load

Control Logic

Circuit (PIC,

Comparator, etc)

Fig. 17

DS30749 Rev. 3 - 2

7 of 9

www.diodes.com

LBN150B01

© Diodes Incorporated