Copyright

© ANPEC Electronics Corp.

Rev. A.2 - Dec., 2012

APW7334

www.anpec.com.tw

5

Pin Description

PIN

SOP-8

NAME

FUNCTION

1

BS

High-Side Gate Drive Boost Input. BS supplies the voltage to drive the high-side N-channel MOSFET.

At least 10nF capacitor should be connected from LX to BS to supply the high side switch.

2

VIN

Power Input. VIN supplies the power (4.5V to 24V) to the control circuitry, gate drivers and step-down

converter switches. Connecting a ceramic bypass capacitor and a suitably large capacitor between

VIN and GND eliminates switching noise and voltage ripple on the input to the IC.

3

LX

Power Switching Output. LX is the Drain of the N-Channel power MOSFET to supply power to the

output LC filter.

4

GND

Ground.

5

FB

Output feedback Input. The APW7334 senses the feedback voltage via FB and regulates the voltage

at 0.8V. Connecting FB with a resistor-divider from the converter’s output sets the output voltage from

0.8V to 20V.

6

COMP

Output of the error amplifier. Connect a series RC network from COMP to GND to compensate the

regulation control loop. In some cases, an additional capacitor from COMP to GND is required.

7

EN

Enable Input. EN is a digital input that turns the regulator on or off. EN threshold is 2.5V with 0.2V

hysteresis. Pull up with 100k

Ω resistor for automatic startup.

8

SS

Soft-Start Control Input. SS controls the soft-start period. Connect a capacitor from SS to GND to set

the soft-start period. A 0.1

µF capacitor sets the soft-start period to 15ms. To disable the soft-start

feature, leave SS unconnected.

Block Diagram

LX

Gate

Control

V

REF

Fault

Logics

Error

Amplifier

FB

Inhibit

GND

POR

Power-On-

Reset

5V

UVLO

Current Sense

Amplifier

EN

COMP

Oscillator

340kHz/

110kHz

Slope

Compensation

Current

Compartor

1.5V

Over

Temperature

Protection

Current

Limit

Gate

Driver

Gate

Driver

Gm

VIN

2.5/2.3V

1 BS

3

4

2

5

6

7

8

SS

5V

VIN

Internal

Regulator

5V

FB

0.6V

Enable

120%V

REF

OVP

6

µA

5V

OTP

Current Sense

Amplifier

LOC

LOC