Copyright

 ANPEC Electronics Corp.

Rev. A.3 - Mar., 2005

APW7058

www.anpec.com.tw

1

ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and advise

customers to obtain the latest version of relevant information to verify before placing orders.

Synchronous Buck PWM and Linear Controllers

- One Synchronous-Rectified Buck PWM

Controller

- One Linear Controller

- Both Controllers : 0.8V ± 2% Over

Temperature

- PWM Controller Drives Dual N-Channel

MOSFETs

- Linear Controller Drives N-Channel MOSFET

- No Steady-State Error

- Full 0~100% Duty Ratio

- Fast Transient Response

- 600kHz Constant Switching Frequency

- Built-In Soft-Start

- Simple SO-8 Package

Features

Applications

General Description

The APW7058 integrates one synchronous-rectified

Buck PWM controller and one linear controller to pro-

vide two regulated voltages for graphics cards and

other embedded processor applications. The PWM

controller which drives dual N-channel MOSFETs uses

fixed 600kHz frequency, voltage-mode PWM control

and integrates power-on-reset(POR), built-in soft-start,

output under-voltage monitoring and shutdown func-

tions into a single chip. The linear controller which

drives a N-channel MOSFET bypass transistor allows

users to optimize the transient response by external

components. The POR circuit with hysteresis moni-

tors both 5VCC and 12VCC supply voltages to start

up/shutdown the IC at power-on/off. An internal 0.8V

temperature-compensated reference is designed to

meet the low output voltage requirement for further

applications. The built-in soft-start function sets the

soft-start interval to prevent the output voltages from

overshoot as well as limiting the input currents. The

under-voltage protections monitor the voltages at FB

and FB2 for short-circuit protection. The under-volt-

age protections cycle the soft-start function until 3

times of UVP events are happened. Pulling and hold-

ing the FB2 pin above 1.28V to disable the both

controllers.

Pin Description

1

2

3

45

6

7

8

12VCC

UGATE

GND

LGATE

5VCC

DRIVE2

FB2

FB