Copyright

© ANPEC Electronics Corp.

Rev. A.8 - Aug., 2009

APW7066

www.anpec.com.tw

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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.

Dual Synchronous Buck PWM Controllers and One Linear Controller

Features

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Two Synchronous Buck Converters and A

Linear Regulator

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VIN Range up to 12V

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Input Power Supplies Require 12V and 5V or

Use 12V to Generate a Shunt Regulator 5.8V

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0.6V Reference for VOUT1 and VOUT3

with 0.8% Accurate

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3.3V Reference for VOUT2 with 0.8% Accurate

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Buffered VTT Reference Output

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Three Outputs have Independent Soft-Start

and Enable

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Internal 300kHz Oscillator and Programmable

Frequency Range from 70 kHz to 800kHz

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Synchronous Switching Frequency

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DDR Mode or Independent Mode Selection

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Phase Shift Selection

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Power Good Function

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Short-Circuit Protection for VOUT1 and VOUT2

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Thermally Enhanced TSSOP-24P and

QFN5x5-32 Packages

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Lead Free and Green Devices Available

(RoHS Compliant)

Applications

General Description

The APW7066 has two synchronous buck PWM control-

lers and one linear controller with high precision internal

references voltage to offer accurate outputs. The PWM

controllers are designed to drive two N-channel MOSFETs

in synchronous buck topology, and the linear controller

drives an external N-channel MOSFET. The device re-

quires 12V and 5V power supplies, if the 5V supply is not

available, VCC12 can offer an optional shunt regulator

5.8V for 5V supply.

All outputs have independent soft-start and enable func-

tions by SS/EN pins to control. Connect a capacitor from

each SS/EN pin to the ground for setting the soft-start

time, and pulling the SS/EN pin below 1V to disable

regulator. Pull the SS2/EN2 to VCC, enter the DDR mode,

the SS1/EN1 controls both VOUT1 and VOUT2, and al-

lows VOUT2 to track VOUT1. It also offers the phase shift

function by REFOUT pin to select the phase shift between

VOUT1 and VOUT2 in DDR mode or Independent mode.

W hen all SS/EN pins exceed 3.3V and no faults are

detected, the PGOOD pin goes high to indicate the regu-

lators are ready. If any of the SS/EN pins goes below 3.2V

or any of the outputs has a fault condition, the PGOOD pin

will be pulled low.

The internal oscillator is nominally 300kHz (keep the FS/

SYNC pin open or short to GND), and it offers the pro-

grammable frequency function from 70kHz to 800kHz; con-

necting a resistor from FS/SYNC to VCC12 to decrease

the frequency, conversely, connect a resistor from FS/

SYNC to GND to increase the frequency.The IC also pro-

vides the synchronous frequency function. Connect the

LGATE signal of another converter to FS/SYNC pin; forc-

ing the switching frequency to follow the external clock.

The possible synchronous frequency is from 150kHz to

800kHz. There is no R

ing on APW7066. However, it provides a simple short-

circuit protection by monitoring the COMP1 and COMP2

for over-voltage. When any of two pins exceeds their trip

point and the condition persists for 1-2 internal clock cycle

(3-6

µs at 300kHz), then it will shut down all regulators.

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Graphic Cards

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DDR memory Power Supplies

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Low-Voltage Distributed Power Supplies