Copyright  ANPEC Electronics Corp.
Rev. P.4 - Mar., 2001
APW7004
www.anpec.com.tw1
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-Rectifier PWM Controller for Pentium
TM
II Microprocessor
Features
General Description
Applications
• Power Supply for Pentium
TM
, Pentium Pro
TM
,
Pentium
TM
II,PowerPC
TM
, K6
TM
, 6´86
TM
and
Alpha
TM
Microprocessors
• High-Power 5V to 3.xV (or below) DC-DC Regu-
lators
• Low-Voltage Distributed Power Supplies
The APW7004 provides a complete control and mul-
tiple protection for a DC-DC converter optimized for
high performance microprocessor applications. It is
designed to drive two N-Channel MOSFETs in a syn-
chronous-rectified buck topology. The APW7004 in-
tegrates output voltage control, output voltage
programming, monitoring and protection functions into
a single chip IC.
The APW7004 includes a 5-bit digital-to-analog con-
verter (DAC) that provides a easily adjustable and
precisely output voltage from 2.1V
DC
to 3.5V
DC
in 0.
1 increments and from 1.3 V
DC
to 2.05 V
DC
in 0.
05V increments. Any selected output voltage can be
maintained within ±1% accuracy over temperature
and line voltage variations.
With a 200kHz free-running triangle-wave oscillator
and a error amplifier featuring a 15MHz unity-gain
bandwidth and 6V/us slew rate inside the chip,
APW7004 can implement a simple, single feedback
loop, voltage-mode control topology with high tran-
sient performance.
The APW7004 also features with multiple protections
against over-current and over-voltage conditions by
inhibiting PWM operation. The APW7004 uses the
R
DS(ON)
of the upper MOSFET as the current sensing
element which eliminates the demend for an extra
component. The APW7004 also monitors the output
voltage using a comparator with hysteresis that tracks
the DAC output and issues a Power Good signal once
the output is within ±10%.
6´ 86
TM
is a trademark of Cyrix Corporation
Alpha
TM
is a trademark of Digital Equipment
Corporation
K6
TM
is a trademark of Advanced Micro Devices,
Inc.
Pentium
TM
is a trademark of Intel Corpora-
tion
PowerPC
TM
is a trademark of IBM
• Simple Single-Loop Control Design-Voltage-
Mode PWM Control
• Fast Transient Response
• High-Bandwidth Error Amplifier
• 5-Bit Digital-to-Analog Output Voltage Selec-
tion
• Wide Range from1.3V
DC
to 3.5V
DC
• 0.1V Binary Steps from 2.1V
DC
to 3.5V
DC

.05V Binary Steps from 1.3V
DC
to 2.05 V
DC
• VID0-4 Input Pins with Pull High Resistors Built
in
• Power-Good Output Voltage Monitor, PGOOD
Pin with an Open Collector Configuration
• Over-Voltage and Over-Current Fault Monitors
• Uses MOSFET’s R
DS(ON)
as Current Sensing,
No Extra Element Required
• Programmable Switching Frequency Setting
• 200kHz

Free-Running Oscillator