APW7004 Datasheet, PDF (1/10 Pages) Anpec Electronics Coropration – Synchronous-Rectifier PWM Controller for Pentium II Microprocessor

APW7004
Synchronous-Rectifier PWM Controller for Pentium^TM II Microprocessor
Features
• 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
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
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
General Description
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%.
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.
Copyright  ANPEC Electronics Corp.
1
Rev. P.4 - Mar., 2001
www.anpec.com.tw