ISL6434
TM
Data Sheet
August 2001
File Number
9021
Advanced Dual PWM and Dual Linear
Power Controller for Gateway
Applications
The ISL6434 provides the power control and protection for
four output voltages in high-performance, graphics intensive
gateway microprocessor applications. The IC integrates two
PWM controllers and two linear controllers, as well as the
monitoring and protection functions into a 28-lead SOIC
package. One PWM controller regulates the microprocessor
core voltage with a synchronous-rectified buck converter.
The second PWM controller supplies the computer system鈥檚
AGP 1.5V or 3.3V bus power with a standard buck converter.
The linear controllers regulate power for the 1.5V GTL bus
and the 1.8V power for the North/South Bridge core voltage
and/or cache memory circuits.
The ISL6434 includes an Intel廬 -compatible, TTL 5-input
digital-to-analog converter (DAC) that adjusts the core PWM
output voltage from 1.3V
DC
to 2.05V
DC
in 0.05V steps and
from 2.1V
DC
to 3.5V
DC
in 0.1V increments. The precision
reference and voltage-mode control provide
鹵1%
static
regulation. The second PWM controller鈥檚 output is user-
selectable, through a TTL-compatible signal applied at the
SELECT pin, for levels of 1.5V or 3.3V with
鹵3%
accuracy.
The linear regulators use external N-Channel MOSFETs or
bipolar NPN pass transistors to provide fixed output voltages
of 1.5V
鹵3%
(V
OUT3
) and 1.8V
鹵3%
(V
OUT4
).
The ISL6434 monitors all the output voltages. A single
Power Good signal is issued when the core is within
鹵10%
of
the DAC setting and all other outputs are above their under-
voltage levels. Additional built-in overvoltage protection for
the core output uses the lower MOSFET to prevent output
voltages above 115% of the DAC setting. The PWM
controllers鈥?overcurrent function monitors the output current
by using the voltage drop across the upper MOSFET鈥檚
r
DS(ON)
, eliminating the need for a current sensing resistor.
Features
鈥?Provides Four Regulated Voltages
- Microprocessor Core, AGP Bus, North/South Bridge
and/or Cache Memory, and GTL Bus Power
鈥?Drives N-Channel MOSFETs
鈥?Linear Regulator Drives Compatible with both MOSFET
and Bipolar Series Pass Transistors
鈥?Simple Single-Loop Control Designs
- Voltage-Mode PWM Control
鈥?Fast PWM Converter Transient Response
- High-Bandwidth Error Amplifiers
- Full 0% to 100% Duty Ratios
鈥?Excellent Output Voltage Regulation
- Core PWM Output:
鹵1%
Over Temperature
- AGP Bus PWM Output:
鹵3%
Over Temperature
- Other Outputs:
鹵3%
Over Temperature
鈥?TTL-Compatible 5 Bit DAC Microprocessor Core Output
Voltage Selection
- Wide Range . . . . . . . . . . . . . . . . . . . 1.3V
DC
to 3.5V
DC
鈥?Power-Good Output Voltage Monitor
鈥?Overvoltage and Overcurrent Fault Monitors
- Switching Regulators Do Not Require Extra Current
Sensing Elements, Use MOSFET鈥檚 r
DS(ON)
鈥?Small Converter Size
- Constant Frequency Operation
- 200kHz Free-Running Oscillator; Programmable From
50kHz to Over 1MHz
- Small External Component Count
Applications
鈥?Motherboard Power Regulation for Computers
Pinout
ISL6434 (SOIC)
TOP VIEW
UGATE2 1
PHASE2 2
VID4 3
VID3 4
VID2 5
VID1 6
VID0 7
PGOOD 8
OCSET2 9
VSEN2 10
SELECT 11
SS 12
FAULT/RT 13
VSEN4 14
28 VCC
27 UGATE1
26 PHASE1
25 LGATE1
24 PGND
23 OCSET1
22 VSEN1
21 FB1
20 COMP1
19 VSEN3
18 DRIVE3
17 GND
16 VAUX
15 DRIVE4
Ordering Information
PART NUMBER
ISL6434CB
ISL6434EVAL1
TEMP.
RANGE (
o
C)
0 to 70
PACKAGE
28 Ld SOIC
PKG.
NO.
M28.3
Evaluation Board
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143
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Intersil and Design is a trademark of Intersil Americas Inc.
Intel廬 is a registered trademark of Intel Corporation.
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Copyright 漏 Intersil Americas Inc. 2001, All Rights Reserved
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