1
FN9064.1
ISL6524A
VRM8.5 PWM and Triple Linear Power
System Controller
The ISL6524A provides the power control and protection for
four output voltages in high-performance microprocessor and
computer applications. The IC integrates one PWM controller
and three linear controllers, as well as the monitoring and
protection functions into a 28-pin SOIC package. The PWM
controller regulates the microprocessor core voltage with a
synchronous-rectified buck converter. One linear controller
supplies the computer system’s AGTL+ 1.2V bus power. The
other two linear controllers regulate power for the 1.5V AGP
bus and the 1.8V power for the chipset core voltage and/or
cache memory circuits.
The ISL6524A includes an Intel VRM8.5 compatible, TTL
5-input digital-to-analog converter (DAC) that adjusts the
microprocessor core-targeted PWM output voltage from
1.050V to 1.825V in 25mV steps. The precision reference and
voltage-mode control provide 1% static regulation. The linear
regulators use external N-channel MOSFETs or bipolar NPN
pass transistors to provide fixed output voltages of 1.2V 3%
(V
OUT2
), 1.5V 3% (V
OUT3
) and 1.8V 3% (V
OUT4
).
The ISL6524A monitors all the output voltages. A delayed-
rising VTT (V
OUT2
output) Power Good signal is issued
before the core PWM starts to ramp up. Another system
Power Good signal is issued when the core is within 10% of
the DAC setting and all other outputs are above their under-
voltage levels. Additional built-in over-voltage protection for
the core output uses the lower MOSFET to prevent output
voltages above 115% of the DAC setting. The PWM
controllers’ over-current function monitors the output current
by using the voltage drop across the upper MOSFET’s
r
DS(ON)
, eliminating the need for a current sensing resistor.
Features
• Provides 4 Regulated Voltages
- Microprocessor Core, AGTL+ Bus, AGP Bus Power,
and North/South Bridge Core
• Drives N-Channel MOSFETs
• Linear Regulator Drives Compatible with both MOSFET
and Bipolar Series Pass Transistors
• Simple Single-Loop Control Design
- Voltage-Mode PWM Control
• Fast PWM Converter Transient Response
- High-Bandwidth Error Amplifier
- Full 0% to 100% Duty Ratio
• Excellent Output Voltage Regulation
- Core PWM Output: 1% Over Temperature
- All Other Outputs: 3% Over Temperature
• VRM8.5 TTL-Compatible 5-Bit DAC Microprocessor Core
Output Voltage Selection
- Wide Range - 1.050V to 1.825V
• Power-Good Output Voltage Monitors
- Separate delayed VTT Power Good
• Over-Voltage and Over-Current Fault Monitors
- Switching Regulator Doesn’t Require Extra Current
Sensing Element, Uses MOSFET’s r
DS(ON)
• Small Converter Size
- Constant Frequency Operation
- 200kHz Internal Oscillator
• Pb-Free Available (RoHS Compliant)
Applications
•
Motherboard Power Regulation for Computers
Pinout
ISL6524A (SOIC) TOP VIEW
Ordering Information
PART NUMBER
TEMP.
RANGE
(°C) PACKAGE
PKG.
DWG.
#
ISL6524ACB* 0 to 70 28 Ld SOIC M28.3
ISL6524ACBZ* (Note) 0 to 70 28 Ld SOIC (Pb-free) M28.3
ISL6524ACBZA-T (Note) 0 to 70 28 Ld SOIC (Pb-free) M28.3
ISL6524EVAL1 Evaluation Board
*Add “-T” suffix for tape and reel.
NOTE: Intersil Pb-free products employ special Pb-free material sets;
molding compounds/die attach materials and 100% matte tin plate
termination finish, which are RoHS compliant and compatible with
both SnPb and Pb-free soldering operations. Intersil Pb-free products
are MSL classified at Pb-free peak reflow temperatures that meet or
exceed the Pb-free requirements of IPC/JEDEC J STD-020.
DRIVE2
FIX
VID3
VID2
FAULT/RT
VSEN2
SS24
SS13
VSEN4
VCC
PGND
LGATE
PHASE
DRIVE3
COMP
GND
VAUX
DRIVE4
UGATE
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
PGOOD
VID1
VTTPG
VSEN1
VSEN3
VID0
VID25
OCSET
FB
Data Sheet April 8, 2005
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-352-6832
| Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2002, 2005. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
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