1
FN9024.2
ISL6523
VRM8.5 Dual PWM and Dual Linear Power
System Controller
The ISL6523 provides the power control and protection for
four output voltages in high-performance microprocessor
and computer applications. The IC integrates two PWM
controllers and two linear controllers, as well as the
monitoring and protection functions into a 28-pin SOIC
package. One PWM controller regulates the microprocessor
core voltage with a synchronous-rectified buck converter.
The second PWM controller supplies the computer system’s
AGTL+ 1.2V bus power with a standard buck converter. The
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 ISL6523 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
second PWM controller’s output provides a voltage level of
1.2V with 3% accuracy. The linear regulators use external
N-channel MOSFETs or bipolar NPN pass transistors to
provide fixed output voltages of 1.5V 3% (V
OUT3
) and 1.8V
3% (V
OUT4
).
The ISL6523 monitors all the output voltages. A delayed-
rising VTT (standard buck 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 overvoltage
protection for the core output uses the lower MOSFET to
prevent output voltages above 115% of the DAC setting. The
PWM controllers’ overcurrent 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 Designs
- Voltage-Mode PWM Control
• Fast PWM Converter Transient Response
- High-Bandwidth Error Amplifiers
- Full 0% to 100% Duty Ratios
• 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
• Overcurrent Fault Monitors
- Switching Regulators Do Not Require Extra Current
Sensing Elements, Use MOSFET’s r
DS(ON)
• Small Converter Size
- Constant Frequency Operation
- 200kHz Internal Oscillator
• Pb-free available
Applications
•
Motherboard Power Regulation for Computers
Pinout
ISL6523 (SOIC)
TOP VIEW
Ordering Information
PART NUMBER
TEMP.
RANGE (
o
C) PACKAGE
PKG.
DWG. #
ISL6523CB 0 to 70 28 Ld SOIC M28.3
ISL6523CBZ
(See Note)
0 to 70 28 Ld SOIC
(Pb-free)
M28.3
ISL6523EVAL1 Evaluation Board
*Add “-T” suffix to part number for tape and reel packaging.
NOTE: Intersil Pb-free products employ special Pb-free material sets; molding
compounds/die attach materials and 100% matte tin plate termination finish, which
is 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-020B.
UGATE2
PHASE2
VID3
VID2
OCSET2
VSEN2
SS24
SS13
VSEN4
VCC
PGND
LGATE1
PHASE1
DRIVE3
COMP1
GND
VAUX
DRIVE4
UGATE1
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
OCSET1
FB1
Data Sheet July 2004
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143
| Intersil (and design) is a trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2001-2002, 2004. All Rights Reserved
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