1
®
FN9015.3
ISL6524
VRM8.5 PWM and Triple Linear Power
System Controller
The ISL6524 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 chip
set core voltage and/or cache memory circuits.
The ISL6524 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 ISL6524 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 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 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
• Overcurrent Fault Monitor
- 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
ISL6524 (SOIC) TOP VIEW
Ordering Information
PART NUMBER
TEMP.
RANGE (°C) PACKAGE
PKG.
DWG. #
ISL6524CB* 0 to 70 28 Ld SOIC M28.3
ISL6524CBZ*
(See Note)
0 to 70 28 Ld SOIC
(Pb-free)
M28.3
ISL6524CBZA*
(See 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 18, 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. 2001-2002, 2004-2005. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
