®
ISL6524
Data Sheet
April 18, 2005
FN9015.3
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
Ordering Information
PART NUMBER
ISL6524CB*
ISL6524CBZ*
(See Note)
ISL6524CBZA*
(See Note)
ISL6524EVAL1
TEMP.
RANGE (°C)
0 to 70
0 to 70
0 to 70
PACKAGE
28 Ld SOIC
28 Ld SOIC
(Pb-free)
28 Ld SOIC
(Pb-free)
PKG.
DWG. #
M28.3
M28.3
M28.3
Pinout
ISL6524 (SOIC)
TOP VIEW
DRIVE2 1
FIX 2
VID3 3
VID2 4
VID1 5
VID0 6
VID25 7
PGOOD 8
VTTPG 9
FAULT/RT 10
VSEN2 11
SS24 12
SS13 13
VSEN4 14
28 VCC
27 UGATE
26 PHASE
25 LGATE
24 PGND
23 OCSET
22 VSEN1
21 FB
20 COMP
19 VSEN3
18 DRIVE3
17 GND
16 VAUX
15 DRIVE4
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.
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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