November 2001 File Number 9003.1
Microprocessor CORE Voltage Regulator
Using Multi-Phase Buck PWM Control
Without Programmable Droop
The ISL6554 is the ﬁrst controller in the Intersil Multi-Phase
family without the programmable droop feature. The ISL6554
in combination with the HIP6601A, HIP6602A or HIP6603A
companion gate drivers and Intersil MOSFETs form a
complete solution for high-current, high slew-rate
applications. The ISL6554 regulates output voltage,
balances load currents and provides protective functions for
two to four synchronous-rectiﬁed buck-converter channels.
A novel approach to current sensing is used to reduce
overall solution cost. The voltage developed across the lower
MOSFET’s parasitic on-resistance during conduction is
sampled and fed back to the controller. This lossless current-
sensing approach allows the controller to maintain phase-
current balance between the power channels and
A 5-bit DAC allows digital programming of the output voltage
in 25mV steps over a range from 0.95V to 1.70V with a
system accuracy of ±1%. Internal pull ups on each DAC
input make external pull-up resistors unnecessary when
interfacing with open-drain output signals.
The PGOOD signal is held low during Soft-Start until the
output voltage increases to within 4% of the programmed.
When the CORE voltage falls 9% below the programmed
VID level, an undervoltage condition is detected and results
in PGOOD transitioning low.
In the event of an overvoltage condition, The converter shuts
down and turns ON the lower MOSFETs to clamp and
protect the microprocessor. Overcurrent protection reduces
the regulator RMS output current to 41% of the programmed
overcurrent trip value. These features provide monitoring
and protection for the microprocessor and power system.
• Multi-Phase Power Conversion
• Precision Channel Current Balance
- Lossless Current Sampling - Uses rDS(ON)
• Precision CORE Voltage Regulation
- ±1% System Accuracy Over Temperature
- No Programmable Droop
• Microprocessor Voltage Identiﬁcation Input
- 5-Bit VID Decoder
- 0.95V to 1.70V in 25mV Steps
• Fast Transient Response
• Over Current Protection
• Selection of 2, 3, or 4 Phase Operation
• High Ripple Frequency (80kHz to 2MHz)
• Power Supply Controller for Intel® Itanium™ Processor
• Voltage Regulator Modules
• Servers and Workstations
PART NUMBER TEMP. (oC) PACKAGE PKG. NO.
0 to 70 20 Ld SOIC M20.3
20 Ld SOIC Tape and Reel
Intel™ is a trademark of Intel Corporation.
1 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. All Rights Reserved
Intel® is a registered trademark of Intel Corporation. Itanium™ is a trademark of Intel Corporation