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Introduction
The AMD Hammer family microprocessors feature higher
clock speeds and greater device density than previous
product families. The power management solution for this
next generation family of microprocessors must contend with
lower core voltages, tighter transient specifications, and
higher peak current demands. Responding to the changing
power management needs of its customers, Intersil
introduces the ISL6559 controller to power the AMD
Hammer family microprocessors.
Intersil ISL6559 and ISL6605
The ISL6559EVAL1 is a versatile voltage regulator-module
(VRM) design. The evaluation board comes configured for
4-phase multi-phase buck operation, designed to meet AMD
Hammer Family Desktop Processor specifications. The
board can easily be modified to support evaluation at lower
current specifications. The ISL6559 controller functions are
specifically designed to compliment and support the
Hammer Family feature set with ISL6605 drivers. The
chipset forms a highly integrated solution for AMD Hammer
processor applications.
The ISL6559 regulates output voltage and balances load
currents for two to four synchronous buck converter
channels. The controller features a 5-bit DAC, which
provides a digital interface for accurate voltage programming
over the entire Hammer Family range of 0.800V to 1.550V.
New multi-phase family features include differential remote
output voltage sensing, to improve regulation tolerance;
pin-adjustable reference offset, for ease of implementation;
VID-on-the-Fly, to respond to DAC changes during
operation; and optional load line regulation. For a more
detailed description of the ISL6559 functionality, refer to the
data sheet [1].
The ISL6605 driver is chosen to drive two N-Channel power
MOSFETs in a synchronous-rectified buck converter
channel. Each channel has a single logic input that controls
the upper and lower MOSFETs. Dead time is optimized on
both switching edges to provide shoot-thru protection.
Internal bootstrap circuitry only requires an external
capacitor and provides better enhancement of the upper
MOSFET. For a more detailed description of the ISL6605,
refer to the data sheet [2].
The Intersil multi-phase family controller and driver portfolio
continues to expand with new selections to better fit our
customer’s needs. Refer to our website for updated
information, www.intersil.com.
ISL6559 VRM Reference Design
The evaluation kit consists of the ISL6559EVAL1 board,
associated data sheets on the ISL6559 controller and
ISL6605 driver, as well as this application note. The
evaluation kit also includes the Elcon VRM test board which
has an edged connector for the VRM to plug into. The
evaluation kit provides convenient test points, a banana jack
for power supply connectors, and an on-board transient load
generator to facilitate the evaluation process. The
ISL6559EVAL1 board and test board is configured to run off
of a single 12V supply.
The evaluation board meets the output voltage and current
specifications, shown in Table 1, with the VID DIP switch (set
to 01100 (1.250V). The 1U VRM board is fabricated using 6
layers with 3oz copper on outer and 4oz copper on inner
layers. The test board is implemented in 4-layer, 2oz copper.
Layout plots and part lists are provided at the end of the
application note for this design.
Quick Start Evaluation
Circuit Setup
The ISL6559EVAL1 board will arrive with the VID DIP switch
(U2) set to 01100 (1.250V). If another output voltage level is
desired, refer to the ISL6559 data sheet for the complete
DAC table and change the VID switches accordingly. Note
that changing the U2 VID states will change the dynamics of
the load generator.
Input Power Connections
A single power supply connection is provided on the VRM
test board. Insure connection is secure.
Two female banana jacks are provided for connection of the
bench top power supply. Connect the +12V terminal to J5,
and the common ground to terminal J6.
TABLE 1. 4-PHASE VRM DESIGN PARAMETERS
PARAMETER MIN MAX
Static Regulation 1.109V 1.250V
Transient Regulation 1.109V 1.250V
Continuous Load Current 3A 100A
Load Current Step 100A
Load Current Transient ~560A/µs
AN1132
1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2004. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
ISL6559EVAL1: Voltage Regulator Module
Solution for AMD Hammer Family Processors
Application Note June 2004
Author: Thomas Victorin
