ISL6557 Datasheet, PDF (1/17 Pages) Intersil Corporation – Multi-Phase PWM Controller for Core-Voltage Regulation

®
Data Sheet
August 2003
ISL6557
FN9059.2
Multi-Phase PWM Controller for
Core-Voltage Regulation
The ISL6557 provides core-voltage regulation by driving up
to four interleaved synchronous-rectified buck-converter
channels in parallel. Intersil multi-phase controllers together
with Intersil MOSFET drivers form the basis for the most
reliable power-supply solutions available to power the latest
industry-leading microprocessors. Multi-phase buck-
converter architecture uses interleaved timing to multiply
ripple frequency and reduce input and output ripple currents.
Lower ripple results in lower total component cost, reduced
dissipation, and smaller implementation area. Pre-
configured for 4-phase operation, the ISL6557 offers the
flexibility of selectable 2- or 3-phase operation. Simply
connect the unused PWM pins to VCC. The channel
switching frequency is adjustable in the range of 50kHz to
1.5MHz giving the designer the ultimate flexibility in
managing the balance between high-speed response and
good thermal management.
New features on the ISL6557 include Dynamic-VID™
technology allowing seamless on-the-fly VID changes with
no need for any additional external components. When the
ISL6557 receives a new VID code, it incrementally steps the
output voltage to the new level. Dynamic VID changes are
fast and reliable with no output voltage overshoot or
undershoot. The RGND and VSEN pins provide inputs for
differential remote voltage sensing to improve regulation and
protection accuracy. A threshold-sensitive enable pin (EN)
can be used with an external resistor divider to optionally set
the power-on voltage level. This allows optional start-up
coordination with Intersil MOSFET drivers or any other
devices powered from a separate supply.
Like other Intersil multiphase controllers, the ISL6557 uses
cost and space-saving r_DS(ON) sensing for channel current
balance, dynamic voltage positioning, and overcurrent
protection. Channel current balancing is automatic and
accurate with the integrated current-balance control system.
Overcurrent protection can be tailored to any application with
no need for additional parts. The IOUT pin carries a signal
proportional to load current and can be optionally connected
to FB for accurate load-line regulation.
An integrated DAC decodes the 5-bit logic signal present at
VID4-VID0 and provides an accurate reference for precision
voltage regulation. The high-bandwidth error amplifier,
differential remote-sensing amplifier, and accurate voltage
reference all work together to provide better than 0.8% total
system accuracy, and to enable the fastest transient
response available.
Features
• Multi-Phase Power Conversion
• Active Channel Current Balancing
• Precision r_DS(ON) Current Sensing
- Low Cost
- Lossless
• Precision CORE Voltage Regulation
- Differential Remote Voltage Sensing
- ±0.8% System Accuracy
• Microprocessor Voltage Identification Input
- Dynamic VID technology
- 5-Bit VID Input
- 1.100V to 1.850V in 25mV Steps
• Programmable Power-On Bias Level
• Programmable Droop Voltage
• Fast Transient Recovery Time
• Precision Enable Threshold
• Overcurrent Protection
• 2-, 3-, or 4-Phase Operation
• High Ripple Frequency. Channel Frequency Times
Number Channels (100kHz to 6MHz)
Ordering Information
PART NUMBER TEMP. (^oC) PACKAGE PKG. DWG. #
ISL6557CB
0 to 70
24-Ld SOIC M24.3
ISL6557CB-T
24-Ld SOIC Tape and Reel
Pinout
ISL6557 24 PIN (SOIC)
TOP VIEW
VID4 1
VID3 2
VID2 3
VID1 4
VID0 5
COMP 6
FB 7
IOUT 8
VDIFF 9
VSEN 10
RGND 11
GND 12
24 VCC
23 EN
22 FS
21 PGOOD
20 PWM4
19 ISEN4
18 ISEN1
17 PWM1
16 PWM2
15 ISEN2
14 ISEN3
13 PWM3
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 registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2003. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners. Dynamic VID™ is a trademark of Intersil Americas Inc.