ISL6557A Datasheet, PDF (1/19 Pages) Intersil Corporation – Multi-Phase PWM Controller for Core-Voltage Regulation

®
Data Sheet
July 2004
ISL6557A
FN9068.3
Multi-Phase PWM Controller for
Core-Voltage Regulation
The ISL6557A 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-suppply 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 ISL6557A 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
igMHz giving the designer the ultimate flexibility in managing
the balance between high-speed response and good
thermal management.
New features on the ISL6557A include Dynamic-VID™
technology allowing seamless on-the-fly VID changes with
no need for any additional external components. When the
ISL6557A 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 ISL6557A 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
- 0.800V to 1.550V 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)
• Pb-free available
Ordering Information
PART NUMBER TEMP. (^oC) PACKAGE PKG. DWG. #
ISL6557ACB
0 to 70
24-Ld SOIC M24.3
ISL6557ACBZ
(See Note)
0 to 70
24-Ld SOIC M24.3
(Pb-free)
*Add “-T” suffix to part number for tape and reel packaging.
NOTE: Intersil Pb-free products employ special Pb-free material sets; molding
compounds/die attach materials and 100% matte tin plate termination finish, which
is 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-020B.
Pinout
ISL6557A 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 trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2003, 2004. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners. Dynamic VID™ is a trademark of Intersil Americas Inc.