ISL6431A Datasheet, PDF (1/10 Pages) Intersil Corporation – Advanced Pulse Width Modulation (PWM) Controller for Broadband Applications

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Data Sheet
October 2002
ISL6431A
FN9088
Advanced Pulse Width Modulation (PWM)
Controller for Broadband Applications
The ISL6431A is a high efficiency, fixed frequency,
synchronous buck PWM controller. It is designed for use in
applications that convert 5V to lower distributed voltages
required for DSL modems, cable and DSL routers and
broadband gateway core processor, memory and peripheral
power supplies.
The ISL6431A makes simple work out of implementing a
complete control and protection scheme for a DC-DC
stepdown converter. Designed to drive N-channel MOSFETs
in a synchronous buck topology, the ISL6431A integrates
the control, output adjustment, monitoring and protection
functions into a single 8-Lead package.
The ISL6431A provides simple, single feedback loop,
voltage-mode control with fast transient response. The
output voltage can be precisely regulated to as low as 0.8V,
with a maximum tolerance of ±1.5% over temperature and
line voltage variations. The device is capable of sinking, as
well as sourcing current. A fixed frequency oscillator reduces
design complexity, while balancing typical application cost
and efficiency.
The error amplifier features a 15MHz gain-bandwidth
product and 8V/µs slew rate which enables high converter
bandwidth for fast transient performance. The resulting
PWM duty cycles range from 0% to 100%.
Protection from overcurrent conditions is provided by
monitoring the r_DS(ON) of the upper MOSFET to inhibit PWM
operation appropriately. This approach simplifies the
implementation and improves efficiency by eliminating the
need for a current sense resistor.
Ordering Information
TEMP. RANGE
PART NUMBER
(^oC)
PACKAGE
ISL6431ACB
ISL6431EVAL1
0 to 70 8 Ld SOIC
Evaluation Board
PKG.
NO.
M8.15
Features
• Operates from +5V Input
• 0.8V to V_IN Output Range
- 0.8V Internal Reference
- ±1.5% Over Line Voltage and Temperature
• Drives N-Channel MOSFETs
• Simple Single-Loop Control Design
- Voltage-Mode PWM Control
• Fast Transient Response
- High-Bandwidth Error Amplifier
- Full 0% to 100% Duty Cycle
• Lossless, Programmable Overcurrent Protection
- Uses Upper MOSFET’s r_DS(on)
• Converter Can Source and Sink Current
• Small Converter Size
- 300kHz Fixed Frequency Oscillator
- Internal Soft Start
- 8-Lead SOIC Package
Applications
• Cable/DSL Routers and DSL Modems
• DSP and Core Communications Processor Supplies
• Broadband Gateways
• Memory Supplies
• Industrial Power Supplies
• 5V-Input DC-DC Regulators
• Low-Voltage Distributed Power Supplies
Pinout
BOOT 1
UGATE 2
GND 3
LGATE 4
8 PHASE
7 COMP/OCSET
6 FB
5 VCC
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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