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ISL6545, ISL6545A
®
Data Sheet
November 15, 2006
FN6305.3
5V or 12V Single Synchronous Buck
Features
Pulse-Width Modulation (PWM) Controller
• Operates from +5V or +12V Supply Voltage (for bias)
The ISL6545 makes simple work out of implementing a
complete control and protection scheme for a DC/DC stepdown
converter driving N-channel MOSFETs in a synchronous buck
topology. Since it can work with either 5V or 12V supplies, this
one IC can be used in a wide variety of applications within a
system. The ISL6545 integrates the control, gate drivers, output
adjustment, monitoring and protection functions into a single 8
Ld SOIC or 10 Ld DFN package.
- 1.0V to 12V V Input Range (up to 20V possible with
IN
restrictions; see Input Voltage Considerations)
- 0.6V to V Output Range
IN
- Integrated Gate Drivers use V
(5V to 12V)
CC
- 0.6V Internal Reference; ±1.0% tolerance
• Simple Single-Loop Control Design
- Voltage-Mode PWM Control
- Drives N-Channel MOSFETs
The ISL6545 provides single feedback loop, voltage-mode
control with fast transient response. The output voltage can be
precisely regulated to as low as 0.6V, with a maximum
tolerance of ±1.0% over temperature and line voltage
variations. A selectable fixed frequency oscillator (ISL6545 for
300kHz; ISL6545A for 600kHz) reduces design complexity,
while balancing typical application cost and efficiency.
• Fast Transient Response
- High-Bandwidth Error Amplifier
- Full 0% to 100% Duty Cycle
• Lossless, Programmable Overcurrent Protection
- Uses Lower MOSFET’s r
DS(ON)
• Small Converter Size in 8 Ld SOIC or 10 Ld DFN
- 300kHz or 600kHz Fixed Frequency Oscillator
The error amplifier features a 20MHz gain-bandwidth
product and 9V/μs slew rate which enables high converter
bandwidth for fast transient performance. The resulting
PWM duty cycles range from 0% to 100%.
- Fixed Internal Soft-Start, Capable into a Pre-biased
Load
- Integrated Boot Diode
Protection from overcurrent conditions is provided by
- Enable/Shutdown Function on COMP/SD Pin
- Output Current Sourcing and Sinking
monitoring the r
of the lower MOSFET to inhibit PWM
DS(ON)
operation appropriately. This approach simplifies the
implementation and improves efficiency by eliminating the
need for a current sense resistor.
• Pb-Free Plus Anneal Available (RoHS Compliant)
Applications
Pinout
• Power Supplies for Microprocessors or Peripherals
- PCs, Embedded Controllers, Memory Supplies
- DSP and Core Communications Processor Supplies
ISL6545 (SOIC)
TOP VIEW
• Subsystem Power Supplies
- PCI, AGP; Graphics Cards; Digital TV
BOOT
UGATE
1
2
3
4
8
7
6
5
PHASE
COMP/SD
FB
- SSTL-2 and DDR/DDR2/DDR3 SDRAM Bus
Termination Supply
GND
• Cable Modems, Set Top Boxes, and DSL Modems
• Industrial Power Supplies; General Purpose Supplies
• 5V or 12V-Input DC/DC Regulators
LGATE/OCSET
VCC
ISL6545 (10 LD 3x3 DFN)
• Low-Voltage Distributed Power Supplies
TOP VIEW
1
2
3
4
5
10
9
BOOT
PHASE
UGATE
COMP/SD
FB
GND
8
N/C
GND
7
N/C
6
LGATE/OCSET
VCC
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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