ISL9440, ISL9440A, ISL9441
®
Data Sheet
December 5, 2007
FN6383.1
Triple, 180° Out-of-Phase, Step-Down
PWM and Single Linear Controller
Features
• Three Integrated Synchronous Buck PWM Controllers
- Internal Bootstrap Diodes
The ISL9440, ISL9440A and ISL9441 are quad-output
synchronous buck controllers that integrate 3 PWM
- Internal Compensation
controllers and 1 low drop-out linear regulator controller, which
are full featured and designed to provide multi-rail power for
use in products such as cable and satellite set-top boxes,
VoIP gateways, cable modems, and other home connectivity
products as well as a variety of industrial and general purpose
applications. Each output is adjustable down to 0.8V. The
PWMs are synchronized at 180° out of phase thus reducing
the RMS input current and ripple voltage.
- Internal Soft-Start
• Independent Control for Each Regulator and
Programmable Output Voltages; Independent
Enable/Shutdown
• Fixed Switching Frequency: 300kHz (ISL9440, ISL9441);
600kHz (ISL9440A)
• Adaptive Shoot Through Protection on all Synchronous
Buck Controllers
The ISL9440, ISL9440A and ISL9441 offer internal soft-start,
independent enable inputs for ease of supply rail
sequencing, and integrated UV/OV/OC/OT protections in a
space conscious 5mmx5mm QFN package. The ISL9440
and ISL9440A offer an early warning function to output a
logic signal to warn the system to back up data when input
voltage falls below a certain level.
• Independently Programmable Voltage Outputs
• Out-of-Phase Switching to Reduce Input Capacitance
(0°/180°/0°)
• No External Current Sense Resistor
- Uses Lower MOSFET’s rDS(ON)
• Current Mode Controller with Voltage Feed Forward
The ISL9440, ISL9440A and ISL9441 utilize internal loop
compensation to keep minimum peripheral components for
compact design and a low total solution cost. These devices
are implemented with current mode control with feed forward
to cover various applications even with fixed internal
compensations.
• Complete Protection
- Overcurrent, Overvoltage, Undervoltage Lockout,
Over-Temperature
• Cycle by Cycle Current Limiting
• Wide Input Voltage Range
The table below shows the difference in terms of ISL9440,
ISL9440A and ISL9441 features.
- Input Rail Powers VIN Pin: 5.6V to 24V
- Input Rail Powers VCC_5V Pin (VIN tied to VCC_5V, for
5V input applications): 4.5V to 5.6V
PART
NUMBER
EARLY
WARNING
SWITCHING FREQUENCY
(kHz)
• Early Warning (ISL9440, ISL9440A) on Input Voltage
Failure
ISL9440
YES
YES
NO
300
600
300
ISL9440A
ISL9441
• Integrated Reset Function (ISL9440, ISL9440A)
• Pb-free (RoHS compliant)
Applications
• Satellite and Cable Set-Top Boxes
• Cable Modems
• VoX Gateway Devices
• NAS/SAN Devices
Related Literature
• Technical Brief TB389 “PCB Land Pattern Design and
Surface Mount Guidelines for QFN (MLFP) Packages”
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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1
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