ISL9440B Datasheet, PDF (1/24 Pages) Intersil Corporation – Triple Step-Down PWM and Single Linear Controller with Programmable Soft-Start

®
Data Sheet
ISL9440B, ISL9440C
June 24, 2010
FN6799.3
Triple Step-Down PWM and Single Linear
Controller with Programmable Soft-Start
The ISL9440B and ISL9440C are quad-output synchronous
buck controllers that integrate three PWM controllers and one
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.
The ISL9440B and ISL9440C offer programmable 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. An early
warning function is offered to output a logic signal to warn
the system to back up data when input voltage falls below a
certain level.
The ISL9440B and ISL9440C 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.
Table 1 shows the difference in terms of ISL944xx family
features.
TABLE 1.
PART
NUMBER
SWITCHING
EARLY FREQUENCY
WARNING
(kHz)
SOFT-STARTING
TIME (ms)
ISL9440
Yes
300
1.7
ISL9440A
Yes
600
1.7
ISL9441
No
300
1.7
ISL9440B
Yes
300
Programmable
ISL9440C
Yes
600
Programmable
Features
• Three Integrated Synchronous Buck PWM Controllers
- Internal Bootstrap Diodes
- Internal Compensation
• Independent Control for each Regulator and
Programmable Output Voltages; Independent
Enable/Shutdown/Soft-start
• Fixed Switching Frequency: 300kHz(B), 600kHz(C)
• Adaptive Shoot-Through Protection on all Synchronous
Buck Controllers
• Pre-biased Output Start-up Capability
• Out-of-Phase Switching to Reduce Input Capacitance
(0°/180°/0°)
• No External Current Sense Resistor
- Uses Lower MOSFET’s r_DS(ON)
• Current Mode Controller with Voltage Feed-Forward
• Complete Protection
- Overcurrent, Overvoltage, Undervoltage Lockout,
Over-Temperature
• Cycle-by-Cycle Current Limiting
• Wide Input Voltage Range
- 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
• Early Warning on Input Voltage Failure
• Integrated Reset Function
• Pb-Free (RoHS Compliant)
Applications
• Satellite and Cable Set-Top Boxes
• Cable Modems
• VoX Gateway Devices
• NAS/SAN Devices
• ATX Power Supply
Related Literature
• Technical Brief TB389 “PCB Land Pattern Design and
Surface Mount Guidelines for QFN (MLFP) Packages”
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2009, 2010. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.