September 9, 2005
1.4MHz Dual, 180° Out-of-Phase,
Step-Down PWM Controller
The ISL6445 is a high-performance, dual-output PWM
controller optimized for converting wall adapter, battery or
network intermediate bus DC input supplies into the system
supply voltages required for a wide variety of applications.
Each output is adjustable down to 0.8V. The two PWMs are
synchronized 180o out of phase reducing the RMS input
current and ripple voltage.
The ISL6445 incorporates several protection features. An
adjustable overcurrent protection circuit monitors the output
current by sensing the voltage drop across the lower
MOSFET. Hiccup mode overcurrent operation protects the
DC/DC components from damage during output
overload/short circuit conditions. Each PWM has an
independent logic-level shutdown input (SD1 and SD2).
A single PGOOD signal is issued when soft-start is complete
on both PWM controllers and their outputs are within 10% of
the set point. Thermal shutdown circuitry turns off the device
if the junction temperature exceeds +150°C.
1 LGATE2 LGATE1 24
2 BOOT2 BOOT1 23
3 UGATE2 UGATE1 22
4 PHASE2 PHASE1 21
6 PGOOD PGND 19
10 OCSET2 OCSET1 15
• Wide Input Supply Voltage Range
- 5.6V to 24V
- 4.5V to 5.6V
• Two Independently Programmable Output Voltages
• Switching Frequency . . . . . . . . . . . . . . . . . . . . . . .1.4MHz
• Out of Phase PWM Controller Operation
- Reduces Required Input Capacitance and Power
Supply Induced Loads
• No External Current Sense Resistor
- Uses Lower MOSFET’s rDS(ON)
• Programmable Soft-Start
• Extensive Circuit Protection Functions
- Independent Shutdown for Both PWMs
• Excellent Dynamic Response
- Voltage Feed-Forward with Current Mode Control
• Pb-Free Plus Anneal Available (RoHS Compliant)
• Power Supplies with Two Outputs
• xDSL Modems/Routers
• DSP, ASIC, and FPGA Power Supplies
• Set-Top Boxes
• Dual Output Supplies for DSP, Memory, Logic, µP Core
• Telecom Systems
NUMBER MARKING RANGE (°C) PACKAGE DWG. #
ISL6445IAZ* ISL6445IAZ -40 to 85 24 Ld QSOP M24.15
NOTE: Intersil Pb-free plus anneal products employ special Pb-free
material sets; molding compounds/die attach materials and 100%
matte tin plate termination finish, which are RoHS compliant and
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-020.
*Add “-TK” suffix for tape and reel.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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