ISL6446A View Datasheet(PDF) - Renesas Electronics

Part Name

Description

MFG CO.

ISL6446A

Dual (180°Out-of-Phase) PWM and Linear Controller

Renesas Electronics 

DATASHEET

ISL6446A

Dual (180°Out-of-Phase) PWM and Linear Controller

FN8384

Rev 3.00

Aug 27, 2015

The ISL6446A is a high-performance, triple output controller

that provides a single high-frequency power solution primarily

for Broadband, DSL and Networking applications. This device

integrates complete control, monitoring and protection

functions for two synchronous buck PWM controllers and one

linear controller. Input voltage ripple and total RMS input

current is substantially reduced by synchronized 180°

out-of-phase operation of the two PWMs.

The two PWM buck converters provide simple voltage mode

control. The output voltage of the converters can be precisely

regulated to as low as 0.6V, with a maximum tolerance of

±1.5% over-temperature and line variations. Programmable

switching frequency down to 100kHz provides optimized low

cost solution for ATX power supplies. It is also able to operate

up to 2.5MHz to deliver compact solutions. The linear

controller provides a low-current output.

Each PWM controller has soft-start and independent enable

functions combined on a single pin. A capacitor from SS/EN to

ground sets the soft-start time; pulling SS/EN pin below 1V

disables the controller. Both outputs can soft-start into a

prebiased load.

The ISL6446A incorporates robust protection features. An

adjustable overcurrent protection circuit monitors the output

current by sensing the voltage drop across the upper MOSFET

rDS(ON). Latch-off mode overcurrent operation protects the

DC/DC converters from damage under overload and

short-circuit conditions. A PGOOD signal is issued when

soft-start is complete and PWM outputs are within 10% of

their regulated values and the linear regulator output is higher

than 75% of its nominal value. Thermal shutdown circuitry

turns the device off if the IC temperature exceeds +150°C.

Features

• 4.5V to 5.5V or 5.5V to 24V input voltage range

• Three programmable power output voltages

- Two PWM controllers with out-of-phase operation

- Voltage-mode PWM control

- One linear controller

• Programmable switching frequency from 100kHz to 2.5MHz

• Fast transient response

- High-bandwidth error amplifier

• Extensive circuit protection functions

- Undervoltage, and over-temperature

- Overvoltage with latch-off mode

- Programmable overcurrent limit with latch-off mode

- Lossless current sensing (no sense resistor needed)

• Externally adjustable soft-start time

- Independent enable control

- Voltage tracking capability

- Able to soft-start into a prebiased load

• PGOOD output with delay

Applications

• ATX power supplies

• DSP, ASIC, and FPGA point-of-load regulation

• Industrial and security networking applications

FN8384 Rev 3.00

Aug 27, 2015

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