The ISL78322 is a high efficiency, dual synchronous step-down

DC/DC regulator that can deliver up to 2A/1.7A continuous

output current per channel. The channels are 180° out-of-phase

for input RMS current and EMI reduction. The supply voltage

range of 2.8V to 5.5V allows for the use of a single Li+ cell, three

NiMH cells or a regulated 5V input. The current mode control

architecture enables very low duty cycle operation at high

frequency with fast transient response and excellent loop

stability. The ISL78322 operates at 2.25MHz switching frequency

which allows for the use of small, low cost inductors and

capacitors. Each channel is optimized for generating an output

voltage as low as 0.6V.

The ISL78322 has a user configurable mode of operation-forced

PWM mode and PFM/PWM mode. The forced PWM mode

reduces noise and RF interference while the PFM mode provides

highest efficiency by reducing switching losses at light loads. In

PFM mode of operation, both channels draw a total quiescent

current of only 40µA, hence enabling high light load efficiency

and maximizing battery life.

The ISL78322 offers a 1ms Power-Good (PG) signal to monitor

both outputs at power-up. When shut down, ISL78322

discharges the output capacitors. Other features include internal

digital soft-start, enable for power sequence, overcurrent

protection, and thermal shutdown. The ISL78322 is offered in a

4mmx3mm, 12 Lead DFN package with 1mm maximum height.

The complete converter occupies less than 1.8cm2 area.

The ISL78322 is qualified to AEC-Q100 and specified for

operation across the -40°C to +105°C (grade 2) ambient

temperature range.

Features

• Dual 2A/1.7A high efficiency synchronous buck regulator with

up to 97 efficiency, low IQ (40µA)

• 180° out-of-phase outputs reduce ripple current and EMI

• Start-up with prebiased output prevents negative current flow

in output stage

• Selectable forced PWM mode and PFM mode

• External synchronization up to 8MHz

• Negative current detection and protection

• 100 maximum duty cycle for lowest dropout

• Internal current mode compensation

• Peak current limiting, hiccup mode short circuit protection and

over-temperature protection

• Pb-free (RoHs compliant)

• AEC-Q100 qualified component

Applications

• DC/DC POL modules

• µC/µP, FPGA and DSP power

• Automotive embedded processor power supply systems