ISL78322

Dual 2A/1.7A, 2.25MHz High-Efficiency, Synchronous Buck Regulator

Product Status: Mass Production

OVERVIEW

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 forced PWM mode that reduces noise and RF interference.

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.

KEY FEATURES

  • Dual 2A/1.7A high-efficiency, synchronous buck regulator with up to 97% efficiency
  • 2.8V to 5.5V input supply range
  • 180° out-of-phase outputs reduce ripple current and EMI
  • Start-up with prebiased output prevents negative current flow in output stage
  • 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

BLOCK DIAGRAM

 Block Diagram

PARAMETRICS

Parameters
ISL78322
Basic Information
Production Status
Mass Production
iSim Model
YES
# of Outputs
2
Topology [Rail 1]
Buck
Input Voltage Min (V) [Rail 1]
2.8
Input Voltage Max (V) [Rail 1]
5.5
Output Voltage Min (V) [Rail 1]
0.6
Output Voltage Max (V) [Rail 1]
5.5
Output Current Max (A) [Rail 1]
2
IQ [Rail 1]
40 µA
Switching Freq. (max) (MHz)
2.7
Switching Freq. (min) (MHz)
1.8
Max Duty Cycle (%)
See Datasheet
Qualification Level
Automotive
Peak Efficiency (%)
97
POR
Yes
BOM Total Footprint (mm2)
180
SYNCH Capability
Yes
Control Type
Current Mode
Switching Frequency Range (MHz)
1.8 to 2.7
Temperature Range
-40 to +105

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