ISL8088

Dual 800mA Low Quiescent Current 2.25MHz High Efficiency Synchronous Buck Regulator

OVERVIEW

The ISL8088 is a high efficiency, dual synchronous step-down DC/DC regulator that can deliver up to 800mA continuous output current per channel. The supply voltage range of 2.75V to 5.5V allows 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 ISL8088 operates at 2.25MHz switching frequency allowing the use of small, low cost inductors and capacitors. Each channel is optimized for generating an output voltage as low as 0.6V.

The ISL8088 has a user configurable mode of operation-forced PWM mode and PFM/PWM mode. The forced PWM mode operation reduces noise and RF interference while the PFM mode operation provides high efficiency by reducing switching losses at light loads. In PFM mode of operation, both channels draw a total quiescent current of only 30µA hence enabling high light load efficiency in order to maximize battery life.

The ISL8088 offers a 1ms Power-Good (PG) to monitor both output at power-up. When shutdown, ISL8088 discharges the outputs capacitor. Other features include internal digital soft-start, enable for power sequence, overcurrent protection, and thermal shutdown. The ISL8088 is offered in a 3mmx3mm 10 Ld DFN package with 1mm maximum height. The complete converter occupies less than 1.8cm2 area.

KEY FEATURES

  • Internal Current Mode Compensation
  • 100% Maximum Duty Cycle for Lowest Dropout
  • Selectable Forced PWM Mode and PFM Mode
  • External Synchronization up to 4MHz
  • Start-up with Pre-biased Output
  • Soft-Stop Output Discharge During Disabled
  • Internal Digital Soft-Start - 2ms
  • Power-Good (PG) Output with 1ms Delay

BLOCK DIAGRAM

 Block Diagram

PARAMETRICS

Parameters
ISL8088
Basic Information
Production Status
Mass Production
Topology
Buck
# of Outputs
2
Input Voltage Min (V)
2.75
Input Voltage Max (V)
5.5
Output Voltage Min (V)
0.6
Output Voltage Max (V)
5.5
Output Current Max (A)
0.8
Switching Freq. (max) (MHz)
2.25
Switching Freq. (min) (MHz)
2.25
Qualification Level
Standard
Peak Efficiency (%)
96
POR
Yes
SYNCH Capability
Yes
Control Type
Current Mode
Switching Frequency Range (MHz)
2.25
Can Sample
YES
Temperature Range
-40 to +85

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