ISL8088 Datasheet, PDF (1/18 Pages) Intersil Corporation – Dual 800mA Low Quiescent Current 2.25MHz High Efficiency Synchronous Buck Regulator

Dual 800mA Low Quiescent Current 2.25MHz High
Efficiency Synchronous Buck Regulator
ISL8088
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.
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
Applications*(see page 17)
• DC/DC POL Modules
• µC/µP, FPGA and DSP Power
• Plug-in DC/DC Modules for Routers and Switchers
• Test and Measurement Systems
• Li-ion Battery Power Devices
• Bar Code Readers
Efficiency Characteristics Curve
100
90
80
2.5V_OUT-PFM
70
1.8V_OUT-PFM
2.5V_OUT-PWM
60
50
1.8V_OUT- PWM
VIN = 5V
40
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
OUTPUT LOAD (A)
Pin Configuration
ISL8088
(10 LD 3X3 DFN)
TOP VIEW
FB1 ₁
EN1 2
VIN 3
LX1 4
NC 5
11 PGND
10 ^FB2
9 EN2
8 PG
7 LX2
6 SYNC
September 21, 2009
FN6858.0
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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