AIC1555 Datasheet, PDF (1/15 Pages) Analog Intergrations Corporation – Low-Noise Synchronous PWM Step-Down DC/DC Converter

AIC1555
Low-Noise Synchronous PWM Step-Down
DC/DC Converter
FEATURES
95% Efficiency or up
700mA Guaranteed Output Current.
Adjustable Output Voltage from 0.75V to VIN
of a range from +2.5V to 6.5V.
Very Low Quiescent Current: 35µA (Typ.).
Fixed- 500KHz or Adjustable Frequency
Synchronous PWM Operation.
Synchronizable external Switching Frequency
up to 1MHz.
Constant Over-current-protection mode.
Accurate Reference: 0.75V (±2.5%).
100% Duty Cycle in Dropout.
Low Profile 8-Pin MSOP Package.
APPLICATIONS
PDAs.
Digital Still Cameras.
Handy-Terminals.
Cellular Phones.
CPU I/O Supplies.
Cordless Phones.
Notebook Chipset Supplies.
Battery-Operated Devices (4 NiMH/ NiCd or 1
Li-ion Cells).
DESCRIPTION
The AIC1555 is a low-noise pulse-width-
modulated (PWM) DC-DC step-down converter.
It powers logic circuits in PDAs and small
wireless systems such as cellular phones,
handy-terminals.
The device features an internal synchronous
rectifier for high conversion efficiency. Excellent
noise characteristics and fixed-frequency
operation provide easy post-filtering. The
AIC1555 is ideally suited for Li-ion battery
applications. It is also suitable for +3V or +5V
fixed input applications. The device can operate
in either one of the following four modes.
(1) Forced PWM mode operates at a fixed
frequency regardless of the load.
(2) Synchronizable PWM mode allows the
synchronization by using an external
switching frequency with a minimum
harmonics.
(3) PWM/PFM Mode extends battery life by
switching to a PFM pulse-skipping mode
under light loads.
(4) Shutdown mode sets device to standby,
reducing supply current to 0.1µA or under.
The AIC1555 can deliver over 700mA output
current. The output voltage can be adjusted
from 0.75V to VIN ranging from +2.5V to +6.5V.
Other features of the AIC1555 include low
quiescent current, low dropout voltage, and a
0.75V reference of ±2.5% accuracy. It is
available in a space-saving 8-pin MSOP
package.
Analog Integrations Corporation
Si-Soft Research Center
3A1, No.1, Li-Hsin Rd. I , Science Park , Hsinchu 300, Taiwan , R.O.C.
TEL: [phone]
FAX: [phone] www.analog.com.tw
DS-1555G-01 121608
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