AIC1639
3-PIN ONE-CELL STEP-UP DC/DC CONVERTER
SPEC NO: DS-1639-00 05/26/00
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FEATURES
DESCRIPTION
l Guaranteed Start-Up from Below 0.9 V.
The AIC1639 is a high efficiency step-up DC/DC
converter for applications using 1 to 4 battery cells.
Only three external components are required to de-
liver a fixed output voltage of 2.7, 3.0V, 3.3V, or 5V.
The AIC1639 starts up from below 0.9V input with
1mA load. Pulse Frequency Modulation scheme
brings optimized performance for applications with
light output loading and low input voltages. The out-
put ripple and noise are lower compared with the
circuits operating in PSM mode.
l High Efficiency.
l Low Quiescent Current.
l Few Number of External Components needed.
l Low Ripple and Low Noise.
l Fixed Output Voltage: 2.7, 3.0V, 3.3V, and 5V.
l Driver for External Transistor.
l Space Saving SOT-89 and TO-92 Packages.
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APPLICATIONS
l Pagers.
The PFM control circuit operating in 100KHz (max.)
switching rate results in smaller passive compo-
nents. The space saving SOT-89 and TO-92 pack-
ages make the AIC1639 an ideal choice of DC/DC
converter for space conscious applications, like
pagers, electronic cameras, and wireless micro-
phones.
l Cameras.
l Wireless Microphones.
l Pocket Organizers.
l Battery Backup Suppliers.
l Portable Instruments.
Provided with an external transistor driver pin (EXT),
the AIC1639 is recommended for applications re-
quiring current as large as several tens to several
hundreds of milli-amperes.
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TYPICAL APPLICATION CIRCUIT
V
IN
D1
V
OUT
L1
33 H
+
C2
m
47 F
m
AIC1639-27
AIC1639-30
AIC1639-3 3
AIC1639-50
R1 300
VOUT
EXT
Q1
2SD1803
+
C2
100 F
10nF
m
GND
100mA Load Current Step-Up Converter
ANALOG INTEGRATIONS CORPORATION
www.analog.com.tw
TEL: (8863)577-2500 FAX:(8863)577-2510
4F, 9IndustryE. 9thRoad, Science-basedIndustrialPark, Hsinchu, Taiwan, R.O.C.
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