1/11November 2000
a73 ONLY TWO CELL NEED AS INPUT
a73 THREE REGULATED OUTPUT
1) HIGH EFFICENCY PFM DC/DC
CONVERTER 3.3V AT 200mA (87%
EFFICENCY)
2) VERY LOW NOISE AND VERY LOW
DROP V
REG
(3V AT 20mA)
3) VERY LOW NOISE AAND VERY LOW
DROP V
REG
(1.9V AT 20mA)
a73 LOGIC CONTROLLED ELECTRONIC
SHUTDOWN
a73 LOW BATTERY DETECTOR
a73 VIRTUAL GND PIN
a73 TEMPERATURA RANGE: -40 TO 85°C
ST3M01
TRIPLE VOLTAGE REGULATOR

SHDN
DC/DC
Linear A
Linear B
IN_Linear
OUT DC/DC
OUT LA
OUT LB
150 µF
1 µF
15 µH
DC/DC
Reff
Vref
Lx
Virtual GND
100 nF
GND_SW
-
+
GND_Signal
IN_SW
Vin
150 µF
1 µF
1 KΩ
LBO
On-Mode
Off-Mode
SCHEMATIC DIAGRAM
SO-14