AS1320_1 AMSCO [austriamicrosystems AG], AS1320_1 Datasheet - Page 8

• Manufacturer Part Number: AS1320_1
• Description: 200mA Step-Up DC-DC Converter
• Manufacturer: AMSCO [austriamicrosystems AG]

AS1320
Data Sheet - D e t a i l e d D e s c r i p t i o n
Low-Battery Cutoff
The AS1320 SHDNN trip threshold (1.228V) can be used as an input voltage detector that disables the device when
the battery input voltage falls to a pre-set level. An external resistor-divider network can be used to set the battery-
detection voltage
Figure 16. Low-Battery Cutoff Application Diagram
For the resistor-divider network shown in
Where:
V
V
The value of R
Note: Input ripple can cause false shutdowns, therefore to minimize the effect of ripple, a low-value capacitor from
Power-On Reset
The AS1320 provides a power-on reset output (RESETN) that goes high-impedance when the output reaches 90% of
its regulation point. RESETN goes low when the output is below 90% of the regulation point. A 100kΩ to 1MΩ pullup
resistor between pin RESETN and pin OUT can provide a microprocessor logic control signal.
Note: Connect pin RESETN to GND when the power-on reset feature is not used.
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OFF
SHDNN
is the battery voltage at which the AS1320 shuts down.
SHDNN to GND should be used to filter out input noise. The value of the capacitor should be such that the R/C
time constant is > 2ms.
+1.5 to +3.5V
= 1.228V
Battery
2
should be between 100kΩ and 1MΩ to minimize battery drain.
(see Figure
22µF
C
IN
220kΩ
1MΩ
R
R
1
2
16).
10nF
10µH
L1
R
Figure
1
= R
SHDNN
BATT
2
LX
16, calculate the value for R
x ((V
2
4
1
Revision 1.03
OFF
/V
AS1320
SHDNN
) - 1)
6
RESETN
5
OUT
3
GND
1
by:
100kΩ
R
3
C
22µF
OUT
Power-On
Output
+3.3V
Reset
(EQ 1)
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