230nA Low Power µP Supervisory Circuit, Push-Pull Active-Low Reset0 pages

AS1901, AS1902, AS1903
Ultra Low-Power ìP Supervisory Circuit
Data Sheet
www.austriamicrosystems.com Revision 1.51 1 - 9
1 General Description
The AS1901/2/3 family is an ultra low-power supervisory
circuit device.
The device can be used to monitor the supply voltage of
digital systems and microprocessors and initiate a reset
when the voltage goes below a predefined threshold.
The duration of the reset is 5/20/100/500ms (typ.) after
the supply voltage has risen above the threshold.
The AS1901/2/3 exhibit excellent reliability and can
reduce application costs by eliminating all external components.
The device is available with different output drivers:
! The AS1901 has a push-pull driver with an active low
reset.
! The AS1902 uses the same output stage as the
AS1901, but has an active high reset.
! The AS1903 has an open drain output with active low
reset.
All devices operate down to a voltage of 1V.
The reset thresholds are factory-trimmable between
2.2V and 3.08V in steps of approximately 100mV.
Each device of the AS1901/2/3 family is offered with four
time-out periods of 5/20/100/500ms.
The extremely low current consumption of only 230nA
(typ) at 3.3V makes the device ideal for use in portable
applications.
All devices are available in a 3-pin SOT23 package.
Figure 1. Functional Block Diagrams
2 Key Features
! Low 230nA (typ) Supply Current
! Precision Monitoring of 2.5-, 3-, and 3.3V-Power
Supplies
! Supply Voltage Range: 1.0 to 3.6V
! Reset Threshold Range: 2.2 to 3.1V
! Available in 3 Versions:
- AS1901 Push Pull RESETN
- AS1902 Push Pull RESET
- AS1903 Open Drain RESETN
! 4 Time-Out Periods Ranging from 5 to 500ms
! Detection Voltage Accuracy: ±1.5%
! Temperature Range: -40 to +85°C
! Package: SOT23-3
3 Applications
The devices are ideal for computers, intelligent instruments,
controllers, critical microprocessor and microcontroller,
power monitoring and portable/batterypowered
equipment.
VCC
AS1903 Microprocessor
VDD
GND GND
RESETN RESET I/O
VCC
1
2
3
VCC
AS1901
AS1902
Microprocessor
VDD
GND GND
RESETN,
RESET
RESET
VCC
1
2
3