austriamicrosystems
AS1910 - AS1915
Dual-Voltage Microprocessor Supervisory Circuits
with Reset and Watchdog
Product Brief
© 1997-2005, austriamicrosystems AG, 8141 Unterpremstaetten, Austria-Europe. All Rights Reserved.
www.austriamicrosystems.com Revision 0.3 1 - 2
1 General Description
The AS1910 - AS1915 microprocessor supervisory cir-
cuits were designed to generate a reset when one of the
two monitored supply voltages falls below a factory-
trimmed threshold, and to maintain the reset for a mini-
mum timeout period when both supplies are above their
reset thresholds. Guaranteed to be in the correct state
for VCC higher than +1.0V, these devices are ideal for
multiple-voltage systems with strict monitoring require-
ments.
The AS1913/AS1914/AS1915 feature factory-trimmed
thresholds to monitor a primary voltage between 1.8 and
3.6V, and a secondary voltage between 0.9 and 2.5V.
For the AS1910/AS1911/AS1912, a secondary monitor-
ing voltage can be user-adjusted via an external resistor
divider down to 0.6V.
The devices are available with the reset output types
listed in Table 1.
The AS1910 - AS1915 include a manual-reset input for
systems that never fully power down the microproces-
sor. Additionally, these devices feature a watchdog timer
to help ensure that the processor is operating within
proper code boundaries.
The AS1910 - AS1915 are available in a 6-pin SOT23
package.
Figure 1. Typical Application Diagram
2 Key Features
! Primary VCC Supervisory Range: +1.8 to +3.6V
! Secondary VCC Supervisory Range: +0.9 to +2.5V
(AS1913/AS1914/AS1915)
! User-Adjustable Threshold Down to +0.63V
(AS1910/AS1911/AS1912)
! Guaranteed Reset Valid Down to VCC = +1.0V
! Reset Timeout Delay: 215ms
! Manual Reset Input
! Three Reset Output Types
- Active-High Push/Pull
- Active-Low Push/Pull
- Active-Low Open-Drain
! Watchdog Timeout Period: 1.5s
! Immune to Fast Negative VCC Transients
! External Components Not Required
! 6-pin SOT23 Package
3 Applications
The devices are ideal for portable and battery-powered
systems, embedded controllers, intelligent instruments,
automotive systems, critical CPU monitoring, and any
multi-supply application.
Table 1. Standard Products
Model Reset Output Type
AS1910/AS1913 Active-Low Push/Pull
AS1911/AS1914 Active-High Push/Pull
AS1912/AS1915 Active-Low Open-Drain
External
Reset
CPU
Core
Supply
I/O Supply
VCC
VCC2
GND
RESETN
I/O
4
WDI
6
VCC
3
MRN
GND 2
1
RESETN
5
VCC2
AS1913/
AS1915