AS1916 - AS1918
Microprocessor Supervisory Circuits with Manual
Reset and Watchdog
austriamicrosystems
Data Sheet
www.austriamicrosystems.com Revision 0.52 1 - 13
1 General Description
The AS1916 - AS1918 microprocessor supervisory cir-
cuits were designed to generate a reset when the moni-
tored supply voltage falls below a factory-trimmed
threshold. The reset remains asserted for a minimum
timeout period after the supply voltage stabilizes.
Guaranteed to be in the correct state for VCC higher than
+1.0V, these devices are ideal for portable and battery-
powered systems with strict monitoring requirements.
The devices feature factory-trimmed thresholds to moni-
tor a supply voltage between 1.8 and 3.6V.
The devices are available with the reset output types
listed in Table 1.
The AS1916 - AS1918 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 AS1916 - AS1918 are available in a 5-pin SOT23
package.
Figure 1. Typical Application Diagram
2 Key Features
! VCC Supervisory Range: +1.8 to +3.6V
! Guaranteed Reset Valid Down to VCC = +1.0V
! Reset Timeout Delay: 215ms
! Manual Reset Input
! Three Reset Output Types
- Active-Low Push/Pull (AS1916)
- Active-High Push/Pull (AS1917)
- Active-Low Open-Drain (AS1918)
! Watchdog Timeout Period: 1.5s
! Immune to Fast Negative VCC Transients
! External Components Not Required
! 5-pin SOT23 Package
3 Applications
The devices are ideal for portable and battery-powered
systems, embedded controllers, intelligent instruments,
automotive systems, and critical CPU monitoring appli-
cations.
Table 1. Standard Products
Model Reset Output Type
AS1916 Active-Low Push/Pull
AS1917 Active-High Push/Pull
AS1918 Active-Low Open-Drain
AS1916/
AS1918
External
Reset
CPU
I/O Supply
VCC
GND
RESETN
I/O
4
WDI
5
VCC
3
MRN
GND 2
1
RESETN