AS1920/AS1922
Datasheet - Detailed Description
8 Detailed Description
The AS1920/AS1922 microprocessor supervisory circuits were designed to generate a reset when at least one of the
three monitored supply voltages falls below its respective trip threshold.
These very-low-current (6.5µA, typ) devices maintain reset for a minimum timeout period after all supplies have stabi-
lized. Guaranteed to be in the correct state for VCC > +1.0V, these devices are perfect for multiple-voltage systems with
low current requirements and strict monitoring requirements.
Figure 9. AS1920 Block Diagram
5
–
VCC3
Power
VCC
+
Detect Internal
4
VCC18
–
+
200ms Pulse Generator
200ms
Delay
VCC3
1
RESETN
3
VCCA
2
GND
–
+
Bandgap
Reference
AS1920
Figure 10. VCC Monitor Timing Diagram
VCCX
RESETN
VRTX
tUV
tRST
1.5V
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