AAT3520/2/4
MicroPower™ Microprocessor Reset Circuit
Functional Block Diagram
VCC
Reset
RESET
Generator
+ Timer
(RESET)
Oscillator
VREF
GND
VCC voltage falls below a factory-programmed
threshold. This threshold is accurate within ±1.5%
at 25ºC and within ±2.5% over the entire operating
temperature range. The reset signal remains
asserted for a fixed time period (tRDY) after VCC has
risen above the threshold, as shown in Figure 1.
See Ordering Information for available RESET
active timeout periods
Functional Description
General
During start-up, the reset pin on a microprocessor
ensures that it is fully reset and starts up in a known
condition. The AAT3520 series of microprocessor
reset devices monitor the supply voltage to a micro-
processor and assert a reset signal whenever the
VCC
VTH
VTH
VTH
tRDY
tRDY
RESET
Figure 1: Reset Timing Diagram (AAT3522, AAT3524).
6
3520.2006.03.1.2
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
