AAT3520 Datasheet, PDF (6/9 Pages) Advanced Analogic Technologies – MicroPower Microprocessor Reset Circuit

AAT3520/2/4
MicroPower™ Microprocessor Reset Circuit
Functional Block Diagram
VCC
VREF
Reset
Generator
+ Timer
RESET
(RESET)
Oscillator
GND
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
V_CC 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 (t_RDY) after V_CC has
risen above the threshold, as shown in Figure 1.
See Ordering Information for available RESET
active timeout periods
V_CC
V_TH
V_TH
V_TH
RESET
t_RDY
t_RDY
Figure 1: Reset Timing Diagram (AAT3522, AAT3524).
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3520.2006.03.1.2