AAT3520/2/4
MicroPower™ Microprocessor Reset Circuit
Functional Block Diagram
VCC
Reset
Generator
+ Timer
RESET
(RESET)
Oscillator
V
REF
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).
6
3520.2006.03.1.2
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
