sp690acp Exar Corporation, sp690acp Datasheet - Page 13

• Manufacturer Part Number: sp690acp
• Description: Low Power Microprocessor Supervisory With Battery Switch-over
• Manufacturer: Exar Corporation

Figure 19. Monitoring a Negative Voltage
Interfacing to Microprocessors with
Bidirectional Reset Pins
Microprocessors with bidirectional reset pins,
such as the Motorola 68HC11 series, can con-
tend with this series' RESET output. If, for
example, the RESET output is driven high and
the µP wants to pull it low, indeterminate logic
levels may result. To correct this, connect a
4.7KΩ resistor between the RESET output and
the µP reset I/O, as in Figure 20. Buffer the
RESET output to other system components.
Date: 11/29/04
+5V
GND
V
CC
PFO
PFI
SP690A/692A Low Power Microprocessor Supervisory with Battery Switch-Over
5.0 - 1.25
*V
*V
R
1
TRIP
TRIP
PFO
is a negative voltage
0V
+5V
0V
=
1.25 - V
R
2
TRIP
V-
V-
R
R
2
1
13
Figure 20. Interfacing to Microprocessors with
Bidirectional RESET I/O
Buffered RESET connects to System Components
+5V
GND
V
CC
RESET
4.7KΩ
© Copyright 2004 Sipex Corporation
RESET
+5V
µP
V
GND
CC