|
CAT810SEUR-T Datasheet, PDF (7/11 Pages) ON Semiconductor – 3-Pin Microprocessor Power Supply Supervisors | |||
|
◁ |
CAT803, CAT809, CAT810
Valid RESET with VCC Under 1.0 V
To ensure that the CAT809 RESET pin is in a known state when VCC is under 1.0 V, a >10 kW pullâdown resistor between
RESET pin and GND is recommended. For the CAT810, a pullâup resistor from RESET pin to VCC is needed.
Power
Supply
Power
Supply
VCC
CAT809
RESET
GND
10 kW
VCC
CAT810
RESET
GND
10 kW
Figure 8. RESET Valid with VCC Under 1.0 V
Figure 9. RESET Valid with VCC Under 1.1 V
Biâdirectional Reset Pin Interfacing
The CAT809/810 can interface with mP/mC biâdirectional reset pins by connecting a 4.7 kW resistor in series with the
CAT809/810 reset output and the mP/mC biâdirectional reset pin.
Power
Supply
BUF
Buffered
RESET
VCC
CAT809
RESET
4.7 kW
GND
Biâdirectional
I/O Pin
VCC
mP
RESET
INPUT
GND
(For example:
68HC11)
Figure 10. Biâdirectional Reset Pin Interfacing
CAT803 OpenâDrain RESET Application
The CAT803 features an openâdrain RESET output and
therefore needs a pullâup resistor on the output for proper
operation, as shown on Figure 11. An advantage of the
openâdrain output includes the ability to âwire ANDâ
several outputs together to form an inexpensive logic circuit.
It is also possible to have the pullâup resistor connected to
a different supply which can be higher than the CAT803 VCC
pin. The value of the pullâup resistor is not critical in most
applications, typical values being between 5 kW and 10 kW.
Power
Supply
VCC
CAT803
RESET
GND
5 kW
VCC
mP
RESET
INPUT
GND
Figure 11. Typical CAT803 OpenâDrain
Circuit Configuration
http://onsemi.com
7
|
▷ |