CAT809 Datasheet, PDF (8/13 Pages) Catalyst Semiconductor – 3-Pin Microprocessor Power Supply Supervisors

CAT809, CAT810
VALID RESET WITH V_CC UNDER 1.0 V
To ensure that the CAT809 RESET pin is in a known state when VCC is under 1.0 V, a 100 kΩ pull-down resistor
between RESET pin and GND is recommended; the value is not critical. For the CAT810, a pull-up resistor from
RESET pin to VCC is needed.
Power
Supply
Power
Supply
VCC
CAT809
RESET
GND
100kΩ
VCC
CAT810
RESET
GND
100kΩ
FIGURE 3. RESET Valid with VCC Under 1.0 V
FIGURE 4. RESET Valid with VCC Under 1.1 V
BI-DIRECTIONAL RESET PIN INTERFACING
The CAT809/810 can interface with µP/µC bi-directional reset pins by connecting a 4.7 kΩ resistor in series with the
CAT809/810 reset output and the µP/µC bi-directional reset pin.
Power
Supply
VCC
BUF
Buffered
RESET
CAT809
RESET
4.7kΩ
µP
RESET
INPUT
GND
GND
Bi-directional I/O Pin
(For example: 68HC11)
FIGURE 5. Bi-directional Reset Pin Interfacing
Doc. No. 3004, Rev. S
8
Patent Pending