IMP705/6/7/8, 8 13L
Application Information
Ensuring That RESET is Valid Down to V
CC
= 0V
When V
CC
falls below 1.1V, the IMP705-708 RESET output no
longer pulls down; it becomes indeterminate. To avoid the possi-
bility that stray charges build up and force RESET to the wrong
state, a pull-down resistor should be connected to the RESET pin,
thus draining such charges to ground and holding RESET
low. The resistor value is not critical. A 100kΩ resistor will pull
RESET to ground without loading it.
V
CC
< 1.1V
V
CC
V
CC
Bi-directional Reset Pin Interfacing
The IMP705/6/7/8 can interface with
µP/µC
bi-directional reset
pins by connecting a 4.7kΩ resistor in series with the RESET
output and the
µP/µC
bi-directional RESET pin.
BUF
Buffered
RESET
IMP70x
100k
9
RESET
GND
Power
Supply
IMP70x
4.7kΩ
RESET
GND
Bi-directional I/O Pin
(Example: 68HC11)
µC
or
µP
RESET
Input
GND
705_08.eps
705_06.eps
Figure 3. Ensuring That RESET is Valid Down to V
CC
= 0V
Figure 3. Bi-directional Reset Pin Interfacing
6
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©
1999 IMP, Inc.
IMP [ IMP, INC ]
