stm6717tz STMicroelectronics, stm6717tz Datasheet - Page 10

• Manufacturer Part Number: stm6717tz
• Description: Dual/triple Ultra-low Voltage Supervisors With Push-button Reset With Delay Option
• Manufacturer: STMicroelectronics

2
2.1
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Operation
Applications information
1.
2.
Figure 11. STM67xx interface to processor with bi-directional reset pins
Figure 12. Ensuring RST valid to V
Interfacing to processors with bi-directional reset pins
Most processors with bi-directional reset pins can interface directly to the open drain
RST outputs (STM6717/19/77/79). Systems simultaneously requiring a push-pull RST
output and a bi-directional reset interface can be in logic contention. To prevent this
contention, connect a 4.7kΩ resistor between RST and the processor’s reset I/O as
shown in
Ensuring a Valid RST Output Down to V
The STM67xx Supervisors are guaranteed to be in the correct RST output logic state
when V
levels down to V
Figure
sink or source current. This scheme does NOT work with the open drain outputs of the
STM6717/19/77/79.
The resistor value used is not critical, but it must be large enough not to load the reset
output when V
adequate.
12) will ensure that the reset line is valid while the reset output can no longer
CC1
Figure
and/or V
V CC2
CC
CC
11.
is above the reset threshold. For most applications, 100kΩ is
= 0, a pull-down resistor to active-low outputs (push-pull only, see
V CC1
CC2
is greater than 0.8V. In applications which require valid reset
V CC1
V CC2
STM67xx
AI10426
V SS
CC
V SS
RST
= 0 (active-low, push-pull outputs)
STM67xx
CC
components
To other
system
V CC1
= 0V
RST
4.7kΩ
V CC1
R1
RESET
Processor
V SS
AI10425