M51957A,B/M51958A,B
Example of Application Circuit
Reset Circuit of M5195xx Series
VCC
Power-
supply
Power-
supply
R1
RL
Input
Output
M51957x
M51958x
RESET (RESET)
Logic circuit
R2
GND
Delay capacitor
Cd
GND
Figure 1 Reset Circuit of M5195xx Series
Notes: 1. When the detecting supply voltage is 4.25 V, M51951, M51952, M51953 and M51954 are used. In this case,
R1 and R2 are not necessary.
When the voltage is anything except 4.25 V, M51955, M51956, M51957 and M51958 are used. In this case,
the detecting supply voltage is 1.25 × (R1 +R2)/R2 (V) approximately. The detecting supply voltage can be
set between 2 V and 15 V.
2. When the delay time is short, M51951, M51952, M51955 and M51956 are available. These ICs have a
delay capacity and the delay time is about 200 µs.
If a longer delay time is necessary, M51953, M51954, M51957 and M51958 are used. In this case, the delay
time is about 0.34 × Cd (pF) µs.
3. If the M5195xx and the logic circuit share a common power source, type A (built-in load type) can be used
whether a pull-up resistor is included in the logic circuit or not.
4. The logic circuit preferably should not have a pull-down resistor, but if one is present, add load resistor RL to
overcome the pull-down resistor.
5. When the reset terminal in the logic circuit is of the low reset type, M51951, M51953, M51955 and M51957
are used and when the terminal is of the high reset type, M51952, M51954, M51956 and M51958 are used.
6. When a negative supply voltage is used, the supply voltage side of M5195xx and the GND side are
connected to negative supply voltage respectively.
Case of Using Reset Signal except Supply Voltage in the M5195xx Series
(a) Reset at ON
(b) Reset at transistor ON
Power-
VCC
VCC
Power-
supply
Power-
supply
Power-
supply
supply
R1
R1
RL
RL
Out
put
Out
put
Input
Input
M5195xx
(External delay
capacitor type)
M5195xx
(External delay
capacitor type)
RESET (RESET)
Logic circuit
RESET (RESET)
Logic circuit
R2
R2
GND
Delay capacitor
Cd
GND
GND
Delay capacitor
Cd
GND
Control
signal
Figure 2 Case of Using Reset Signal except Supply Voltage in the M5195xx Series
REJ03D0778-0200 Rev.2.00 Aug 20, 2007
Page 6 of 13
RENESAS [ RENESAS TECHNOLOGY CORP ]
