LTC692/LTC693
16
0692fb
APPLICATIONS INFORMATION
Pushbutton Reset
The LTC692/LTC693 do not provide a logic input for direct
connection to a pushbutton. However, a pushbutton in
series with a 100Ω resistor connected to the RESET output
pin (Figure 13) provides an alternative for manual reset.
Connecting a 0.1μF capacitor to the RESET pin debounces
the pushbutton input.
The 100Ω resistor in series with the pushbutton is required
to prevent the ringing, due to the capacitance and lead
inductance, from pulling the RESET pins of the MPU and
LTC692/LT693 below ground.
5V
100Ω
V
CC
LTC692
LTC693
GND
692_3 • F13
RESET
0.1μF
MPU
(e.g. 6805)
RESET
Figure 13. The External Pushbutton Reset
TYPICAL APPLICATIONS
Capacitor Backup with 74HC4016 Switch
Write-Protect for Additional RAMs
R1
10k
R2
30k
0.1μF
0.1μF
14121110
1
7
100μF
13
2
5V
V
CC
V
OUT
V
BATT
74HC4016
692_3 • TA03
LOW LINE
GND
LTC693
+
10μF
V
BATT
V
CC
LTC693
V
OUT
GND
692_3 • TA04
V
CC
LOW LINE
CE IN
CE OUT
0.1μF
0.1μF
0.1μF
CS
20ns PROPAGATION
DELAY
62512
RAM
A
5V
3V
0.1μF
V
CC
62128
RAM
C
V
CC
CS
2
62128
RAM
B
CS
A
CS
B
CS
C
CS
1
CS
1
OPTIONAL CONNECTION FOR
ADDITIONAL RAMs
CS
2
+
