RS5C313 RICOH Co.,Ltd., RS5C313 Datasheet - Page 19

• Manufacturer Part Number: RS5C313
• Description: Ultra-compact Real-time Clock Ic
• Manufacturer: RICOH Co.,Ltd.

7. Oscillation Frequency Adjustment
7.2 Oscillation Frequency Adjustment
7.1 Oscillation Frequency Measurement
*
*
*
1) To ensure that the crystal is matched to the IC, inquire its crystal supplier about its C
2) To allow for the possible effects of floating capacitance, select the optimum capacitance of the C
3) Collate the central variable capacitance value of the C
OSCOUT
OSCIN
ues. It is recommended that the crystal should have the C
mendable capacitance values of the C
accuracy, change the C
the C
that the central variable capacitance value should be slightly less than one half of the actual variable capacitance value because the smaller is vari-
able capacitance, the greater are fluctuations in oscillation frequency.) In the case of an excessive deviation of the oscillation frequency from its
required value, change the C
INTR
Change C
value of crystal.
VDD
VSS
CE
G
in such a manner that the actual variable capacitance value is slightly smaller than the central variable capacitance value. (It is recommended
L
32kHz
NG
(For fixed capacitance)
L
C
value of the crystal.
G
L
value of the crystal.
Optimize C
OK
Fix C
End
G
range from 5 to 24pF and 8 to 20pF, respectively. When you need to change the frequency to get higher
G
+5V or +3V
Frequency
.
counter
G
.
Select crystal oscillator
*
2
G
with its oscillation frequency by adjusting the angle of rotation of the variable capacitance of
L
value range of 6 to 8pF and the typical R1 value of 30k ohms.
1) When switch the CE pin to the high level after low level or
2) Ensure that the frequency counter has more than six digits
3) Place the C
Make fine frequency adjustment
open state, a 1-Hz interrupt pulse is output from the INTR
pin about 2.5 seconds later. Measure this interrupt pulse by
using a frequency counter
(on the order of 1 ppm).
pull up the INTR pin output to the V
with variable capacitance.
Fix the capacitance of C
Optimize central variable
(For variable capacitance)
capacitance value
*
1
OK
G
End
L
between the OSCIN pin and the V
(load capacitance) and R1 (equivalent series resistance) val-
G
on the mounted PCB. The standard and recom-
G.
*
*
3
3
NG
Change the C
value of crystal.
DD
.
RS5C313
L
SS
level and
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