UPD4991ACX Renesas Electronics America, UPD4991ACX Datasheet - Page 54

• Manufacturer Part Number: UPD4991ACX
• Manufacturer: Renesas Electronics America

Specifications of UPD4991ACX

• Lead Free Status / RoHS Status: Supplier Unconfirmed

4.3 Adjusting Oscillation Frequency
however, it is mostly determined by the accuracy of adjustment of the oscillation frequency. To improve the accuracy,
therefore, adjustment is essential.
or the interval signal is output to TP2. While this signal is measured with a frequency counter or cycle counter, adjust
the trimmer capacitor so that the frequency reaches the specified value or that the specified cycle is reached.
of the capacitance of the probe, making correct measurement impossible.
accuracy of 10 ppm. Similarly, when the 1-second interval signal is output to TP2, 1.000 00 0.000 01 sec. must
be directly read.
52
The accuracy of the watch depends on the stability of the oscillation frequency. In the actual operating conditions,
C
Be sure to use TP1 or TP2 for measurement.
If a test probe touches X
Caution Because the interval timer does not output an accurate 0.1-second interval signal, this signal
To output 2048 Hz to TP1, for example, the counter must be able to read 2048.00 0.02 Hz to ensure an adjustment
G
or C
D
is used as a trimmer capacitor. To make an adjustment, the alarm coincidence signal is output to TP1
Measurement
should not be used for adjusting the oscillation frequency.
frequency counter or
cycle counter
CHAPTER 4 ELECTRICAL SPECIFICATIONS AND INTERFACE
IN
or X
Figure 4-7. Adjusting Oscillation Frequency
OUT
, oscillation may be stopped or the oscillation frequency may change because
TP1
TP2
or
V
V
DD
SS
X
X
IN
OUT
PD4991A
X
C
D
C
G
V
DD
or V
SS
C
C
G
D
= 10 to 30 pF trimmer
= 20 pF