S-35190A Datasheet, PDF (37/53 Pages) Seiko Instruments Inc – 3-WIRE REAL-TIME CLOCK

Rev.2.4_00
3-WIRE REAL-TIME CLOCK
S-35190A
2. Measurement of oscillation frequency
When the S-35190A is turned on, the internal power-on detector operates and a signal of 1 Hz is output from the INT pin
to select the crystal oscillator and optimize the C_g value. Turn the power on and measure the signal with a frequency
counter following the circuit configuration shown in Figure 46.
If 1 Hz signal is not output, the power-on detector does not operate normally. Turn off the power and then turn it on
again. For how to apply power, refer to “„ Power-on Detector and Register Status”.
Remark If the error range is ±1 ppm in relation to 1 Hz, the time is shifted by approximately 2.6 seconds per month
(calculated using the following expression).
10^–6 (1 ppm) × 60 seconds × 60 minutes × 24 hours × 30 days = 2.592 seconds
10 kΩ 10 kΩ
SIO
SCK
Open
CS
VDD
XIN
S-35190A
XOUT
INT
VSS
Cg 10 kΩ
Frequency
counter
Figure 46 Configuration of Oscillation Frequency Measurement Circuit
Caution
1. Use a high-accuracy frequency counter of 7 digits or more.
2. Measure the oscillation frequency under the usage conditions.
3. Since the 1 Hz signal continues to be output, initialization must be executed during normal
operation.
Seiko Instruments Inc.
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