ACE5372

Low Power Real-Time Clock (RTC)

VER 1.3

21

According to this standard, the best CL is chosen to adjust frequency and clock frequency. For example:

Time Trimming Circuit

Using the time trimming circuit gain or lose of clock may be adjusted with high precision by changing

clock pulses for one second every 20 seconds.

1.When oscillation frequency

Adjustment amount

*3

=

= (Oscillation frequency

– Target frequency) x 10 +1

*1) Oscillation frequency: Clock frequency output from the

INTRB pin

*2) Target frequency: TYP. 32.768KHz to 32.000KHz

*3) Adjustment amount: A value to be set finally to F6 to F0 bits. This value is expressed in 7 bit binary

digits with sign bit (two’s compliment).

2.When oscillation frequency = target frequency (no clock gain or loss)

Set the adjustment value to 0 or +1, or

–64, or –63 to disable adjustment.

3.When oscillation frequency < target frequency (clock losses)

Adjustment amount

=

=

(Oscillation frequency

– Target frequency) x 10

ACE5372

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