R2033K Datasheet, PDF (29/50 Pages) RICOH electronics devices division – 3 wire interface Real-Time Clock ICs

• Measurement of Oscillation Frequency
VDD
CLKC
OSCIN
OSCOUT
32KOUT
VSS
32768Hz
Frequency
Counter
R2033K/T
* 1) The R2033K/T is configured to generate 32.768-kHz clock pulses for output from the 32KOUT pin.
* 2) A frequency counter with 6 (more preferably 7) or more digits on the order of 1ppm is recommended for
use in the measurement of the oscillation frequency of the oscillation circuit.
• Adjustment of Oscillation frequency
The oscillation frequency of the oscillation circuit can be adjusted by varying procedures depending on the
usage of Model R2033K/T in the system into which they are to be built and on the allowable degree of time count
errors. The flow chart below serves as a guide to selecting an optimum oscillation frequency adjustment
procedure for the relevant system.
Start
Use 32-kHz
clock output?
YES
NO ^{Allowable time count precision on order of oscillation YES}
frequency variations of crystal oscillator (*1) plus NO
frequency variations of RTC (*2)? (*3)
YES
Use 32-kHz clock output without regard
to its frequency precision
NO
Allowable time count precision on order of oscillation ^YES
frequency variations of crystal oscillator (*1) plus NO
frequency variations of RTC (*2)? (*3)
Course (A)
Course (B)
Course (C)
Course (D)
* 1) Generally, quartz crystal units for commercial use are classified in terms of their center frequency
depending on their load capacitance (CL) and further divided into ranks on the order of ±10, ±20, and ±50ppm
depending on the degree of their oscillation frequency variations.
* 2) Basically, Model R2033K/T is configured to cause frequency variations on the order of ±5 to ±10ppm at
25°C.
* 3) Time count precision as referred to in the above flow chart is applicable to normal temperature and actually
affected by the temperature characteristics and other properties of quartz crystal units.
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