RV5C386A-E2 Просмотр технического описания (PDF) - RICOH Co.,Ltd.

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RV5C386A-E2

I2C-Bus Real-Time Clock ICs with Voltage Monitoring Function

RICOH Co.,Ltd. 

PRELIMINARY

14.2.2. Measurement of Oscillation Frequency

RV5C386A

VDD

OSCIN

OSCOUT

CLKC

32KOUT

VSS

32768Hz

Frequency

Counter

* 1) The RV5C386A 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.

* 3) The CLKC pin should be connected to the VDD pin as a pull-up resistor.

14.2.3. Adjustment of Oscillation frequency

The oscillation frequency of the oscillation circuit can be adjusted by varying procedures depending on the

usage of Model RV5C386A 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, crystal oscillators 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 RV5C386A is configured to cause frequency variations on the order of ±5 to ±10ppm at

normal temperature.

* 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 crystal oscillators.

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