RV-3029 Datasheet, PDF (42/67 Pages) MICORO CRYSTAL SWITZERLAND – DTCXO Temperature Compensated Real Time Clock

Micro Crystal
DTCXO Temperature Compensated Real Time Clock / Calendar Module
RV-3029
Effect of correction clocks:
• CLKOUT 32.768 kHz:
not affected, this frequency is not compensated
• CLKOUT 1024 / 32 / 1 Hz: affected, these frequencies are compensated
• Timer / INT Output:
• Time / Date
affected; the internal Timer Source Clocks are compensated
affected; time & date information are compensated
5.3.1.CORRECT METHOD FOR TESTING THE TIME ACCURACY
The compensation method of adding or subtracting correction clocks is changing the period of a single second;
therefore the duration of single seconds may vary within a compensation cycle of 32 seconds.
For a test result correctly representing the time accuracy of the RTC module, it is mandatory to measure the device
during one complete compensation cycle of 32 seconds.
When the device is tested over a shorter period of time, an error will be caused by the test method and shall be
considered for interpretation of the test-results:
Measuring Time
1 second
2 seconds
4 seconds
8 seconds
32 seconds
Resolution of Compensation Method
± 1 clock (32.768 kHz)
± 1 clock (32.768 kHz)
± 1 clock (32.768 kHz)
± 1 clock (32.768 kHz)
± 1 clock (32.768 kHz)
Test Error / Deviation per Day
± 30.5 ppm / ± 2.7 sec. per day
± 15.3 ppm / ± 1.3 sec. per day
± 7.7 ppm / ± 0.7 sec. per day
± 3.9 ppm / ± 0.4 sec. per day
represents real performance
5.3.2.TESTING THE TIME ACCURACY USING CLKOUT OUTPUT
The simplest method to test the time accuracy of the Frequency Compensation Unit (FCU) is by measuring the
compensated frequencies at the CLKOUT pin.
Enable temperature compensation:
• Select scanning interval 1 s:
• Enable thermometer:
set “ThP” = “0” (bit 0 register EEPROM Control)
set “ThE” = “1” (bit 1 register EEPROM Control)
Select compensated frequency at CLKOUT:
• Set CLKOUT frequency:
set “FD0” / “FD1” (bits 1&3 register EEPROM Control) to select
CLKOUT frequency = 1024Hz or alternatively 1Hz
Measuring equipment and setup:
• Use appropriate frequency counter: for example Agilent A53132A Universal Counter
• Correct setup:
set gate time to 32 seconds (one complete compensation cycle)
to measure frequency and calculate time deviation upon the
measured frequency deviation
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