
26
4979D–GPS–06/08
ATR0635P1
5.2 RTC Oscillator
Figure 5-3. Crystal Connection
Table 5-1. Specification of GPS TCXOs Appropriate for the Application Example Shown in
Figure 5-1 on page 25
Parameter Comment Min Typ Max Units
Frequency Characteristics
Nominal Frequency
Nominal frequency referenced to
25°C
23.104 MHz
Frequency deviation
Over operating temperature range 0.5 ±ppm
Including calibration, temperature,
soldering and ageing effects
8 ±ppm
Temperature range Operating temperature range –40.0 +85.0 °C
Electrical
Output waveform DC coupled clipped sine wave
Output voltage
(peak-to-peak)
Operating range 0.8 1.5 V
Output load capacitance Tolerable load capacitance 10 pF
Table 5-2. Specification of an External Reference Signal for the Application Example Shown
in Figure 5-2 on page 25
Parameter Comment Min Typ Max Units
Signal Characteristics
Nominal Frequency 23.104 MHz
Waveform Sine wave or clipped sine wave
Amplitude Voltage peak-to-peak 0.6 0.9 1.2 V
XT_IN
XT_OUT
RTC
ATR0635 internal
32 kHz
Crystal
Oscillator
32.768 kHz clock
32.768 kHz
50 ppm
CC
C = 2 × C
load
, C
load
can be derived from the crystal datasheet. Maximum value for C is 25 pF.
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