Intel PXA250 and PXA210 Applications Processors
Intel PXA250 and PXA210 Applications Processors
Intel PXA250 and PXA210 Applications Processors
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Power <strong>and</strong> Clocking<br />
Table 8-4. 32.768 kHz Oscillator Specifications (Sheet 2 of 2)<br />
Symbol Description Min Typical Max<br />
t S_XT Stabilization Time 2s — 10 s<br />
Board Specifications<br />
R P_XT Parasitic Resistance, TXTAL/TEXTAL to any node 20 MΩ — —<br />
C P_XT Parasitic Capacitance, TXTAL/TEXTAL, total — — 5pF<br />
C OP_XT Parasitic Shunt Capacitance, TXTAL to TEXTAL — — 0.4 pF<br />
To drive the 32.768 kHz crystal pins from an external source:<br />
• Drive the TEXTAL pin with a digital signal that has a low level near 0 V <strong>and</strong> a high level near<br />
VCC. Do not exceed VCC or go below VSS by more than 100 mV. The minimum slew rate is<br />
1V per µs. The maximum current drawn by the external clock source when the clock is at its<br />
maximum positive voltage should be about 1mA.<br />
• Float the TXTAL pin or drive it complementary to the TEXTAL pin, using the same voltage<br />
level, slew rate, <strong>and</strong> input current restrictions.<br />
8.4.2 3.6864 MHz Oscillator Specifications<br />
The 3.6864 MHz Oscillator is connected between the PXTAL (amplifier input) <strong>and</strong> PEXTAL<br />
(amplified output). The 3.6864 MHz specifications are shown in Table 8-5<br />
Table 8-5. 3.6864 MHz Oscillator Specifications<br />
Symbol Description Min Typical Max<br />
Crystal Specifications - Typical is FOX HC49S<br />
F XP Crystal Frequency, PXTAL/PEXTAL — 3.6864 MHz —<br />
L MP Motional Inductance, PXTAL/PEXTAL — 0.50593 H —<br />
C MP Motional Capacitance, PXTAL/PEXTAL — 3.68488 fF —<br />
R MP Motional Resistance, PXTAL/PEXTAL 50 Ω 99.3 Ω 200 Ω<br />
C OP Shunt Capacitance PXTAL to PEXTAL — 1.7 pF —<br />
C LP Load Capacitance PXTAL/PEXTAL — 20 pF —<br />
Amplifier Specifications<br />
V IH_X Input High Voltage, PXTAL 0.8V*VCC — VCC<br />
V IL_X Input Low Voltage, PXTAL VSS — 0.2 V*VCC<br />
I IN_XP Input Leakage, PXTAL — — 10 µA<br />
C IN_XP Input Capacitance, PXTAL/PEXTAL — 40 pF 50 pF<br />
t S_XP Stabilization Time 17.8 ms — 67.8 ms<br />
Board Specifications<br />
R P_XP Parasitic Resistance, PXTAL/PEXTAL to any node 20 MΩ — —<br />
C P_XP Parasitic Capacitance, PXTAL/PEXTAL, total — — 5pF<br />
C OP_XP Parasitic Shunt Capacitance, PXTAL to PEXTAL — — 0.4 pF<br />
To drive the 3.6864 MHz crystal pins from an external source:<br />
<strong>PXA250</strong> <strong>and</strong> <strong>PXA210</strong> <strong>Applications</strong> <strong>Processors</strong> Design Guide 8-5