
Electrical, Mechanical, and Thermal Specification
5-9
Intel PXA270 Processor
Electrical Specifications
5.5
Oscillator Electrical Specifications
The PXA270 processor contains two oscillators: a 32.768-kHz oscillator and a 13.000-MHz
oscillator. Each oscillator requires a specific crystal.
5.5.1
32.768-kHz Oscillator Specifications
The 32.768-kHz oscillator is connected between the TXTAL_IN (amplifier input) and
specifications.
To drive the 32.768-kHz crystal pins from an external source:
1. Drive the TXTAL_IN pin with a digital signal that has low and high levels as listed in
Table 5-10. Do not exceed VCC_PLL or go below VSS_PLL by more than 100 mV. The
minimum slew rate is 1 volt per 1 s. The maximum current drawn from the external clock
source when the clock is at its maximum positive voltage is typically 1 mA.
2. Float the TXTAL_OUT pin or drive it in complement to the TXTAL_IN pin, with the same
voltage level and slew rate.
Caution: The TXTAL_IN and TXTAL_OUT pins must not be driven from an external source if the PXA270
processor sleep / deep sleep DC-DC converter is enabled.
VOH1
Output high voltage, all standard output and I/
O pins, relative to applicable VCC (VCC_IO,
VCC_MEM, VCC_BB, VCC_LCD, VCC_USB,
or VCC_USIM)
VCC - 0.3
VCC
V
IOH = -4 mA2,
-3 mA3
VOL1
Output low voltage, all standard output and I/O
pins, relative to applicable VSS (VSS_IO,
VSS_MEM, or VSS_BB)
VSS
VSS + 0.3
V
IOH = 4 mA2,
3 mA3
NOTES:
1. Programmable drive strengths set to 0x5 for memory and LCD programmable signals.
2. The current for the high-strength pins are MA<25:0>, MD<31:0>, nOE, nWE, nSDRAS, nSDCAS, DQM<3:0>, nSDCS<3:0>,
SDCKE<1>, SDCLK<3:0>, RDnWR, nCS<5:0>, and nPWE.
3. The current for all other output and I/O pins are low strength.
Table 5-8. Standard Input, Output, and I/O Pin DC Operating Conditions (Sheet 2 of 2)
Symbol
Description
Min
Max
Unit
s
Testing Conditions
/ Notes
Table 5-9. Typical 32.768-kHz Crystal Requirements (Sheet 1 of 2)
Parameter
Minimum
Typical
Maximum
Units
Frequency range
—
32.768
—
kHz
Frequency tolerance
–30
—
+30
ppm
Frequency stability, parabolic coefficient
—
–0.04
ppm/
(
°C)2
Drive level
—
1.0
uW
Load capacitance (CL)
—
12.5
—
pf
Shunt capacitance (CO)—
0.9
—
pf