s1r72900 Epson Electronics America, Inc., s1r72900 Datasheet - Page 46

• Manufacturer Part Number: s1r72900
• Description: Physical Layer Ic Compliant With The Ieee 1394-1995 And Ieee 1394a-2000 Standards.
• Manufacturer: Epson Electronics America, Inc.

S1R72900F00A
7.5 Oscillating Circuit
The SIR72900F00A carries a built-in crystal oscillation circuit. The output frequency of the external quarts oscillator
should be 24.576MHz ( 80ppm (including the temperature characteristics).
As the quarts oscillator, we recommend our MA-406 (24.576MHz., CL = 10pF) to secure the necessary frequency
precision.
Position the quarts oscillator and capacitor in the neighborhood of this IC and maintain the wiring pattern as short as
possible.
Fig. 7.24 shows an example of external connection when using the MA-406.
* The SIR72900F00A does not support external oscillator inputs.
XO
XI
24.576MHz
CL=10pF
15pF
15pF
Figure 7.24 Connection of external oscillating circuit
7.6 Power Down
The SIR72900F00A carries the power down mode. The power down mode can be obtained by inputting "1" into the
PD pin and under the power down mode, all the internal functions will stop. The power down mode can be cancelled
by changing the input to the PD pin from "1" to "0" and, a few ms (the time required for initialization) after the PD pin
input became "0", normal operation will be restored.
EPSON
42
Rev. 1.0