C9834
Low EMI Clock Generator for Intel 810 Chipset / Pentium II and Pentium III Systems
Preliminary
Spectrum Spread Clocking (Cont.)
Center Spread (Fig.8A) is when the modulation does not effect the center frequency and the energy is redistributed
equally on both sides of the center, which remains the same as the center frequency in the non-spread mode.
Therefore, in Center spread, Fcs = Fcr.
Center Spread Spectrum
Up Spread Spectrum
Fig.8A
Fig. 8B
Spread Spectrum Selection Table‡
Note‡ In the default spread option, (+/- 0.25), spread
spectrum is applicable to all frequencies in Table 1. For other
spread options, (+0.5, +/-0.125, and +/-0.5), spread spectrum
is applicable to those frequencies at the following selection:
S(4:0) = 01100
BW1 (Byte0-bit7), BW0 (Byte0-bit6)
Spread%
10
11
01
00
+0.5
+/-0.125
+/-0. 5
+/-0.25, Default
S(4:0) = 01101
Table 3.
S(4:0) = 01110
S(4:0) = 01111
Maximum Ratings
This device contains circuitry to protect the inputs
against damage due to high static voltages or electric
field; however, precautions should be taken to avoid
application of any voltage higher than the maximum
rated voltages to this circuit. For proper operation, Vin
and Vout should be constrained to the range:
VSS<(Vin or Vout)<VDD
Maximum Input Voltage Relative to VSS: VSS - 0.3V
Maximum Input Voltage Relative to VDD: VDD + 0.3V
Storage Temperature:
Operating Temperature:
Maximum ESD protection
Maximum Power Supply:
-65ºC to + 150ºC
0ºC to +85ºC
2000V
5.5V
Unused inputs must always be tied to an appropriate
logic voltage level (either VSS or VDD).
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
MILPITAS, CA 95035 TEL 408-263-6300, FAX 408-263-6571
http://www.imicorp.com
Rev. 1.1
9/7/1999
Page 8 of 15
CYPRESS [ CYPRESS ]
