ICS1893AGLF View Datasheet(PDF) - Integrated Circuit Systems
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Description
MFG CO.
'ICS1893AGLF' PDF : 135 Pages View PDF
ICS1893AG Data Sheet - Preliminary
Chapter 6 Interface Overviews
6.4 Clock Reference Interface
The REF_IN pin provides the ICS1893AG Clock Reference Interface. The ICS1893AG requires a single
clock reference with a frequency of 25 MHz ±50 parts per million. This accuracy is necessary to meet the
interface requirements of the ISO/IEEE 8802-3 standard, specifically clauses 22.2.2.1 and 24.2.3.4. The
ICS1893AG supports two clock source configurations: a CMOS oscillator or a CMOS driver. The input to
REF_IN is CMOS (10% to 90% VDD), not TTL. Alternately, a 25 MHz crystal may be used. The Oscillator
specifications are shown in Table 6.1.
Figure 6-3. Crystal or Oscillator Operation
Crystal
REF_OUT
54
REF_IN
55
25.000MHz
33 pF
33 pF
Oscillator
REF_OUT
54
REF_IN
55
NC
CMOS
25.000
MHz
33 Ohm
10 pF
ICS1893AG, Rev A 04/14/05
Copyright © 2005, Integrated Circuit Systems, Inc.
All rights reserved.
28
April, 2005
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