IDT1893CFLFT IDT, Integrated Device Technology Inc, IDT1893CFLFT Datasheet - Page 20

• Manufacturer Part Number: IDT1893CFLFT
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT1893CFLFT

• Lead Free Status / RoHS Status: Compliant

5.4 Clock Reference Interface
ICS1893CF, Rev. J, 08/11/09
Oscillator
The REF_IN pin provides the ICS1893CF Clock Reference Interface. The ICS1893CF 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
ICS1893CF 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 25MHz crystal may be used. The Oscillator
specifications are shown in Table 5.2.
Figure 5-2. Crystal or Oscillator Operation
Crystal
ICS1893CF Data Sheet - Release
33 pF
25.000
CMOS
MHz
REF_OUT
REF_OUT
46
NC
46
ICS1893CF
25.000MHz
Copyright © 2009, Integrated Device Technology, Inc.
ICS1893CF
33 Ohm
REF_IN
REF_IN
All rights reserved.
47
47
20
33 pF
10 pF
Chapter 5 Interface Overviews
August, 2009