ics84330c Integrated Device Technology, ics84330c Datasheet - Page 9

• Manufacturer Part Number: ics84330c
• Description: 700mhz, Low Jitter, Crystal-to-3.3v Differential Lvpecl Frequency Synthesizer
• Manufacturer: Integrated Device Technology

LVCMOS to XTAL Interface
The XTAL_IN input can accept a single-ended LVCMOS signal
through an AC coupling capacitor. A general interface diagram is
shown in Figure 3. The XTAL_OUT pin can be left floating. The
input edge rate can be as slow as 10ns. For LVCMOS signals, it is
recommended that the amplitude be reduced from full swing to half
swing in order to prevent signal interference with the power rail and
to reduce noise. This configuration requires that the output
Figure 3. General Diagram for LVCMOS Driver to XTAL Input Interface
Figure 4. Cycle-to-Cycle Jitter vs. fOUT (using a 16MHz crystal)
IDT™ / ICS™ LVPECL FREQUENCY SYNTHESIZER
ICS84330C
700MHZ, LOW JITTER, CRYSTAL-TO-3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
V
50
40
30
20
10
CC
Ro
0
200
Rs
Zo = Ro + Rs
300
Output Frequency (MHz)
50Ω
400
V
CC
R1
R2
0.1µf
500
XTAL_IN
XTAL_OUT
9
impedance of the driver (Ro) plus the series resistance (Rs) equals
the transmission line impedance. In addition, matched termination
at the crystal input will attenuate the signal in half. This can be
done in one of two ways. First, R1 and R2 in parallel should equal
the transmission line impedance. For most 50Ω applications, R1
and R2 can be 100Ω. This can also be accomplished by removing
R1 and making R2 50Ω.
600
700
ICS84330CV REV. C JANUARY 28, 2009
Spec Limit
N = 1