ics84330c Integrated Device Technology, ics84330c Datasheet - Page 10

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

Termination for 3.3V LVPECL Outputs
The clock layout topology shown below is a typical termination for
LVPECL outputs. The two different layouts mentioned are
recommended only as guidelines.
FOUT and nFOUT are low impedance follower outputs that
generate ECL/LVPECL compatible outputs. Therefore, terminating
resistors (DC current path to ground) or current sources must be
used for functionality. These outputs are designed to drive 50Ω
Figure 5A. 3.3V LVPECL Output Termination
IDT™ / ICS™ LVPECL FREQUENCY SYNTHESIZER
ICS84330C
700MHZ, LOW JITTER, CRYSTAL-TO-3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
RTT =
((V
FOUT
OH
+ V
OL
) / (V
1
CC
Z
Z
– 2)) – 2
o
o
= 50Ω
= 50Ω
Z
o
50Ω
RTT
50Ω
V
CC
FIN
- 2V
10
transmission lines. Matched impedance techniques should be
used to maximize operating frequency and minimize signal
distortion. Figures 5A and 5B show two different layouts which are
recommended only as guidelines. Other suitable clock layouts may
exist and it would be recommended that the board designers
simulate to guarantee compatibility across all printed circuit and
clock component process variations.
Figure 5B. 3.3V LVPECL Output Termination
FOUT
Z
Z
o
o
= 50Ω
= 50Ω
ICS84330CV REV. C JANUARY 28, 2009
125Ω
84Ω
3.3V
125Ω
84Ω
FIN