85314AGI-11 Integrated Device Technology (Idt), 85314AGI-11 Datasheet - Page 11

• Manufacturer Part Number: 85314AGI-11
• Description: Clock Driver 2-IN LVPECL 20-Pin TSSOP Tube
• Manufacturer: Integrated Device Technology (Idt)

Specifications of 85314AGI-11

• Package: 20TSSOP
• Configuration: 1 x 2:1
• Input Signal Type: HCSL|LVDS|LVHSTL|LVPECL|SSTL
• Maximum Output Frequency: 700 MHz
• Operating Supply Voltage: 3.3 V

ICS85314I-11 Data Sheet
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.
The differential outputs 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 4A. 3.3V LVPECL Output Termination
ICS85314AGI-11 REVISION E MAY 4, 2010
RTT =
((V
3.3V
OH
LVPECL
+ V
OL
) / (V
1
CC
Z
Z
– 2)) – 2
o
o
= 50Ω
= 50Ω
* Z
R1
50Ω
o
RTT
R2
50Ω
V
+
_
CC
3.3V
- 2V
Input
11
transmission lines. Matched impedance techniques should be used
to maximize operating frequency and minimize signal distortion.
Figures 4A and 4B 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 4B. 3.3V LVPECL Output Termination
LOW SKEW, 1-TO-5 DIFFERENTIAL-TO-2.5V, 3.3V LVPECL FANOUT BUFFER
3.3V
LVPECL
Z
Z
o
o
= 50Ω
= 50Ω
R3
125Ω
©2010 Integrated Device Technology, Inc.
R1
84Ω
3.3V
R4
125Ω
R2
84Ω
+
_
3.3V
Input