ICS85356AGI IDT, Integrated Device Technology Inc, ICS85356AGI Datasheet - Page 8

• Manufacturer Part Number: ICS85356AGI
• Manufacturer: IDT, Integrated Device Technology Inc
• Type: Clock Multiplexerr

Specifications of ICS85356AGI

• Number Of Clock Inputs: 4/2
• Mode Of Operation: Differential
• Output Frequency: 900MHz
• Output Logic Level: ECL/LVPECL
• Operating Supply Voltage (min): -3/3V
• Operating Supply Voltage (typ): -3.3/3.3V
• Operating Supply Voltage (max): -3.8/3.6V
• Package Type: TSSOP
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 20
• Lead Free Status / RoHS Status: Not Compliant

ICS85356I 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 3A. 3.3V LVPECL Output Termination
ICS85356AMI REVISION B MAY 10, 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
8
transmission lines. Matched impedance techniques should be used
to maximize operating frequency and minimize signal distortion.
Figures 3A and 3B 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 3B. 3.3V LVPECL Output Termination
3.3V
2:1, DIFFERENTIAL-TO-3.3V LVPECL/ECL CLOCK MULTIPLEXER
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