ICS8430002 Datasheet, PDF (19/27 Pages) Integrated Device Technology – High-Performance Fractional-N Frequency Synthesizer

ICS8430002 Data Sheet
HIGH-PERFORMANCE FRACTIONAL-N FREQUENCY SYNTHESIZER
Termination for 2.5V LVPECL Outputs
Figure 8A and Figure 8B show examples of termination for 2.5V
LVPECL driver. These terminations are equivalent to terminating 50Ω
to V_CC – 2V. For V_CCO = 2.5V, the V_CCO – 2V is very close to ground
level. The R3 in Figure 8B can be eliminated and the termination is
shown in Figure 8C.
V_CC = 2.5V
50Ω
50Ω
2.5V LVPECL Driver
2.5V
R1
R3
250
250
2.5V
+
–
R2
R4
62.5
62.5
VCC = 2.5V
50Ω
50Ω
2.5V LVPECL Driver
2.5V
+
–
R1
R2
50
50
R3
18
Figure 8A. 2.5V LVPECL Driver Termination Example
Figure 8B. 2.5V LVPECL Driver Termination Example
V_CC = 2.5V
50Ω
50Ω
2.5V LVPECL Driver
2.5V
+
–
R1
R2
50
50
Figure 8C. 2.5V LVPECL Driver Termination Example
ICS8430002AY REVISION C NOVEMBER 12, 2009
19
©2009 Integrated Device Technology, Inc.