SI53303 Datasheet, PDF (15/30 Pages) Silicon Laboratories – DUAL 1:5 LOW JITTER BUFFER/LEVEL TRANSLATOR

Si53303
2.8. Output Clock Termination Options
The recommended output clock termination options are shown below. Unused output clocks should be left floating.
VDDO
DC Coupled LVPECL Termination Scheme 1
R1
R1
VDDO _{= 3.3V or 2.5V}
Si533xx
Q
50
Qn
50
3.3V LVPECL: R1 = 127 Ohm, R2 = 82.5 Ohm
2.5V LVPECL: R1 = 250 Ohm, R2 = 62.5 Ohm
R2
R2
VDD = VDDO
LVPECL
Receiver
VTERM = VDDO – 2V
R1 // R2 = 50 Ohm
DC Coupled LVPECL Termination Scheme 2
VDDO _{= 3.3V or 2.5V}
Si533xx
Q
50
Qn
50
50
VDD = VDDO
LVPECL
Receiver
50
VTERM = VDDO – 2V
VDDO
AC Coupled LVPECL Termination Scheme 1
VDDO _{= 3.3V or 2.5V}
Si533xx
Q
Qn
Rb Rb
R1
0.1 uF
50
50
0.1 uF
R2
R1
VDD _{= 3.3V or 2.5V}
LVPECL
Receiver
R2
VBIAS = VDD – 1.3V
R1 // R2 = 50 Ohm
3.3V LVPECL: R1 = 82.5 Ohm, R2 = 127 Ohm, Rb = 120 Ohm
2.5V LVPECL: R1 = 62.5 Ohm, R2 = 250 Ohm, Rb = 90 Ohm
AC Coupled LVPECL Termination Scheme 2
VDDO = 3.3V or 2.5V
Si533xx
Q
Qn
Rb Rb
0.1 uF
50
50
0.1 uF
50
VDD _{= 3.3V or 2.5V}
LVPECL
Receiver
50
3.3V LVPECL: Rb = 120 Ohm
2.5V LVPECL: Rb = 90 Ohm
Figure 6. LVPECL Output Termination
Preliminary Rev. 0.4
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