AN1318 - APPLICATION NOTE

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12. CAPACITIVE COUPLING ECL TO LVDS USING VOS REFERENCE VOLTAGE.

Some devices with LVDS interfaces supply VOS reference voltage, like the STLVD111. This can be used

for capacitive coupling. When the transmission line length is very short, a parallel termination should be

used and replaced as close as possible to the coupling capacitors.

Figure 12: Capacitive Coupling ECL to LVDS Using VOS Reference Voltage

ECL

LVDS

3.3V

Z=50

Ω

Z=50

Ω

10pF

10pF

1k

Ω

1k

Ω

VOS=1.2V

100k

Ω

VTT

50

Ω

50

Ω