HD74CDC857 Datasheet, PDF (9/12 Pages) Hitachi Semiconductor – 3.3/2.5-V Phase-lock Loop Clock Driver

HD74CDC857
Differential clock outputs are directly terminated by a 120 Ω resistor. Figure 2 is typical usage conditions
of outputs load.
V _DDQ
Device
under _OUT
test
OUT
V _DDQ
R_T=
120 Ω
Figure 2 Differential signal using direct termination resistor
Differential cross
point voltage
V_ref 0.5 × V_DDQ
V_IH 1.7 V
V_IL 0.8 V
V_IH
V_ref +0.35 V
V_ref
V_ref –0.35 V
V_IL
Figure 3 CLKIN waveforms
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