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an input or output is not being monitored, an external 50

Ω resistance must be applied to serve as R

Note: The TTL 3-STATE pull-up switch is connected to

+7V only for ZL and LZ tests.

Note: TTL and ECL force signals are brought to the DUT via 50

Ω coax lines.

FIGURE 3. ECL-to-TTL AC Test Circuit

Note: DIR is LOW, OE is HIGH

FIGURE 4. ECL-to-TTL Transition—Propagation Delay and Transition Times