Test Circuitry (ECL-to-TTL)
Notes:
Rt = 50Ω termination. When an input or output is being monitored by a scope, Rt is supplied by the scope’s 50Ω resistance. When an input or output is not
being monitored, and external 50Ω resistance must be applied to serve as Rt.
The TTL 3-STATE pull up switch is connected to +7V only for ZL and LZ tests.
TTL and ECL force signals are brought to the DUT via 50Ω coax lines.
VTTL is decoupled to ground with 0.1 µF to ground, VEE is decoupled to ground with 0.01 µF and GND is connected to ground.
FIGURE 3. ECL-to-TTL AC Test Circuit
Note:
DIR is LOW, and OE is HIGH
FIGURE 4. ECL-to-TTL Transition—Propagation Delay and Transition Times
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