Test Circuitry
(ECL-to-TTL)
DS100306-10
Note 18:
R
T
= 50Ω termination resistive load. When an input or output is being monitored by a scope, R
T
is supplied by the scope’s 50Ω input resistance. When
an input or output is not being monitored, an external 50Ω resistance must be applied to serve as R
T
.
Note 19:
The TTL TRI-STATE pull-up switch is connected to +7V only for ZL and LZ tests.
Note 20:
TTL and ECL force signals are brought to the DUT via 50Ω coax lines.
Note 21:
V
TTL
is decoupled to ground with 0.1 µF, V
EE
is decoupled to ground with 0.01 µF and V
CC
is connected to ground.
FIGURE 3. ECL-to-TTL AC Test Circuit
Switching Waveforms
(ECL-to-TTL)
DS100306-11
Note:
DIR is LOW, OE is HIGH
FIGURE 4. ECL-to-TTL Transition — Propagation Delay and Transition Times
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