Description:
The PRL-444 is a four channel TTL/CMOS input, 50 Ω output TTL/CMOS Line Driver. It is intended for interfacing with computer I/O cards that have TTL outputs not suitable for driving 50 Ω
lines. Each input has a 10 kΩ pulled up to 2.5 V so that it can also be driven by open-collector devices. The 50 Ω back-terminated outputs of the PRL-444 can drive long lines with or without 50 Ω
load terminations. With 50 Ω load terminations, however, all outputs can drive 100 ft of 50 Ω cables at clock rates greater than 60 MHz.
If the inputs are left open, all outputs will go Hi, because the inputs are pulled up to
+2.5 V. All outputs can be set to the LO state, however, by either setting the polarity inverting switch to the down position or terminating all
inputs to
2 kΩ or lower. The polarity- inverting switch enables easy generation of four static Hi/Lo logic signals when the inputs are not driven.
The PRL-444 is housed in a 1.3 x 2.9 x 2.9-in. extruded aluminum enclosure and is supplied with a ±8.5 V/±1.4 A AC/DC Adapter. A maximum of four units can share a single AC/DC adapter using the
PRL-730
voltage distribution module. If mounting is desired, a pair of the #35001420
mounting brackets can accommodate any two PRL modules of the same length. Please refer to the Accessories Section of the literature for more detail.
A block diagram showing the equivalent input and output circuits of the PRL-444 is shown in
Fig.
1.
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