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DescriptionThe PRL-422RS is a dual channel, high speed logic level translator designed specifically for use with high speed data communications applications. The PRL-422RS converts differential 124 Ω RS422 inputs to differential 50 Ω NECL outputs. A functional block diagram is shown in Fig. 1. The inputs of the PRL-422RS consist of two triax connectors, each internally terminated with 124 Ω between the pin and the ring. They are designed to interface with the 124 Ω differential Serial Data/Data or Clock/Clock outputs from data communications equipment. The complementary NECL outputs have SMA connectors. They are designed for driving 50 Ω loads terminated to -2 V, and with internal pull-down resistors, they can be AC-coupled to ground-referenced 50 Ω loads as well. The PRL-422RS is housed in an attractive 1.3 x 2.9 x 3.9-in. extruded aluminum enclosure. Optional mounting brackets are available. Each unit is supplied with a ±8.5 V/1.4 A AC/DC Adapter. |
*Since the high frequency signals to and from the 124 Ω I/O ports can not be easily measured, the 124 Ω I/O ports of these adapters were first cascaded using shielded twisted pair cables, Trompeter P/N PCGOW10PCG-36 or equivalent. Input signals were applied to the 50 Ω inputs of the PRL-422NECL, and outputs of the PRL-422RS were terminated into 50 Ω /-2 V, using the PRL-550NQ4X, four-channel ECL Terminator, connected to a 50 Ω input sampling oscilloscope.
Notes:
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Trompeter P/N CBBJR79.
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Trompeter P/N PCGOW10PCG-36
(0° C ≤ TA ≤ 35° C)*
| Symbol | Parameter | PRL-422RS | Unit | ||
|---|---|---|---|---|---|
| Min | Typ | Max | |||
| RIN | Input Resistance | 122 | 124 | 126 | Ω |
| VTT | Input Termination Voltage | NA | V | ||
| IDC1 | DC Input Current, +8.5 V | 30 | 60 | mA | |
| IDC2 | DC Input Current, -8.5 V | -130 | -150 | mA | |
| VDC | DC Input Voltage | ±7.5 | ±8.5 | ±12 | V |
| VAC | AC/DC Adapter Input Voltage | 103 | 115 | 127 | V |
| tPLH | Propagation Delay to output ↑ | 2000 | ps | ||
| tPHL | Propagation Delay to output ↓ | 2000 | ps | ||
| tr/tf | Rise/Fall Times1 (20%-80%) | 750 | 850 | ps | |
| fmax | Maximum Clock Frequency2 | 400 | 600 | MHz | |
| tSKEW1 | Skew between outputs | 20 | 200 | ps | |
| tSKEW2 | Skew from unit to units | 40 | 400 | ps | |
| Input Connector | Triax3 | ||||
| Output Connector | SMA | ||||
| Input Cables | 124 Ω TP4 | ||||
| Output Cables | 50 Ω Coax | ||||
| Size | 1.3 x 2.9 x 3.9 | in. | |||
| Weight, excluding AC adapter | 7 | Oz | |||
| Shipping Weight, including AC adapter | 4 | lb. | |||
Notes:
(1). The 50 Ω output rise and fall times were measured with both the Q and Q outputs terminated into 50 Ω/-2 V. If one output is not terminated, both the rise and fall times will increase by approximately 15%, and output waveform degradation will occur.
(2). fMAX is measured using the differential input mode (switch up). The differential outputs are first divided by four, using the PRL-255 ÷2 and ÷4 frequency divider module, and then measured using the PRL-550NQ4X, four channel ECL Terminators, connected to a sampling scope.
(3). Trompeter P/N CBBJR79.
All PRL products with Triax connectors use Trompeter P/N CBBJR79, Right Angle Circuit Board Bulkhead Jack, 3-lug (Numbered page 10, document page 11 of 142). Any Trompeter 70-series Triax Cable Plug with 3 lugs (e.g. PL75-9, 3-lug) will mate with CBBJR79.
