2 Ch. Translator, NECL to RS422

SKU:

$ 1,063.75

Applications:

  • Essential tool for interfacing with High speed data communications equipment
  • Converts single-ended or differential 50 Ω SMA NECL inputs to differential 124 Ω RS-422 Triax outputs

Features:

  • 400 MHz maximum Clock Rate
  • Internal Single Ended or Differential 50 Ω/-2 V Input termination
  • Differential 124 Ω RS-422 Outputs
  • Ready-to-Use 1.3 x 2.9 x 3.9-in. modules, include AC/DC Adapters

Description

The PRL-422NECL is a dual channel, high speed logic level translator designed specifically for use with high speed data communications applications. The PRL-422NECL converts single ended or differential 50 Ω NECL inputs to differential 124 Ω RS422 outputs. A functional block diagram is shown in Fig. 1.

The differential inputs of the PRL-422NECL have SMA connectors. A switch selects either single-ended or differential inputs. In the differential input mode, both inputs D and D are terminated internally into 50 Ω/-2 V, and, therefore, either one or both inputs can accept AC coupled signals as well. In the single input mode, signals should be connected to the D inputs only. The D inputs are switched internally to VBB, nominally -1.3 V, and termination resistors RT's for the D input channels are changed to 62 Ω.

The outputs of the PRL-422NECL have two triax connectors, and they are designed to interface with the 124 Ω differential Serial Data/Data or Clock/Clock inputs of the data communications equipment. Internal pull-down resistors enable these outputs to drive differential 75 Ω loads as well.

The PRL-422NECL 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/1.8 A AC/DC Adapter.

PRL-422NECLFig. 1 PRL-422NECL Dual Ch. NECL to RS-422 Translator

*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:
  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 Terminator, connected to a sampling 'scope.
  3. Trompeter P/N CBBJR79.
  4. Trompeter P/N PCGOW10PCG-36

(0° C ≤ TA ≤ 35° C)*

Symbol Parameter PRL-422NECL Unit
Min Typ Max
RIN Input Resistance 49.5 50 50.5 Ω
VTT Input Termination Voltage -1.8 -2.0 -2.2 V
IDC1 DC Input Current, +8.5 V   30 60 mA
IDC2 DC Input Current, -8.5 V   -250 -300 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%)   NA   ps
fmax Maximum Clock Frequency2 400 600   MHz
tSKEW1 Skew between outputs   20 200 ps
tSKEW2 Skew from unit to unit   40 400 ps
  Input Connector SMA  
  Output Connector Triax3  
  Input Cables 50 Ω Coax  
  Output Cables 124 Ω TP4  
  Size 1.3 x 2.9 x 3.9  in.
  Weight, excluding AC adapter 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.