2 Ch. Translator, NECL to TTL


$ 1,174.15


  • Converting Single Ended or Differential NECL Signals to TTL Signals
  • High Speed Digital Communications Systems Testing
  • High Speed SONET Clock Level Translation


  • fmax > 300 MHz
  • 1.1 ns Typical Output Rise & Fall Times
  • 50 Ω/-2 V Input for NECL
  • Single Ended or Differential Inputs.
  • Complementary 50 Ω TTL Level Outputs
  • SMA I/O Connectors
  • Self-contained 1.3 x 2.9 x 3.9-in. unit including AC/DC Adapter


The PRL-450ND logic translator converts NECL signals to TTL signals. It can receive either single ended or differential input signals, selected by a switch. The outputs of these translators have 50 Ω back terminations, and, therefore, they can drive 50 Ω terminated or unterminated lines. These high speed translators facilitate testing of high speed digital communications circuits, where conversion of NECL clock and data signals to TTL level signals is often required.

The PRL-450ND is designed to interface with NECL circuits operating with a -5.2 V or -4.5 V supply.

In the differential input mode, both inputs D and D of the PRL-450ND are terminated into 50 Ω/-2 V. In this mode, 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. The termination resistors, RT, for the D input channels are changed to 62 Ω.

Each unit is supplied with a ±8.5 V AC/DC Adapter and housed in an attractive 1.3 x 2.9 x 3.9-in. extruded aluminum enclosure.

Fig. 1A PRL-450ND Block Diagram

(0° C ≤ TA ≤ 35° C)*

Symbol Parameter PRL-450ND Unit
Min Typ Max
Rin Input Resistance 49.5 50.0 50.5 Ω
Rout Output Resistance 49.5 50.0 50.5 Ω
VTT D Input Termination Voltage (fixed) -2.2 -2.0 -1.8 V
VT1 D Input Termination Voltage -2.2 -2.0 -1.8 V
VT2 D Input Termination Voltage (variable) -1.17 -1.30 -1.43 V
VOL Output Low Level -150 0 300 mV
VOH Output High Level 2.0 2.2   V
IDC1 DC Input Current, +8.5 V   280 300 mA
IDC2 DC Input Current, -8.5 V   -395 -415 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 ↑   2   ns
tPHL Propagation Delay to output ↓   2   ns
tr/tf Rise/Fall Times (10%-90%)   1.10 1.25 ns
tSKEW Skew between any 2 outputs   200 500 ps
fmax Max Clock Frequency 300 400   MHz
  Size 1.3 x 2.9 x 3.9 in.
  Weight, excluding AC adapter 7 Oz
  Shipping weight, including AC adapter 4 lb.
* Unless otherwise specified, dynamic measurements are made with all outputs terminated into 50 Ω.

While we believe these models to be accurate, no representations are made as to accuracy or suitability for any application: