2 Ch. Translator, TTL to Differential TTL


$ 1,130.45


  • Converting TTL/CMOS signals to Differential TTL Signals
  • Converting TTL/CMOS Signals to RS-422 Signals
  • High Speed Digital Communications system testing
  • 1 PPS/IRIG-B Line Driver
  • Differential Line Drivers


  • fMAX > 300 MHz
  • 1.1 ns Typical tr 
  • 50 Ω TTL/CMOS Input
  • 1.5 V or 1.0 V Selectable Input Threshold
  • Complementary 50 Ω TTL Outputs
  • BNC Input/SMA Output Connectors
  • DC-Coupled I/Os
  • Self-contained 1.3 x 2.9 x 3.9-in. units including AC/DC Adapters


The PRL-420TD is a dual channel single-ended input, differential output TTL Line Driver. Each channel has a 50 Ω TTL/CMOS compatible input and a pair of differential 50 Ω outputs for driving long lines with or without 50 Ω terminations. The input threshold voltage can be selected between 1.5 V and 1.0 V using a front panel switch. The 1.0 V threshold is useful when dealing with weak signals.

The PRL-420TD is intended for use in testing and interfacing of high speed digital communication circuits, where conversion from single-ended TTL/CMOS level signals to differential signals is often required. The differential TTL outputs can also drive RS-422 input circuits. It is an ideal building block that complements other PRL Level Translators, such as the PRL-450ND, PRL-450PD and PRL-460NPD, in systems integration applications where interconnections of signals having different logic levels are often necessary.

The PRL-420TD is a ready-to-use functional module housed in a 1.3 x 2.2 x 2.9-in. extruded aluminum enclosure and is supplied with a ±8.5 V AC/DC Adapter. BNC input and SMA output connectors are provided. A block diagram showing the equivalent input and output circuits of the PRL-420TD is shown in Fig. 1.

The PRL-420TD may be ordered without a power supply as "PRL-420TD-OEM" or with a NRTL-approved power supply (equivalent to PRL-765-1) as "PRL-420TD-NRTL".

Fig. 1, PRL-420TD Block Diagram

(0° C ≤ TA ≤ 35° C)*

Symbol Parameter PRL-420TD Unit
Min Typ Max
RIN Input Resistance 49.5 50.0 50.5 Ω
ROUT Output Resistance 49.5 50.0 50.5 Ω
VTOSH Input Threshold Voltage (high) 1.4 1.5 1.6 V
VTOSL Input Threshold Voltage (low) 0.9 1.0 1.1 V
VIL TTL input Low Level -0.5 0.0 0.5 V
VOL TTL Output Low Level -0.1 0.0 0.5 V
VOH TTL Output High Level 2.0 2.5 2.6 V
IDC1 DC Input Current, +8.5 V 340 360 mA
IDC2 DC Input Current, -8.5 V -360 -340 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(1) Rise/Fall Times (10%-90%) 1.2 1.4 ns
tSKEW Skew between any 2 outputs 150 400 ps
fMAX Max Clock Frequency 250 300 MHz
Size 1.3 x 2.9 x 3.9 in.
Weight, excl. AC adapter 7 Oz
Shipping weight, incl. AC adapter 4 lb.

*Unless otherwise specified, dynamic measurements are made with all outputs terminated into 50 Ω.