1:2 Differential LVPECL Fanout Buffer, SMA I/Os


$ 1,229.35


  • Fanout Single-ended Input signals into two pairs of Differential signals for driving long lines
  • Ideal for receiving signals from long lines
  • Fanout GHz Sinewave signals into two pairs of Differential LVPECL signals
  • 1 PPS Distribution/IRIG-B Distribution
  • An Essential Lab Tool for Working with LVPECL Circuits


  • 3 GHz fMAX
  • Single-ended or Differential Inputs
  • Internal 50 Ω/VTT Input Terminations also accept AC coupled Signals
  • Complementary Outputs drive 50 Ω loads terminated to VTT, AC coupled or floating 50 Ω loads
  • DC Coupled I/Os Compatible with ECLinPS or 10KH Devices
  • SMA I/O Connectors
  • Ready-to-Use 1.3 x 2 9 x 2 2-in. Module includes a ±8.5 V AC/DC Adapter


The PRL-431LP is a 1:2 Differential Fanout LVPECL Buffer module. It is an essential lab tools for applications where it is necessary to drive two different loads from a single source of single-ended or differential LVPECL signals. It can also be used for converting GHz sine wave signals into differential LVPECL signals.

A switch selects either single-ended or differential inputs, as shown in Fig. 1. In the differential input mode, both inputs D and D are terminated internally into 50 Ω/VTT*, and, therefore, either one or both inputs can accept AC-coupled signals as well. In the single input mode, signal should be connected to the D input only. The D input is switched internally to VBB**, and termination resistor RT for the D input is changed to 62 Ω. Complementary outputs of the PRL-431LP are designed for driving 50 Ω loads terminated into +1.3 V. With internal pull-down resistors, these outputs can also be AC-coupled for driving 50 Ω loads terminated to ground or to other voltages.

The PRL-431LP complementary outputs must be used together for driving differential LVPECL inputs only, because the reduced output logic swing of 400 mVPP (for short circuit protection reasons) is not logic level compatible with some single-ended LVPECL inputs.

The PRL-431LP is housed in a 1.3 x 2.9 x 2.2-in. extruded aluminum enclosure and supplied with a ±8.5 V/1.8 A AC/DC Adapter.

VTT is nominally -2.0 V for ECL, +3.0 V for PECL, and +1.3 V for LVPECL. VBB is nominally -1.3 V for ECL, +3.7 V for PECL, and 2.0 V for LVPECL.

PRL-431LP Block Diagram

(0° C ≤ TA ≤ 35° C)*

Symbol Parameter PRL-431LP UNIT
Min Typ Max
RIN Input Resistance 49.5 50.0 50.5 Ω
VTT D Input Termination Voltage (fixed) 1.18 1.30 1.43 V
VT1 D Input Termination Voltage 1.18 1.30 1.43 V
VT2 D Input Termination Voltage (variable) 1.80 2.00 2.20 V
VIL Input Lo Voltage 1.35 1.48 1.67 V
VIH Input Hi Voltage 2.08 2.28 2.42 V
VOL Output  Lo Voltage 1.35 1.48 1.61 V
VOH Output Hi Voltage 2.15 2.28 2.51 V
IDC DC Input Current   150 170 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 ↑   750 950 ps
TPHL Propagation Delay to output ↓   750 950 ps
tr/tf(1) Rise/Fall Times (20%-80%)   220 300 ps
TSKEW Skew between Q & Q outputs   20 75 ps
FMAX(2) Max clock frequency 2.5 3.0   GHz
VCMR Common Mode Range 2.0   3.3 V
  Size 1.3 x 2.9 x 2.2 in.
  Weight, excluding AC adapter 5 Oz
  Shipping weight, excluding AC adapter 4 lb.

*All measurements are made with outputs terminated into 50 Ω/VTT, using the PRL-550LPQ4X four channel LVPECL Terminator, connected to a 50 Ω input sampling oscilloscope.


(1). The output rise and fall times are measured with both the Q and Q outputs terminated into 50 Ω/VTT. An unused complementary output must be either terminated into 50 Ω/VTT or AC coupled into a 50 Ω; otherwise, output waveform distortion and rise time degradation will occur. Use the PRL-550LPQ4X four channel LVPECL Terminator for the 50 Ω/+1.3 V termination and for connection of LVPECL signals to 50 Ω input oscilloscopes.

(2). fMAX is measured by AC coupling a sine wave to the D input using the differential input mode (switch up). The differential outputs are first divided by four, using the PRL-255LP, and then measured using the PRL-550LPQ4X, four channel LVPECL Terminator, connected to a sampling scope.