2 Ch. LVPECL to NCML Level Translator

Applications:

• Converting Single-ended or Differential LVPECL Inputs to Differential NCML Outputs
• Differential LVPECL Inputs also accept Sinewave Signals
• High Speed Digital Communications System Testing
• Satellite/Radar/Telecommunications System Integration

Features:

• f_MAX > 1.5 GHz
• 650 ps t_r
• 50 Ω/+1.3 V LVPECL Input Termination
• Complementary NCML Outputs
• DC Coupled SMA I/O Connectors
• Self-contained 1.3H x 2.9W x 3.9D unit includes AC/DC adapter

Description

The PRL-427LP is a 2-channel LVPECL to differential NCML Logic Level Translator module. Each channel has a single-ended or differential LVPECL input and a ground-referenced differential 35 Ω NCML output. The NCML DC output logic Hi/Lo levels are 0 V and -350 mV, respectively, when terminated to ground-referenced 50 Ω loads.

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/V_TT, where V_TT is equal to +1.3 V for LVPECL. In the differential input mode, 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 V_BB, nominally +2.0 V for LVPECL, and termination resistors R_T for the D input channels are changed to 62 Ω.

These Logic Level Translators are designed specifically for use in testing and interfacing of high speed digital communications circuits, where conversion between LVPECL and NCML logic signals is often required. The PRL-427LP is part of the Mini Modular Instrument™ (MMI) family that find increasing applications in high speed digital data recording instruments, transient recording instruments and other high speed measurement equipment where LVPECL and NCML signals are often specified.