1:8 Diff. Fanout Buffer, Univ. Diff./TTL Input, RS-422 Output

Applications:

• 1:8 Fanout Buffer
• Converting Differential NECL/LVPECL/RS-422 or TTL Signals to RS-422
• Long Line Driver/Level Translator
• Reference Clock Distribution/Translation
• 1 PPS Distribution/IRIG-B Distribution
• Telemetry and Avionics Distribution
• Test and System Integration

Features:

• f_max > 150 MHz for Differential Inputs
• f_max > 100 MHz for TTL Inputs
• 1.6 ns Typical Rise & Fall Times for RS-422
• Channel-to-channel skew less than 500 ps
• Floating 100 Ω Universal Differential Inputs Accept LVDS, LVPECL, NECL, or RS-422 Inputs
• Separate TTL input (1 V minimum) Logically ORed with the Floating Differential Input
• 8 Complementary Outputs
• SMA or Triax Connectors for LVDS/LVPECL/NECL Inputs, BNC Connectors for TTL Input
• SMA, BNC, or Triax Output Connectors
• Self-contained 3.0H x 6.8W x 7.3L-in. unit includes ±8.5V/1.8A AC/DC Adapter
• The related PRL-4216U series permits simultaneous CLK/DATA fanout with low skew

Description

The PRL-4108UR is a series of 1:8 fanout differential line driver modules. All models have a floating 100 Ω universal differential input suitable for accepting LVDS, LVPECL, NECL, or RS422 signals.⁽¹⁾ They also have a logically ORed, 50 Ω TTL input with a minimum 1.0 V triggering threshold. Because the inputs are ORed a Hi level applied to either input can be used as a gate signal. Please see the block diagrams for more details.

The output is RS-422, available either with dual SMA connectors per differential output or one Triax connector per differential output.

The PRL-4108UR high speed fanout line driver facilitates testing of high speed digital communications circuits and distribution of satellite or telemetry signals. The product suffix specifies the input and output connectors, e.g. BNC, SMA, or TR (Triax):

For example, model PRL-4108UR-SMA has SMA differential I/O connectors, while PRL-4108UR-TR has Triax differential I/O connectors. The TTL input connector is always BNC, and the differential input connectors can be SMA or Triax. Additional connector and output logic options may be available upon special order.

The floating differential input accepts differential LVDS, LVPECL, NECL, RS422, or any 75 mV minimum differential signal within a common-mode range of -2.0 V to +3.0 V. When driven by LVPECL or NECL inputs, these signals must have internal 150 Ω pull-up or 200 Ω pull down resistors, respectively (known as a "source-biased" output). The PRL-4108UR differential input is compatible with all LVPECL or NECL output signals from the PRL family of products.

The TTL input has a selectable 50 Ω/1 kΩ input load and will trigger on a minimum 1.0 V threshold. The 1 kΩ is useful for interfacing with low-power circuits.

The eight pairs of complementary outputs are back-terminated and are designed for driving long lines. See the Specifications page for output levels.

The PRL-4108UL is supplied with a ±8.5 V/1.8 A AC/DC Adapter and housed in a 3.0 x 6.8 x 6.0-in. extruded aluminum enclosure. Available accessories include voltage distribution modules and mating cables.

(1) A related series, the PRL-4108NR, has a true NECL input terminated into 50 Ω/-2 V, and can accept single-ended or differential NECL signals that do not have internal pull-downs.