1:4 TTL/CMOS Fanout Buffer and Line Driver


$ 592.25


  • TTL/CMOS Clock Distribution
  • 1:4 Fanout Line Drivers
  • 1 PPS Distribution/IRIG-B Distribution
  • High Speed Digital Communications System Testing
  • Essential Lab Tool


  • fmax > 100 MHz
  • Drives 100 ft of cable @ 80 MHz
  • 2 ns Typical Output Rise & Fall Times
  • TTL Compatible 50 Ω or 1 kΩ Input
  • 500 ps typical channel to channel skew
  • Four in-phase 50 Ω TTL Outputs
  • BNC or SMA I/O Connectors
  • DC Coupled I/O's
  • Self-contained 1.3 x 2.9 x 2.9-in unit includes an AC/DC Adapter


The PRL-414B is a 1:4 fanout 50 Ω TTL Line Driver.  It is intended for distribution of high-speed clock and logic signals to multiple loads via long lines.  The 50 Ω back-terminated outputs can drive long lines with or without 50 Ω load terminations; With 50 Ω load terminations, however, all outputs of the PRL-414B can drive 100 ft of 50 Ω cables at clock rates greater than 80 MHz.  In one important application, the PRL-414B is used for distributing a precision clock signal to a number of test stations in the lab.

The input resistance of the PRL-414B can be selected to be either 50 Ω or 1 kΩ by a switch.  The 1 kΩ-input is desirable when interfacing with low power circuits.  All I/Os are DC coupled and have BNC or SMA connectors.

The PRL-414B is housed in a 1.3 x 2.9 x 2.9-in. extruded aluminum enclosure and is supplied with a ±8.5 V/±1.8 A AC/DC Adapter.  A maximum of four units can share a single AC/DC adapter using the PRL-730 voltage distribution module.  If mounting is needed, a pair of the #35001420 mounting brackets can accommodate any two PRL modules of the same length.  

A block diagram showing the equivalent input and output circuits of the PRL-414B is shown in Fig. 1.


Fig. PRL-414B Block Diagram

Sample Applications and Related Products for PRL-414B

Crystal Clock Sources

  • PRL-171, Fanout Crystal Clock Source
  • PRL-172, Four-Phase Crystal Clock Source (f, f/2, f/4, f/8)
  • PRL-173, Two-Phase Crystal Clock Source (f, f/5)

RF Switches & Scanners

Frequency Dividers

  • PRL-220A, Four Phase Frequency Divider (f/2, f/4, f/8, f/16)
  • PRL-240A, Two Phase Frequency Divider (f/2, f/10)

Comparators/Sinewave Convertors

Logic Level Translators

PRL-470 High Speed Line Driver and Level Translator


  • Mounting Brackets
  • Extra AC/DC Adapters (one included with unit)
  • Voltage Distribution Modules, for sharing AC adapters among several modules
  • Cables


Symbol Parameter Min Typ Max Unit Comments
RIN LO Input Resistance Low Range 49.5 50 50.5 Ω
RIN HI Input Resistance High Range 990 1000 1010 Ω
ROUT Output Resistance 50 Ω
VIL TTL Input Low Level -0.5 0 0.5 V
VIH TTL Input High Level 2.0 2.4 5.0 V
VOL TTL Output Low Level 0 0.25 0.5 V RL=50 Ω
VOH1 TTL Output High Level 2.2 2.5 V RL=50 Ω @ DC
VOH2 TTL Output High Level 4.4 5 V RL=1 MΩ @ DC
IDC1 TTL Output High Level 280 350 mA f ≤ 100 MHz
IDC2 DC Input Currents 220 250 mA f =50 MHz sq. wave(1)
VDC DC Input Voltages 7.5 8.5 12 V
VAC AC/DC Adapter Input Voltage 103 115 127 V
TPLH Propagation Delay to output ↑ 10 12 ns
TPHL Propagation Delay to output ↓ 8 12 ns
tr Rise Time (10%-90%) 2.2 3 ns f =50 MHz sq. wave
tf Fall Time (10%-90%) 1.8 3 ns f =50 MHz sq. wave
TSKEW Skew between any 2 outputs 500 1500 ps f =50 MHz sq. wave
FMAX1 Max. Clock Frequency(2) 100 120 MHz RG58C/U Cable length =3 ft
FMAX2 Max. Clock Frequency(3) 80 RG58C/U Cable length =100 ft
PWMIN Min. Pulse Width 4 ns ↑ Input
PWMIN Min. Pulse Width 6 ns ↓ Input
Size 1.3 x 2.9 x 2.9 in
Weight 5 Oz Excluding AC adapter
Shipping Weight 4 lb Including AC adapter
Unless otherwise specified, dynamic measurements are made with all outputs terminated into 50 Ω.
(1) For sharing a single PRL-760C, ±8.5 V ±1.8 A AC/DC adapter, the total current should not exceed 1.8 A.
(2) fMAX should not exceed 120 MHz; otherwise, damage of the unit due to overheating may result.
(3) fMAX2 is measured by connecting a second PRL-414B at the end of the 100 ft. cable.