The PRL-4122-BNC is a 1:22 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-4122 can drive 100 ft of 50 Ω cables at clock rates greater than 80 MHz.
The PRL-4122 is implemented as a 1:4 fanout buffer (equivalent to a PRL-414B module) with two of its outputs externally cabled to the inputs of two 1:10 fanout buffers (each equivalent to a PRL-4110 module). The twenty outputs from the two 1:10 modules are in phase, while the additional two outputs of the 1:4 module are advanced by approximately 10 ns. These auxiliary outputs can be used to drive the inputs of downstream PRL-4110 or PRL-4220 units for additional in-phase outputs.
The input resistance of the PRL-4122’s primary input 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. The 50 Ω back terminated outputs typically deliver 2.5 V into 50 Ω or 5.0 V into Hi-Z loads. All I/Os are DC coupled and have BNC or SMA connectors, except for the auxiliary outputs which are SMA.
Each 1:10 fanout bank also has an independent TTL-compatible EN input pulled down via a 1 kΩ resistor. When left open the Enable is active, and the fanout bank will output signals. Each bank can be disabled by driving its EN input high. A block diagram showing the equivalent input and output circuits of the PRL-4122 is shown in Fig. 1.
The PRL-4122 is housed in a 3.0 x 6.8 x 4.0-in. extruded aluminum enclosure and is supplied with the PRL-760C, ±8.5 V/±1.8 A AC/DC Adapter.
(0° C ≤ TA ≤ 35° C)*
|RIN LO||Input Resistance Low Range||49.5||50||50.5||Ω|
|RIN HI||Input Resistance High Range||9.9||10.0||10.1||KΩ|
|RIN EN||Input Resistance, Enable||1||kΩ|
|VIL||TTL Input Low Level||-0.5||0.0||0.5||V|
|VIH||TTL Input High Level||2.0||2.4||5.0||V|
|VIL EN||EN Input Low Level||-0.5||0.0||0.5||V|
|VIH EN||EN Input High Level||2.0||2.4||5.0||V||Drive EN High to disable output|
|VOL||TTL Output Low Level||0.0||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||5.0||V||RL=1 MΩ @ DC|
|IDC1||DC Input Current||1220||mA||F =50 MHz sq. wave(1)|
|IDC2||DC Input Current||1510||mA||F ≤ 100 MHz|
|IDC3||DC Input Current||1800||mA||F =125 MHz|
|VDC||DC Input Voltages||7.75||8.50||12.00||V|
|VAC||AC/DC Adapter Input Voltage||103||115||127||V|
|TPLH1||Propagation Delay to output ↑||19||22||ns||For 1:20 primary outputs|
|TPHL1||Propagation Delay to output ↓||19||22||ns||For 1:20 primary outputs|
|TPLH2||Propagation Delay to output ↑||10||12||ns||For 2 auxiliary outputs|
|TPHL2||Propagation Delay to output ↓||8||12||ns||For 2 auxiliary outputs|
|tr||Rise Time (10%-90%)||1.8||2.5||ns|
|tf||Fall Times (10%-90%)||1.5||2.5||ns|
|TSKEW1||Skew between any 2 outputs||500||900||ps||Within one 1:10 bank|
|TSKEW2||Skew between any 2 outputs||1200||1600||ps||Any two primary outputs|
|FMAX1||Max. Clock Frequency(2)||100||125||MHz||RG58C/U, cable length =3 ft|
|FMAX2||Max. Clock Frequency(3)||80||RG58C/U, cable length = 100 ft|
|PWMIN1||Minimum Pulse Width||4||ns||↑ Input|
|PWMIN2||Minimum Pulse Width||6||ns||↓ Input|
|Size||3.0 x 6.8 x 4.0||in|
|Weight||2||lb||Excluding AC adapter|
|Shipping Weight||6||lb||Including AC adapter|