The PRL-420ND translator converts TTL/CMOS logic to NECL levels.
Each unit has a switch-selectable 1.5 V or 1.0 V input threshold voltage with a fixed 50 Ω input termination. The complementary NECL outputs from the PRL-420ND are suitable for driving 50 Ω loads terminated to -2 V. The outputs of all units can also drive AC-coupled or floating 50 Ω loads.
(0° C ≤ TA ≤ 35° C)*
|Rout||Output Resistance||NPN emitter||Ω|
|VTOSH||Input Threshold Voltage (High)||1.4||1.5||1.6||V|
|VTOSL||Input Threshold Voltage (Low)||0.9||1.0||1.1||V|
|VOL||Output Low Level||-1.85||-1.70||-1.55||V|
|VOH||Output High Level||-1.0||-0.8||-0.7||V|
|IDC1||DC Input Current, +8.5 V||35||45||mA|
|IDC2||DC Input Current, -8.5 V||-132||-145||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 ↑||1.5||ns|
|tPHL||Propagation Delay to output ↓||1.5||ns|
|tr/tf(1)||Rise/Fall Times (20%-80%)||750||850||ps|
|tSKEW||Skew: VO1↑↔ VO2↑||200||500||ps|
|Max Clock Frequency
Input Threshold Voltage (High)
|Max Clock Frequency
Input Threshold Voltage (Low)
|Size||1.3 x 2.9 x 3.9||in.|
|Weight, excl. AC adapter||7||Oz|
|Shipping weight, incl. AC adapter||4||lb.|
*Unless otherwise specified, dynamic measurements are made with all outputs terminated into 50 Ω /-2 V for PRL-420ND.
The output rise and fall times are measured with with all inputs terminated into 50 Ω/VTT. For best performance all outputs should be terminated into 50 Ω/VTT or else AC- coupled into 50 Ω loads. If a single output is used, its complement must be terminated; otherwise output waveform distortion will occur. If one pair of complementary outputs is used, the other complementary pair may remain unterminated. Use the PRL-550NQ4X, four channel NECL Terminator, for the 50 Ω/VTT termination and for connection of NECL signals to 50 Ω input oscilloscopes. The PRL-ACT-50, Dual Channel AC-Coupled 50 Ω Terminator, may also be used to provide the 50 Ω/VTT termination. If preservation of DC levels is not required, then the PRL-SC-104, 0.1 µf DC block or a 12 dB AC-coupled attenuator may be used to connect the PECL outputs to 50 Ω input instruments.
(2). fMAX for the PRL-420ND is measured by connecting its inputs to the PRL-450ND, NECL to TTL Logic Level Translator, and its outputs to the ÷2 differential inputs of the PRL-255N NECL frequency divider. The outputs of the PRL- 255N are then measured using the PRL-550NQ4X, four channel NECL Terminator, connected to a 50 Ω input sampling 'scope.