2 Ch. Translator, TTL to NECL

SKU:

$ 1,130.45

Quantity

Item	Description
88000102-4	Cable, triple voltage, with modular plugs, Length in ft.
88000103-4	Cable, triple voltage, with modular plug and pig tail leads, Length in ft.

Product Description
Diagrams
Applications
Specifications
Documents

Applications:

Converting TTL/CMOS signals to Differential NECL Signals
High Speed Digital Communications system testing
High Speed SONET Clock Level Translation
Converting TTL/CMOS Clocks to NECL Clocks for connection to Transient Recorders

Features:

f_MAX > 300 MHz
750 ps t_r
50 Ω TTL/CMOS Input
1.5 V or 1 V Selectable Input Threshold
Complementary NECL Outputs
BNC Input Connector
SMA or Triax Output Connectors
DC-Coupled I/O's
Self-contained 1.3 x 2.9 x 3.9-in. units including AC/DC Adapters

Description

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.

These Logic Level Translators are designed specifically for use in testing and interfacing of high speed digital communications circuits, where conversions from TTL/CMOS level signals to NECL level signals are often required. They are ideal building blocks that complement other PRL Logic Level Translators, such as the PRL-450ND, PRL-450PD, PRL-460NPD and PRL-460PND, etc. in systems integration applications where interconnections of mixed logic signals are often necessary.

They are ready-to-use functional modules housed in 1.3 x 2.9 x 3.9-in. extruded aluminum enclosures and are supplied with ±8.5V AC/DC Adapters. The TTL input connector is BNC. The NECL output connectors can be SMA or Triax. Block diagrams is shown in Fig. 1A and 1B.

If mounting is desired, a pair of 35001420 mounting brackets can accommodate two PRL modules of the same length. A number of PRL modules can also share a single ±8.5V AC/DC adapter using the PRL-730 or PRL-735 voltage distribution module.

Fig. 1A, PRL-420ND Block Diagram

Fig. 1B, PRL-420NDTR Block Diagram

(0° C ≤ T_A ≤ 35° C)*

Symbol	Parameter	PRL-420ND			Unit
Symbol	Parameter	Min	Typ	Max	Unit
R_in	Input Resistance	49.5	50	50.5	Ω
R_out	Output Resistance	NPN emitter			Ω
V_TOSH	Input Threshold Voltage (High)	1.4	1.5	1.6	V
V_TOSL	Input Threshold Voltage (Low)	0.9	1.0	1.1	V
V_OL	Output Low Level	-1.85	-1.70	-1.55	V
V_OH	Output High Level	-1.0	-0.8	-0.7	V
I_DC1	DC Input Current, +8.5 V		35	45	mA
I_DC2	DC Input Current, -8.5 V		-132	-145	mA
V_DC	DC Input Voltage	±7.5	±8.5	±12	V
V_AC	AC/DC Adapter Input Voltage	103	115	127	V
t_PLH	Propagation Delay to output ↑		1.5		ns
t_PHL	Propagation Delay to output ↓		1.5		ns
t_r/t_f⁽¹⁾	Rise/Fall Times (20%-80%)		750	850	ps
t_SKEW	Skew: V_O↑↔V_O↓		200	500	ps
t_SKEW	Skew: V_O1↑↔ V_O2↑		200	500	ps
f_MAX⁽²⁾V_TOSH	Max Clock Frequency Input Threshold Voltage (High)	200	300		MHz
f_MAX⁽²⁾V_TOSL	Max Clock Frequency Input Threshold Voltage (Low)	300	400		MHz
	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.

Notes:

The output rise and fall times are measured with with all inputs terminated into 50 Ω/V_TT. For best performance all outputs should be terminated into 50 Ω/V_TT 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/V_TT 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/V_TT 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). f_MAX 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.

While we believe these models to be accurate, no representations are made as to accuracy or suitability for any application:

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