PRL-174ANT NECL/TLL Programmable VCO Clock Source

Mini Modular Instruments > Clock Sources > PRL-174ANT

Applications:

• System clock simulation
• Xtal Clock Replacement
• Frequency Margining
• Low Jitter ECL/TTL Clock Source
• SONET Clock Generator
• An Essential Lab Tool for Working with ECL and TTL Circuits

Features:

• 1.2 MHz to 1.35 GHz Frequency Range
• Other frequencies available by quote.
• 100 ppm Typical Setting Resolution and Short-term Stability
• NECL f and f Outputs
• NECL and TTL f/n and f/n Outputs
• 20 ps Typical Edge Jitter
• 50 ps Typical Skew Between f/n & f/n NECL Outputs
• 500 ps Typical Skew Between f/n & f/n TTL outputs
• Complementary NECL/TTL Outputs drive 50 Ω loads
• DC-Coupled Outputs with SMA Connectors
• Ready-to-Use 1.3 x 2.9 x 8.1-in. Module includes AC/DC Adapter

Description

The PRL-174ANT is a manually programmable clock source module, designed specifically for applications where continuously variable frequency with Xtal-like precision is required. Substituting for a hard-to-find crystal oscillator in system test and frequency margining in telecommunication network checkout are two of the most important applications.

The internal VCO frequency f is continuously variable from 600 MHz to 1.35 GHz using a 10-turn pot in the coarse control mode. In the fine control mode, a 16-position rotary switch first divides the 750 MHz frequency span into 16 increments, and the 10-turn pot further fine tunes each segment and sets the VCO frequency to within 100 ppm of the desired value. The 100 ppm setting and stability remain valid over a short term period of at least a half hour, provided the ambient temperature variation is less than 2° C and the VCO frequency is set above 650 MHz. Stability over 12 hours with ±2° C temperature variation is typically 250 ppm.

The VCO frequency f is then divided by 2 to 256 through D1-D8 of a 9-position DIP switch. D9 further divides the f/n outputs by 2, extending the maximum division to 512 and providing square wave outputs. The maximum output frequency available is greater than 1.35 GHz and the minimum less than 1.2 MHz. The PRL-174ANT has complementary NECL f and f outputs and f/n and f/n NECL and TTL outputs. 

The NECL outputs are designed for driving 50 Ω loads terminated into -2 V and they can also drive AC coupled or floating 50 Ω loads. The 50 Ω back-terminated TTL outputs can drive long 50 Ω lines with or without 50 Ω terminations and are usable up to 250 MHz.

Applications of the PRL-174ANT include Xtal clock replacement, frequency margining, precision clock for high speed digital systems, low jitter clock source for testing A/D's, SONET Clock generator, and Mini Modular Instrument for working with high speed NECL and TTL/CMOS circuits. A binary table showing the codes for all the possible division ratios is given in the Divisor Table spreadsheet. 

The PRL-174ANT is housed in a 1.3 x 2.9 x 8.1-in. extruded aluminum enclosure and is supplied with a ±8.5 V, +17 V AC/DC Adapter.

Related and Complementary Products:

• PRL-260ANT, 2-Φ Programmable NECL/TTL Frequency Divider
• PRL-414B, 1:4 TTL Fanout Buffer
• PRL-431N/P, 1:2 NECL/PECL Fanout Buffer
• PRL-550 Series, NECL/PECL Terminators/Translators
• PRL-470A, Variable Output Pulse Driver

Replaced Product:

The PRL-174ANT replaces the discontinued PRL-174NT.

Accessories

• PRL-SC-104, DC Block, 0.1 µf
• PRL-SC-225, DC Block, 2.2 µf
• PRL-FTC-104, Feedthru Decoupling Cap, 0.1 µf
• PRL-FTR-50, Feedthru 50 Ω Termination
• PRL-ACT-50, Dual Ch. AC Coupled 50 Ω Termination 
• PRL-ACX-12dB, AC Coupled 12dB (4X) Attenuator
• Mounting Brackets, for mounting to flat surfaces
• Voltage Distribution Modules, for sharing AC adapters among multiple modules
• Cables, various lengths of RG-174 50 Ω coax with SMA plugs

Detail | Diagram | Specifications | Datasheet | Divisor Table (xls)