PRL-260ANT 2-Phase Programmable NECL/TTL Frequency Divider

Basic Lab Tools > Frequency Dividers > PRL-260ANT

Applications:

• System clock simulation
• Low-jitter NECL/TTL clock source
• Laser system synchronization (Ti:S photodiode division)
• SONET clock generator
• An essential lab tool for working with TTL/CMOS and ECL circuits
• See also the PRL-260BNT variant with a comparator input for small signals

Features:

• f/2 to f/4096, manually programmable
• Common divider f/n (2 = n = 256) has 8-bit resolution
• Φ1 output=(f/n)/(1, 2, 4 or 8), for max ratio of 2048
• Φ2 output=(f/n)/(2, 4, 8 or 16), for max ratio of 4096
• Φ1 has complementary NECL& TTL outputs and square wave outputs except when the final divisor is 1
• Φ2 has complementary NECL square wave outputs only
• Single-ended NECL, differential NECL, or AC-coupled sinewave inputs with internal 50 Ω/V_TT terminations
• Additional logically-ORed TTL input requires 0.7 V only
• 20 ps typical edge jitter
• 50 ps typical skew between f/n & f/n NECL outputs
• 200 ps typical skew between f/n & f/n TTL outputs
• 1.25 GHz typical max. external clock input frequency
• Complementary NECL outputs drive 50 Ω loads terminated to V_TT, AC-coupled or floating 50  Ω loads 
• Complementary TTL outputs drive long lines with or without 50  Ω load terminations
• DC-coupled I/O's
• SMA I/O connectors except for TTL Input (BNC)
• Ready-to-use 1.3 x 2.9 x 6.1-in. module includes a ±8.5V AC/DC adapter

Description

The PRL-260ANT is a DC-coupled, manually programmable, two-phase frequency divider with two sets of divided outputs, Φ1 and Φ2. It is capable of running at input clock frequencies in excess of 1 GHz and outputting divided TTL and NECL clock signals. The input frequency f is first divided down to f/n, where 2 ≤ n ≤ 256, via D1-D8 of a ten-bit DIP switch. The f/n signal is further divided by 1, 2, 4, or 8 for the Φ1 ECL and TTL outputs via D9 and D10, for a maximum ratio of 2048, and by 2, 4, 8 or 16 for the Φ2 ECL output via D11 and D12 of a second two-bit DIP switch, for a maximum ratio of 4096. All outputs are synchronous with the input frequency and are square waves (50% duty cycle), except for Φ1 output when the final divisor is set to 1 (D9-D10=00). When the final divisor is set to 1 the output pulse width is equal to the input pulse period. All outputs are complementary and will drive long lines. TTL outputs are back-matched and will drive terminated or unterminated loads. NECL outputs can drive 50 Ω loads terminated into -2 V or AC-coupled 50 Ω loads.

A complementary NECL input is logically ORed with a TTL input, enabling the unit to accept TTL input, single-ended or differential NECL input, or AC-coupled sinewave or other logic inputs. For differential NECL inputs, both SMAs are used with the input mode switch up. For single-ended NECL input the lower SMA is used with the switch down. For AC-coupled input either SMA can be used with the switch up. For TTL input the BNC input is used with the switch down. The NECL inputs are internally terminated to 50 Ω/-2 V in the differential input mode, and the inverted input to 62 Ω/-1.3 V in the single-ended input mode. The TTL input has a ground-referenced 50 Ω termination and the minimum signal required is only 0.75 V.

The PRL-260ANT is ideal for applications where a frequency divider or prescalar is needed for triggering or down-sampling, and the multiple logic inputs and outputs make it extremely useful in mixed-logic environments. The two phases of output enable applications requiring two different ratios from a common reference frequency. Applications for the PRL-260ANT include data acquisition, test, measurement, R&D, and system integration. 

The unit includes an AC adapter for ready-to-use convenience on the bench or in a system. All I/O connectors are SMA, except for the TTL input, which is BNC. The extruded aluminum housing is suitable for mounting with the optional brackets.

Replaced Product:

The PRL-260ANT replaces the discontinued PRL-260NT.

Related BLT's:

• 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

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 | DivisorTable.xls