6 GHz Programmable 2-Phase Frequency Divider (f/2-f/32)


$ 862.50


  • System Clock Simulation
  • Low Jitter NECL Clock Source
  • SONET Clock Generator
  • Scope triggering
  • PRBS/BERT synchronization
  • Optimizing outputs from frequency synthesizers
  • Testing high-speed serial/SERDES links (GB Ethernet, eSATA, PCIe, HT, etc)
  • An Essential Lab Tool for Working with NECL Circuits


  • 6.6 GHz typical maximum External Clock Input frequency
  • f/2 to f/32 with independent 2Φ outputs
  • Common Divide by 2 pre-scalar for both Φ1 and Φ2
  • Φ1 output = (f/2)/(1, 2, 4 or 8), for max. ratio of f/16
  • Φ2 output = (f/2)/(2, 4, 8 or 16), for max. ratio of f/32
  • Both Φ1 and Φ2 have two pairs of complementary NECL square wave outputs
  • Single-ended AC Coupled Input with internal 50 Ω termination
  • 5 ps typical Edge Jitter
  • 40 ps typical skew between f/n & f/n NECL outputs
  • Complementary DC coupled NECL Outputs drive 50 Ω loads terminated to -2 V, AC-coupled or floating 50 Ω loads
  • SMA I/O Connectors
  • Ready-to-Use 1.3 x 2.9 x 2.9-in. Module includes a ±8.5V AC/DC Adapter


The PRL-257-2 is an AC-coupled input, manually programmable, two phase frequency divider with two sets of complementary NECL outputs. It is capable of running at input frequencies in excess of 6.6 GHz.

It has a common divide-by-2 pre-scalar front end followed by two banks of independent manually programmable dividers, Φ1 and Φ2. The f/2 pre-scalar output is further divided by 1, 2, 4, or 8 for the Φ1 bank via D0 and D1 of a two-bit DIP switch, providing a maximum ratio of 16. It is divided by 2, 4, 8 or 16 for the Φ2 bank via D2 and D3 of a second two-bit DIP switch, providing a maximum ratio of 32. All outputs are synchronous with the input frequency and are square waves (50% duty cycle) suitable for driving long lines terminated into 50 Ω/-2 V or AC-coupled 50 Ω loads.

The PRL-257-2 is ideal for applications where a high frequency divider or pre-scalar is needed for triggering or down-sampling. The two phases of output enable applications requiring two different ratios from a common reference frequency, and the 1:2 fanout feature enables system synchronization and monitoring/triggering applications from a single reference clock source. Applications for the PRL-257-2 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. The extruded aluminum housing is suitable for mounting with the optional brackets.

Fig. 2: PRL-257-2 Block Diagram


Symbol Parameter PRL-257-2 Unit Comments
Min Typ Max
RIN Input Resistance   50   Ω AC Coupled
CC Coupling Capacitor 0.08 0.10 0.12 µf Input TC=50 µs
IDC1 DC Input Current, +8.5 V   +80 +100
IDC2 DC Input Current, -8.5 V -285 -300 mA
VDC DC Input Voltage ±7.5 ±8.5 ±12 V  
VAC AC/DC Adapter Input Voltage 103 115 127 V  
VINmin Minimum p-p Input Amplitude 500
Sine Wave@ FMIN In I
Square Wave, tr < 2 ns
Square Wave, tr < 500 ps
VINmax Maximum p-p Input Amplitude   2.00 1.25 V Sine or Square Wave
VOH Output Hi Voltage @ 100 MHz -1.13 -0.90 -0.81 V Output terminated to 50 Ω/-2 V
VOL Output Lo Voltage @ 100 MHz -1.95 -1.60 -1.48 V Output terminated to 50 Ω/-2 V
tPLH Propagation Delay to Φ1 output ↑   2500   ps  
tPHL Propagation Delay to Φ1 output ↓   2500   ps  
tr/tf Rise/Fall Times (20%-80%)   200 250 ps Note (1)
tSKEW1 Skew ↔ Φ1 or Φ2 outputs   40 120 ps  
tSKEW2 Skew ↔ Φ1 and Φ2 outputs   40 120 ps D0/D1=10, D2/D3=00
  Jitter, p-p   5 10 ps Note (2)
FMIN In I Minimum Input frequency 120 100   MHz Sine wave input
FMIN In II Minimum Input frequency 150 100   KHz Square wave input, tr < 2 ns
FMAX In I Maximum Input frequency 6.0 6.6   GHz  
FMAX Out1 Maximum Output frequency, Φ1 3.00 3.30 GHz Φ1 outputs
FMAX Out2 Maximum Output frequency, Φ2 1.50 1.65 GHz Φ2 outputs
  Size 1.3 x 2.9 x 2.9 in.  
  Weight, excl. AC adapter 10 Oz.  
  Shipping weight, incl. AC adapter 4 lb.  
* All measurements are made with outputs terminated into 50 Ω/VTT.
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-550 Series, four channel ECL/PECL/LVPECL Terminators, for the 50 Ω/VTT termination and for connection of ECL/PECL/LVPECL 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 NECL/PECL/LVPECL outputs to 50 Ω input instruments.
Jitter specification limited by PRL production test equipment. Independent testing of a related model shows typical jitter performance of < 1 ps one-sigma RJ.