Universal Pi Network Kit

SKU:

$ 48.30

Applications:

  • DC Blocks
  • Feed-through 50 Ω Termination
  • Custom Attenuators
  • Multi-Pole Filters
  • Series Resistor, Inductor or R-L Network
  • Feed-through Decoupling Capacitor
  • Schottky Diode Line Terminator
  • Diode Detector
  • In Line Amplifier*
  • Diode Recovery Test Fixture*
  • Transistor Switching Test Fixture* 

* w/optional Bias Tee

Features:

  • π-Network, T-Network, or Multi-Pole Filter Footprint on Both Sides of PCB
  • Ground Plane and 50 Ω Transmission Line For Up To 5 GHz Bandwidth (SMA π model)
  • Accepts #1206 and #0805 size SMT Components
  • Populate With 1 to 28 Series or Shunt Components
  • Accepts Mini-Circuits™ HFCN-2700 Series Filters ( BNC π and T models only)
  • SMA or BNC Male/Female or Female/Female Connector Styles
  • Metal Enclosure Included for Shielding
  • 15 mm OD x 67.5 mm or 78 mm Length (BNC style)
  • 0.44" W x 0.37" H outside dimension, 1.50" or 2.06" L Modules (SMA style)

Description:

PRL's Signal Conditioning Kits enable quick and easy fabrication of custom signal-conditioning circuits for RF and high-frequency digital signals. SMA models run up to 5 GHz, and BNC models run up to 3 GHz.

There are three PCB layouts, each with different connector type and gender option:

  • PRL-PINET, π network with up to 2 series components and 8 shunt components.
  • PRL-TNET, T network with up to 4 series components and 12 shunt components.
  • PRL-MNET, multi-pole network with up to 8 series components and 20 shunt components.

Applications include attenuators, filters, DC blocks, feed-thru 50 Ω terminations, etc. They can be used to build commonly-used circuits, such as a 50 Ω shunt termination, or to build one-of a-kind fixtures not commercially available. Three PCB designs (π, T and multi-pole) enable easy construction of nearly any series and or parallel network. The double-sided footprint (identical on both sides of the PCB) allows non-standard resistor, inductor, and capacitor values to be fabricated easily and economically. With the addition of a Bias Tee, active device test fixtures can be built as well. 

In one example, we easily fabricated a 24 dB attenuator with non-standard impedance for the interface between a vacuum tube output and a TTL input circuit, using a two-stage design with discrete SMT resistors. In another example, we level-shifted a -6V to +10V pulse to 0V to +16V for driving a high impedance circuit. In this case, we constructed a simple DC Restorer using a coupling capacitor and a shunt Schottky diode to ground. 

Other examples include a feed-through decoupling capacitor, using one shunt capacitor to make an ideal low pass filter for noise reduction at I/O ports. The kits can be populated with as few as one series component, or as many as 28 series and shunt components, enabling a wide range of applications. 

Five available connector styles (BNC M/F, BNC F/F, SMA M/F, SMA F/F, and SMA M/M) and a low-profile design enable inline insertion into your transmission line, with or without cables. Male/male styles are available for the SMA π and T configurations only. A gender changer may be used to create a M/M style for other configurations.

For BNC models a metal tube enclosure provides protection and shielding. A toothed washer and nut secure the enclosure and provide DC contact. For SMA models an extruded rectangular enclosure is provided. The enclosure makes contact by friction, and can be secured with a cyanoacrylate adhesive (Superglue) or epoxy. Contact conductance ensures DC connectivity, and the capacitive coupling between the SMA body and enclosure provides AC connectivity.


Diagrams show all possible component positions on both sides of PCB. Unpopulated series positions may require 0 Ω jumpers. This page may also be printed out and used as a worksheet. Schematics of sample applications are available here.


Fig 1a: π Network Component Positions

Fig 1b: T Network Component Positions

Fig 1c: Multi-pole Network Component Positions

Schematics:

Diagrams show only the component positions used in the specified circuit. Unpopulated series positions may require 0 Ω jumpers. Diagrams showing all possible component positions are available here. Component values calculators are available here.

Application Schematic Kit Type
Pi Tee Multi
DC Block/Coupling Cap Y Y Y
AC Block/RF Choke Y Y Y
Series Termination Y Y Y
Shunt Termination Y Y Y
Precision Shunt Termination Y Y Y
Feed-through Decoupling Cap Y Y Y
Diode Detector Y Y Y
Attenuator Y Y Y
Low-pass Filter N Y Y
High-pass Filter N Y Y

Online Filter and Attenuator Calculators:

These calculators will provide schematics and ideal component values for a variety of filter types (e.g. Butterworth, Chebyshev/Tchebysheff, Bessel) and attenuator configurations. Some will also provide response curves.

To implement the desired design with standard components, it may be necessary to use multiple component values in series or parallel configurations to approximate the calculated values. For example, the design for a 6 dB 50 Ω attenuator calls for a 37.4 Ω resistor, a value that is not commonly available. The attenuator can instead be built with two 75 Ω resistors in parallel, producing a very good 6 dB attenuator from standard components:

"Ideal" 6 dB Attenuator Design Actual 6 dB Attenuator Implementation

A more complete Attenuator Application Note describes these techniques in more detail, including examples of many commonly-required attenuation ratios, measured performance, and oscilloscope captures.

(0° C ≤ TA ≤ 35° C)*


BNC Kits

Parameter π Network T Network Multi-pole
Maximum series components 2 4 8
Maximum shunt components 8 12 20
Length, including BNC connectors 68 mm/2.7 in 68 mm/2.7 in 78 mm/3.1 in
Diameter, including hex nut for cover 16 mm/0.6 in 16 mm/0.6 in 16 mm/0.6 in

SMA Kits

Parameter π Network T Network Multi-pole
Maximum series components 2 4 8
Maximum shunt components 8 12 20
Length, including SMA M/F connectors 38 mm/1.5" 52 mm/2.1"
Length, including SMA F/F connectors 35 mm/1.4" 49 mm/2.0"
Length, including SMA M/M connectors 41 mm/1.6" N/A
Cross-section (W x H), including cover 11.18 mm x 9.40 mm/0.44" x 0.37"