Coupling and Termination Modules


Applications:

  • AC coupling between signals
  • Waveform Clipping
  • RF Signal Isolation
  • RF I/O Port Decoupling
  • Precision 50 Ω Termination
  • RF Signal Detection
  • DC Restoration

Features:

  • DC Blocks with 0.1, 2.2 or 300 µf
  • RF Chokes with 1 µh or 10 µh
  • Series- or Shunt-connected Diodes
  • Series-Connected Resistors from 50 Ω to 1 MΩ
  • 0.5% 50 Ω Feedthru Terminations
  • Dual AC- or DC-coupled 50 Ω Terminations
  • SMA Male/Female I/O Connectors for inline use with no cabling required
  • 0.44" W x 0.37" H x 1.5" L Modules

Description

The PRL Series of Coupling and Termination Modules are two-terminal devices containing components which are series-connected, shunt-connected, or combination of both. They are intended for use in general purpose lab and production test environments.

For example, in a given test setup one may need to insert a DC Block, a 50 Ω Termination, a Feed-through Decoupling Capacitor, an RF Choke, a Series Diode, etc. in order to accommodate a change in the test requirement.

As of this date, the following modules are available, and more are being developed:

Series-Connected Shunt-Connected Series and Shunt-connected
Series Capacitor Feed-thru Shunt Capacitor AC-Coupled 50 Ω Termination
Series Inductor Feed-thru Shunt Resistor
Series Schottky Diode Feed-thru Shunt Schottky Diode
Series Resistor

 

As of February 2011, PRL has discontinued the ready-to-use attenuator series, due to low demand. We will honor and support all outstanding quotations and orders, but we will not be offering new items for sale in quantities of less than 100. For volume orders, please contact sales@pulseresearchlab.com . To build your own attenuator, please see our Signal Conditioning Kits and our Custom Attenuators application note.

If you don't see what you need, you can use our kits to build your own. Custom configurations containing combinations of different components may be available on special order.


Clockwise from top-left:

  1. PRL-ACX-12dB, AC-Coupled 50 Ω Attenuator (12 dB)
  2. PRL-ACT-50, Dual Ch. AC-Coupled 50 Ω Termination
  3. PRL-FTC-104, Feedthru Decoupling Cap (0.1 µf)
  4. PRL-SC-104, DC Block (0.1 µf)
  5. PRL-FTR-50, Feedthru 50 Ω Termination

A DC block connected between a source and a load is shown in Fig.1, where RT is the total resistance of the circuit, consisting mainly of the sum of the source and load resistance, and C is the coupling capacitor. The time constant τ of the circuit is RTC, and it has the unit of ms if RT is in Ohms and C is in µf, or ns if RT is in kΩ and C is in pf. In most practical cases, the stray capacitance across the load can be neglected. The case where RS=RL=50 Ω is of special interest, where RT is 100 Ω, and this value is used in Table I below.

When a voltage step with amplitude E is applied to the input at t0, the output immediately rises to E/2. At t0+,the output starts to decay towards zero with a time constant τ. After 4τ, the output will have discharged 98% of E/2 and is nearly at ground potential. 

For coupling pulse signals, it is clear that one needs a capacitor large enough so that the output signal remains essentially rectangular in shape as the pulse duration increases. Table I lists the coupling capacitor values verses % pulse level tilt* for different values of pulse width. Instead of the exponential decay, a linear decay approximation of the output is used.

It should be noted that the value of RS is generally not 50 Ω when the drive circuit is an ECL device, because the output resistance of an emitter follower is typically 5 Ω. Therefore, the values shown in Table I need to be modified when AC coupling a signal from an ECL emitter follower. A simple and quick approximation is to either divide all the PW values by two or multiply the % tilt values by two.

C(µf) f3 dB τ=RTC PW (1% tilt) PW (2% tilt) PW (5% tilt) PW (10% tilt)
0.01 159 KHz 1 µs 10 ns 20 ns 50 ns 100 ns
0.1 15.9 KHz 10 µs 100 ns 200 ns 500 ns 1 µs 
1.0 1.59 KHz 100 µs 1 µs  2 µs  5 µs  10 µs 
10 159 Hz 1 µs  10 µs  20 µs  50 µs  100 µs 
100 15.9 Hz 10 µs  100 µs  200 µs  500 µs  1 ms

Table I. Transmission of a rectangular pulse train through a high-pass filter with time constant t=RTC, f3 dB=1/2πRTC. RT=100 Ω.

* For a thorough treatment of this subject, please see Millman and Taub, Pulse, Digital, and Switching Waveforms.

Coming soon!

(0° C ≤ TA ≤ 35° C)*


DC Blocks, Series-Connected Capacitor:

Model No. Capacitance value/Type VSWR Tr/3dB BW Application
PRL-SC-104A 0.1 µf, ±10%, 30 V,X7R <1.1@3.0 GHz 40 ps/>8 GHz AC Coupling
PRL-SC-225A 2.2 µf, ±20%, 30 V, Z5U <1.2@2.5 GHz 50 ps/7 GHz AC Coupling

RF Chokes, Series-Connected Inductor:

Model No. Inductance Value Irms Max DCR max SRF Typical Application
PRL-SL-102A 1000 nh, ±5% 300 mA 3.5 Ω 400 MHz RF Isolation
PRL-SL-103A 10 µh, ±5% 300 mA 3 Ω 60 MHz RF Isolation

Series-Connected Schottky or PN Junction Diode:

Model No. Equivalent Device Type VBR If @ 1V Vf CT Application Comments
PRL-SSDP HSMS-2813/-2814 (Schottky) 20 V 70 mA 2.4 pf RF Detector 2 devices in //
PRL-SDP 1N914 100 V 10 mA 4 pf General purpose detector

Series-Connected Resistors:

Model No. Resistance Value Max. Vr Application
PRL-SR-50 50 Ω ±1% 5 V Back 50 Ω Term.
PRL-SR-450 450 Ω ±1% 10 V . 10X attenuator
PRL-SR-950 950 Ω ±1% 15 V. 20X attenuator
PRL-SR-106A 1 MΩ ±1% 100 V Current source

Shunt-Connected Capacitors:

Model No. Value/Type Application
PRL-FTC-104A 0.1 uf, ±10%, 30 V,X7R Decoupling/AC short
 

Shunt-Connected Resistive Terminations:

Model No. Value/Type Max Vr/Ir Application/Description
PRL-ACT-50 50 Ω, ±1% 5 V Max. Dual AC Coupled 50 Ω termination
PRL-DCT-50 50 Ω, ±1% 5 V Max. Dual DC Coupled 50 Ω termination
PRL-FTR-50 50 Ω, ±0.5% 5 V Max. Precision Feed-Thru Termination.
PRL-FTR-0 0 Ω, +0.005 Ω 500 mA Max. Short circuit termination

Shunt-Connected Diodes:

Model No. Type VBR If @ 1V Vf CT Application Comments
PRL-FTSDPD HSMS-2813/-2814, SBD 20 V 70 mA 2.4 pf +Signal clipping Grounded Cathode, 2 devices in //
PRL-FTSDND HSMS-2813/-2814, SBD 20 V 70 mA 2.4 pf -Signal clipping Grounded Anode, 2 devices in //

Attenuators:

As of February 2011, PRL has discontinued the ready-to-use attenuator series, due to low demand. We will honor and support all outstanding quotations and orders, but we will not be offering new items for sale in quantities of less than 100. For volume orders, please contact sales@pulseresearchlab.com . To build your own attenuator, please see our Signal Conditioning Kits and our Custom Attenuators application note.

Qty. Item Description Price
Total price: $0.00