PG-TIA Broadband IF Amplifier

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The performance of a receiver or transmitter depends on careful impedance matching between its sub-systems: its mixers, filters, and amplifiers. Mismatches can cause loss of signal strength, inter-modulation distortion, and deep ripples in the audio passband that can make human speech hard to understand.

A termination-insensitive amplifier (TIA) such as this one always presents a 50Ω impedance at both its input and output ports, providing a stable and predictable impedance to whatever it’s hook up to. This simplifies the design of the mixers, modulators, product detectors, and filters these TIA amplifiers serve in a complete radio system. The circuit on which this broadband TIA IF amp is based was devised by Wes Hayward, W7ZOI, and Bob Kopski, K3NHI.

The TIA Broadband IF Amp has these features:

  • Input and output port impedance is always 50Ω and does not pass through or “telegraph” to the other port.
  • “Programmable” gain from 7 to 24dB.
  • Useful from 1 to 30MHz (with slightly-lower gain above 14MHz).
  • Uses 12VDC power.
  • PCB pads for edge-style SMA connectors (also usable for direct solder connection).
  • Mounting holes for 4-40 (M3) screws.
  • 1.58″ (4cm) long, 0.84″ (2.6cm) wide.

The PG-TIA is available as a bare PCB, a kit of PCB and components (SMAs not included), or as a fully-assembled and tested unit (SMAs not included).

Schematic diagram (PDF)

User’s guide (PDF)

Github Repository

PC board only $4.49 Buy on eBay Buy on Tindie
Kit of PC board with discrete components (SMA connectors not included) $9.95 Buy on eBay Buy on Tindie
Fully assembled and tested (SMA connectors not included). Produced on demand, shipment within fourteen days of order. $16.95 Buy on eBay Buy on Tindie