Group Actions
Engagement
  • Author Author: Jan Cumps
  • Date Created: Date Created
  • Views 115 views
  • Likes 7 likes
  • Comments 6 comments
Related
Recommended

Discrete difference amplifier - AC analysis: gain and bandwidth

Jan Cumps

This is the DC gain and BW analysis of the difference amplifier module that  designed for a Direct Conversion Receiver.

image

I'm searching for these points:

  • gain at 1 kHz (approx. mid of bandwidth)
  • -3 dB frequencies

I use Vrms values in the post - common for audio circuits. When measuring one of the differential channels, I tie the other to ground.

image

Specs:

  • Gain: ~10 dB
  • Bandwidth (-3 dB): ~30 Hz to 40 kHz (approximate)

Measurements:

image

IN1: gain (1 kHz): 9.2 dB, bw (-3 dB): 30 Hz - 80 kHz

IN2: gain (1 kHz): 9.3 dB, bw (-3 dB): 30 Hz - 80 kHz

image

  published the KiCad project on GitHub, including simulation. You could load it into KiCad and check if the small signal simulation and my measurements match ...

For all blog posts in this series, click here

spreadsheet: differenceamp.zip