Review and tests of Femto HVA low-noise amplifier

https://www.femto.de/en/products/overview.html

Test results and benchmarks

Test setup with Keysight N9912A FieldFox RF Analyzer

SA+TG 2MHz to 100 MHz, with external 40 dB attenuator in front of Femto HVA preamp.

Thru BNC (no amplifier) test.

With HVA amplifier, AC coupled, 40 dB setting.

With HVA amplifier, AC coupled, 60 dB setting.

Test setup with HP 3245A Universal Source and oscilloscope

With HVA amplifier, DC coupled, 60 dB setting, 50 ohm BNC terminator at the input.

0 VDC output connected to HVA + 40 dB attenuator.

400 mVAC 0.1 Hz output connected to HVA + 40 dB attenuator (actual voltage at the input around 400 µV), DC coupled.

400 mVAC 1 Hz output connected to HVA + 40 dB attenuator, DC coupled.

400 mVAC 1 kHz output connected to HVA + 40 dB attenuator, DC coupled.

400 mVAC 1 MHz output connected to HVA + 40 dB attenuator, DC coupled.

HP3245A demo mode, output connected to HVA + 40 dB attenuator, DC coupled.

Based on test results next parameters were verified:

  • AC coupling cut-off frequency (-3 dB point) is 1223 Hz.
  • DC coupling worked OK below 0.001 Hz
  • Amplifier bandwidth (-3 dB point) is at least 11 MHz
  • Unit consume about 90 mA +15V and 50 mA -15V from power supply
  • Gain switch repeatability error is negligible
  • Input referenced amplifier noise is ~23.5 µV with 50 Ω terminated input and A = 60 dB, BW = 10 MHz?
  • Maximum input signal A=40 dB before compression starts = 28 mV at 1 kHz
  • Maximum input signal A=60 dB before compression starts = 2.8 mV at 1 kHz
Author: Illya Tsemenko
Published: April 21, 2020, 5:45 p.m.
Modified: June 8, 2020, 7:42 a.m.

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