0
\$\begingroup\$

I am attempting to convert a single ended signal (0-5V) to a differential signal (+/- 5V about 0V) using an AD8131ARZ. I have it wired as per the attached schematic. When I supply +5V to the positive input DIN+ of the AD8131, the output behaves correctly with +/- 5V. However, if I ground the DIN+ input the outputs hold at or near 0V instead of inverting. So, it halfway works.

Experimenting, if I disconnect DIN- from ground and apply a voltage slightly more positive than zero to it while grounding DIN+ I begin to get the desired effect of the signals inverting. However, the amplitude is not correct. The amplitude appears to be the difference only (gain of 1).

How can I achieve my stated goal with this IC?

AD8131 Single to Differential.

\$\endgroup\$
  • \$\begingroup\$ You cannot apply 5V Vin to this amplifier, it has Gain=2, and only +-5V supplies. To convert 0-5V to differential, you need something with much higher power rails, +-15V or somethiing. \$\endgroup\$ – Ale..chenski Jan 14 '17 at 17:16
  • \$\begingroup\$ What happens if you disconnect DIN- from GND? \$\endgroup\$ – Matt Young Jan 14 '17 at 17:30
0
\$\begingroup\$

\$25°C, V_S = ±5 V, V_{OCM} = 0 V, G = 2, R_{L, dm} = 200 Ω\$

Input Common-Mode Voltage = −1.0 to +4.0 V

Output Voltage Swing Maximum ΔV OUT ; single-ended output 1.0 to 3.7 V

These are the specs. Read carefully.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.