Problem with AD620 Amplifier - Pressure Sensor Signal Amplification

Thread Starter

Kevin Mark

Joined Mar 20, 2016
I am trying to map the Pressure sensor output voltage which in mV to Volt scale. The pressure sensor output is connected to the AD620's pin 2 & 3 and I am taking the output from pin 6. While making the circuit I am facing two problems.

My question has two parts

Part 1: How to connect -5v and +5v to this IC? I mean how to make -5v or is it just connected with ground? I am not able to understand this part. I have tried using a LM7805 and I gave AD620's +vcc [+5v] to incoming +5V which is connected to LM7805 pin 1 and connected pin 3 to AD620's -vcc [-5v]. The ground of LM7805 [ pin 2] is connected to Ad620's ground. Please tell me if I am doing it wrong.

Part 2: For the experiment purpose, I have taken -5V and +5V from the FG and connected it to AD620 and tested the circuit. The output of AD620 is pretty weird, I am getting either 1.47v [max] output or 0.77v [min]. I am confused
  1. Why the minimum voltage is not 0.00v ?
  2. Why output is not varying according to the input? I have been expecting to get a range of voltage not just some max and min voltage and nothing in between?