Category: Hardware
Product Number: ADXL327
I'm currently working on a project using the ADXL327 accelerometer connected to an INA126 differential amplifier, with the system powered by 3.3V. My goal is to achieve highly accurate G-value readings, but I'm noticing an asymmetry in the sensitivity between +G and -G measurements, which affects my results.
- Open Circuit Setup (Amplifier Disconnected):
- +1G Output: 2.128V; Sensitivity: 0.478 mV/G (from 2.128V - 1.65V)
- -1G Output: 1.189V; Sensitivity: 0.461 mV/G (from 1.65V - 1.189V)
- Connected to Differential Amplifier (INA 126) (X-Axis Output Connected):
- +1G Output: 2.079V; Sensitivity: 0.429 mV/G (from 2.079V - 1.65V)
- -1G Output: 1.191V; Sensitivity: 0.459 mV/G (from 1.65V - 1.191V)
These indicate a slight asymmetry in sensitivity for both setups, which I would like to address.
Attached Files:
- Schematic Diagram – Showing the ADXL327 connection to the INA126.
- PCB Layout – Illustrating the component placement, trace routing, and grounding.
Additional Notes:
- Supply Voltage: System is powered with 3.3V.
- Single-Axis Requirement: My application requires only one axis, so I’m currently using the X-axis.
- Component Note: R24 is marked DNP (Do Not Place) and is not present in the circuit.
- INA126 Input Impedance: The input impedance of the INA126 is very high, specified as 10⁹ Ω in the datasheet, which should minimize loading effects on the accelerometer.
- Accelerometer Output: The ADXL327 output is connected only to the INA126 input and a test point; it is not connected to any other circuitry.
Question:-
Achieving Symmetric Output: How can I adjust the circuit to achieve more symmetric output between +G and -G to improve the accuracy of my G-value measurements?
