Has anyone observed difficulties with AD8211 during BCI EMC testing in the 800MHz to 1.5 GHz range? Device is configured as current sense amplifier in PWM solenoid driver. Sense resistor is located between coil and low-side FET switch.
At about 1 GHz CW mode, the system diagnostics report an over current condition in the solenoid circuit. The AD8211 acts as a high-side shunt amplifier, its output sent to a a-to-d in the system micro. Data is downloaded continuously over CAN. We can see current signal go from 300 mA nominal to 2.5A (apparently) We are in the process of trying to determine if PWM control is at fault, resulting in over current due to incorrect FET control, or if it is the op-amp. The data we are looking for is if common mode RF can upset the Op-Amp’s bias circuit, resulting in incorrect output. If so, what behavior? Goes to a rail, goes to some fixed level, etc.