SBOS844C May 2021 – March 2023 INA234
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
The INA234 has the ability to assert the Alert pin on several different fault conditions as described in ALERT Pin. The desired fault condition to assert the Alert pin needs to be selected by appropriately programming the Mask/Enable Register (6h). Fault thresholds are set by programming the desired trip threshold into the Alert Limit Register (7h).
For example, an overcurrent fault condition would be selected by setting the SOL bit in the Mask/Enable Register to 1. The desired threshold for the over current condition would have to be programmed in the Alert Limit Register. In this example, the over current threshold is 9.0 A and the value of the current sense resistor is 8.0 mΩ, which give a shunt voltage limit of 72 mV. Once the shunt voltage limit is known, the value for the shunt over voltage limit register is calculated by dividing the shunt voltage limit by the shunt voltage LSB size.
For this case, the calculated value of the alert limit register is 72 mV / 40 μV = 1800d (708h). Since the bottom 4 bits of the shunt register are reserved the value programmed into the fault register must be left shifted by 4 or multiplied by 16. This results in a final alert limit register value of 28800 (7080h)
Values stored in the alert limit register are set to the default values after VS power cycle events and need to be reprogrammed each time power is applied.