A replacement temperature or pressure sensor must reproduce the measurement the product needs, not just offer the same digital interface. Range, accuracy conditions, response time, calibration and mounting all affect the result. Begin by defining the physical quantity being measured and the error allowed at the final product output.
Compare measurement conditions rather than headline resolution
Bosch Sensortec's BMP390 documentation identifies an absolute barometric pressure sensor and states accuracy under defined pressure and temperature conditions. This illustrates why absolute accuracy, relative accuracy, noise and digital resolution should be compared separately.
For pressure applications, identify whether the design measures absolute, gauge or differential pressure and how the medium reaches the sensor. For temperature, define whether the target is board, surface, air or process temperature. A sensor's available temperature reading may support internal compensation without meeting a separate ambient-temperature measurement requirement.
Review calibration, firmware and physical integration
Compare supply and I/O voltage, interface timing, addresses, register maps and startup behavior. Identify factory calibration coefficients and the compensation algorithm required to convert raw data. A new device may respond on the same bus while returning values that the old driver interprets incorrectly.
Review oversampling, filtering, conversion time and power modes against the required response speed. Check sensor-port orientation, enclosure openings, thermal coupling and assembly restrictions. Mounting stress, contamination or heat from nearby circuitry can alter the installed result even when the sensor's laboratory specification is better.
Validate the complete measurement chain
Compare the original and candidate assemblies against a suitable reference across the operating range. Include temperature changes, stabilization time and the product's normal duty cycle. Test startup and any switching between measurement modes. Record both steady-state error and dynamic response when the application depends on changing conditions.
Update calibration and end-of-line test procedures when needed, including stored coefficients and acceptance limits. Keep the sensor ordering code, firmware version, enclosure revision and reference conditions with the results. If the replacement follows an EOL notice, verify the notice separately rather than assuming every older sensor in the family is discontinued.
Frequently asked questions
Does higher bit resolution guarantee better accuracy?
No. Noise, calibration, drift, installation and the measurement conditions determine how useful those output bits are.
Can a sensor with the same I2C address reuse the old driver?
Not automatically. Register definitions, scaling, compensation and timing still require comparison and testing.
Request sensor alternatives with the original code, measured quantity, range and accuracy requirements. Stock, price and lead time are confirmed in the quotation.