Evaluating I2C Multiplexers against Bus Translators for Multi Sensor Boards
I2C multiplexers resolve address collisions and isolate bus capacitance via software channels, while translators match voltage rails without addressing control.
Voltage Offset Drop
Conductive Loss
Electrical current flowing through the resistance of wires, connectors, jumpers and traces creates a small reduction in the potential along the path. Voltage offset drop represents the difference between the intended source voltage and the actual voltage that arrives at the load.
Measurement Error
Precision circuits that rely on stable reference voltages are particularly sensitive to these small losses in the power delivery network. Even a few milliohms of resistance in a ground plane can cause a voltage offset drop that introduces an error in a high-resolution analog-to-digital converter. For example, if a sensor draws varying amounts of current, the fluctuating voltage drop will appear as noise or drift in the measurement signal.
Compensation Technique
Four-wire Kelvin sensing allows the system to measure the voltage directly at the load, which bypasses the effect of the leads. Designers minimize voltage offset drop by using wider traces and shorter wire runs for critical signal paths and high-current power rails.
Thermal Effect
Resistance in the conductors increases as the temperature rises, which can cause the voltage drop to change during operation. Monitoring the voltage offset drop is essential for maintaining the calibration of high-power test equipment and battery management systems.