RL-HSB-001 · Sensors · Hall Sensor Breakout
Theory of operation
How the DRV5055A2 produces a ratiometric analog output and why ADC reference choice matters.
01Ratiometric output#
The Texas Instruments DRV5055A2 is a linear analog Hall-effect sensor. Its output is ratiometric, meaning the no-field midpoint voltage and the sensitivity both scale with the supply rail. At zero field, the output sits at VCC / 2. Magnetic flux density passing perpendicular to the top face of the IC moves the output linearly above or below that midpoint.
02Why ratiometric matters#
If you power the breakout from the same rail the ADC uses as its reference, the conversion is independent of small supply variations. A 50 mV rail dip becomes a 25 mV midpoint dip, but the ratio between VOUT and VREF is unchanged, so the digital ADC code is unchanged. This is the cleanest way to use the part.
03Sensitivity vs supply#
| Supply rail | Sensitivity (typical) | Linear range (typical) |
|---|---|---|
| 5.0 V | 50 mV/mT | +/-42 mT |
| 3.3 V | 30 mV/mT | +/-44 mT |
The A2 variant trades raw resolution for wider linear range, which is useful for tracking rotors or gimbal magnets where field strength varies through several tens of millitesla.