AN884 Datasheet, PDF (2/6 Pages) Maxim Integrated Products – Miniature Flow Sensor Has Electronic Temperature Compensation

Figure 1. This cross section shows the dual piezo-resistive pressure sensors mounted
on a thick ceramic substrate.
Piezo-resistive pressure sensors exhibit excellent sensitivity and reproducibility, but they are
quite sensitive to changes in environmental temperature. Until recently, there was no way to
compensate these errors while achieving the small size and fast response needed in micro-
fluidic flow sensing. One solution to this problem is the new MAX1458 sensor-signal
processor, which compensates piezo-resistive sensors for initial and temperature-dependent
errors. Figure 2 compares the output of an uncorrected sensor with the same output
compensated with this IC.
Figure 2. This before-and-after comparison shows the reduction in sensor error
achieved with the MAX1458 sensor-signal conditioner.
Digital and user-programmable registers perform a fully electronic compensation of the analog
signal path. For applications exposed to large environmental temperature changes such as the -
40°C to +125°C automotive range, the MAX1458 delivers a total output accuracy better than
1%. For a more limited span such as +15°C to +45°C, the total pressure accuracy approaches
0.1%.
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