A3515

Calibrated linear Hall devices, which can be used to deter-mine the actual flux density presented to the sensor in a particu-lar application, are available.

For safe, reliable operation, the output should not be pulled above the supply voltage or pulled below the device ground.

For optimum performance, a 0.1 F capacitor between the supply and ground, and a 100 pF capacitor between the output and ground, should be added.

The ratiometric feature is especially valuable when these devices are used with an analog-to-digital converter.  A/D converters typically derive their LSB step size by ratioing off a reference voltage line.  If the reference voltage varies, the LSB will vary proportionally.  This is a major error source in many sensing systems.  The A3515xUA and A3516xUA can eliminate this source of error by their ratiometric operation.  Because their gain and offsets are proportional to the supply voltage, if they are powered from the A/D reference voltage, the sensor output voltage will track changes in the LSB value.

These devices can withstand infrequent temperature excur-sions, beyond the Absolute Maximum Ratings, to T_A   = 170°C provided the junction temperature, T _J, does not exceed 200°C.

Extensive applications information on Hall-effect sensors and magnets is also available in the "Hall-Effect IC Applications Guide", which can be found in the latest issue of the Allegro
MicroSystems Electronic Data Book, AMS-702 or Application Note 27701, or at www.allegromicro.com