SC9203 Datasheet

Self-Adjusting Hall Effect Gear Tooth Sensor IC

The SC9203 is a dual-channel gear tooth senor, with two Hall sensing elements, each providing a separate digital output, for speed and direction signal processing capability. The SC9203 does not have a chopper delay. The bias magnet can be from 100mT to 400mT.

The dual-channel outputs (OUTA and OUTB) are provided in SC9203. The OUTA and OUTB will turn off (BRP) after the flux has reached its peak and then decreased by an amount equal to the hysteresis. Similarly the OUTA and OUTB will turn on (BOP) after the flux has reached its minimum value and then increased by an amount equal to the hysteresis.

In the case of Ferromagnetic toothed wheel application the IC has to be biased by the South pole of a permanent magnet (Maximum 400mT). When assembling the sensor system, a magnet as back bias flux from 100mT to 400mT is suggested. Normally the South pole of magnet faces the unbranded side of the IC and be glued to the back surface (non branded side) of the IC using a adhesive or suitable epoxy. Duo to the SC9203’s “Self-adjusting” over a wide range of back bias flux, the need for any trimming in the application is eliminated.

At the chip power on state, if the power is raised quickly and the output is reset to the high state whatever the field is. The output will change to low after the flux has reached its minimum value and then increased by an amount equal to the hysteresis. The output will change to high after the flux has reached its peak and then decreased by an amount equal to the hysteresis similarly. However if the supply is raised slowly, then the reset state is not determined; the output can be either high or low.

The pull-up resistor should be chosen to limit the current through the output transistor, without exceeding the maximum continuous output current of the device.

The device is available in a 4-pin SIP package and is lead (Pb) free, with 100% matte tin leadframe plating.