12 June 2006 -- The iC-ML is an integrated magnetic linear position sensor/encoder assembled in a space-saving TSSOP20 package (6.6 x 6.4 x 1.1mm). The circuit contains four Hall sensors for the generation of analogue sine/cosine signals at a pole pitch of 2.56mm; it also has an integrated signal conditioning unit with an A/D convertor and output interfaces. Three configuration inputs allow 26 different modes of operation to be selected for the position evaluation of the magnetic tape placed above the chip.
Magnetic field strengths from 20mT upwards are sufficient for safe operation; a suitable gain or error signal can be used to both monitor the distance of the magnet and to centre it.
Operating distances of 1-2mm between the magnetic tape and package can be achieved, depending on the material and size of the magnet used.
In addition to providing pure analogue sine and cosine signals for position determination with external interpolators, the iC-ML also uses these signals to generate output signals with a resolution of 6, 7 and 8bit, enabling resolutions of 20um and up to 256 linear steps to be acquired.
The linear displacement of iC-ML with respect to the magnetic tape is provided in analogue form as a periodic sawtooth and triangle voltage, where the amplitudes are freely selectable.
Digital signals are available as A/B quadrature signals with a zero pulse Z and as up/down pulses used to trigger counters.
Additional power reduction modes permit the halving of the supply current.
Speeds up to 5m/s can be processed.
It is possible to cascade several iC-ML devices at once, allowing various co-ordinates to be scanned; here the chips are activated one after the other in a chain and the position signals output via a four-wire bus.
This simplifies the connecting up of the device to a microcontroller or interpolator for further processing.
Deactivated chips with high-impedance bus connections have a very low standby current draw.
Possible areas of application for iC-ML include analogue/digital incremental linear scales, contactless sliding switches/linear potentiometers, level sensors, commutation of linear motors and linear sensors in various industrial applications within a temperature range of -40 to +125C.
The iC-ML's noncontact sensor principle and generous distance tolerance make it particularly suitable for applications where the hermetic separation of the electronics and the mechanical drive is advantageous, such as those used in wet and dusty mechanical engineering environments, for example.
