News Release

iC-TW4: Space-saving 64-fold interpolation with signal conditioning 14.10.2008
Pin-programmable 8-bit interpolator with automatic offset correction
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The new encoder device iC-TW4 is a highly integrated sine-to-digital converter for the evaluation of magnetic or optical linear and angle sensors. Two setup pins deter-mine the chip function, the signal gain and the rate of interpolation within a range of x2 to x64; the sine/cosine sensor signal can be divided up into 256 angle steps and output as an encoder quadrature signal via the RS422 drivers.

iC-TW4 combines all the necessary encoder functions in a tiny QFN package measuring just 4 x 4 mm; signal gain, conditioning, A/D conversion and serial line drivers are integrated in the device. Apart from the angle sensor a measurement system does thus not require any further active external circuit components for operation.

The chip is configured using two configuration pins. A static network of resistors consisting of two resistors apiece defines the factor of interpolation, the converter hysteresis and the input voltage range, making a digital interface or an external EEPROM for the storage of the configuration superfluous.

The front-end instrumentation amplifiers permit both referenced and differential input signals (from 10 mVpp to 1.5 Vpp), enabling magnetic sensor bridges to be directly connected up to the chip, for example. Thanks to the automatic offset compensation feature there is no need to calibrate the signal manually; the automatic compensation also intercepts an offset drift of the sensor signals with changes in temperature during operation.

The angle position is output via encoder quadrature signals with A, B and AND-gated zero signals via differential RS422 line drivers. With a single-sided supply of +3.3 V to +5.5 V the device operates within an extended industrial temperature range of -40° to +125 °C and is designed for use in industrial applications for optical and magnetic linear scales and rotary encoders.

Product iC-TW4
Press Release iC-TW4 (2863 kb)
Presseinformation iC-TW4 (2863 kb)
 
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