IC-LTA Datasheet, PDF (2/14 Pages) IC-Haus GmbH – 6-CH. INCREMENTAL OPTO ENCODER ARRAY

iC-LTA
preliminary
6-CH. INCREMENTAL OPTO ENCODER ARRAY
Rev A4, Page 2/14
DESCRIPTION
iC-LTA is a versatile optical sensor IC with integrated
photosensors whose signals are converted into volt-
ages by low-noise transimpedance amplifiers. Pre-
cise voltage comparators with hysteresis are used to
generate the digital signals, supplied to the output
pins via differential +/- 4 mA push-pull drivers.
The built-in LED power control with its 40 mA driver
stage permits a direct connection of the encoder
LED. Regardless of aging or changes in temperature
the received optical power is kept constant. An inter-
nal resistor presets the photocurrent operating point
and thus the desired illumination level.
Selection input SEL chooses for three different op-
erating modes: regular A/B operation, A/B operation
with 2-fold interpolation, or analog operation. With
analog operation the amplified signal voltages are
available at the outputs for inspection and monitoring
encoder assembly.
The typical application of iC-LTA are incremental en-
coders for motor feedback and commutation. To this
end, iC-LTA provides a differential scanning for A/B
and the index track Z. The layout of the signal ampli-
fiers is such that there is an excellent paired channel
matching, eliminating the needs for signal calibration
in most cases.
Additionally, three more tracks are provided to gener-
ate motor commutation information for the U, V and
W outputs, for instance with 120 degree phase shift
to operate 3-phase brushless motors (period count
and phase shift can be varied by the code disc ap-
plied).