iC-WT
INCREMENTAL ENCODER
Rev A0, Page 2/13
DESCRIPTION
The device iC-WT is an evaluator IC for optical increment linear and rotary motion sensors, e.g. glass
scales or shaft encoders.
A photodiodes array supplies the input signals for the monolithically integrated amplifiers, comparators and
the TTL compatible push-pull output drivers. Two tracks, A and B, are evaluated differentially, the index
track Z as a constant light.
An integrated LED current control with driver stage enables the direct connection of a transmit LED with
series resistor and ensures a constant optical receive power. Two external resistors are used to set the
relative index track comparator threshold and to determine the receive photocurrents.
The internally available logical AND operation of index track Z to tracks A and B can be switched off for
adjustment.
A monitor circuit triggers an error message when the LED current control range is violated. The fault output
designed as an open collector is low active and simultaneously functions as an input to turn off the AND
operation of the index track.
All connections are protected against damage due to ESD. The outputs are short-circuit proof.
PACKAGES SO16N to JEDEC Standard
PIN CONFIGURATION SO16N
(top view)
PIN FUNCTIONS
No. Name Function
1 GND Ground
2 VCC +5V Supply Voltage
3A
Track A TTL Output
4B
Track B TTL Output
5Z
Track Z TTL Output
6 NERR Fault Output / AND Gate Disable
7 LED Cathode LED
8 CLR Capacitor for LED Current Control
9 IZ Threshold for Index Track
10 ILR Current Control Adjust
11 DZ Cathode Photodiode Index Track Z
12 DPB Cathode Photodiode Track B+
13 DNB Cathode Photodiode Track B-
14 DPA Cathode Photodiode Track A+
15 DNA Cathode Photodiode Track A-
16 AGND Common Anode for all photodiodes,
connected to GND internally
