AN4625 Datasheet, PDF (1/26 Pages) STMicroelectronics – STEVAL-IFP023V1 evaluation board for CLT01-38S4 input termination

AN4625
Application note
STEVAL-IFP023V1 evaluation board for
CLT01-38S4 input termination
Introduction
The CLT01-38S4 is an 8-channel industrial protected current limiter and a serializer for
interfacing automation digital inputs. It meets type 1, 2 and 3 input characteristics in
accordance with the IEC 61131-2, programmable controller international standard.
It integrates the SPI serializer, which is important for applications with high channel counts.
The serial communication allows the number of lines to be reduced which, in most
applications, need to be galvanically isolated. Furthermore, its structure allows the transfer
of the data and the additional information including thermal alarm, undervoltage indication
and checksum bits.
The device optimizes input VI characteristic shape to reduce power dissipation. This
becomes critical when the application enclosure requires higher protection levels with
closed cabinets. The power dissipated inside the module is very limited, no air circulation is
present inside the box. Current limitation also reduces power losses on the sensor side.
LED drivers, providing input states and using current from sensors, are energy-less.
5 V regulator is included to drive opto-coupler when galvanic isolation is needed.
Another important parameter is the electrical protection and susceptibility of the application.
The CLT01-38S4 implements large protection diodes on each input and supply voltage line.
Thanks to its compact package, the CLT01-38S4 is smaller, in terms of PCB area, than a
discrete solution.
January 2015
DocID027187 Rev 1
1/26
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