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CLT3-4BT6
Current Limited Termination for PLC Digital Inputs
Datasheet | Orderable Products | Features and Description | Documentation
 
Datasheets
Reference Title
CLT3-4B Current Limited Over-Voltage Protected Quad Digital Termination
(16 Oct 2002, 99KB) Download
 
Orderable Products
Device Status RoHS Package Purchase
CLT3-4BT6 Active Converted TSSOP20
CLT3-4BT6-TR Active Converted TSSOP20
Features and Description
4 input channel topology
Wide range operation:
  VCC = 19 to 35V (RC = 4.7kOhms)
  VI = - 30 to 35V (RI = 1.2kOhms)
  Ambient temperature range: -25 / +85°C
Fully integrated 3mA current limiter:
  IEC 61131-2 type 1 input compatible
  High accuracy: 2.1 to 3.7mA
  Activation voltage < 5V
  Temperature compensated
Opto-coupler interface:
  Bypasses opto-coupler when IIN < 1.5mA
The CLT3-4 is a 3mA quadruple input digital termination device designed for 24V DC automation applications. It achieves the compact front-end of a digital input by minimizing the external component count. Housed in a TSSOP20 surface mount package, it reduces the printed board size. Each channel is made up of an input voltage protection, a serial current limiting circuit and an opto-coupler driver. The current limiting circuit connected between the input and the output pins is compensated over all the temperature range.
Thanks to its high accuracy, the current limitation allows the dissipation of the whole sensor and the input circuit to be cut by 2 when compared to a digital input using resistors. In the module itself the losses are reduced by more than a third. Therefore, the cooling system becomes smaller. The output section of each termination controls the operation of an opto-coupler. When the input current is less than 1.5mA, this output circuit diverts all the input current and keeps the opto-coupler turned off. When the input voltage is higher than 11V with RI = 1.2kOhms, the opto-coupler turns on.
The original structure of the CLT limiter allows its activation threshold to be low and insensitive to the output voltage up to a maximum value of 2.0V.
Application diagram
CLT3-4B application diagram
Main applications:
Termination for IEC61131-2 type 1 input
Logic interface of EN60947-5-2 proximity sensor
Industrial Automation I/O modules:
 
Programmable Logic Controller
  Field bus nodes
  Machine tool interface
Benefits:
Reduced dissipation of the module:
  By 50% in the sensor and the input 95mW maximum per input
Compact module:
  SMD thin TSSOP20 package
  Component count halved
Insensitivity to:
  Sensor impedance
  Voltage and temperature variations
High functional reliability:
  Over-voltage protected
  Fast transient resistant
  Reverse polarity protected
  Limited input current
Documentation
Application Notes
Reference Title
AN1608 CLT3-4BT6 Demoboard: check the robusteness of CLT3-4BT6
(16 Oct 2002, 92KB) Download
 

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