November 2007

Rev 5

1/13

CLT3-4B

Current limited over-voltage protected quad digital termination

Features

– Low side configuration with common

ground

– Input current limiter activation voltage < 5 V

– Temperature compensated operation

– No coupler activation below 1.5 mA input

current

– IEC 61000-4-2 electrostatic discharge

ESD, Class 3

In contact, ± 6 kV; in air, ± 8 kV

Level B: temporary disruption; no

change of opto-coupler state

– IEC 61000-4-5 voltage surge, Class 3

± 1000 V with 42

Ω serial resistor in

differential mode

Level B: temporary disruption

– IEC 61000-4-4 transient burst immunity

± 4 kV peak voltage; 5 kHz repetitive

rate

Level A: fully functional

Benefits

characteristic of IEC 61131-2 standard

proximity sensor according EN60947-5-2

standard

assembly

Applications

Description

The CLT3-4 is a quadruple input digital

termination device designed for 24 V dc

automation applications. It provides the front-end

circuitry of a digital input module (I/O) in industrial

automation, and drives an isolating opto-coupler.

Figure 1.

Pin configuration

TSSOP20

COM

IN

COM

COM

COM

COM

12

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

COM

13, 15, 16, 18, 20) must be connected together

externally. This common pad COM is enlarged to

reduce the thermal resistance and improve the device

cooling. The COM and IN pins are designed to

minimize the EMI effects on the circuit.

www.st.com