CLT3-4BT6

7/10

COM

GND

PE/FE

I

5 nF

CLT3-4

V

= ± 100V with 42

PP

Ω

Fig. 6: Input pin IN voltage surge test circuit.

COM

GND

PE/FE

5 nF

CLT3-4

SM15T39C

± 1kV

2

Ω

± 1kV

42

Ω

Each input of the CLT device may be biased to a reverse polarity. This case corresponds to a connection

mistake or a reverse biasing that is generated by the demagnetization of a monitored inductive solenoid.

The involved input withstands the high reverse current up to 20 mA; its opto-coupler is OFF and protected

by the conducting input diode. The other inputs remain operational, and some extra dissipation is

generated in their clamping protections.

Considering the supply operation, a reverse blocking diode can be connected between the module ground

and the common pin COM to protect the CLT device against any spurious reverse supply connection.

Then, the whole module supply voltage rating is extended to ± 30V.

INPUT REVERSE POLARITY ROBUSTNESS

4.7k

Ω

1.2k

Ω

1.2k

Ω

I = + 30V

N

N = 1,2 or 3

I = -30V

4

GND (0V)

Vcc = + 30V

1.1 mA

4.3 mA

14 mA

COM

1N4007

CLT3-4

V

= 38 V

CL