9

Reverse polarity on VDD

The reverse polarity on VDD can be implemented on the board by placing a diode between the GNDDD pin and

GND digital ground.

The diode must be chosen by taking into account VRRM > |VDD| and its power dissipation capability:

PD≥IDD×VF

(4)

Note:

In normal operation (no reverse polarity), due to the diode, there is a voltage drop (ΔV = VF@(Idd)) between

GNDDD of the device and digital ground of the system. In order to guarantee proper triggering of the input signal,

ΔV(max.) must result lower than VIH(MIN).

Figure 26. VDD reverse polarity protection

Note:

Input(i) is intended as any input pin on logic side.

ISO808, ISO808-1

Reverse

polarity on VDD

DS14169 - Rev 1

page 25/38