Datasheet

DocID15917 Rev 6 17/33

VNL5050N3-E, VNL5050S5-E Electrical characteristics

3.2 MCU I/O protection

ST suggests to insert a resistor (R

prot

) in line to prevent the microcontroller I/O pins from

latching up

(a)

. The value of these resistors is a compromise between the leakage current of

microcontroller and the current required by the LSD I/Os (input levels compatibility) with the

latch-up limit of microcontroller I/Os:

Equation 1

Let:

• I

latchup

> 20 mA

• V

OHµC

> 4.5 V

• 35 Ω ≤ R

prot

≤ 100 KΩ

Then, the recommended value is R

prot

= 1 KΩ

Figure 18 shows the turn-off current drawn during the demagnetization.

a. In case of negative transient on the drain pin

(

)

maxIH

IHCOH

prot

latchup

−

≤≤