AN588 APPLICATION NOTE

8/12

Figure 9. Inter-Line Interface (duration)

The ±2.5V superimposed on the ±12V of the real signal are not detected by line receivers whose threshold

is generally ajusted to ± 1V.

Additionally, the sampling system of the UART series interface circuits "hides" the disturbances of 0.4 us

among the 51 us of one bit at 19600 bauds (see Figure 9).

Use of the ITAxxx

In conclusion, the table below gives a matrix of the uses of the ITAxxx according to the type of line to be

protected. The main products are listed here, but others are equally available for more specific applica-

tions (see Annex 2: Transil Arrays-Configurations).

Table 1. Transil Array Utilization

Data Line

2/4 Lines

SO8

5/8 Lines

SO20

18 Lines

SO20

CENTRONICS 0/5V

ITA6V1U1

ITA6V1U3

ITA6V1M3

LCTA6V1M3

(Low Capacitance)

RS485/422 0/–6V

ITA6V1U1

ITA6V1U3

-

RS423 ±6V

ITA10B1

ITA10B3

-

RS232 ±12V

ITA18B1

ITA25B1

ITA18B3

ITA25B3

-

Chanel 1

0.5

s 5V

Chanel 2

0.5

s 5V

Ch 1

5 V ~

T/div0.5

Trig

1.28 div+CHAN 1 =

100

0

5V/Div

0

5V/Div

Ve

Vr

0.5

s/div

Signal transmitted on

one of the lines

Parasitic signal on

an adjacent line