AN2689 datasheet(12/42 Pages) STMICROELECTRONICS

12 / 42 page

Data line protection

AN2689

12/42

Doc ID 14310 Rev 3

This solution requires that the Vcc voltage track be accessible and a decoupling capacitor is

required close to the diode array device. On the other hand this topology is suitable for high

speed data lines that often requires low parasitic line capacitance.

3.2

Data line protection example

Let’s consider the ISO 10605 standard.

The ESD current waveform, shown in Figure 14, has the corresponding generator circuit

given in Figure 15 when the generator output is in short circuit.

This surge is specified for contact or air-discharge as shown in Table 1 and maximum

voltage occurring is a 25 KV (air-discharge)

Figure 14.

ESD current waveform with generator output in short circuit

Figure 15.

Equivalent circuit schematic (occupant discharge model)

Table 1.

Surge voltage levels for contact and air discharge

Contact discharge

Air discharge

Level

Test voltage (kV)

Level

Test voltage (kV)

1±4

1±8

2±6

±15

3±8

±25

1 ns

≤

High voltage

supply

R (M

Ω )2 kΩ

330 pf

Device

under test

AN2689 Datasheet(PDF) 12 Page - STMicroelectronics