8.2.1.4 Transient Protection

The bus pins of the THVD24xxV-EP transceivers include on-chip ESD protection against ±30kV HBM and ±12kV

IEC 61000-4-2 contact discharge. The International Electrotechnical Commission (IEC) ESD test is far more

severe than the HBM ESD test. The 50% higher charge capacitance, C(S), and 78% lower discharge resistance,

R(D), of the IEC model produce significantly higher discharge currents than the HBM model. As stated in the IEC

61000-4-2 standard, contact discharge is the preferred transient protection test method.

R

(C)

R

(D)

C

(S)

High-Voltage

Pulse

Generator

Device

Under

Test

40

35

30

25

20

15

10

5

0

Time (ns)

0

50

100

150

200

250

300

10-kV IEC

10-kV HBM

330 Ω

(1.5 kΩ)

150 pF

(100 pF)

50 M

(1 M)

Figure 8-3. HBM and IEC ESD Models and Currents in Comparison (HBM Values in Parenthesis)

The on-chip implementation of IEC ESD protection significantly increases the robustness of equipment.

Common discharge events occur because of human contact with connectors and cables. Designers may choose

to implement protection against longer duration transients, typically referred to as surge transients.

EFTs are generally caused by relay-contact bounce or the interruption of inductive loads. Surge transients

often result from lightning strikes (direct strike or an indirect strike which induce voltages and currents), or

the switching of power systems, including load changes and short circuit switching. These transients are often

encountered in industrial environments, such as factory automation and power-grid systems.

Figure 8-4 compares the pulse-power of the EFT and surge transients with the power caused by an IEC

ESD transient. The left side diagram shows the relative pulse-power for a 0.5kV surge transient and 4kV EFT

transient, both of which dwarf the 10kV ESD transient visible in the lower-left corner. 500V surge transients are

representative of events that may occur in factory environments in industrial and process automation.

The right side diagram shows the pulse power of a 6kV surge transient, relative to the same 0.5kV surge

transient. 6kV surge transients are most likely to occur in power generation and power-grid systems.

22

20

18

16

14

12

10

8

6

4

2

0

Time (µs)

0

5

10

15

20

25

30

35

40

0.5-kV Surge

10-kV ESD

4-kV EFT

2.2

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

Time (µs)

0

5

10

15

20

25

30

35

40

0.5-kV Surge

6-kV Surge

3.0

2.8

2.6

2.4

Figure 8-4. Power Comparison of ESD, EFT, and Surge Transients

www.ti.com

THVD2410V-EP, THVD2450V-EP, THVD2452V-EP

SLLSFQ9B – MAY 2024 – REVISED OCTOBER 2024

Copyright © 2024 Texas Instruments Incorporated

Submit Document Feedback

23

Product Folder Links: THVD2410V-EP THVD2450V-EP THVD2452V-EP