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

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)

17

THVD1500

www.ti.com

SLLSEY4A – JULY 2017 – REVISED NOVEMBER 2018

Product Folder Links: THVD1500

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Copyright © 2017–2018, Texas Instruments Incorporated

Typical Application (continued)

9.2.1.5 Transient Protection

The bus pins of the THVD1500 transceiver family include on-chip ESD protection against ±16-kV HBM and ±8-

kV 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.

Figure 19. 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 20 compares the pulse-power of the EFT and surge transients with the power caused by an IEC ESD

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

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

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

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

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

Figure 20. Power Comparison of ESD, EFT, and Surge Transients