ST AN3107 APPLICATION NOTE

AN3107

Application note

ESD immunity-level optimization of a high-side switch application based on the VNI4140K

Introduction

The VNI4140K is a quad-channel high-side driver designed for industrial applications. It is a monolithic device manufactured using STMicroelectronics’ most advanced VIPower® technology, intended for driving four independent resistive or inductive loads with one side connected to ground. The device fully complies with standards including JEDEC (JESD22) and IEC 61131-2. It conforms to the “human body model” ESD test in accordance with the JESD22-A114 definition. The immunity level is 2000 V, as stated in the datasheet of the device.

When the VNI4140K is mounted in the complete application, the system must meet minimum requirements defined by generic standard IEC 61000-4-2. However, the actual immunity level depends on the manufacturer of the final application. To achieve the required level of immunity, the device must be equipped with a suitable application environment, external components and/or a suitable PCB layout.

This application note provides some recommendations on how to optimize the ESD immunity level of the VNI4140K high-side switch application in accordance with the IEC 61000-4-2 standard.

Figure 1. VNI4140K ESD optimized PCB example

March 2010

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Contents	AN3107

Contents

1	Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. 1
2	Test setup according to IEC 61000-4-2 . . . . . . . . . . . . . . . . . . . . . . . . . .		5
	2.1	Test conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
	2.2	Classification of the test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
3	Application solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		6
	3.1	Cap filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
	3.2	Π filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	8
	3.3	Dual LC filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11
4	Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		14
5	References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		15
6	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		16

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AN3107	List of tables

List of tables

Table 1. Application immunity with C filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Table 2. Application immunity with Π filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Table 3. Application immunity with dual LC filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Table 4. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

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List of figures	AN3107

List of figures

Figure 1. VNI4140K ESD optimized PCB example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Figure 2. ESD test setup according to IEC 61000-4-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 3. Application schematic diagram with capacitive filter protection . . . . . . . . . . . . . . . . . . . . . . 7 Figure 4. Example of a spiral PCB inductor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Figure 5. Midi Spring inductors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 6. Application schematic diagram with Π filter protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 7. Application schematic diagram with dual LC filter protection . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 8. Test board views. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

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AN3107	Test setup according to IEC 61000-4-2

2 Test setup according to IEC 61000-4-2

The IEC 61000-4-2 standard provides the test procedure for various types of applications. The test setup for ungrounded (tabletop) equipment is selected. The structure is shown in

Figure 2.

Figure 2. ESD test setup according to IEC 61000-4-2

2.1Test conditions

●Supply voltage: 24 VDC, always ON

●Inputs OFF, outputs OFF

●Air discharge

●Polarity: positive/negative

●Discharge unit: 150 pF / 330 Ω

●Applied to: board output terminal

2.2Classification of the test

A - normal performance

B - temporary degradation or loss of function or performance, with automatic return to normal operation

C - temporary degradation or loss of function which requires external intervention to recover normal operation

D - degradation or loss of function, need substitution of damaged components to recover normal operation.

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Application solutions	AN3107

3 Application solutions

Ideas (application environment) on how to optimize the immunity of the device are listed in

Section 3.1, Section 3.2 and Section 3.3.

3.1Cap filters

This basic configuration uses 22 nF ceramic capacitors connected between the device outputs and ground. It protects the VNI4140K primarily against radio-frequency and fast transient disturbances.

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