SLAA530B March   2012  – July 2021 MSP430F5131 , MSP430F5132 , MSP430F5151 , MSP430F5152 , MSP430F5171 , MSP430F5172 , MSP430F5212 , MSP430F5214 , MSP430F5217 , MSP430F5219 , MSP430F5222 , MSP430F5224 , MSP430F5229 , MSP430F5232 , MSP430F5234 , MSP430F5237 , MSP430F5239 , MSP430F5242 , MSP430F5244 , MSP430F5247 , MSP430F5249 , MSP430F5252 , MSP430F5253 , MSP430F5254 , MSP430F5255 , MSP430F5256 , MSP430F5257 , MSP430F5258 , MSP430F5259 , MSP430F5304 , MSP430F5308 , MSP430F5309 , MSP430F5310 , MSP430F5324 , MSP430F5325 , MSP430F5326 , MSP430F5327 , MSP430F5328 , MSP430F5328-EP , MSP430F5329 , MSP430F5333 , MSP430F5335 , MSP430F5336 , MSP430F5338 , MSP430F5340 , MSP430F5341 , MSP430F5342 , MSP430F5358 , MSP430F5359 , MSP430F5418 , MSP430F5418A , MSP430F5419 , MSP430F5419A , MSP430F5435 , MSP430F5435A , MSP430F5436 , MSP430F5436A , MSP430F5437 , MSP430F5437A , MSP430F5438 , MSP430F5438A , MSP430F5438A-EP , MSP430F5500 , MSP430F5501 , MSP430F5502 , MSP430F5503 , MSP430F5504 , MSP430F5505 , MSP430F5506 , MSP430F5507 , MSP430F5508 , MSP430F5509 , MSP430F5510 , MSP430F5513 , MSP430F5514 , MSP430F5515 , MSP430F5517 , MSP430F5519 , MSP430F5521 , MSP430F5522 , MSP430F5524 , MSP430F5525 , MSP430F5526 , MSP430F5527 , MSP430F5528 , MSP430F5529 , MSP430F5630 , MSP430F5631 , MSP430F5632 , MSP430F5633 , MSP430F5634 , MSP430F5635 , MSP430F5636 , MSP430F5637 , MSP430F5638 , MSP430F5658 , MSP430F5659 , MSP430F6433 , MSP430F6435 , MSP430F6436 , MSP430F6438 , MSP430F6458 , MSP430F6459 , MSP430F6459-HIREL , MSP430F6630 , MSP430F6631 , MSP430F6632 , MSP430F6633 , MSP430F6634 , MSP430F6635 , MSP430F6636 , MSP430F6637 , MSP430F6638 , MSP430F6658 , MSP430F6659 , MSP430F6720 , MSP430F6720A , MSP430F6721 , MSP430F6721A , MSP430F6723 , MSP430F6723A , MSP430F6724 , MSP430F6724A , MSP430F6725 , MSP430F6725A , MSP430F6726 , MSP430F6726A , MSP430F6730 , MSP430F6730A , MSP430F6731 , MSP430F6731A , MSP430F6733 , MSP430F6733A , MSP430F6734 , MSP430F6734A , MSP430F6735 , MSP430F6735A , MSP430F6736 , MSP430F6736A , MSP430F6745 , MSP430F67451 , MSP430F67451A , MSP430F6745A , MSP430F6746 , MSP430F67461 , MSP430F67461A , MSP430F6746A , MSP430F6747 , MSP430F67471 , MSP430F67471A , MSP430F6747A , MSP430F6748 , MSP430F67481 , MSP430F67481A , MSP430F6748A , MSP430F6749 , MSP430F67491 , MSP430F67491A , MSP430F6749A , MSP430F67621 , MSP430F67621A , MSP430F67641 , MSP430F67641A , MSP430F6765 , MSP430F67651 , MSP430F67651A , MSP430F6765A , MSP430F6766 , MSP430F67661 , MSP430F67661A , MSP430F6766A , MSP430F6767 , MSP430F67671 , MSP430F67671A , MSP430F6767A , MSP430F6768 , MSP430F67681 , MSP430F67681A , MSP430F6768A , MSP430F6769 , MSP430F67691 , MSP430F67691A , MSP430F6769A , MSP430F6775 , MSP430F67751 , MSP430F67751A , MSP430F6775A , MSP430F6776 , MSP430F67761 , MSP430F67761A , MSP430F6776A , MSP430F6777 , MSP430F67771 , MSP430F67771A , MSP430F6777A , MSP430F6778 , MSP430F67781 , MSP430F67781A , MSP430F6778A , MSP430F6779 , MSP430F67791 , MSP430F67791A , MSP430F6779A , MSP430FR2000 , MSP430FR2032 , MSP430FR2033 , MSP430FR2100 , MSP430FR2110 , MSP430FR2111 , MSP430FR2153 , MSP430FR2155 , MSP430FR2310 , MSP430FR2311 , MSP430FR2353 , MSP430FR2355 , MSP430FR2422 , MSP430FR2433 , MSP430FR2475 , MSP430FR2476 , MSP430FR2512 , MSP430FR2522 , MSP430FR2532 , MSP430FR2533 , MSP430FR2632 , MSP430FR2633 , MSP430FR2672 , MSP430FR2673 , MSP430FR2675 , MSP430FR2676 , MSP430FR4131 , MSP430FR4132 , MSP430FR4133 , MSP430FR5041 , MSP430FR5043 , MSP430FR50431 , MSP430FR5720 , MSP430FR5721 , MSP430FR5722 , MSP430FR5723 , MSP430FR5724 , MSP430FR5725 , MSP430FR5726 , MSP430FR5727 , MSP430FR5728 , MSP430FR5729 , MSP430FR5730 , MSP430FR5731 , MSP430FR5732 , MSP430FR5733 , MSP430FR5734 , MSP430FR5735 , MSP430FR5736 , MSP430FR5737 , MSP430FR5738 , MSP430FR5739 , MSP430FR5739-EP , MSP430FR5847 , MSP430FR58471 , MSP430FR5848 , MSP430FR5849 , MSP430FR5857 , MSP430FR5858 , MSP430FR5859 , MSP430FR5867 , MSP430FR58671 , MSP430FR5868 , MSP430FR5869 , MSP430FR5870 , MSP430FR5872 , MSP430FR58721 , MSP430FR5887 , MSP430FR5888 , MSP430FR5889 , MSP430FR58891 , MSP430FR5922 , MSP430FR59221 , MSP430FR5947 , MSP430FR59471 , MSP430FR5948 , MSP430FR5949 , MSP430FR5957 , MSP430FR5958 , MSP430FR5959 , MSP430FR5962 , MSP430FR5964 , MSP430FR5967 , MSP430FR5968 , MSP430FR5969 , MSP430FR5969-SP , MSP430FR59691 , MSP430FR5970 , MSP430FR5972 , MSP430FR59721 , MSP430FR5986 , MSP430FR5987 , MSP430FR5988 , MSP430FR5989 , MSP430FR5989-EP , MSP430FR59891 , MSP430FR5992 , MSP430FR5994 , MSP430FR59941 , MSP430FR6005 , MSP430FR6007 , MSP430FR6035 , MSP430FR6037 , MSP430FR60371 , MSP430FR6041 , MSP430FR6043 , MSP430FR60431 , MSP430FR6045 , MSP430FR6047 , MSP430FR60471 , MSP430FR6820 , MSP430FR6822 , MSP430FR68221 , MSP430FR6870 , MSP430FR6872 , MSP430FR68721 , MSP430FR6877 , MSP430FR6879 , MSP430FR68791 , MSP430FR6887 , MSP430FR6888 , MSP430FR6889 , MSP430FR68891 , MSP430FR6920 , MSP430FR6922 , MSP430FR69221 , MSP430FR6927 , MSP430FR69271 , MSP430FR6928 , MSP430FR6970 , MSP430FR6972 , MSP430FR69721 , MSP430FR6977 , MSP430FR6979 , MSP430FR69791 , MSP430FR6987 , MSP430FR6988 , MSP430FR6989 , MSP430FR69891

 

  1.   Trademarks
  2. 1Introduction to ESD
    1. 1.1 Component-Level ESD Rating
      1. 1.1.1 Human Body Model (HBM)
      2. 1.1.2 Charged Device Model (CDM)
    2. 1.2 System-Level ESD Rating
    3. 1.3 ESD Waveforms
  3. 2General System-Level ESD Design Guidelines
    1. 2.1 Enclosures
      1. 2.1.1 Enclosure Openings
      2. 2.1.2 Enclosure Cables
    2. 2.2 PCB Design and Layout
      1. 2.2.1 Example Layout – Current Loop
    3. 2.3 On-Board ESD Protection Devices
      1. 2.3.1 Simple Passive Components
      2. 2.3.2 ESD Suppression Devices
      3. 2.3.3 ESD Protection Using Series Resistor
    4. 2.4 Circuit Design and Software Considerations
      1. 2.4.1 Circuit Design
      2. 2.4.2 Software Considerations
    5. 2.5 ESD Testing
  4. 3System Efficient ESD Design (SEED)
    1. 3.1 System-Level ESD Protection Methodology
      1. 3.1.1 On-Board Protection – Primary Clamp
      2. 3.1.2 On-Chip Protection – Secondary Clamp
      3. 3.1.3 Two-Stage Protection – Fundamental SEED Concept
    2. 3.2 SPICE Simulation Methodology for System-Level ESD Design
  5. 4SEED-Based IEC Protection Design and Verification – Real World Example 1
    1. 4.1 Modeling IEC Stress Waveform
    2. 4.2 Modeling TVS Device
    3. 4.3 Modeling MSP430 I/O Pin
    4. 4.4 Isolated Impedance Calculation
    5. 4.5 SPICE Simulation – SEED Method
    6. 4.6 Board-Level Verification
  6. 5System-Level ESD Protection – Real World Example 2
  7. 6Summary
  8. 7Modeling Using TLP Parameters
    1. 7.1 Modeling TVS Device Using TLP Parameters [8]
    2. 7.2 Modeling IC Interface Pin to be Protected Using TLP Parameters [8]
  9. 8References
  10.   Revision History

1.2 System-Level ESD Rating

Typically in ESD protected areas (EPA), the ESD voltage levels are low due to ESD-control measures as standardized by ANSI/ESD S20.20 [13] and IEC 61340 [14] that are followed world-wide during assembly, packaging, and other production processes. The same cannot be assured when the end-product ships and reaches the hands of the customer. A consumer product deployed to the field is usually handled outside of an EPA and can be subjected to higher-voltage ESD strikes.

The IEC 61000-4-2 is recognized industry-wide as the standard for end-product ESD rating. The primary purpose of IEC 61000-4-2 test is to determine the immunity of systems to external ESD events during operation. It relates to equipment, systems, subsystems, and peripherals without further defining them. Its scope and description clearly indicate the purpose: to test electrical and electronic equipment that may be subjected to ESD from operators directly or from personnel to adjacent objects [1]. It additionally defines ranges of test levels, which relate to different environmental and installation conditions and establishes test procedures.

The system-level IEC current discharge curve is more severe than the HBM test and is generated from a hand-held unit (sometimes identified as ESD gun). The method targets both direct and indirect ESD events between a person and a piece of equipment. Direct discharges are applied to metal locations accessible to persons during normal use of equipment and indirect discharges are always done by contact discharge to a coupling plane. Contact discharge mode is the preferred IEC test method, and only insulated covers and connector pins with a plastic shell are stressed with air discharge.

In contrast to the automotive ESD standard ISO 10605 [6], the ESD generator is connected to the Ground Reference Plane (GRP). The indirect discharge part of the test uses two other planes: Horizontal Coupling Plane (HCP) and Vertical Coupling Plane (VCP) that are connected to the ground plane with two 470-kΩ resistors. Discharges to these planes simulate the stress caused by the radiated field from real-life discharges to nearby objects. This test setup is shown in Figure 1-3.

GUID-CB43C81E-076D-4464-A2B1-1D1F02F5A3A7-low.png
The ground connections of the ESD gun are highlighted in red.
Figure 1-3 ESD Test Bench for Powered Condition From IEC 61000-4-2 [1]

Table 1-2 lists the IEC 61000-4-2 test specifications.

Table 1-2 IEC 61000-4-2 Test Specifications [1]
Test Parameter IEC 61000-4-2
Discharge Type Contact Air
Output Voltage 2 kV to 8 kV 2 kV to 15 kV
Interval Time Minimum 1s
Polarity at Each Stress Voltage Level Positive and negative
Network Capacitance 150 pF
Network Resistance 330 Ω
Number of Discharge Pulses Minimum 10
Test Condition Powered

When testing a system to this or similar system-level standards, the end-products are required to remain functional in the presence of or following an ESD event. The IEC specified system-level failure criteria classifications are as follows:

  • Normal performance within limits specified by the manufacturer.
  • Temporary loss of function or degradation of performance that ceases after the disturbance ceases. Equipment under test recovers its normal performance without operator intervention.
  • Temporary loss of function or degradation of performance. Recovery requires operator intervention.
  • Temporary loss of function or degradation of performance which is not recoverable, caused by damage to hardware or software, or loss of data.

It is clear that most of above categories don't relate to physical device damage, but rather system upsets. The acceptance criterion for any particular system or application is specific to that case. Therefore, the board designers and OEMs should handle the system-level ESD robustness by taking necessary precautions to prevent or minimize ESD coupling into the system or device (either directly through device pins or via connected cables) that develop errors on signal traces or damages the device itself.

The later sections in this document highlight a few general guidelines that can help create an ESD-robust system solution. Too often ESD testing is carried out as an after-thought and board designers and OEMs find themselves failing IEC-type tests because they have not taken the necessary precautions while designing their application. Hence, board designers and OEMs are encouraged to see this document and numerous published materials available with regards to ESD safety before starting their design.