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

5 System-Level ESD Protection – Real World Example 2

Figure 5-1 shows two MSP430-based real-time clock (RTC) boards.

The MSP430-based RTC Rev A board on the left follows poor layout techniques (no GND plane, traces beneath the 32-kHz crystal) and was known to cause system-level ESD issues where in, the MSP430 on the board consistently reset and sometimes latched when ESD pulses of 1.5 kV and 3.0 kV were applied to the top pins of the LCD.

To increase the system-level ESD robustness, the RTC Rev B board was designed (see board on right) following good layout techniques (extensive ground plane compared to Rev A) and with resistor arrays in series on the LCD signal lines (circled in red). The series resistors limit the ESD voltage reaching the device via the LCD signal, thus reducing the risk of system-level ESD failures.

GUID-D658116F-5267-4C44-9DE6-4ABC52DA6C9B-low.png Figure 5-1 MSP430-Based Real-Time Clock Test Boards

For system-level ESD tests, the Keytek Minizap ESD simulator was used to apply high voltage ESD strikes to the top pins of the LCD via indirect discharge; thus simulating electrostatic discharge between human and a piece of equipment. Table 5-1 lists the test recordings with the Rev A and Rev B boards, with and without the series resistors on the LCD signal traces.

Table 5-1 System-Level ESD Performance - Real World Example 2 Results
Rev A Board
(No Ground Plane)		 Rev B Board (With Ground Plane)
Series Resistance 0 Ω 0 Ω 39 Ω 1 kΩ
Consistent Device Reset 1.5 kV 2.5 kV 2.5 kV 3.5 kV
Device Latch-Up 3.0 kV 3.0 kV 3.0 kV >12 kV

It is clear from the results in Table 5-1 that the ESD robustness of the system improves by following good layout guidelines and by including additional protection circuitry like external series resistors on specific signals that couple the external ESD energy into the system or device. In particular, increasing the value of the series resistor on the Rev B board largely improved the ESD robustness; that is, units passed system-level ESD tests without device latch-up up to 12 kV.

Note:

A crystal clock failure was reported on Rev A board due to the poor layout techniques. On the Rev A board, it can be noticed that the digital signal traces are running underneath the 32-kHz crystal on the PCB. Toggling these digital signals cause the crystal clock generated by the MSP430 on-chip oscillator to fail. This failure was not seen on the Rev B due to good layout techniques (that is, no traces underneath the crystal layout). For more information regarding crystal layout considerations, see the application report MSP430 32-kHz Crystal Oscillator [11].