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080930 Ipc 2152 Standard For Determining Current Carrying Capacity

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080930 Ipc 2152 Standard For Determining Current Carrying Capacity

  1. 1. IPC Current Carrying Capacity Task Group (1-10b) August 2008 Michael R. Jouppi, Thermal Man, Inc., Task Group Chair <ul><ul><li>IPC-2152, Standard for Determining Current-Carrying Capacity in </li></ul></ul><ul><ul><li>Printed Board Design </li></ul></ul>
  2. 2. <ul><ul><li>Mike Jouppi is a mechanical engineer who specializes in heat transfer. He has a bachelor’s of science in mechanical engineering from the University of Arizona and a master’s of science in computer information systems from Regis University. </li></ul></ul><ul><ul><li>Mike has been a thermal analyst since 1982. He has been a team member on projects such as the International Space Station, satellites, airships, missiles systems and, most recently, the Mars Lander. </li></ul></ul><ul><ul><li>Mike started with the IPC-1-10b </li></ul></ul><ul><ul><li>task group in 1999 and has chaired </li></ul></ul><ul><ul><li>the group since 2000. </li></ul></ul>
  3. 3. IPC-2152 <ul><li>Introduction </li></ul><ul><ul><li>The amount of current that can be applied to a conductor and its resulting temperature rise is a printed circuit board (PCB) design concern. </li></ul></ul><ul><ul><ul><li>Design constraints have created a need for more precise guidelines for sizing conductors than those currently found in IPC-2221. </li></ul></ul></ul><ul><ul><li>Simple and accurate design guidelines, with an explanation to their origin, is the vision for IPC-2152. </li></ul></ul>Vision: Simple and Accurate Design Guidelines Standard for Determining Current Carrying Capacity in Printed Board Design
  4. 4. IPC-2152 <ul><li>Introduction </li></ul><ul><li>The temperature rise of a PCB conductor is a complex problem, yet the desire is to have general guidelines. </li></ul><ul><li>A compromise has resulted that provides general guidelines in a main document and detailed guidelines in an attached appendix. </li></ul>IPC-2152 is divided into two sections, a main document with simple charts and an appendix that discusses details that impact the temperature rise of a conductor and more.
  5. 5. IPC-2152 <ul><li>Introduction </li></ul><ul><li>The new standard is based on testing that was performed following IPC-TM-650, Method 2.5.4.1a, Conductor Temperature Rise Due to Current Changes in Conductors . </li></ul><ul><li>Computer simulations were also used to improve the understanding of the impact that certain variables have on the temperature rise of a conductor. </li></ul>IPC-2152 is based on industry standards test procedures and correlated computer simulations.
  6. 6. IPC-2152 <ul><li>Test Considerations </li></ul><ul><ul><li>Environment </li></ul></ul><ul><ul><ul><li>Testing was performed in air and vacuum </li></ul></ul></ul><ul><ul><li>Internal and external conductors </li></ul></ul><ul><ul><li>PCB thickness </li></ul></ul><ul><ul><ul><li>0.038-inch, 0.059-inch and 0.07-inch thick test vehicles </li></ul></ul></ul><ul><ul><li>Copper thickness/weight (1/2-oz, 1-oz, 2-oz and 3-oz) </li></ul></ul><ul><ul><li>PCB material </li></ul></ul><ul><ul><ul><li>Polyimide and FR4 test vehicles </li></ul></ul></ul>Current carrying capacity testing considered multiple environments, conductor width and thickness, PCB thickness and PCB materials.
  7. 7. IPC-2152 <ul><li>Test Results </li></ul><ul><li>Environment: Still air vs. vacuum </li></ul><ul><ul><li>Internal conductors in a board tested in vacuum are 55 percent higher in temperature rise than the same conductors in a still air environment. </li></ul></ul><ul><ul><li>External conductors in a board tested in vacuum are 35 percent higher in temperature rise than the same conductors in a still air environment. </li></ul></ul>Conductors run hotter in a vacuum than in air by as much as 55% or more.
  8. 8. <ul><li>Test Results </li></ul><ul><li>Conductors: Comparing internal vs. external conductors </li></ul><ul><ul><li>An external conductor designed for a 10 o C rise will operate 20 percent higher in temperature than the same size internal conductor in a still air environment. </li></ul></ul><ul><ul><li>Identical external and internal conductors in a vacuum experience the same increase in temperature for the same applied current. </li></ul></ul>External conductors run hotter than internal traces in a still air environment . IPC-2152
  9. 9. <ul><li>Test Results </li></ul><ul><li>Board Thickness: Conductor temperature and PCB thickness </li></ul><ul><ul><li>Conductors in a 0.965 mm (0.038 in.) thick PCB are approximately 30 to 35 percent higher in temperature than in a 1.78 mm (0.07 in.) thick PCB. </li></ul></ul><ul><ul><li>Conductors in a 1.498 mm (0.059 in.) thick PCB are approximately 20 percent higher in temperature than in a 1.78 mm (0.07 in.) thick PCB. </li></ul></ul><ul><ul><li>Test boards thicker than 1.78 mm have not been evaluated. </li></ul></ul>Conductors in thin PCBs run hotter than the same size conductor in thicker PCBs. IPC-2152
  10. 10. <ul><li>Test Results </li></ul><ul><li>Comparing Copper Weights: </li></ul><ul><ul><li>Half-ounce copper conductors are similar in temperature rise for the same size cross-sectional area as 1 oz. conductors. </li></ul></ul><ul><ul><li>Two ounce copper conductors increase in temperature by 10 to 15 percent above 1 oz. conductors for the same size trace and applied current. </li></ul></ul><ul><ul><li>Three ounce copper conductors increase in temperature by 15 to 20 percent above 1 oz. conductors for the same size trace and applied current. </li></ul></ul><ul><ul><li>The higher percentages are related to a 45 o C delta T and the lower percentages are related to a 10 o C rise. </li></ul></ul>For the same cross-sectional area a wider conductor (1 oz.) will run 15 to 20 percent cooler than a narrow conductor (3 oz). IPC-2152
  11. 11. <ul><li>Main Document </li></ul><ul><ul><li>Designed to be as simple as possible with conservative guidelines for sizing conductors. </li></ul></ul><ul><ul><li>The IPC-2221 internal conductor sizing chart will be kept as the most conservative chart to use for sizing conductors. </li></ul></ul><ul><ul><li>A single chart is included that envelopes both internal and external conductors in air environments </li></ul></ul><ul><ul><ul><li>External conductor heating data from a 1.78 mm (0.07 in.) thick PCB, 3 oz. copper, in an air environment </li></ul></ul></ul><ul><ul><li>A single chart is included that envelopes both internal and external conductors in a vacuum environment </li></ul></ul><ul><ul><ul><li>Based on external conductors heating data for a 1.78 mm (0.07 in.) thick PCB, 3 oz. copper, in a vacuum environment </li></ul></ul></ul>IPC-2152
  12. 12. <ul><li>Appendix </li></ul><ul><li>Purpose: </li></ul><ul><li>A place in the document to add clarity on topic areas and a place for expanding on current carrying capacity in electrical conductors. </li></ul><ul><ul><ul><li>Example problems </li></ul></ul></ul><ul><ul><ul><li>New research: PCB materials, embedded resistors, high current, etc. </li></ul></ul></ul>IPC-2152
  13. 13. <ul><li>Appendix </li></ul><ul><li>Topics Discussed: </li></ul><ul><ul><li>New and Old Conductor Sizing Charts </li></ul></ul><ul><ul><li>PCB Thickness </li></ul></ul><ul><ul><li>Parallel Conductors </li></ul></ul><ul><ul><li>Perpendicular Conductors </li></ul></ul><ul><ul><li>Flex circuits </li></ul></ul><ul><ul><li>PCB Material </li></ul></ul><ul><ul><li>Environments </li></ul></ul>IPC-2152
  14. 14. <ul><li>Appendix </li></ul><ul><li>Topics Discussed (Continued) </li></ul><ul><ul><li>Vias </li></ul></ul><ul><ul><li>Neck down of conductors </li></ul></ul><ul><ul><li>High Density Interconnect </li></ul></ul><ul><ul><ul><li>Fine line and space conductors </li></ul></ul></ul><ul><ul><ul><li>Microvias </li></ul></ul></ul><ul><ul><li>Copper thickness </li></ul></ul><ul><ul><li>Thermal analysis of conductors, vias, odd shaped geometries </li></ul></ul>IPC-2152
  15. 15. <ul><li>New Charts </li></ul><ul><ul><li>Multiple charts and chart formats </li></ul></ul><ul><ul><li>Charts for air and vacuum </li></ul></ul><ul><ul><li>Charts specifically for 1/2 oz., 1 oz., 2 oz. and 3 oz. copper weights (thicknesses) </li></ul></ul><ul><ul><li>Internal and external conductors </li></ul></ul><ul><ul><li>Linear charts and log-log charts </li></ul></ul><ul><ul><li>Charts showing finer resolution </li></ul></ul><ul><ul><li>SI (metric) and English (inch) units </li></ul></ul>IPC-2152
  16. 16. IPC-2152 Chart Format Example
  17. 17. IPC-2152 Chart Format Example
  18. 18. <ul><li>Thermal Modeling (Computer Simulations) </li></ul><ul><ul><li>Thermal models developed and correlated to test data </li></ul></ul><ul><ul><li>Thermal models were used to investigate the influence of variables on conductor temperature rise: </li></ul></ul><ul><ul><ul><li>Copper planes </li></ul></ul></ul><ul><ul><ul><li>Distance from conductor to copper plane </li></ul></ul></ul><ul><ul><ul><li>Board level details </li></ul></ul></ul>IPC-2152
  19. 19. <ul><li>PCB Level Details </li></ul><ul><ul><li>Conductors </li></ul></ul><ul><ul><ul><li>Parallel conductors </li></ul></ul></ul><ul><ul><li>Vias </li></ul></ul><ul><ul><li>Thermals </li></ul></ul><ul><ul><li>Odd-shaped geometries </li></ul></ul><ul><ul><li>Neck-down </li></ul></ul>IPC-2152
  20. 20. <ul><li>Summary </li></ul><ul><ul><li>IPC-2152 will replace the conductor sizing charts that currently exist in IPC-2221. </li></ul></ul><ul><ul><li>IPC-2152 is a document that will be updated over time (embedded devices, microvias, etc.) as task group members continue adding to the knowledge base regarding current carrying capacity in printed board design. </li></ul></ul><ul><ul><li>IPC-2152 is the result of volunteer efforts that started in 1998. </li></ul></ul>IPC-2152
  21. 21. For more information … If you would like more information, contact IPC by e-mail at perrjo@ipc.org.

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