Ipc Slideshow Ipc2152
- 1. IPC Current Carrying Capacity Task Group (1-10b) August 2008 Michael R. Jouppi, Thermal Man, Inc., Task Group Chair IPC-2152, Standard for Determining Current-Carrying Capacity in Printed Board Design
- 2. 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. 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. Mike started with the IPC-1-10b task group in 1999 and has chaired the group since 2000.
- 3. IPC-2152 Introduction The amount of current that can be applied to a conductor and its resulting temperature rise is a printed circuit board (PCB) design concern. Design constraints have created a need for more precise guidelines for sizing conductors than those currently found in IPC-2221. Simple and accurate design guidelines, with an explanation to their origin, is the vision for IPC-2152. Vision: Simple and Accurate Design Guidelines Standard for Determining Current Carrying Capacity in Printed Board Design
- 4. IPC-2152 Introduction The temperature rise of a PCB conductor is a complex problem, yet the desire is to have general guidelines. A compromise has resulted that provides general guidelines in a main document and detailed guidelines in an attached appendix. 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. IPC-2152 Introduction 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 . Computer simulations were also used to improve the understanding of the impact that certain variables have on the temperature rise of a conductor. IPC-2152 is based on industry standards test procedures and correlated computer simulations.
- 6. IPC-2152 Test Considerations Environment Testing was performed in air and vacuum Internal and external conductors PCB thickness 0.038-inch, 0.059-inch and 0.07-inch thick test vehicles Copper thickness/weight (1/2-oz, 1-oz, 2-oz and 3-oz) PCB material Polyimide and FR4 test vehicles Current carrying capacity testing considered multiple environments, conductor width and thickness, PCB thickness and PCB materials.
- 7. IPC-2152 Test Results Environment: Still air vs. vacuum Internal conductors in a board tested in vacuum are 55 percent higher in temperature rise than the same conductors in a still air environment. External conductors in a board tested in vacuum are 35 percent higher in temperature rise than the same conductors in a still air environment. Conductors run hotter in a vacuum than in air by as much as 55% or more.
- 8. Test Results Conductors: Comparing internal vs. external conductors 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. Identical external and internal conductors in a vacuum experience the same increase in temperature for the same applied current. External conductors run hotter than internal traces in a still air environment . IPC-2152
- 9. Test Results Board Thickness: Conductor temperature and PCB thickness 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. 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. Test boards thicker than 1.78 mm have not been evaluated. Conductors in thin PCBs run hotter than the same size conductor in thicker PCBs. IPC-2152
- 10. Test Results Comparing Copper Weights: Half-ounce copper conductors are similar in temperature rise for the same size cross-sectional area as 1 oz. conductors. Two ounce copper conductors increase in temperature by 10 to 15 percent above 1 oz. conductors for the same size trace and applied current. Three ounce copper conductors increase in temperature by 15 to 20 percent above 1 oz. conductors for the same size trace and applied current. The higher percentages are related to a 45 o C delta T and the lower percentages are related to a 10 o C rise. 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. Main Document Designed to be as simple as possible with conservative guidelines for sizing conductors. The IPC-2221 internal conductor sizing chart will be kept as the most conservative chart to use for sizing conductors. A single chart is included that envelopes both internal and external conductors in air environments External conductor heating data from a 1.78 mm (0.07 in.) thick PCB, 3 oz. copper, in an air environment A single chart is included that envelopes both internal and external conductors in a vacuum environment Based on external conductors heating data for a 1.78 mm (0.07 in.) thick PCB, 3 oz. copper, in a vacuum environment IPC-2152
- 12. Appendix Purpose: A place in the document to add clarity on topic areas and a place for expanding on current carrying capacity in electrical conductors. Example problems New research: PCB materials, embedded resistors, high current, etc. IPC-2152
- 13. Appendix Topics Discussed: New and Old Conductor Sizing Charts PCB Thickness Parallel Conductors Perpendicular Conductors Flex circuits PCB Material Environments IPC-2152
- 14. Appendix Topics Discussed (Continued) Vias Neck down of conductors High Density Interconnect Fine line and space conductors Microvias Copper thickness Thermal analysis of conductors, vias, odd shaped geometries IPC-2152
- 15. New Charts Multiple charts and chart formats Charts for air and vacuum Charts specifically for 1/2 oz., 1 oz., 2 oz. and 3 oz. copper weights (thicknesses) Internal and external conductors Linear charts and log-log charts Charts showing finer resolution SI (metric) and English (inch) units IPC-2152
- 16. IPC-2152 Chart Format Example
- 17. IPC-2152 Chart Format Example
- 18. Thermal Modeling (Computer Simulations) Thermal models developed and correlated to test data Thermal models were used to investigate the influence of variables on conductor temperature rise: Copper planes Distance from conductor to copper plane Board level details IPC-2152
- 19. PCB Level Details Conductors Parallel conductors Vias Thermals Odd-shaped geometries Neck-down IPC-2152
- 20. Summary IPC-2152 will replace the conductor sizing charts that currently exist in IPC-2221. 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. IPC-2152 is the result of volunteer efforts that started in 1998. IPC-2152
- 21. For more information … If you would like more information, contact IPC by e-mail at perrjo@ipc.org.