electronics:torque_standards_for_power_packages
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electronics:torque_standards_for_power_packages [2022/06/02 21:33] – created mithat | electronics:torque_standards_for_power_packages [2024/01/18 02:50] (current) – [onsemi] mithat | ||
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====== Torque Standards for Power Packages ====== | ====== Torque Standards for Power Packages ====== | ||
- | STMicroelectionics(([[https:// | + | <WRAP center round info 60%> |
+ | The recommendations below are based on current data. As more sources are found, these recommendations may change. | ||
+ | </ | ||
+ | |||
+ | ===== Recommendations ===== | ||
+ | |||
+ | ==== STMicroelectionics | ||
+ | |||
+ | Comprehensive data and test results for various packages is provided in STMicroelectronics' | ||
^ Package | ^ Package | ||
|TO-220 | |TO-220 | ||
- | |TO-220SG | ||
- | |Pentawatt | ||
- | |Heptawatt | ||
|TO-220FP | |TO-220FP | ||
- | |ISOWATT220 | ||
|TO-247 | |TO-247 | ||
- | |TO-218 | 0.55 | 1.00 | | + | |TO-247-4 | 0.55 | 1.00 | |
+ | |TO-3P | ||
+ | |TO-3PF | ||
- | The kind of insulator (mica, silicone, etc.) isn't specified | + | The kind of insulator (mica, silicone, etc.) isn't specified. |
+ | {{: | ||
- | A different | + | STMicroelectronics' AN260 reference |
However, the maximum torque is slightly contradicted here (emphasis added): | However, the maximum torque is slightly contradicted here (emphasis added): | ||
- | > Suggested maximum torques for M3 screws are _80Nxcm_ | + | > Suggested maximum torques for M3 screws are // |
+ | |||
+ | This leads to the following table for packages covered by this note. | ||
+ | |||
+ | ^ Package | ||
+ | |TO-220SG | ||
+ | |TO-220 | ||
+ | |Pentawatt | ||
+ | |Heptawatt | ||
+ | |Multiwatt | ||
+ | |Clipwatt | ||
+ | |FLEXIWATT | ||
+ | |||
+ | The hardware stackup shows only a screw entering the device tab through an optional washer and a bolt on the heatsink side: | ||
+ | |||
+ | {{: | ||
+ | ===== Data from other sources ===== | ||
+ | |||
+ | ==== Infineon ==== | ||
+ | |||
+ | Infineon ran a test on TO-247 packages with torques ranging from 0.2 N*m to 2 N*m.(([[https:// | ||
+ | |||
+ | ==== Texas Instruments ==== | ||
+ | |||
+ | TI mentions 50N-cm as the recommended maximum for their multi-lead TO-247 packages.(([[https:// | ||
- | The data given in the table above is the more conservative and therefore preferred: 0.55 N*m nominal for all packages listed with a maximum 0.7 N*m for everything except TO-247 and TO-218, which can be squeezed up to 1 N*m. | + | ==== onsemi ==== |
+ | onsemi' | ||
+ | For Power Semiconductors]]. onsemi. Accessed Jan 17, 2024.)) advocates the use of conical " | ||
+ | {{: | ||
+ | However, the text implies that torque cannot be used to set the device pressure with conical washers because, "The assembler applies torque until the washer depresses to half its original height. (Tests should be run prior to setting up the assembly line to determine the proper torque for the fastener used to achieve 50% deflection." | ||
- | Infineon(([[https:// | + | Perhaps not surprisingly then, specific torque ratings are difficult to derive from this note. However, it shows for TO-220 packages remarkable consistent thermal resistances for greased mica mounting with unspecified hardware over 2 to 6 in-lbs (0.23 to 0.68 N*m). One table shows a torque of 8 in-lbs (0.90 N*m) used with a TO−220AB device. |
- | TI(([[https:// |
electronics/torque_standards_for_power_packages.1654205605.txt.gz · Last modified: 2022/06/02 21:33 by mithat