ZHCSNR6G June 1999 – March 2023 LM2576 , LM2576HV
PRODUCTION DATA
請參考 PDF 數據表獲取器件具體的封裝圖。
In many cases, only a small heat sink is required to keep the LM2576 junction temperature within the allowed operating range. For each application, to determine whether or not a heat sink is required, the following must be identified:
Total power dissipated by the LM2576 can be estimated in Equation 11:
where
The dynamic losses during turnon and turnoff are negligible if a Schottky type catch diode is used.
When no heat sink is used, the junction temperature rise can be determined by Equation 12:
To arrive at the actual operating junction temperature, add the junction temperature rise to the maximum ambient temperature.
If the actual operating junction temperature is greater than the selected safe operating junction temperature determined in step 3, then a heat sink is required.
When using a heat sink, the junction temperature rise can be determined by Equation 13:
The operating junction temperature is:
As in Equation 15, if the actual operating junction temperature is greater than the selected safe operating junction temperature, then a larger heat sink is required (one that has a lower thermal resistance).