This webpage doesn't work with Internet Explorer. Please use the latest version of Google Chrome, Microsoft Edge, Mozilla Firefox or Safari.
型號需要超過三個文字以上
The information presented in this cross reference is based on TOSHIBA's selection criteria and should be treated as a suggestion only. Please carefully review the latest versions of all relevant information on the TOSHIBA products, including without limitation data sheets and validate all operating parameters of the TOSHIBA products to ensure that the suggested TOSHIBA products are truly compatible with your design and application.
Please note that this cross reference is based on TOSHIBA's estimate of compatibility with other manufacturers' products, based on other manufacturers' published data, at the time the data was collected.
TOSHIBA is not responsible for any incorrect or incomplete information. Information is subject to change at any time without notice.
型號需要超過三個文字以上
The power dissipation (P) of an LDO regulator can be calculated as follows:
When the term VIN × IB is negligibly small, Equation 1 can be approximated as follows:
The junction temperature Tj of the LDO regulator can be calculated as follows:
where Rth(j-a) is the thermal resistance of the LDO regulator when it is mounted on a board. If Rth(j-a) is not shown in the datasheet, you can calculate it from the power dissipation (PD) value:
Substituting Equation 4 into Equation 3, we obtain:
Suppose that Tj(max) = 150°C, PD = 600 mW, VIN = 3.6 V, VOUT = 1.8 V, IOUT = 100 mA, Ta = 40°C. Then, Tj is calculated as follows:
Note that the power dissipation and thermal resistance values in the datasheet are the values under the specified board conditions. It is therefore necessary to evaluate LDO regulators carefully to ensure that they work properly under actual usage conditions.
The following application notes also provide a description of the power dissipation and junction temperature of an LDO regulator.
Application note: Basics of Low-Dropout (LDO) Regulator ICs
Application note: Thermal Design to Maximize the Performance of LDO Regulators
Application note: Power Efficiency Optimization and Application Circuits Using Dual-Supply LDO Regulators