SLPA021 November   2024 CSD13303W1015 , CSD16301Q2 , CSD16321Q5 , CSD16322Q5 , CSD16323Q3 , CSD16325Q5 , CSD16327Q3 , CSD16340Q3 , CSD16342Q5A , CSD16401Q5 , CSD16403Q5A , CSD16404Q5A , CSD16406Q3 , CSD16407Q5 , CSD16408Q5 , CSD16409Q3 , CSD16410Q5A , CSD16411Q3 , CSD16412Q5A , CSD16413Q5A , CSD16414Q5 , CSD16415Q5 , CSD16556Q5B , CSD17301Q5A , CSD17302Q5A , CSD17303Q5 , CSD17304Q3 , CSD17305Q5A , CSD17306Q5A , CSD17307Q5A , CSD17308Q3 , CSD17309Q3 , CSD17310Q5A , CSD17311Q5 , CSD17312Q5 , CSD17313Q2 , CSD17322Q5A , CSD17327Q5A , CSD17381F4 , CSD17501Q5A , CSD17505Q5A , CSD17506Q5A , CSD17507Q5A , CSD17510Q5A , CSD17522Q5A , CSD17527Q5A , CSD17551Q3A , CSD17551Q5A , CSD17552Q3A , CSD17552Q5A , CSD17553Q5A , CSD17555Q5A , CSD17556Q5B , CSD17559Q5 , CSD18501Q5A , CSD18502KCS , CSD18502Q5B , CSD18503KCS , CSD18503Q5A , CSD18504KCS , CSD18504Q5A , CSD18531Q5A , CSD18532KCS , CSD18532NQ5B , CSD18532Q5B , CSD18533KCS , CSD18533Q5A , CSD18534KCS , CSD18534Q5A , CSD18537NKCS , CSD18537NQ5A , CSD18563Q5A , CSD22202W15 , CSD25211W1015 , CSD25213W10 , CSD75207W15 , CSD86311W1723 , CSD86330Q3D , CSD86350Q5D , CSD86360Q5D , CSD87312Q3E , CSD87330Q3D , CSD87331Q3D , CSD87350Q5D , CSD87351Q5D , CSD87351ZQ5D , CSD87352Q5D , CSD87353Q5D , CSD87381P , CSD87588N

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Review the Data Sheet Limits
  6. 3Application-specific FETs
  7. 4Gate Drive Voltage Specifications
    1. 4.1 Absolute maximum VGS
    2. 4.2 Gate-to-source Threshold Voltage, VGS(th)
  8. 5High-side and Low-side Switches
    1. 5.1 Driving a High-side N-channel FET
    2. 5.2 Driving a Low-side N-channel FET
    3. 5.3 Driving a High-side P-channel FET
  9. 6Use a Gate-to-source Resistor
  10. 7Lowest RDS(on)≠ Lowest Power Loss
  11. 8Summary
  12. 9References

7 Lowest RDS(on)≠ Lowest Power Loss

Does the MOSFET with the lowest RDS(on) result in the lowest power loss? This depends on the application and how the FET is being used. Conduction or I2R loss is directly proportional to RDS(on) and, for those applications such as hot swap, load switch, and OR’ing, where the FET is not switching at 10s or 100s of kHz, the lowest on resistance device results in the lowest power loss.

In switch-mode applications such as DC-DC converters, switching loss can be a significant portion of the total MOSFET power loss. RDS(on) is a function of the FET die size and a larger die results in lower RDS(on) for a given MOSFET process technology and voltage rating. A larger die also has higher charge and capacitance, which results in increased switching loss. Selecting a FET for a switch-mode application must balance conduction loss and switching loss to achieve the lowest overall power loss in the FET.

TI has released a number of Excel-based FET selection tools for various applications that take this into account. For example, the synchronous buck FET selection tool allows the user to input the requirements and compare up to three different TI FET designs based on power loss, package and 1ku pricing.