The on-resistance of a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) refers to the resistance between the drain and source terminals when the MOSFET is in the ON state (conducting current). Let%27s explore this concept further:

1. Definition:
- The on-resistance is denoted as R_DS(ON) (resistance between drain and source when ON).
- It quantifies how efficiently the MOSFET conducts current when fully turned on.
- Smaller on-resistance values result in lower power losses during operation.

2. Calculation:
- The on-resistance can be calculated by dividing the specified drain current (I_D) by the drain current at the specified gate voltage (I_D).
- It involves increasing the gate-source voltage (V_GS) to the specified value, measuring the drain-to-source voltage (V_DS), and then calculating the on-resistance.

3. Significance:
- The on-resistance directly affects power dissipation and efficiency.
- Lower on-resistance results in less heat generation during operation.
- MOSFETs with low on-resistance are preferred for high-power applications.

4. Variation with Temperature and Gate Voltage:
- The on-resistance varies with temperature and gate-source voltage.
- Care must be taken to account for these variations in practical designs.

5. Comparison:
- Generally, larger MOSFET chip sizes (surface area) lead to smaller on-resistance.
- ROHM offers a variety of low on-resistance products in different package sizes.

In summary, understanding the on-resistance helps in selecting MOSFETs suitable for specific applications, balancing performance and power efficiency¹²³.


(1) ON Resistance | Electronics Basics | ROHM. https://www.rohm.com/electronics-basics/transistors/tr_what9.
(2) Electrical characteristics of MOSFETs (Static Characteristics RDS(ON .... https://toshiba.semicon-storage.com/ap-en/semiconductor/knowledge/faq/mosfet/electrical-characteristics-of-mosfetsstatic-characteristics-rds-.html.
(3) Understanding MOSFET On-State Drain-to-Source Resistance. https://www.allaboutcircuits.com/technical-articles/understanding-mosfet-on-state-drain-to-source-resistance/.

icDirectory Limited | https://www.icdirectory.com/b/blog/what-is-the-on-resistance-of-a-mosfet.html