We have learned that field-effect transistors can be divided into two categories: junction type and insulated gate type. Junction field-effect transistor (JFET) is named after having two PN junctions, while insulated gate field-effect transistor (JGFET) is named after the gate being completely insulated from other electrodes. At present, the most widely used insulating gate field-effect transistor is MOSFET, abbreviated as MOSFET (metal oxide semiconductor field-effect transistor MOSFET); In addition, there are PMOS, NMOS, and VMOS power field-effect transistors, as well as recently introduced π MOS field-effect transistors and VMOS power modules.

Nomenclature method for field-effect transistors

How can we distinguish these products with so many categories and models? Let's take a look at naming conventions and understand their intricacies.

There are currently two naming methods for field-effect transistors. The first naming method is to use the third letter J of the model to represent the junction field-effect transistor and O to represent the insulated gate field-effect transistor. The second letter represents the material, where D is P-type silicon and the inversion layer is an N-channel; C is an N-type silicon P-channel. For example, 3DJ6D is a junction type N-channel field-effect transistor, and 3DO6C is an insulated gate type N-channel field-effect transistor.

The second naming method is CS XX #, where CS represents field-effect transistors, XX represents the model number with numbers, and # represents different specifications within the same model with letters. For example, CS14A, CS45G, etc.

Parameters of field-effect transistors

In addition, when we understand the product, product parameters are also extremely important. There are many parameters for field-effect transistors, including DC parameters, AC parameters, and limit parameters. However, when using them, we usually pay attention to the following main parameters:

1. IDSS - Saturated leakage source current. It refers to the drain source current in a junction or depletion type insulated gate field-effect transistor when the gate voltage UGS=0.

2. UP - clamp off voltage. It refers to the gate voltage in a junction or depletion type insulated gate field-effect transistor when the drain source is just cut off.

3. UT - Turn on voltage. It refers to the gate voltage in an enhanced insulated gate field-effect transistor when the drain source is just conducting.

4. GM - transconductance. It represents the control ability of the gate source voltage UGS over the drain current ID, that is, the ratio of the change in drain current ID to the change in gate source voltage UGS. GM is an important parameter for measuring the amplification capability of field-effect transistors.

5. BUDS - Leakage source breakdown voltage. It refers to the maximum leakage source voltage that a field-effect transistor can withstand during normal operation when the gate source voltage UGS is constant. This is a limit parameter, and the working voltage applied to the field-effect transistor must be less than BUDS.

6. PDSM - Maximum dissipated power. It is also a limit parameter that refers to the maximum allowable leakage source dissipation power when the performance of the field-effect transistor remains unchanged. When in use, the actual power consumption of the field-effect transistor should be less than that of the PDSM and leave a certain margin.

7. IDSM - Maximum leakage source current. It is a limit parameter that refers to the maximum current allowed between the drain and source of a field-effect transistor during normal operation. The working current of the field-effect transistor should not exceed IDSM

These are all relatively simple and easy to understand ways to understand, but if you want to gain a deeper understanding of the product, you need to start from aspects such as functionality, usage, and scenarios. If you want to continue learning, you can follow Jinyu Semiconductor.