What parameters should I pay attention to when selecting Triode and MOSFET?

Electronic components have electrical parameters, and it is important to leave enough margin for the electronic components when selecting the type to ensure the stability and long-term operation of the electronic components. Next briefly introduce the Triode and MOSFET selection method.

Triode is a flow-controlled device, MOSFET is a voltage-controlled device, there are similarities between the two, in the selection of the need to consider the withstand voltage, current and other parameters.

 

1, according to the maximum withstand voltage selection

Triode collector C and emitter E can withstand the maximum voltage between the parameter V (BR) CEO, the voltage between the CE during operation shall not exceed the specified value, otherwise Triode will be permanently damaged.

The maximum voltage also exists between the drain D and the source S of the MOSFET during use, and the voltage across DS during operation must not exceed the specified value. Generally speaking, the voltage withstand value of MOSFET is much higher than Triode.

 

2, the maximum overcurrent capability

Triode has ICM parameter, i.e., collector overcurrent capability, and the overcurrent capability of MOSFET is expressed in terms of ID. When the current operation, the current flowing through the Triode/MOSFET can not exceed the specified value, otherwise the device will be burned.

Considering the operating stability, a margin of 30%-50% or even more is generally allowed.

3、Operating temperature

Commercial-grade chips: general range of 0 to +70 ℃;

Industrial-grade chips: general range of -40 to +85 ℃;

Military grade chips: general range of -55 ℃ to +150 ℃;

When making MOSFET selection, choose the appropriate chip according to the product's use occasion.

 

4, according to the switching frequency selection

Both Triode and MOSFET have parameters of switching frequency/response time. If used in high-frequency circuits, the response time of the switching tube must be considered to meet the conditions of use.

 

5、Other selection conditions

For example, the on-resistance Ron parameter of the MOSFET, the VTH turn-on voltage of the MOSFET, and so on.

 

Everyone in the MOSFET selection, you can combine the above points for selection.