Description of the meaning of MOS tube parameters

Description of the meaning of MOS diodee parameters.
1. Limit parameters:
ID: maximum leakage source current. It refers to the maximum current allowed to pass between the drain sources when the FET is working normally. The working current of FET should not exceed ID. This parameter will decrease with the increase of junction temperature.
IDM: maximum pulse leakage source current. This parameter will decrease with the increase of junction temperature.
PD: maximum dissipated power. It refers to the maximum power dissipated by the drain source when the performance of the FET remains unchanged. When in use, the actual power consumption of FET should be less than that of PDSM and leave a certain margin. This parameter generally decreases with the increase of junction temperature.
VGS: maximum gate source voltage.
Tj: maximum working temperature. It is usually 150 ℃ or 175 ℃. Under the working conditions of the device design, it is necessary to avoid exceeding this temperature and leave a certain margin.
TSTG: storage temperature ran.
2. Static parameters.
V (BR) DSS: drain-source breakdown voltage. It refers to the maximum drain-source voltage that FET can withstand when the gate-source voltage VGS is 0. This is a limit parameter, and the working voltage added to the FET must be less than V (BR) DSS. It has positive temperature characteristics. Therefore, the value of this parameter at low temperature should be considered as a safety consideration. V (BR) DSS/ Tj: the temperature coefficient of the drain-source breakdown voltage, usually 0.1V/ ℃.
RDS (on): the maximum impedance between the drain and source when MOSFET is turned on under the conditions of specific VGS (usually 10V), junction temperature and drain current. It is a very important parameter, which determines the power consumption when MOSFET is turned on. This parameter generally increases with the increase of junction temperature. Therefore, the value of this parameter under the condition of the highest working junction temperature should be used to calculate the loss and voltage drop.
VGS (th): open voltage (threshold voltage). When the external gate control voltage VGS exceeds VGS (th), the surface inversion layer of the drain region and the source region forms a connected channel. In application, the gate voltage under the condition of drain short connection when ID is equal to 1 Ma is often called turn-on voltage. This parameter generally decreases with the increase of junction temperature.
IDSS: saturated drain source current, gate voltage VGS=0, VDS is a certain value of the drain source current. Usually at the microampere level.
IGSS: gate source drive current or reverse current. Due to the high input impedance of MOSFET, IGSS is generally at the nanoampere level.
3. Dynamic parameters.
Gfs: transconductance. It refers to the ratio of the change of the output current of the drain to the change of the gate-source voltage, and is a measure of the ability of the gate-source voltage to control the drain current. The transfer relationship between gfs and VGS pay attention to the chart.
Qg: the total charge of the gate. MOSFET is a voltage type driver, and the driving process is the establishment of gate voltage, which is realized by charging the capacitor between gate source and gate drain. This aspect will be discussed in detail below.
Qgs: gate source charging power.
Qgd: gate drain charging (taking into account the Miller effect).
Td (on): turn-on delay time. The time when the input voltage rises to 10% and the VDS decreases to 90% of its amplitude.
Tr: rise time, time when the output voltage VDS falls from 90% to its amplitude 10%.
Td (off): turn-off delay time, the time from the time the input voltage drops to 90% until the VDS rises to its turn-off voltage.
Tf: the time when the output voltage VDS rises from 10% to 90%.
Ciss: input capacitor, Ciss= CGD + CGS (CDS short circuit).
Coss: output capacitance, Coss = CDS + CGD.
Crss: reverse transmission capacitance, Crss = CGD.
The interpole capacitance of MOS transistors and the inductive capacitance of MOSFET are divided into input capacitance, output capacitance and feedback capacitance by most manufacturers. The value quoted is when the drain source voltage is a fixed value. These capacitances vary with the drain-source voltage, and the effect of capacitance value is limited. The input capacitance value only gives a general description of the charging required by the drive circuit, while the gate charging information is more useful. It indicates the amount of electricity that must be charged to reach a particular gate source voltage gate.
4. Avalanche breakdown characteristic parameters.
These parameters are indicators of the ability of MOSFET to withstand overpressure in the turn-off state. If the voltage exceeds the drain source limit voltage, the device will be in an avalanche state.
EAS: single pulse avalanche breakdown energy. This is a limit parameter, indicating the maximum avalanche breakdown energy that MOSFET can withstand.
IAR: avalanche current.
EAR: repetitive avalanche breakdown energy.
5. Parameters of diode in vivo.
IS: continuous maximum continuous current (from source).
ISM: pulse maximum continuous current (from source).
VSD: positive guide voltage drop.
Trr: reverse recovery time.
Qrr: reverse charge recovery.
Ton: forward conduction time.