Technological capabilities and advances in the development of high-power field-effect transistors have led to the fact that nowadays it is not difficult to purchase them at an affordable price.
In this regard, the interest of radio amateurs in the use of such MOSFET transistors in their electronic homemade products and projects has increased.
It is worth noting the fact that MOSFETs differ significantly from their bipolar counterparts, both in parameters and in their design.
It's time to become more familiar with the design and parameters of powerful MOSFET transistors, so that, if necessary, you can more consciously select an analogue for a specific instance, and also be able to understand the essence of certain quantities indicated in the datasheet.
What is a HEXFET transistor?
In the family of field-effect transistors there is a separate group of powerful semiconductor devices called HEXFET. Their operating principle is based on a very original technical solution. Their structure consists of several thousand MOS cells connected in parallel.
The cellular structures form a hexagon. Due to the hexagonal or otherwise hexagonal structure this type power MOSFETs are called HEXFETs. The first three letters of this abbreviation are taken from the English word hex agonal– “hexagonal”.
Under multiple magnification, the crystal of a powerful HEXFET transistor looks like this.
As you can see, it has a hexagonal structure.
It turns out that a powerful MOSFET is essentially a kind of super-microcircuit that combines thousands of individual simple field-effect transistors. Together, they create one powerful transistor that can pass a large current through itself and at the same time provide virtually no significant resistance.
Thanks to the special structure and manufacturing technology of HEXFET, the resistance of their channel RDS(on) managed to significantly reduce. This made it possible to solve the problem of switching currents of several tens of amperes at voltages of up to 1000 volts.
Here is just a small area of application of high-power HEXFET transistors:
Power supply switching circuits.
Charging device.
Electric motor control systems.
Low frequency amplifiers.
Despite the fact that mosfets made using HEXFET technology (parallel channels) have a relatively low open-channel resistance, their scope is limited, and they are used mainly in high-frequency, high-current circuits. In high-voltage power electronics, IGBT-based circuits are sometimes preferred.
Image of a MOSFET transistor on the circuit board electrical diagram(N-channel MOS).
Like bipolar transistors, field structures can be forward or reverse conduction. That is, with a P-channel or N-channel. The conclusions are indicated as follows:
D-drain (drain);
S-source (source);
G-gate (shutter).
About how field-effect transistors are designated different types Schematic diagrams can be found on this page.
Basic parameters of field-effect transistors.
The entire set of MOSFET parameters may be required only by developers of complex electronic equipment and, as a rule, are not indicated in the datasheet (reference sheet). It is enough to know the basic parameters:
V DSS(Drain-to-Source Voltage) – voltage between drain and source. This is typically the supply voltage for your circuit. When selecting a transistor, you must always remember the 20% margin.
I D(Continuous Drain Current) – drain current or continuous drain current. Always indicated at a constant gate-source voltage (for example, V GS =10V). The datasheet usually indicates the maximum possible current.
RDS(on)(Static Drain-to-Source On-Resistance) – drain-to-source resistance of the open channel. As the crystal temperature increases, the open channel resistance increases. This is easy to see in the graph taken from the datasheet of one of the high-power HEXFET transistors. The lower the on-channel resistance (R DS(on)), the better the mosfet. It heats up less.
P D(Power Dissipation) – transistor power in watts. In another way, this parameter is also called dissipation power. In the datasheet for a specific product, the value this parameter indicated for a specific crystal temperature.
VGS(Gate-to-Source Voltage) – gate-to-source saturation voltage. This is the voltage above which the current through the channel does not increase. Essentially, this is the maximum voltage between gate and source.
V GS(th)(Gate Threshold Voltage) – threshold voltage for turning on the transistor. This is the voltage at which the conductive channel opens and it begins to pass current between the source and drain terminals. If a voltage less than V GS(th) is applied between the gate and source terminals, the transistor will be turned off.
The graph shows how the threshold voltage V GS(th) decreases with increasing temperature of the transistor crystal. At a temperature of 175 0 C it is about 1 volt, and at a temperature of 0 0 C it is about 2.4 volts. Therefore, the datasheet usually indicates the minimum ( min.) and maximum ( max.) threshold voltage.
Let's consider the main parameters of a powerful HEXFET field-effect transistor using the example IRLZ44ZS from International Rectifier. Despite its impressive performance, it has a compact body D 2 PAK for surface mounting. Let's look at the datasheet and evaluate the parameters of this product.
Drain-source voltage limit (V DSS): 55 Volts.
Maximum drain current (I D): 51 Ampere.
Gate-source voltage limit (V GS): 16 Volts.
Open channel drain-source resistance (R DS(on)): 13.5 mOhm.
Maximum power (P D): 80 Watt.
The IRLZ44ZS open channel resistance is only 13.5 milliohms (0.0135 ohms)!
Let's take a look at the “piece” from the table where the maximum parameters are indicated.
It is clearly visible how, at a constant gate voltage, but with increasing temperature, the current decreases (from 51A (at t=25 0 C) to 36A (at t=100 0 C)). Power at a housing temperature of 25 0 C is equal to 80 Watts. Some parameters in pulse mode are also indicated.
MOSFET transistors have high speed, but they have one significant drawback - large gate capacitance. In the documents, the gate input capacitance is designated as C iss (Input Capacity).
What does gate capacitance affect? It greatly influences certain properties of field-effect transistors. Since the input capacitance is quite large and can reach tens of picofarads, the use of field-effect transistors in circuits high frequency limited.
Important features of MOSFET transistors.
It is very important when working with field-effect transistors, especially those with an insulated gate, to remember that they are “deadly” afraid of static electricity. You can solder them into the circuit only by first short-circuiting the leads together with a thin wire.
When storing, it is better to short-circuit all terminals of the MOS transistor using ordinary aluminum foil. This will reduce the risk of static electricity damaging the gate. When installing it on printed circuit board It is better to use a soldering station rather than a regular electric soldering iron.
The fact is that an ordinary electric soldering iron does not have protection against static electricity and is not “isolated” from the mains through a transformer. Its copper tip always contains electromagnetic interference from the electrical network.
Any voltage surge in the electrical network can damage the soldered element. Therefore, when soldering a field-effect transistor into a circuit with an electric soldering iron, we risk damaging the MOSFET transistor.
POWERFUL IMPORTED FIELD TRANSISTORS
| Brand | Voltage, V | Transition resistance, Ohm | Drain current, A | Power, W | Frame | ||
| 1 | 2 | 3 | 4 | 5 | 6 | ||
| STH60N0SFI | 50 | 0,023 | 40,0 | 65 | ISOWATT218 | ||
| STVHD90FI | 50 | 0,023 | 30,0 | 40 | ISOWATT220 | ||
| STVHD90 | 50 | 0,023 | 52,0 | 125 | TO-220 | ||
| STH60N05 | 50 | 0,023 | 60,0 | 150 | TO-218 | ||
| IRFZ40 | 50 | 0,028 | 35.0 | 125 | TO-220 | ||
| BUZ15 | 50 | 0.03 | 45,0 | 125 | TO-3 | ||
| SGSP592 | 50 | 0,033 | 40,0 | 150 | TO-3 | ||
| SGSP492 | 50 | 0.033 | 40,0 | 150 | TO-218 | ||
| IRFZ42FI | 50 | 0,035 | 24,0 | 40 | ISOWATT220 | ||
| IRFZ42 | 50 | 0,035 | 35,0 | 125 | TO-220 | ||
| BUZ11FI | 50 | 0,04 | 20,0 | 35 | ISOWATT220 | ||
| BUZ11 | 50 | 0,04 | 30,0 | 75 | TO-220 | ||
| BUZ14 | 50 | 0,04 | 39,0 | 125 | TO-3 | ||
| BUZ11A | 50 | 0,06 | 25,0 | 75 | TO-220 | ||
| SGSP382 | 50 | 0.06 | 28,0 | 100 | TO-220 | ||
| SGSP482 | 50 | 0.06 | 30.0 | 125 | TO-218 | ||
| BUZ10 | 50 | 0.08 | 20.0 | 70 | TO-220 | ||
| BUZ71FI | 50 | 0,10 | 12,0 | 30 | ISOWATT220 | ||
| IRF20FI | 50 | 0,10 | 12,5 | 30 | ISOWATT220 | ||
| BUZ71 | 50 | 6,10 | 14,0 | 40 | TO-220 | ||
| IRFZ20 | 50 | 0,10 | 15.0 | 40 | TO-220 | ||
| BUZ71AFI | 50 | 0,12 | 11,0 | 30 | ISOWATT220 | ||
| IRFZ22FI | 50 | 0,12 | 12,0 | 30 | ISOWATT220 | ||
| BUZ71A | 50 | 0,12 | 13,0 | 40 | TO-220 | ||
| IRFZ22 | 50 | 0,12 | 14,0 | 40 | TO-220 | ||
| BUZ10A | 50 | 0,12 | 17,0 | 75 | TO-220 | ||
| SGSP322 | 50 | 0,13 | 16,0 | 75 | TO-220 | ||
| SGSP358 | 50 | 0.30 | 7,0 | 50 | TO-220 | ||
| MTH40N06FI | 60 | 0,028 | 26,0 | 65 | ISOWATT218 | ||
| MTH40N06 | 60 | 0,028 | 40,0 | 150 | TO-218 | ||
| SGSP591 | 60 | 0,033 | 40,0 | 150 | TO-3 | ||
| SGSP491 | 60 | 0,033 | 40,0 | 150 | TO-218 | ||
| BUZ11S2FI | 60 | 0,04 | 20,0 | 35 | ISOWATT220 | ||
| BUZ11S2 | 60 | 0,04 | 30,0 | 75 | TO-220 | ||
| IRFP151FI | 60 | 0,055 | 26,0 | 65 | ISOWATT218 | ||
| IRF151 | 60 | 0.055 | 40,0 | 150 | TO-3 | ||
| IRFP151 | 60 | 0.055 | 40,0 | 150 | TO-218 | ||
| SGSP381 | 60 | 0,06 | 28,0 | 100 | TO-220 | ||
| SGSP481 | 60 | 0.06 | 30.0 | 125 | TO-218 | ||
| IRFP153FI | 60 | 0,08 | 21,0 | 65 | ISOWATT218 | ||
| IRF153 | 60 | 0,08 | 33,0 | 150 | TO-3 | ||
| IRFP153 | 60 | 0,08 | 34.0 | 150 | TO-218 | ||
| SGSP321 | 60 | 0,13 | 16,0 | 75 | TO-220 | ||
| MTP3055EFI | 60 | 0,15 | 10,0 | 30 | ISOWATT220 | ||
| MTP3055E | 60 | 0,15 | 12.0 | 40 | TO-220 | ||
| IRF521FI | 80 | 0,27 | 7,0 | 30 | ISOWATT220 | ||
| IRF521 | 80 | 0.27 | 9,2 | 60 | TO-220 | ||
| IRF523FI | 80 | 036 | 6,0 | 30 | ISOWATT220 | ||
| IRF523 | 80 | 0.36 | 8,0 | 60 | TO-220 | ||
| SGSP472 | 80 | 0,05 | 35.0 | 150 | TO-218 | ||
| IRF541 | 80 | 0,077 | 15,0 | 40 | ISOWATT220 | ||
| IRF141 | 80 | 0.077 | 28,0 | 125 | TO-3 | ||
| IRF541 | 80 | 0.077 | 28,0 | 125 | TO-220 | ||
| IRF543F1 | 80 | 0,10 | 14,0 | 40 | SOWATT220 | ||
| SGSP362 | 80 | 0,10 | 22.0 | 100 | TO-220 | ||
| IRF143 | 80 | 0,10 | 25,0 | 125 | TO-3 | ||
| SGSP462 | 80 | 0.10 | 25,0 | 125 | TO-218 | ||
| IRF543 | 80 | 0,10 | 25.0 | 125 | O-220 | ||
| IRF531FI | 80 | 0.16 | 9,0 | 35 | SOWATT220 | ||
| IRF531 | 80 | 0.16 | 14,0 | 79 | O-220 | ||
| IRF533FI | 80 | 0,23 | 8,0 | 35 | ISOWATT220 | ||
| IRF533 | 80 | 0,23 | 12.0 | 79 | TO-220 | ||
| IRF511 | 80 | 0,54 | 5.6 | 43 | TO-220 | ||
| IRF513 | 80 | 0,74 | 4,9 | 43 | TO-220 | ||
| IRFP150FI | 100 | 0,055 | 26,0 | 65 | ISOWATT218 | ||
| IRF150 | 100 | 0,055 | 40,0 | 150 | TO-3 | ||
| IRFP150 | 100 | 0,055 | 40,0 | 150 | TO-218 | ||
| BUZ24 | 100 | 0,6 | 32,0 | 125 | TO-3 | ||
| IRF540FI | 100 | 0,077 | 15,0 | 40 | ISOWATT220 | ||
| IRF140 | 100 | 0,077 | 28,0 | 125 | TO-3 | ||
| IRF540 | 100 | 0,077 | 28,0 | 125 | TO-220 | ||
| SGSP471 | 100 | 0,075 | 30,0 | 150 | TO-218 | ||
| IRFP152FI | 100 | 0,08 | 21,0 | 65 | ISOWATT218 | ||
| IRF152 | 100 | 0,08 | 33,0 | 150 | TO-3 | ||
| IRFP152 | 100 | 0,08 | 34.0 | 150 | TO-218 | ||
| IRF542FI | 100 | 0,10 | 14,0 | 40 | ISOWATT220 | ||
| BUZ21 | 100 | 0,10 | 19.0 | 75 | TO-220 | ||
| BUZ25 | 100 | 0,10 | 19.0 | 78 | TO-3 | ||
| IRF142 | 100 | 0,10 | 25,0 | 125 | TO-3 | ||
| IRF542 | 100" | 0,10 | 25,0 | 125 | TO-220 | ||
| SGSP361 | 100 | 0,15 | 18,0 | 100 | TO-220 | ||
| SGSP461 | 100 | 0,15 | 20.0 | 125 | TO-218 | ||
| IRF530FI | 100 | 0,16 | 9,0 | 35 | ISOWATT220 | ||
| IRF530 | 100 | 0,16 | 14.0 | 79 | TO-220 | ||
| BUZ20 | 100 | 0,20 | 12.0 | 75 | TO-220 | ||
| IRF532FI | 100 | 0.23 | 8.0 | 35 | ISOWATT220 | ||
| IRF532 | 100 | 0,23 | 12,0 | 79 | TO-220 | ||
| BUZ72A | 100 | 0,25 | 9,0 | 40 | TO-220 | ||
| IRF520FI | 100 | 0.27 | 7,0 | 30 | ISOWATT220 | ||
| IRF520 | 100 | 0,27 | 9,2 | 60 | TO-220 | ||
| SGSP311 | 100 | 0,30 | 11.0 | 75 | TO-220 | ||
| IRF522FI | 100 | 0,36 | 6.0 | 30 | ISOWATT220 | ||
| IRF522 | 100 | 0,36 | 8,0 | 60 | TO-220 | ||
| IRF510 | 100 | 0,54 | 5,6 | 43 | TO-220 | ||
| SGSP351 | 100 | 0,60 | 6,0 | 50 | TO-220 | ||
| IRF512 | 100 | 0,74 | 4,9 | 43 | TO-220 | ||
| SGSP301 | 100 | 1,40 | 2,5 | 18 | TO-220 | ||
| IRF621FI | 160 | 0,80 | 4.0 | 30 | ISOWATT220 | ||
| IRF621 | 150 | 0,80 | 5,0 | 40 | TO-220 | ||
| IRF623FI | 150 | 1,20 | 3,5 | 30 | ISOWATT220 | ||
| IRF623 | 150 | 1.20 | 4.0 | 40 | TO-220 | ||
| STH33N20FI | 200 | 0.085 | 20.0 | 70 | ISOWATT220 | ||
| SGSP577 | 200 | 0,17 | 20,0 | 150 | TO-3 | ||
| SGSP477 | 200 | 0,17 | 20,0 | 150 | TO-218 | ||
| 8UZ34 | 200 | 0,20 | 19,0 | 150 | TO-3 | ||
| SGSP367 | 200 | 0,33 | 12,0 | 100 | TO-220 | ||
| BUZ32 | 200 | 0,40 | 9,5 | 75 | TO-220 | ||
| SGSP317 | 200 | 0,75 | 6,0 | 75 | TO-220 | ||
| IRF620FI | 200 | 0,80 | 4,0 | 30 | ISOWATT220 | ||
| IRF620 | 200 | 0,80 | 5,0 | 40 | TO220 | ||
| IRF622FI | 200 | 1.20 | 3,5 | 30 | ISOWATT220 | ||
| IRF622 | 200 | 1.20 | 4,0 | 40 | TO-220 | ||
| IRF741FI | 350 | 0.55 | 5,5 | 40 | ISOWATT220 | ||
| IRF741 | 350 | 0,55 | 10,0 | 125 | TO-220 | ||
| IRF743 | 350 | 0.80 | 8,3 | 125 | TO-220 | ||
| IRF731FI | 350 | 1,00 | 3,5 | 35 | ISOWATT220 | ||
| IRF731 | 350 | 1,00 | 5,5 | 75 | TO-220 | ||
| IRF733FI | 350 | 1,50 | 3,0 | 35 | ISOWATT220 | ||
| IRF733 | 350 | 1,50 | 4.5 | 75 | TO-220 | ||
| IRF721FI | 350 | 1,80 | 2.5 | 30 | ISOWATT220 | ||
| IRF721 | 350 | 1,80 | 3.3 | 50 | TO-220 | ||
| IRF723FI | 350 | 2,50 | 2,0 | 30 | ISOWATT220 | ||
| IRF723 | 350 | 2,50 | 2,8 | 50 | TO-220 | ||
| IRFP350FI | 400 | 0,30 | 10,0 | 70 | ISOWATT218 | ||
| IRF350 | 400 | 0,30 | 15,0 | 150 | TO-3 | ||
| IRFP350 | 400 | 0,30 | 16,0 | 180 | TO-218 | ||
| IRF740FI | 400 | 0,55 | 5,5 | 40 | ISOWATT220 | ||
| IRF740 | 400 | 0,55 | 10,0 | 125 | TO-220 | ||
| SGSP475 | 400 | 0,55 | 10,0 | 150 | TO-218 | ||
| IRF742FI | 400 | 0,80 | 4,5 | 40 | ISOWATT220 | ||
| IRF742 | 400 | 0,80 | 8,3 | 125 | TO-220 | ||
| IRF730FI | 400 | 1,00 | 3,5 | 35 | ISOWATT220 | ||
| BUZ60 | 400 | 1,00 | 5,5 | 75 | TO-220 | ||
| IRF730 | 400 | 1,00 | 5,5 | 75 | TO-220 | ||
| IRF732FI | 400 | 1,50 | 3,0 | 35 | ISOWATT220 | ||
| BUZ60B | 400 | 1,50 | 4,5 | 75 | TO-220 | ||
| IRF732 | 400 | 1,50 | 4,5 | 75 | TO-220 | ||
| IRF720FI | 400 | 1,80 | 2,5 | 30 | ISOWATT220 | ||
| BUZ76 | 400 | 1,80 | 3,0 | 40 | TO-220 | ||
| IRF720 | 400 | 1,80 | 3,3 | 50 | TO-220 | ||
| IRF722FI | 400 | 2,50 | 2,0 | 30 | ISOWATT220 | ||
| BUZ76A | 400 | 2,50 | 2,6 | 40 | TO-220 | ||
| IRF722 | 400 | 2,50 | 2,8 | 50 | TO-220 | ||
| SGSP341 | 400 | 20,0 | 0,6 | 18 | TO-220 | ||
| IRFP451FI | 450 | 0,40 | 9,0 | 70 | ISOWATT218 | ||
| IRF451 | 450 | 0,40 | 13,0 | 150 | TO-3 | ||
| IRFP451 | 450 | 0,40 | 14,0 | 180 | TO-218 | ||
| IRFP453FI | 450 | 0,50 | 8,0 | 70 | ISOWATT218 | ||
| IRF453 | 450 | 0,50 | 11,0 | 150 | TO-3 | ||
| IRFP453 | 450 | 0,50 | 12,0 | 180 | TO-218 | ||
| SGSP474 | 450 | 0,70 | 9,0 | 150 | TO-218 | ||
| IRF841FI | 450 | 0,85 | 4,5 | 40 | ISOWATT220 | ||
| IF841 | 450 | 0.85 | 8,0 | 125 | TO-220 | ||
| IRFP441FI | 450 | 0,85 | 5,5 | 60 | ISOWATT218 | ||
| IRF843FI | 450 | 1,10 | 4,0 | 40 | ISOWATT220 | ||
| IRF843 | 450 | 1,10 | 7,0 | 125 | TO-220 | ||
| IRF831FI | 450 | 1,50 | 3,0 | 35 | ISOWATT220 | ||
| IRF831 | 450 | 1,50 | 4,5 | 75 | TO-220 | ||
| SGSP364 | 450 | 1,50 | 5,0 | 100 | TO-220 | ||
| IRF833FI | 450 | 2,00 | 2,5 | 35 | ISOWATT220 | ||
| IRF833 | 450 | 2,00 | 4,0 | 75 | T0220 | ||
| IRF821FI | 450 | 3,00 | 2,0 | 30 | ISOWATT220 | ||
| IRF821 | 450 | 3,00 | 2,5 | 50 | TO-220 | ||
| SGSP330 | 450 | 3,00 | 3,0 | 75 | TO-220 | ||
| IRF823FI | 450 | 4,00 | 1.5 | 30 | ISOWATT220 | ||
| IRF823 | 450 | 4,00 | 2,2 | 50 | TO-220 | ||
| IRFP450FI | 500 | 0,40 | 9,0 | 70 | ISOWATT218 | ||
| IRF450 | 500 | 0,40 | 13,0 | 150 | TO-3 | ||
| IRFP450 | 500 | 0,40 | 14,0 | 180 | TO-218 | ||
| IRFP452FI | 500 | 0,50 | 8,0 | 70 | ISOWATT218 | ||
| IRF452 | 500 | 0,50 | 11,0 | 150 | TO-3 | ||
| IRFP4S2 | 500 | 0,50 | 12,0 | 180 | TO-218 | ||
| BUZ353 | 500 | 0,60 | 9,5 | 125 | TO-218 | ||
| BUZ45 | 500 | 0,60 | 9,6 | 125 | TO-3 | ||
| SGSP579 | 500 | 0,70 | 9,0 | 150 | TO-3 | ||
| SGSP479 | 500 | 0,70 | 9.0 | 150 | TO-218 | ||
| BU2354 | 500 | 0,80 | 8,0 | 125 | TO-218 | ||
| BUZ45A | 500 | 0,80 | 8,3 | 125 | TO-3 | ||
| IRF840FI | 500 | 0,85 | 4,5 | 40 | ISOWATT220 | ||
| IRF840 | 500 | 0,85 | 8,0 | 125 | TO-220 | ||
| IRFP440FI | 500 | 0,85 | 5,5 | 60 | ISOWATT218 | ||
| IRF842FI | 500 | 1,10 | 4,0 | 40 | ISOWATT220 | ||
| IRF842 | 500 | 1.10 | 7,0 | 125 | TO-220 | ||
| IRF830FI | 500 | 1,50 | 3,0 | 35 | ISOWATT220 | ||
| BUZ41A | 500 | 1,50 | 4,5 | 75 | TO-220 | ||
| IRF830 | 500 | 1,50 | 4,5 | 75 | TO-220 | ||
| SGSP369 | 500 | 1,50 | 5,0 | 100 | TO-220 | ||
| IRF832FI | 500 | 2,00 | 2,5 | 35 | ISOWATT220 | ||
| BUZ42 | 500 | 2,00 | 4,0 | 75 | TO-220 | ||
| IRF832 | 500 | 2,00 | 4,0 | 75 | TO-220 | ||
| IRF820FI | 500 | 3,00 | 2,0 | 30 | ISOWATT220 | ||
| BUZ74 | 500 | 3,00 | 2,4 | 40 | TO-220 | ||
| IRF820 | 500 | 3,00 | 2,5 | 50 | TO-220 | ||
| SGSP319 | 500 | 3,80 | 2,8 | 75 | TO-220 | ||
| IRF322FI | 500 | 4,00 | 1,5 | 30 | ISOWATT220 | ||
| BUZ74A | 500 | 4,00 | 2,0 | 40 | TO-220 | ||
| IRF822 | 500 | 4,00 | 2,2 | 50 | TO-220 | ||
| SGSP368 | 550 | 2,50 | 5,0 | 100 | TO-220 | ||
| MTH6N60FI | 600 | 1,20 | 3.5 | 40 | ISOWATT218 | ||
| MTP6N60FI | 600 | 1,20 | 6,0 | 125 | ISOWATT220 | ||
| MTP3N60FI | 600 | .2,50 | 2,5 | 35 | I30WATT220 | ||
| MTP3N60 | 600 | 2,50 | 3,0 | 75 | TO-220 | ||
| STH9N80FI | 800 | 1,00 . | 5,6 | 70 | ISOWATT218 | ||
| STH9N80 | 800 | 1,00 | 9,0 | 180 | TO-218 | ||
| STH8N80FI | 800 | 1,20 | 5,0 | 70 | ISOWATT218 | ||
| STH8N80 | 800 | 1,20 | 8.0 | 180 | TO-218 | ||
| STHV82FI | 800 | 2,00 | 3,5 | 65 | ISOWATT218 | ||
| STHV82 | 800 | 2,00 | 5,5 | 125 | TO-218 | ||
| BUZ80AFI | 800 | 3,00 | 2,4 | 40 | ISOWATT220 | ||
| BUZ80A | 800 | 3,00 | 3,8 | 100 | TO-220 | ||
| BUZ80FI | 800 | 4,00 | 2,0 | 35 | ISOWATT220 | ||
| BUZ80 | 800 | 4,00 | 2,6 | 75 | TO-220 | ||
| STH6N100FI | 1000 | 2,00 | 3,7 | 70 | ISOWATT218 | ||
| STH6N100 | 1000 | 2,00 | 6,0 | 180 | TO-218 | ||
| STHV102FI | 1000 | 3,50 | 3,0 | 65 | ISOWATT218 | ||
| STHV102 | 1000 | 3,50 | 4,2 | 125 | TO-218 | ||
| SGS100MA010D1 | 100 | 0,014 | 50 | 120 | TO-240 | ||
| SGS150MA010D1 | 100 | 0,009 | 75 | 150 | TO-240 | ||
| SGS30MA050D1 | 500 | 0,20 | 15 | 30 | TO-240 | ||
| SGS35MA050D1 | 500 | 0,16 | 17,5 | 35 | TO-240 | ||
| TSD200N05V | 50 | 0,006 | 200 | 600 | Isotop | ||
| TSD4M150V | 100 | 0,014 | 70 | 135 | Isotop | ||
| TSD4M251V | 150 | 0,021 | 70 | 110 | Isotop | ||
| TSD4M250V | 200 | 0,021 | 60 | 110 | Isotop | ||
| TSD4M351V | 350 | 0,075 | 30 | 50 | Isotop | ||
| TSD4M350V | 400 | 0,075 | 30 | 50 | Isotop | ||
| TSD4M451V | 450 | 0,1 | 28 | 45 | Isotop | ||
| TSD2M450V | 500 | 0,2 | 26 | 100 | Isotop | ||
| TSD4M450V | 500 | 0,1 | 28 | 45 | Isotop | ||
| TSD22N80V | 800 | 0,4 | 22 | 77 | Isotop | ||
| TSD5MG40V | 1000 | 0,7 | 9 | 17 | Isotop |
The field effect transistor can be checked for serviceability with a multimeter in the mode P-N testing diode transitions. The resistance value shown by the multimeter at this limit is numerically equal to the forward voltage at P-N junction in millivolts. A working transistor should have infinite resistance between all its terminals. But some modern high-power field-effect transistors have a built-in diode between the drain and source, so it happens that the drain-source channel behaves like a regular diode when tested. Use the black (negative) probe to touch the drain (D), and the red (positive) probe touch the source (S). The multimeter shows the forward voltage drop across the internal diode (500 - 800 mV). In reverse bias, the multimeter should show infinite resistance, the transistor is closed. Next, without removing the black probe, touch the red probe to the gate (G) and again return it to the source (S). The multimeter shows 0 mV, and with any polarity of the applied voltage, the field-effect transistor opened by touch. If you now touch the gate (G) with the black probe, without releasing the red probe, and return it to the drain (D), the field-effect transistor will close and the multimeter will again show the voltage drop across the diode. This is true for most N-channel FETs.
In technology and amateur radio practice, field-effect transistors are often used. Such devices differ from conventional bipolar transistors in that in them the output signal is controlled by a control electric field. Insulated gate field effect transistors are especially often used.
The English designation for such transistors is MOSFET, which means “field-controlled metal-oxide semiconductor transistor.” In the domestic literature, these devices are often called MOS or MOS transistors. Depending on the manufacturing technology, such transistors can be n- or p-channel.
An n-channel type transistor consists of a silicon substrate with p-conductivity, n-regions obtained by adding impurities to the substrate, and a dielectric that insulates the gate from the channel located between the n-regions. The pins (source and drain) are connected to the n-regions. Under the influence of a power source, current can flow from source to drain through the transistor. The magnitude of this current is controlled by the insulated gate of the device.
When working with field-effect transistors, it is necessary to take into account their sensitivity to the effects of an electric field. Therefore, they must be stored with the terminals short-circuited with foil, and before soldering, the terminals must be short-circuited with a wire. Field-effect transistors must be soldered using a soldering station, which provides protection against static electricity.
Before you start checking the serviceability of the field-effect transistor, you need to determine its pinout. Often, on an imported device, marks are applied that identify the corresponding terminals of the transistor.
The letter G denotes the gate of the device, the letter S the source, and the letter D the drain.
If there is no pinout on the device, you must look it up in the documentation for this device.
Circuit for checking an n-channel field-effect transistor with a multimeter
Before checking the serviceability of the field-effect transistor, it is necessary to take into account that in modern MOSFET-type radio components there is an additional diode between the drain and the source. This element is usually present on the device diagram. Its polarity depends on the type of transistor.
General rules that is, they say to begin the procedure by determining the performance of the measuring device itself. Having made sure that it works flawlessly, they move on to further measurements.
Conclusions:
- MOSFET field-effect transistors are widely used in technology and amateur radio practice.
- The performance of such transistors can be checked using a multimeter, following a certain method.
- Testing a p-channel field-effect transistor with a multimeter is carried out in the same way as an n-channel transistor, except that the polarity of the multimeter leads should be reversed.
Video on how to test a field-effect transistor
A transistor is a semiconductor electronic component. We refer it to active elements circuits because it allows electrical signals to be converted (nonlinearly).
Field or MOSFET(Metal-Oxide Semiconductor Field-Effect Transistor) - field-effect transistor with a metal-oxide-semiconductor structure. Therefore, it is often also called simply a MOS transistor.
Transistors produced using this technology consist of three layers:
- The first layer is a wafer cut from a homogeneous silicon crystal or from silicon doped with germanium.
- The second layer in order is the spraying of a very thin layer of dielectric (insulator) made of silicon dioxide or metal oxide (aluminum or zirconium oxides). The thickness of this layer is, depending on the technology, about 10 nm, and in the best option the thickness of this layer can be about 1.2 nm. For comparison: 5 silicon atoms located close to each other make up a thickness close to 1.2 nm.
- The third layer is a layer consisting of a highly conductive metal. Gold is most often used for this purpose.
The design of such a transistor is shown schematically below:
It should be noted that field effect transistors come in two types: N-type and P-type, much the same as is the case with bipolar transistors, which are produced in PNP and NPN variants.
Among field-effect transistors, N-type is much more common. In addition, there are field-effect transistors:
- with a depletion channel, that is, those that pass a weak current through themselves in the absence of voltage on the gate, and in order to completely block it, it is necessary to apply a reverse bias of a couple of volts to the gate;
- with an enriched channel - this is a type of field-effect transistor that, in the absence of voltage at the gate, does not conduct current, but conducts it only when the voltage applied to the gate exceeds the source voltage.
The big advantage of FETs is that they are voltage controlled, unlike bipolar transistors, which are current controlled.
It is easier to understand the principle of their operation of a field-effect transistor using the example of a hydraulic crane.
To control the flow of high pressure fluid in a large pipe, little effort is required to open or close the valve. In other words, with a small amount of work, we get a big effect. The small force we apply to the faucet handle controls a much greater force of water, which presses on the valve.
Thanks to this property of field-effect transistors, we can control currents and voltages that are much higher than those that are given to us, for example, by a microcontroller.
As noted earlier, a conventional MOSFET, as a rule, does not conduct current in the source-drain path. To transfer such a transistor to the conductive state, it is necessary to apply a voltage between the source and the gate as shown in the figure below.
The following figure shows the current-voltage characteristic of the IRF540 transistor.
The graph shows that the transistor begins to conduct when the voltage between the gate and source approaches 4V. However, almost 7 volts are needed to fully open. This is much more than the microcontroller can output.
In some cases, a current of 15 mA and a voltage of 5V may be sufficient. But what if it's too little? There are two ways out.
- You can use special MOSFETs with reduced gate-source voltage, for example, BUZ10L.
- Alternatively, you can use an additional amplifier to increase the control voltage.
Regardless of the scope of application, each field-effect transistor has several key parameters, namely:
- Allowable drain-source voltage: UDSmax
- Maximum drain current: IDmax
- Opening threshold voltage: UGSth
- On-state channel resistance: RDSon
In many cases, RDSon is a key parameter, since it indirectly indicates to us a loss of power, which is extremely undesirable.
For example, let’s take a transistor in a TO-220 package with a resistance of RDSon = 0.05 Ohm and a current of 4A flowing through this transistor.
Let's calculate the power losses:
- UDS=0.05Ohm x 4A=0.2V
- P=0.2V x 4A=0.8W
The power loss that a transistor in a TO-220 package can dissipate is just over 1 W, so in this case you can do without a radiator. However, already for a current of 10A the losses will be 5W, so there is no way to do without a radiator.
Therefore, the smaller the RDSon, the better. Therefore, when selecting a MOSFET transistor for a specific application, this parameter should always be taken into account.
In practice, with increasing permissible voltage UDSmax increases source-drain resistance. For this reason, transistors with a UDSmax greater than that required should not be selected.
MOP (in bourgeois MOSFET) stands for Metal-Oxide-Semiconductor, from this abbreviation the structure of this transistor becomes clear.
If on the fingers, then it has a semiconductor channel that serves as one plate of the capacitor and the second plate is a metal electrode located through a thin layer of silicon oxide, which is a dielectric. When voltage is applied to the gate, this capacitor is charged, and the electric field of the gate pulls charges to the channel, as a result of which mobile charges appear in the channel that can form an electric current and the drain-source resistance drops sharply. The higher the voltage, the more charges and lower the resistance, as a result, the resistance can drop to tiny values - hundredths of an ohm, and if you raise the voltage further, a breakdown of the oxide layer and the Khan transistor will occur.
The advantage of such a transistor, compared to a bipolar one, is obvious - voltage must be applied to the gate, but since it is a dielectric, the current will be zero, which means the required the power to control this transistor will be scanty, in fact, it only consumes at the moment of switching, when the capacitor is charging and discharging.
The disadvantage arises from its capacitive property - the presence of capacitance on the gate requires a large charging current when opening. In theory, equal to infinity on infinitely small periods of time. And if the current is limited by a resistor, then the capacitor will charge slowly - there is no escape from the time constant of the RC circuit.
MOS transistors are P and N duct. They have the same principle, the only difference is the polarity of the current carriers in the channel. Accordingly, in different directions of the control voltage and inclusion in the circuit. Very often transistors are made in the form of complementary pairs. That is, there are two models with exactly the same characteristics, but one of them is N channel, and the other is P channel. Their markings, as a rule, differ by one digit.
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My most popular MOP transistors are IRF630(n channel) and IRF9630(p channel) at one time I made about a dozen of them of each type. Possessing a not very large body TO-92 this transistor can famously pull through itself up to 9A. Its open resistance is only 0.35 Ohm.
However, that's quite old transistor, now there are cooler things, for example IRF7314, capable of carrying the same 9A, but at the same time it fits into an SO8 case - the size of a notebook square.
One of the docking problems MOSFET transistor and microcontroller (or digital circuit) is that in order to fully open until completely saturated, this transistor needs to drive quite a bit more voltage onto the gate. Usually this is about 10 volts, and the MK can output a maximum of 5.
There are three options:
But in general, it is more correct to install a driver, because in addition to the main functions of generating control signals, it also provides current protection, protection against breakdown, overvoltage, as an additional bauble, optimizes the opening speed to the maximum, in general, it does not consume its current in vain. Choosing a transistor is also not very difficult, especially if you don’t bother with limiting modes. First of all, you should be concerned about the value of the drain current - I Drain or I D you choose a transistor based on the maximum current for your load, preferably with a margin of 10 percent. The next important parameter for you is VGS- Source-Gate saturation voltage or, more simply, control voltage. Sometimes it is written, but more often you have to look at the charts. Looking for a graph of the output characteristic Dependency I D from VDS at different values VGS. And you figure out what kind of regime you will have.
For example, you need to power the engine at 12 volts, with a current of 8A. You screwed up the driver and only have a 5 volt control signal. The first thing that came to mind after this article was IRF630. The current is suitable with a margin of 9A versus the required 8. But let’s look at the output characteristic:
If you are going to use PWM on this switch, then you need to inquire about the opening and closing times of the transistor, choose the largest one and, relative to the time, calculate the maximum frequency of which it is capable. This quantity is called Switch Delay or t on,t off, in general, something like this. Well, the frequency is 1/t. It’s also a good idea to look at the gate capacity C iss Based on it, as well as the limiting resistor in the gate circuit, you can calculate the charging time constant of the RC gate circuit and estimate the performance. If the time constant is greater than the PWM period, then the transistor will not open/close, but will hang in some intermediate state, since the voltage at its gate will be integrated by this RC circuit into a constant voltage.
When handling these transistors, keep in mind the fact that They are not just afraid of static electricity, but VERY STRONG. It is more than possible to penetrate the shutter with a static charge. So how did I buy it? immediately into foil and don’t take it out until you seal it. First ground yourself to the battery and put on a foil hat :).