Transistor packages are the styles of the case used to house transistor components, providing the connection between the internal and the external circuit, as well as protection for the delicate internal part and perhaps capacity for removal of heat via heatsinks to avoid thermal damage.
Standards for transistor packages are, "TO" (transistor outline); other standards sometimes use "SOT" (small-outline transistor) for surface mount devices.
| TO | SOT |
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The transistor packages are varied according to their applications, low power transistor packages will be different from the packaging of the high power transistor.
Low power transistor packaging is made of plastic material having a characteristic surface that is flat, while those made of metal have a protrusion (tag) on the plate underneath.
Transistors with a higher power, are usually made of plastic packaging, metal, or a mixture of plastic and metal. Metals in the body transistor generally signify a collector terminal and specialized in high power transistors, the metal tag is useful for attaching a heat sink or appliance exhaust heat dissipation that occurs during the process.
"TO" SERIES
The transistor outline (TO) package family consists of many types of packaging solutions for transistors and similar discrete devices as well as simple IC's with low pin counts. The structures of TO packages varies widely, from metal can enclosures to low-cost plastic-molded package bodies
Transistors are available in various packages such as TO-3, TO-5, TO-8, TO-18, TO-36, TO-39, TO-46, TO-52, TO-66, TO-72, TO-92, TO-126, TO-202, TO-218, TO-220, TO-226, TO-254, TO-257, TO-258, TO-259, TO-264, and TO-267.
TO-92 Package
The TO-92 is a small type of plastic-molded package. It has a flat front face that is marked with the device name or number, while its back is semi-circular in shape. Since it is most often used in transistor packaging, the TO-92 usually has three leads, all of which come out from the bottom of the package.
The main advantage of the TO-92 package is its small size. Unfortunately, this small size means that it is not designed to dissipate much heat and can not be used on devices that have high power consumption
Properties of a Typical TO-92
|
Plastic Body Size (H x W) |
Body Thickness |
Lead Width |
Lead Thickness |
Lead Length |
|
4.58 mm x 4.58 mm |
3.86 mm |
0.46 mm |
0.38 mm |
14.47 mm |
Common Transistors in a TO-92 package:
BC547, general-purpose NPN transistor
BC548, general-purpose NPN transistor
BC558, general-purpose PNP transistor
2N3904, general-purpose NPN transistor
2N3906, general purpose PNP transistor
2N7000, N-channel FET
BS170, N-channel FET
PN2222A, a "plastic" version of the original 2N2222
J3Y Transistor S8050 NPN SOT-23 SMD 0.5A 40V Transistor
TO-18 Package
The TO-18 is a type of 'metal can' (also known as 'metal header') package for semiconductor devices. It is sealed hermetically to protect the device from environmental factors such as moisture and contaminants. The TO-18 looks like a TO-46 but it is slightly bigger than the latter because of its taller cap.
Terminal identification; Pin 1 Emitter, Pin 2 Base, Pin 3 Collector. The Collector is internally connected to the case.
Properties of a Typical 3-lead TO-18 Package
|
Base Diameter |
Cap Diameter |
Cap Height |
Min. Lead Length |
Max. Lead Pitch |
|
5.5 mm |
4.7 mm |
4.8 mm |
12.7 mm |
2.97 mm |
Common transistors in a TO-18 package:
2N2222A or 2N3960 NPN Transistor, a 2N2646 UJT or 2N4091, 2N4092, 2N4093 FETs.
NPN Low-Power Transistor, 2N2484
PNP Switching Transistor, 2N4029, 2N4209
P-Channel Field Effect Transistor, 2N5114, 2N5115, 2N5116
N-Channel Field Effect Transistor, 2N7002
Photo-transistors [lensed TO-18 package], CLT130, CLT131, CLT132 and CLT133
N-Channel FET; 2N4856, 2N4857, 2N4858, 2N4859, 2N4860, 2N4861
N-Channel FET; 2N4091, 2N4092, 2N4093
TO-220 package
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The metal tab at the back of the TO-220 serves as a heat sink itself, but it has a hole so that it can be screwed onto a larger heat sink if higher power handling capability is required.
A typical TO-220 package can have 2 to 7 leads, although TO-220's with 3 leads are most commonly encountered because this package is primarily used on three-terminal devices such as transistors. The typical lead pitch (distance between leads) of a TO-220 package is 2.54 mm.
Properties of a Typical TO-220
|
Body Size (HxW) excl. Metal Tab |
Body Size (HxW)incl. Metal Tab |
Body Thickness |
Metal Tab Thickness |
Lead Length |
|
9.2 mm x 9.9 mm |
15.7 mm x 9.9 mm |
4.5 mm |
1.3 mm |
13.1 mm |
Common transistors that use the TO-220 package
The TO-220 case is found on semiconductor devices handling less than 100 amperes and operating at less than a few hundred volts. These devices operate at DC or relatively low (audio) frequencies so, the TO-220 package is not intended for devices operating at radio frequencies. In addition to bipolar, bipolar Darlington, and power MOSFET transistors.
- TIP31C NPN Bipolar Transistor
- IRFP460 N-Channel Power MOSFET
- IRFZ14 N Channel Power MOSFET
- STP40NF10L N Channel Power MOSFET
- P55NF06 N-Channel Power MOSFET
- IRFZ44N N-Channel Power MOSFET
- IRF1405 N-Channel Power MOSFET
- IRF4905 P-Channel Power MOSFET
- IRF5305 P-Channel Power MOSFET
- IRF9520 P-Channel Power MOSFET
- IRF9530 P-Channel Power MOSFET
- IRF5210 P Channel Power MOSFET
- IRF9533 P Channel Power MOSFET
TO-3 Package
The TO-3 or TO3 is a type of 'metal can' package that is capable of high-power dissipation commonly used by power transistors, SCR's and other high-power semiconductor devices.
The TO-3 is made entirely of metal, with the microchip mounted on its metal can base and then covered with a metal cap. TO-3 packages are designed to accommodate large heat sinks to increase their power handling capability.
A typical power transistor packaged in a TO-3 package has two protruding terminals (one for the base and the other for the emitter), with the collector using the TO-3's body itself as its terminal for direct thermal conduction to the heat sink.
Advantages of the TO-3 package include
- Excellent power handling capability,
- High durability,
- Ease of mounting
- Hermetic sealing that protects the chip from environmental factors.
Properties of a Typical TO-3
|
Base Size (Length x Width x Thickness) |
Cap Diameter |
Cap Height |
Lead Length |
Lead Pitch |
|
39.3 mm x 26.6 mm x 1.7 mm |
22.2 mm |
5.7 mm |
11.7 mm |
10.9 mm |
Common transistors that use the TO-3 package
TO-3 Transistor Types [3-Pin];
NPN Power Transistor 2N3055, 2N5685, 2N5686, 2N6306, 2N6308, 2N6249, 2N6250, 2N6251, 2N6274, 2N6277, 2N6032, 2N6033, 2N6676, 2N6678, 2N6546, KD503
NPN High-Power Transistor 2N3715, 2N3716, 2N3771, 2N3772, 2N5038, 2N5039, 2N5302, 2N5303
NPN Power Darlington Transistor 2N6058, 2N6059, 2N7569, 2N7570, and 2N7571
PNP High-Power Transistor 2N4399, 2N5745, 2N2955
PNP Power Transistor 2N5683, 2N5684, 2N6378 and 2N6379, BU208
PNP Power Darlington Transistor 2N6286, 2N6287, 2N6648, 2N6649, 2N6650
Small Outline Transistor (SOT)
| SOT-523 | SOT-323 | SOT-23 |
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Small Outline Transistor (SOT) packages are very small, surface-mount plastic-molded packages with leads on their two long sides. Due to their low profile, SOT's are widely used in consumer electronics.
SOT-23 Package
The SOT-23 or TO-236AB package is a 3-terminal plastic surface mount component.
A similar package style is the TO-236AA SMD Transistor
SOT-23 is used for small-signal transistors and measures 2.9 mm x 2.4 mm x 1.1 mm.
Because the SOT-23 is a Surface Mount Device [SMD] heat transfer will also be conducted via the component leads.
The text above indicates that this package is used by either transistors or FETs but almost any two or three-terminal semiconductor could use this package: Thyristors, IGBTs, and so on. Because of the package size, the SOT-23 is a low current device
Common transistors that use the SOT-23 package
BC857, S8550, BC817, BC847B, SI2302, BFR540, BFR106, BAP70-05, BFR505, BFT25, BF512, BF513, BF510, BF511, BBY40, BFR94A, BAP65-05, PBR941B, BAT18, PBR941, BAP50-05, BF556C, BAP50-04, BF556B, BFR30, BFR31, PMBFJ113, PMBFJ111, PMBFJ112, PMBFJ310, BB201, BAP64-06, BAP64-05, BFR93AR, BAP64-04, BFS17, BB207, BFR93A, BF556A, PMBFJ110, PBR951, BF545C, KTY82, BAP1321-04, BF545B, BFR520, PMBFJ308, PMBFJ309, BSR57, PMBFJ108, PMBFJ109, BSR12, BSR56, BFS17A, BSR58, BFQ67, BFT46, BFU530A, BFU550A, BFR92A, BF545A, BF861C, BFR92, BF861A, BF861B, PMBF4391, PMBF4392, BFT93, BFT92, PMBF4393, BFU520A, BFT25A
SOT89-3 Package
The SOT89-3 electrically only has three leads. The wide lead (tab) is physically part of the middle lead on the other side of the package.
Surface-mounted package; 3 leads; 1.5 mm pitch; 4.5 mm x 2.5 mm x 1.5 mm body
Common transistors that use the SOT89-3 package
BFU580Q, BFU590Q, BGA7024, BGA6289, BGA6489, BGA7027, BGA6589, BGA3018, BGA3015, BFQ18A, BGA3012, BFQ19, BFQ149, BFQ540, BFQ591
BCX53, BCX53-10T, PBHV9540X, 2SAR375P5, BCX52T, BCX51T, 2SB1189, ZX5 T3Z, 2DA1213YQ, DXT751Q, BC869, FCX591AQ, 2SB1561, 2SAR553P5, BSR33
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POWER TRANSISTORS
General Purpose Transistor
Triac & Mosfet
1 comment
Ovidiu
Hello. I have a transistor in a case TO92 but it has also a small piece of metal aprox 2×5×0,5 mm as a heater which come from inside of the case. What type of case is this? Thank you O.Z.