Metal Can type IC opamp & Transistors VS plastic type IC opamp & transistors

[dextermccoy]

Metal Can type IC opamp & Transistors VS plastic type IC opamp & transistors

What is the difference or advantage of using Metal Can type transistor, rather using black ceramic or plastic type transistors?

The Metal Can type transistor chassis can have it connected to ground or +VCC , this can cause problems when the metal can's chassis touches the PCB board traces which cause a short

- - - Updated - - -

How does the metal can type transistor have better shielding properties? and thermal properties?

Is this the advantage over plastic package type transistors? plastic dual inline package IC op amps or transistors

They make Metal can IC op amps up to 10 pins

But why would a designer choose the metal can op amps and transistors over the plastic transistor and ic op amps?

 

[kam1787]

Re: Metal Can type IC opamp & Transistors VS plastic type IC opamp & transistors

metal can dissipate more heat and is shielded

 

[Analog Ground]

Re: Metal Can type IC opamp & Transistors VS plastic type IC opamp & transistors

For ICs, such as op amps, the metal can package (such as TO-99) is becoming vdery uncommon. Metal cans are associated with special, high reliability parts. I suppose for transistors, they offer a particular type of heat sink to be used. A major disadvantage of any metal can part is not being surface mounted. I will bet there are many designers who have not used a metal can in many years. Cans are definitely "old school". OK, bring it on now that I said it...

 

[dextermccoy]

Re: Metal Can type IC opamp & Transistors VS plastic type IC opamp & transistors

Why can they dissipate more heat? The metal can is a heat sink?
how are they shielded? what is doing the shielding?And plastic aren't

- - - Updated - - -

The shielding helps with transistor oscillations and emf noises or iinterference noises? Why does these signals leak into the plastic transistors and not the metal can types

 

[kam1787]

Re: Metal Can type IC opamp & Transistors VS plastic type IC opamp & transistors

usually the surface area is larger and metal is a better conductor of heat than plastic

 

[Analog Ground]

Re: Metal Can type IC opamp & Transistors VS plastic type IC opamp & transistors

Heat sinking is all about getting heat from the chip or die to an external metal part of the package. The classic can such as a TO-99 has a problem with this requirement. The die is mounted on an insulating plate which has pins passing through it. The die is not mounted on a metal tab or plate such as with a TO-220 or surface mount packages with metal tabs. Just because a part is enclosed in metal, it does not mean the heat can get out! Look at the detailed mechanical design.

Metal cans used to offer the best hermetic seal and were good for harsh environments. Modern plastic packages are much better now and the case for metal gets weaker and weaker. Again, cans are mostly only in special high reliability parts.

 

[dextermccoy]

Re: Metal Can type IC opamp & Transistors VS plastic type IC opamp & transistors

The problem with laying the metal cans flat on the PCB board is that the metal can will short or cause shorts on the traces its laying on top, what can I use under it to be an insulator, we use transistor spacers which are hard to find

- - - Updated - - -

Why can metal can trans. Take harsh environments better? U mean temperature climates?

 

[kam1787]

Re: Metal Can type IC opamp & Transistors VS plastic type IC opamp & transistors

I 'always' mount components on the non-copper side.

 

[dextermccoy]

Re: Metal Can type IC opamp & Transistors VS plastic type IC opamp & transistors

But its double side PCB traces, what would u guys do?

 

[kam1787]

Re: Metal Can type IC opamp & Transistors VS plastic type IC opamp & transistors

I reckon you could either
1) space out the PCB holes so the transistor could not be inserted all the way down
or
2) make your own insulators - make a template from stiff paper with arc's of sufficient diameter, and holes for the transistor leads, then get a sheet of appropriate plastic, mark out the plastic using the template, then drill and punch