Device Encapsulations...

C

Cursitor Doom

Guest
Gentlemen,

I\'ve come across an RF transistor which seems to be available in 3
very different ecapsulations. I\'ll use these links from Ebay for
simplicity and hope they\'re still up by the time anyone reads this.
:)

The first case appears to be based on the TO-220 dimensionos but
appears to be all plastic:

https://tinyurl.com/yfnfchtk

The second is what I would typically expect to see an RF transistor
encased with:

https://tinyurl.com/2p9z3r67

The final one is a conventional TO-220 with metal heat sink.

https://tinyurl.com/32kjhnt3

The optimal casing is number 2, offering good thermal conductivity
away from the device plus low parasitics.

The one with the conventional TO-220 provides heat sinking adequate
for a device of this power rating, but is not so good on the
parasitics. Fortunately these are only used up to about 30Mhz so
presumably get-away-with-able.

I don\'t know what to make of the all plastic encapsulation, which
seems to have nothing to recommend it. Any comments?
Datasheet here: https://disk.yandex.com/i/bgTMTk49ktGrSw
 
Cursitor Doom <cd@notformail.com> Wrote in message:r
> Gentlemen,I\'ve come across an RF transistor which seems to be available in 3very different ecapsulations. I\'ll use these links from Ebay forsimplicity and hope they\'re still up by the time anyone reads this.:)The first case appears to be based on the TO-220 dimensionos butappears to be all plastic:https://tinyurl.com/yfnfchtkThe second is what I would typically expect to see an RF transistorencased with:https://tinyurl.com/2p9z3r67The final one is a conventional TO-220 with metal heat sink.https://tinyurl.com/32kjhnt3The optimal casing is number 2, offering good thermal conductivityaway from the device plus low parasitics. The one with the conventional TO-220 provides heat sinking adequatefor a device of this power rating, but is not so good on theparasitics. Fortunately these are only used up to about 30Mhz sopresumably get-away-with-able.I don\'t know what to make of the all plastic encapsulation, whichseems to have nothing to recommend it. Any comments?Datasheet here: https://disk.yandex.com/i/bgTMTk49ktGrSw

That\'s a isolated to220, you dont need a mica insulator and
ceramic washer.
If your worried about thermals the use th rf power package.

There are newer rf parts you know.

Cheers
--


----Android NewsGroup Reader----
https://piaohong.s3-us-west-2.amazonaws.com/usenet/index.html
 
On Thu, 17 Nov 2022 15:18:40 -0500 (EST), Martin Rid
<martin_riddle@verison.net> wrote:

Cursitor Doom <cd@notformail.com> Wrote in message:r
Gentlemen,I\'ve come across an RF transistor which seems to be available in 3very different ecapsulations. I\'ll use these links from Ebay forsimplicity and hope they\'re still up by the time anyone reads this.:)The first case appears to be based on the TO-220 dimensionos butappears to be all plastic:https://tinyurl.com/yfnfchtkThe second is what I would typically expect to see an RF transistorencased with:https://tinyurl.com/2p9z3r67The final one is a conventional TO-220 with metal heat sink.https://tinyurl.com/32kjhnt3The optimal casing is number 2, offering good thermal conductivityaway from the device plus low parasitics. The one with the conventional TO-220 provides heat sinking adequatefor a device of this power rating, but is not so good on theparasitics. Fortunately these are only used up to about 30Mhz sopresumably get-away-with-able.I don\'t know what to make of the all plastic encapsulation, whichseems to have nothing to recommend it. Any comments?Datasheet here:
https://disk.yandex.com/i/bgTMTk49ktGrSw

That\'s a isolated to220, you dont need a mica insulator and
ceramic washer.
If your worried about thermals the use th rf power package.

There are newer rf parts you know.
Click to expand...

Yes, I know. I\'m not planning on using one of these. I was just
curious about the merits or otherwise of the 3 packages.
 
On Thursday, November 17, 2022 at 9:01:20 PM UTC, Cursitor Doom wrote:
On Thu, 17 Nov 2022 15:18:40 -0500 (EST), Martin Rid
martin...@verison.net> wrote:

Cursitor Doom <c...@notformail.com> Wrote in message:r
Gentlemen,I\'ve come across an RF transistor which seems to be available in 3very different ecapsulations. I\'ll use these links from Ebay forsimplicity and hope they\'re still up by the time anyone reads this.:)The first case appears to be based on the TO-220 dimensionos butappears to be all plastic:https://tinyurl.com/yfnfchtkThe second is what I would typically expect to see an RF transistorencased with:https://tinyurl.com/2p9z3r67The final one is a conventional TO-220 with metal heat sink.https://tinyurl.com/32kjhnt3The optimal casing is number 2, offering good thermal conductivityaway from the device plus low parasitics. The one with the conventional TO-220 provides heat sinking adequatefor a device of this power rating, but is not so good on theparasitics. Fortunately these are only used up to about 30Mhz sopresumably get-away-with-able.I don\'t know what to make of the all plastic encapsulation, whichseems to have nothing to recommend it. Any comments?Datasheet here:
https://disk.yandex.com/i/bgTMTk49ktGrSw

That\'s a isolated to220, you dont need a mica insulator and
ceramic washer.
If your worried about thermals the use th rf power package.

There are newer rf parts you know.
Yes, I know. I\'m not planning on using one of these. I was just
curious about the merits or otherwise of the 3 packages.
Click to expand...

The insulated TO-220, I\'ve seen in mass-market consumer
low to mid-frequency, medium power circuits, where
saving a few assembly steps (labor cost) & parts are key
And also avoids stocking the thermally conductive-insulator pad
(and/or possibly thermal grease).
 
On Fri, 18 Nov 2022 10:44:05 -0800 (PST), Rich S
<richsulinengineer@gmail.com> wrote:

On Thursday, November 17, 2022 at 9:01:20 PM UTC, Cursitor Doom wrote:
On Thu, 17 Nov 2022 15:18:40 -0500 (EST), Martin Rid
martin...@verison.net> wrote:

Cursitor Doom <c...@notformail.com> Wrote in message:r
Gentlemen,I\'ve come across an RF transistor which seems to be available in 3very different ecapsulations. I\'ll use these links from Ebay forsimplicity and hope they\'re still up by the time anyone reads this.:)The first case appears to be based on the TO-220 dimensionos butappears to be all plastic:https://tinyurl.com/yfnfchtkThe second is what I would typically expect to see an RF transistorencased with:https://tinyurl.com/2p9z3r67The final one is a conventional TO-220 with metal heat sink.https://tinyurl.com/32kjhnt3The optimal casing is number 2, offering good thermal conductivityaway from the device plus low parasitics. The one with the conventional TO-220 provides heat sinking adequatefor a device of this power rating, but is not so good on theparasitics. Fortunately these are only used up to about 30Mhz sopresumably get-away-with-able.I don\'t know what to make of the all plastic encapsulation, whichseems to have nothing to recommend it. Any comments?Datasheet here:
https://disk.yandex.com/i/bgTMTk49ktGrSw

That\'s a isolated to220, you dont need a mica insulator and
ceramic washer.
If your worried about thermals the use th rf power package.

There are newer rf parts you know.
Yes, I know. I\'m not planning on using one of these. I was just
curious about the merits or otherwise of the 3 packages.


The insulated TO-220, I\'ve seen in mass-market consumer
low to mid-frequency, medium power circuits, where
saving a few assembly steps (labor cost) & parts are key
And also avoids stocking the thermally conductive-insulator pad
(and/or possibly thermal grease).
Click to expand...

It just seems fundamentally wrong to do such a casing for a power
transistor. I know it\'s not really that powerful and won\'t create that
much heat, but even so....sub-optimal IMO.
 
On Friday, November 18, 2022 at 4:43:12 PM UTC-5, Cursitor Doom wrote:
On Fri, 18 Nov 2022 10:44:05 -0800 (PST), Rich S
richsuli...@gmail.com> wrote:

On Thursday, November 17, 2022 at 9:01:20 PM UTC, Cursitor Doom wrote:
On Thu, 17 Nov 2022 15:18:40 -0500 (EST), Martin Rid
martin...@verison.net> wrote:

Cursitor Doom <c...@notformail.com> Wrote in message:r
Gentlemen,I\'ve come across an RF transistor which seems to be available in 3very different ecapsulations. I\'ll use these links from Ebay forsimplicity and hope they\'re still up by the time anyone reads this.:)The first case appears to be based on the TO-220 dimensionos butappears to be all plastic:https://tinyurl.com/yfnfchtkThe second is what I would typically expect to see an RF transistorencased with:https://tinyurl.com/2p9z3r67The final one is a conventional TO-220 with metal heat sink.https://tinyurl.com/32kjhnt3The optimal casing is number 2, offering good thermal conductivityaway from the device plus low parasitics. The one with the conventional TO-220 provides heat sinking adequatefor a device of this power rating, but is not so good on theparasitics. Fortunately these are only used up to about 30Mhz sopresumably get-away-with-able.I don\'t know what to make of the all plastic encapsulation, whichseems to have nothing to recommend it. Any comments?Datasheet here:
https://disk.yandex.com/i/bgTMTk49ktGrSw

That\'s a isolated to220, you dont need a mica insulator and
ceramic washer.
If your worried about thermals the use th rf power package.

There are newer rf parts you know.
Yes, I know. I\'m not planning on using one of these. I was just
curious about the merits or otherwise of the 3 packages.


The insulated TO-220, I\'ve seen in mass-market consumer
low to mid-frequency, medium power circuits, where
saving a few assembly steps (labor cost) & parts are key
And also avoids stocking the thermally conductive-insulator pad
(and/or possibly thermal grease).
It just seems fundamentally wrong to do such a casing for a power
transistor. I know it\'s not really that powerful and won\'t create that
much heat, but even so....sub-optimal IMO.
Click to expand...

Everything is sub optimal. Mostly because things only need to be \"good enough\".

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
 
On Thu, 17 Nov 2022 19:41:58 +0000, Cursitor Doom <cd@notformail.com>
wrote:

Gentlemen,

I\'ve come across an RF transistor which seems to be available in 3
very different ecapsulations. I\'ll use these links from Ebay for
simplicity and hope they\'re still up by the time anyone reads this.
:)

The first case appears to be based on the TO-220 dimensionos but
appears to be all plastic:

https://tinyurl.com/yfnfchtk

The second is what I would typically expect to see an RF transistor
encased with:

https://tinyurl.com/2p9z3r67

The final one is a conventional TO-220 with metal heat sink.

https://tinyurl.com/32kjhnt3

The optimal casing is number 2, offering good thermal conductivity
away from the device plus low parasitics.

The one with the conventional TO-220 provides heat sinking adequate
for a device of this power rating, but is not so good on the
parasitics. Fortunately these are only used up to about 30Mhz so
presumably get-away-with-able.

I don\'t know what to make of the all plastic encapsulation, which
seems to have nothing to recommend it. Any comments?
Datasheet here: https://disk.yandex.com/i/bgTMTk49ktGrSw


Wny? Cost in volume mfring.
Click to expand...

http://ve3ute.ca/semi_ident/CASE_IDENT.zip

http://ve3ute.ca/semi_ident/bipolar_transistor_database.zip

RL
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top