http://www.mouser.com/ds/2/68/2n3053-46140.pdf
Ft=100M is the tough spec to match...
I could not find any to220 with the same pin order.
TO220 collector tends to be in the middle, your round can is EBC...
TIP31C Ft is only 3Mhz (yours is at least 100).
TIP41C minimum HFE is only 15 (yours is at least 25).
I couldn't find an Ft spec for TIP41C...
Maybe D44H11? Though Ft is only 50MHz...
http://www.fairchildsemi.com/ds/D4/D44H8.pdf
Oh, this one might be even better! 2SC4883
http://www.digikey.com/product-detail/en/2SC4883/2SC4883-ND
Ft=100M is the tough spec to match...
I could not find any to220 with the same pin order.
TO220 collector tends to be in the middle, your round can is EBC...
TIP31C Ft is only 3Mhz (yours is at least 100).
TIP41C minimum HFE is only 15 (yours is at least 25).
I couldn't find an Ft spec for TIP41C...
Maybe D44H11? Though Ft is only 50MHz...
http://www.fairchildsemi.com/ds/D4/D44H8.pdf
Oh, this one might be even better! 2SC4883
http://www.digikey.com/product-detail/en/2SC4883/2SC4883-ND
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Thank you for all your answers!
Mooly, I assume that you mean that nothing higher than a few MHz is needed for a pass transistor in regulators. I don't think I have the required experience to argue with that.
My assumption is the following: lets assume a regulator using an opamp as the error ampifier. The opamp will always try to maintain its inputs at the same potential. Therefore, it will alter its output voltage accordingly. These changes will keep the output voltage constant, by means of the pass transistor. So, for high frequencies (hundreds of kHz), assuming that the opamp is fast enough to make the required changes, you need the pass transistor to be fast enough to pass them to the output before it goes down.
I think that you meant what I wrote in my first paragraph. After all, I will be using a NE5534 in a Sulzer regulator, having a typical UGBW of 10 MHz. So a pass transistor having anything bigger than that is not supposed to ameliorate anything. That's my understanding on your comments.
I hope I have not written anything stupid above. I will go search that TIP41C!
EDIT: Not to be unfair to the other posters for their search, I will try to find these 2SC4883! But, ultimately, if the above are valid, price will decide my final choice.
Mooly, I assume that you mean that nothing higher than a few MHz is needed for a pass transistor in regulators. I don't think I have the required experience to argue with that.
My assumption is the following: lets assume a regulator using an opamp as the error ampifier. The opamp will always try to maintain its inputs at the same potential. Therefore, it will alter its output voltage accordingly. These changes will keep the output voltage constant, by means of the pass transistor. So, for high frequencies (hundreds of kHz), assuming that the opamp is fast enough to make the required changes, you need the pass transistor to be fast enough to pass them to the output before it goes down.
I think that you meant what I wrote in my first paragraph. After all, I will be using a NE5534 in a Sulzer regulator, having a typical UGBW of 10 MHz. So a pass transistor having anything bigger than that is not supposed to ameliorate anything. That's my understanding on your comments.
I hope I have not written anything stupid above. I will go search that TIP41C!
EDIT: Not to be unfair to the other posters for their search, I will try to find these 2SC4883! But, ultimately, if the above are valid, price will decide my final choice.
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Your theorys sound but the regulator (and I haven't seen the circuit), and the circuitry it feeds will almost certainly use rail decoupling caps. Those very caps mean that the output of the reg could never respond "quickly" to any change... in fact the caps mean change can't happen all that quickly. Regulator control loops don't work (and don't need to work) at high frequency. That job is done by rail decoupling.
but the regulator (and I haven't seen the circuit), and the circuitry it feeds will almost certainly use rail decoupling caps. Those very caps mean that the output of the reg could never respond "quickly" to any change... in fact the caps mean change can't happen all that quickly. Regulator control loops don't work (and don't need to work) at high frequency. That job is done by rail decoupling.
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