Replacement for 2n3053s,2n4036 - Page 1
Forum section: electronics / beginners

author: nour
author_rank: Frequent Contributor
timestamp: June 02, 2017, 11:51:33 am
content: As in the title, I want an easy to find replacements for those two transistors.thanks

author: 3db
author_rank: Frequent Contributor
timestamp: June 02, 2017, 11:59:34 am
content: Try Google.

author: Kleinstein
author_rank: Super Contributor
timestamp: June 02, 2017, 12:07:53 pm
content: The manufacturers and some distributors have more or less well working parametric search. So one should be able to find a suitable transistor base on the needs of the circuit, or find a source for exactly that transistor. A suitable replacement can depend on the circuit - at least it gets easier to find one if one knows the circuit.

author: nour
author_rank: Frequent Contributor
timestamp: June 02, 2017, 01:33:32 pm
content: I have tried google and Digikey, the problem is this transistor is 5 watt which I couldn't find a direct substitute for it with the same power dissipation level!Maybe I have used Digikey search in a wrong wayAnyway, this is a pre-stage of a power transistor from output stage in Hp E3631PSUI have attached a PDF for this part

author: Kleinstein
author_rank: Super Contributor
timestamp: June 02, 2017, 02:03:22 pm
content: My first guess would be BD139/BD140. However they are in a different case and would thus need a different heat sink and bend pins.Depending on the power dissipation really needed the slightly smaller (3 W) 2N2219/2N2905 might also work.

author: 2N3055
author_rank: Super Contributor
timestamp: June 02, 2017, 02:25:54 pm
content: As far as I know, you can buy them from Farnell and Mouser...

author: nour
author_rank: Frequent Contributor
timestamp: June 02, 2017, 02:26:16 pm
content: Quote from: Kleinstein on June 02, 2017, 02:03:22 pmI don't actually own the device nor have it on hands, I want to try to build this output stage and try to see how I can use it in my PSU project, I have an open thread talking about other design that folks here said it is not that much great and have some issues, so I said I may try something else, and what else better than HP E3631Anyway, I have viewed the BD139\140 datasheet and they didn't mention anything about the bandwidth\transition frequency? do you have an idea why? the original ones are 100MHZ

author: nour
author_rank: Frequent Contributor
timestamp: June 02, 2017, 02:29:01 pm
content: Quote from: 2N3055 on June 02, 2017, 02:25:54 pmunfortunately, I don't have any fast access to any dealer\distributer other than TME right now which they don't have those parts for now!

author: 2N3055
author_rank: Super Contributor
timestamp: June 02, 2017, 03:10:13 pm
content: I agree with KleinsteinBD 139-16 and BD140-16 are your guys..fT Transition frequency IC=50mA; VCE=5V ;f=100MHz : 190 MHz-16 means grouping for higher HFE....You will have to rearrange pins and provide alternative heatsinking.. But it should work same or better...

author: Benta
author_rank: Super Contributor
timestamp: June 02, 2017, 03:21:04 pm
content: 2N3053 and 2N4036 were popular general purpose parts in the 1970s. There is nothing special about them at all.For your application, it's uncritical, and BD139/140 are as good a choice as any and much, much cheaper (and freely available everywhere).

author: David Hess
author_rank: Super Contributor
timestamp: June 02, 2017, 04:04:28 pm
content: There are a lot of medium power TO-39 transistors that are difficult to find modern substitutes for. The closest modern parts are in TO-126 and TO-225 packages.So it looks like we want a complementary pair with:60 volt Vce1 amp collector current5 watt power dissipation at a 25C case temperature60 to 100 MHz minimum Ft at 50 milliamps50 to 250 hfe at 150 milliampsI agree that the BD139/BD140 series should be a good choice. The Savant datasheets show a typical Ft of 150 to 190 MHz but if you are dubious of that specification, then the 2SA1507/2SC3902, KSA1220A/KSC2690A, and 2SB1143/2SD1683 are suitable also.If the original TO-39 parts did not need a heat sink, then the above TO-126/TO-225 parts should not require one either but I might mount a tiny free standing U shaped heat sink anyway.

author: Cerebus
author_rank: Super Contributor
timestamp: June 02, 2017, 04:44:09 pm
content: Quote from: nour on June 02, 2017, 02:26:16 pmLook at the Op Amps driving them. Their bandwidth is positively slugged by the 2n2 capacitors in the feedback loop (Xcat 100 MHz less than 1 ohm), the Op Amps have a GBW of 3 MHz and it's driving a TIP36C with an Ftof 3 MHz, the base of those transistors will never see anything like 100 MHz. So a high Ftfor that transistor is actually a potential liability, inviting instability and self-oscillation.The BD139/BD140 will do fine here. If anything they are over-specified on the power handling side of things. From memory that transistor only has to sink 30mA (I'm too lazy to dig the schematics out and check) sourced by an LM317 wired as a constant current source. I lied, I'm not too lazy - 39 mA.

author: nour
author_rank: Frequent Contributor
timestamp: June 02, 2017, 05:05:30 pm
content: Quote from: Cerebus on June 02, 2017, 04:44:09 pmYou know what, I really was thinking the same almost as you said, the opamp ahs a GBW 3MHZ and the TIP36C is also 3 MHZ so why on earth would it make any difference to have 100MHZ preamplifier ?, but I am not that expert and I really just wanted to have a replacement without leaving anything to doubt.Anyway thanks.

author: David Hess
author_rank: Super Contributor
timestamp: June 03, 2017, 02:03:24 am
content: Quote from: nour on June 02, 2017, 05:05:30 pmThat does not mean that you want to stack up phase delay in every stage. It is common for the driving transistor to be faster than the output transistor simplifying the frequency compensation and in some cases providing a lower output impedance at higher frequencies.