BAW56 SOT-23 diode alternative? - Page 1
Forum section: electronics / general

author: slybunda
author_rank: Regular Contributor
timestamp: February 01, 2024, 09:34:35 am
content: hi all, i need a diode which is found here:https://uk.rs-online.com/web/p/switching-diodes/7815161Its a BAW56 type but its not in stock. Chatting to the webchat people at RS components they said this here is an alternative part:https://uk.rs-online.com/web/p/switching-diodes/7920793The alternative they suggested is a BAV23A, is this a suitable alternative or does a BAW56 part have to be replaced with another BAW56 part?thanks

author: elektryk
author_rank: Regular Contributor
timestamp: February 01, 2024, 09:55:41 am
content: It depends on application, BAW56 has lower Trr.BTW it looks like BAW56 is still available (for example in Farnell).

author: slybunda
author_rank: Regular Contributor
timestamp: February 01, 2024, 10:19:12 am
content: Yes farnell has it but delivery cost is high. I just need 10 of these. Can get from AliExpress for like £1 for 100pcs but since iv used quality components for everything else i dont want to cheap out right at the end.I buy from rs components because they are a very short drive away from me so saves on high delivery prices.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 01, 2024, 01:34:02 pm
content: There are many variants (e.g. different manufacturers) of the BAW56, and some are still available at RS. There are other types that may be closer (e.g. 1N4148 similar types with 4 ns trr) - here it depends on the application.Other sources also have them in stock (e.g. TME.EU).

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 01, 2024, 06:21:17 pm
content: I would be shocked if the difference between BAW56 and BAV23A mattered. Maybe it's one of those applications, maybe you can give some context as to whether it would matter, but I would most likely think it doesn't.Notable differences seem to be V_R, t_rr, C_d (a little bit, but their tolerances easily overlap), and maybe I_FSM (curiously, both provide a plot of this vs. t_p, but onsemi erroneously rates it at 4A (1µs) while plotting 11A!). It would be weird if V_R is being used as a characteristic (avalanche, but the voltage doesn't matter?*), but again, there's an outside chance it could matter.*In that they're not rated for it, as zeners are; or avalanche rectifiers for that matter. So the actual voltage is anyone's guess. Usually it's 10-40% above V_R, but it could be many times higher as is often the case with rectifiers (I have name-brand 1N4004s that break down ~1.3kV). They will still avalanche, most likely nondestructively at low currents (DC, thermally limited; pulsed may still be destructive), but the V(I) curve and tempco will be all over the place. That's generally the case for rectifiers, anyway; I haven't tested a whole lot of small-signal diodes in breakdown.Tim

author: shapirus
author_rank: Super Contributor
timestamp: February 01, 2024, 06:29:05 pm
content: Where's it used in the circuit? It's very likely that there are quite a few possible substitutes.

author: slybunda
author_rank: Regular Contributor
timestamp: February 01, 2024, 07:24:09 pm
content: used in a solar charge controller probably to power the attiny85 controller chip.pic attached

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 01, 2024, 07:55:33 pm
content: Yeah, that looks general purpose, literally anything will do.Tim

author: shapirus
author_rank: Super Contributor
timestamp: February 01, 2024, 07:59:30 pm
content: That's a nicely made silk screen!

author: slybunda
author_rank: Regular Contributor
timestamp: February 01, 2024, 09:54:12 pm
content: Quote from: shapirus on February 01, 2024, 07:59:30 pmGot it from here:https://github.com/AdamWelchUK/PWM85bought 2 from the guy, needed 2 more so decided to have a go at making them. fun project.