Please suggest a small MOSFET for me - Page 1
Forum section: electronics / projects

author: Mike Warren
author_rank: Unknown
timestamp: February 08, 2013, 02:13:19 am
content: I'm looking for a couple of MOSFETs (N-Ch and P-Ch) to stock as jelly bean parts that I can use in range of different projects.What I want is something very common, in a SOT23 package. About 30V Vds, 200mA or better, low Rdson, and can be switched with 5V.Cost is very important as well.When it comes to bipolar, I always keep lots of BC848 and BC 858s on hand.Searching the usual sources brings up so many choices that it will take me a very long time to get a feel for how commonly available they are. II'm hoping someone can suggest 1 or 2 from experience to cut my research time.For the N-Channel, the 2N7002F looks to fit the bill, but a P-Channel is much harder to find.

author: Harvs
author_rank: Super Contributor
timestamp: February 08, 2013, 04:16:53 am
content: 2n7002 are a great little device, and cheap as you can get. element14 @ 2.8c each in 100 qty.As for the p-channel, I've used BSS84's before. But they're 5x the cost of a 2n7002 and can only handle 130-180mA depending on the manufacturer. That's why, unless there's a specific application that just can't be done with a n-channel device, I always think about circuit configurations where the N-channel can be used.

author: amspire
author_rank: Super Contributor
timestamp: February 08, 2013, 05:28:11 am
content: I have seen the Vishay/Siliconix SI2309, SI2303 and SI2301 fairly cheap - I have seen down to 7c. It is much higher current then the 2N7002 so it is not a real compliment.

author: amyk
author_rank: Super Contributor
timestamp: February 08, 2013, 06:17:58 am
content: FDN358P is another small P-channel FET, but in general P tends to be more expensive than N and have inferior characteristics due to requiring larger dimensions to achieve the same Rds(on). This is due to electron vs hole mobility in the silicon.

author: free_electron
author_rank: Super Contributor
timestamp: February 08, 2013, 06:27:09 am
content: irlml6402 for a pmos. 2n7002 for an nmos

author: Mike Warren
author_rank: Unknown
timestamp: February 08, 2013, 12:39:16 pm
content: Thanks for the replies.Looks like it wasn't just my bad searching. The IRLML6402 is probably closest. The 20V Vds will limit where I could use it, but it has a nice Rdson and current spec and is available from Element14 for 15c. All the others are 40c + unless I go overseas.I have a bunch of stuff in my E14 cart at the moment, so I'll add some of those.

author: amspire
author_rank: Super Contributor
timestamp: February 08, 2013, 01:19:24 pm
content: Ah! You want locally available mosfets.Here are some from Rockby.com.au in Melbourne:Stock No: 40468Part No: BSH203.215Description: 30V 470mA P-CH Logic level FETQty on Hand: 7199Pricing:10 up: $0.319100 up: $0.1761000 up: $0.099---------------------Stock No: 36335Part No: BSS84LT1GDescription: 50V 130mA 250mW P-CH Logic level FETQty on Hand: 23890Pricing:10 up: $0.319100 up: $0.1651000 up: $0.066-----------------------Stock No: 37666Part No: SI2303BDS-TI-E3Description: 30V 1.4A 700mW P-CH FETQty on Hand: 1450Pricing:10 up: $0.495100 up: $0.2861000 up: $0.187

author: ve7xen
author_rank: Super Contributor
timestamp: February 08, 2013, 04:48:27 pm
content: I've been using NTR4003 for N-channel and NTR4101 for P-channel. Both cheap and widely available, NTR4003 is barely more than 2N7002 but with much better specs.

author: free_electron
author_rank: Super Contributor
timestamp: February 08, 2013, 05:03:33 pm
content: Quote from: Mike Warren on February 08, 2013, 12:39:16 pmthere is one with higher standoff.other interesting little mosfets :FDC666 and FDC558 tose pack a punchbss84 is crap due to its high rdson.

author: MrsR
author_rank: Regular Contributor
timestamp: February 08, 2013, 05:45:51 pm
content: Quote from: Mike Warren on February 08, 2013, 02:13:19 amMike give me a few days I have used a few small as in amps and voltage I will check which one is ate a reasonable price and get back to you.Rachael