FS[US] LM399H  - Page 1
Forum section: electronics / general

author: kawal
author_rank: Frequent Contributor
timestamp: September 30, 2020, 04:41:57 pm
content: I have some leftover LM399H from a repair project. I bought a few to get a close match with the original.These are in new condition - legs never soldered.$12 each with free shipping in US. or 10 for $100 shipped.

author: kawal
author_rank: Frequent Contributor
timestamp: October 07, 2020, 04:59:30 pm
content: No takers? - these are originals not fakes bought at reputable supplier.

author: petemate
author_rank: Regular Contributor
timestamp: October 07, 2020, 10:34:21 pm
content: I think people only care about the AH version

author: RoadRunner
author_rank: Frequent Contributor
timestamp: October 08, 2020, 06:19:57 pm
content: Quote from: petemate on October 07, 2020, 10:34:21 pmExactly , I would have taken them for my Reference boards if they were AH.

author: DuPe
author_rank: Regular Contributor
timestamp: October 08, 2020, 06:45:55 pm
content: I am a little bit puzzled now: Does not mean AH that it just comes with the thermal insulator as it is exactly shown in the pictures?

author: wraper
author_rank: Unknown
timestamp: October 08, 2020, 07:06:27 pm
content: Quote from: DuPe on October 08, 2020, 06:45:55 pmAH is grade with better guaranteed spec. Both are the same physically.

author: kawal
author_rank: Frequent Contributor
timestamp: October 08, 2020, 07:56:00 pm
content: AH has the same average ppm/C but better Max .so AH seem to be cream of the crop but both groups will have some samples with the same exact specs.

author: DuPe
author_rank: Regular Contributor
timestamp: October 08, 2020, 07:56:11 pm
content: thanks wraper for the clarification, but I cant find this in the official data sheethttps://www.analog.com/media/en/technical-documentation/data-sheets/199399fc.pdfWhere I am wrong?

author: DuPe
author_rank: Regular Contributor
timestamp: October 08, 2020, 08:02:01 pm
content: Quote from: kawal onTodayat 20:56:00

author: wraper
author_rank: Unknown
timestamp: October 08, 2020, 09:26:28 pm
content: Quote from: DuPe on October 08, 2020, 08:02:01 pmLook for part numbers in the beginning of datasheet. All of them have H in suffix.

author: kawal
author_rank: Frequent Contributor
timestamp: October 09, 2020, 11:08:11 am
content: page 2 is the location there you see A and Non A version difference . Its what i highlighted.Page 1 shows there is only 2 types available LM399H and LM399AHPretty sure the H means there is a plastic cover over the metal can . All of them have it now . Much older versions could be had without the plastic cover.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 09, 2020, 07:17:01 pm
content: noob question what is this max value ?? im not catching thisis it the same thing for the ltz1000 ??

author: kawal
author_rank: Frequent Contributor
timestamp: October 10, 2020, 12:47:39 am
content: Quote from: coromonadalix on October 09, 2020, 07:17:01 pmVery funny coromonadalix

author: coromonadalix
author_rank: Super Contributor
timestamp: October 10, 2020, 02:38:58 am
content: it was a question not a joke, i'm not a volt nut tea guyAnd sorry if it sounded like it was

author: maginnovision
author_rank: Super Contributor
timestamp: October 10, 2020, 02:48:48 am
content: They have a voltage range, like LTZ1000's. So they could be anywhere in that range but typically they're ~6.9V, LTZ1000 are slightly higher. Same with Tempco, there is a range with a typical but the variances can be large enough that it matters for an application. For the Voltage output value it hardly matters.

author: kawal
author_rank: Frequent Contributor
timestamp: October 12, 2020, 11:32:21 am
content: I am no expert but here is how I understand the datasheet.The max and min value is guaranteed by the vendor and the Typical value is the mean value of all the samples shipped.AH version has lower max temperature coefficient ppm/C of 1ppm/C versus 2ppm/C for H version.Both versions have the same typical 0.3 ppm/C . This means that the AH version is most likely a tested and sorted version from the same production.The voltage is not as important for this device but the stability of the voltage over temperature is the critical parameterThe difference between the AH and H would be 7uV/C max. but both AH and H versions will have much better chips in the population.Typical shows that both groups will produce results better than 2.1uV/CChip Voltage ppm/C V/CLM399H 7 2 14uVTyp 7 0.3 2.1uVLM399AH 7 1 7uVLTZ 7 0.05 0.35uVBased on this a 10C change in the ambient temperature will produce mac 140uV change in the H part and 70uV change in the AH part guaranteed . But more likely you will see a 21uV change which is the typical value.LM399H Max @ 10C delta 7.000140VLM399AH Max @ 10C delta 7.000070VLM399 TYP @ 10C delta 7.000021VLTZ1000 @ 10C delta 7.0000035VThe change can be in either direction the example above is just for a positive change and it assumes 7v nominal output which will vary from sample to sample.