Favourite ESD device for USB? - Page 1
Forum section: electronics / projects

author: apelly
author_rank: Unknown
timestamp: June 01, 2015, 11:17:26 pm
content: Have any of you got a favourite ESD device for USB?Digikey has a warehouse full apparently, ranging from individual pins to comprehensive multi-port with over voltage protection. Prices are from ~60c to $3 in single quantities.I can just pick one, or a set, and be done with it, but I'll probably stick with what I choose now for quite some projects to come, so I thought I'd get your input first.

author: marshallh
author_rank: Unknown
timestamp: June 02, 2015, 12:25:28 am
content: I use the same 4terminal ones with low capacitance that work for USB3, HDMI, and everything slowerhttp://www.digikey.com/product-detail/en/HSP061-4M10/497-13410-1-ND/3737646

author: apelly
author_rank: Unknown
timestamp: June 02, 2015, 03:15:29 am
content: Thank you. Looks like a bitch to hand solder, but it'll probably do.

author: luky315
author_rank: Regular Contributor
timestamp: June 02, 2015, 08:04:40 am
content: The NUF2042XV6http://www.onsemi.com/PowerSolutions/product.do?id=NUF2042XV6is great if you need the integrated 22Ohm series resistors.It is possible to solder it by hand.

author: jeroen74
author_rank: Frequent Contributor
timestamp: June 04, 2015, 10:03:48 pm
content: I used the USB6B1 from ST:http://www.st.com/web/en/resource/technical/document/datasheet/CD00001361.pdfComes in SO-8.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 04, 2015, 10:52:28 pm
content: I'm fond of the SOT-23-6 (or 323) varieties. I don't have a particular favorite; TI, ST, NXP and so on all make suitable devices.Do check if you're doing USB 1.1 Full Speed, or USB 2.0 High Speed. The latter is the fast LVDS signal, can't sustain any loading or filtering, and needs to use low-capacitance protection diodes. The former is basically HC CMOS and can be filtered and protected quite modestly, which will also greatly help with possible microwave susceptibility issues.Tim

author: Howardlong
author_rank: Super Contributor
timestamp: June 04, 2015, 11:38:53 pm
content: For USB Full Speed, I have used ON Semi CM1213A-02SR for a few years. It's in tens of thousands of my devices, I've seen less than half a dozen knackered device USB ports in returns, and I strongly suspect that those that were bust were due to non-standard influences.More recently for high speed I have moved to Microchip's USB3751, more expensive but it provides high speed compatibility and battery charger capability detection over I2C as well as ESD protection. Depending on your application, having the ESD protection integrated into this kind of device together with charger detection makes for a reasonable solution, the various potpourri of USB charger "standards" is laughable.As an aside, Microchip really do seem to be producing some interesting non-PIC devices these days in certain niches that are both commonly available and reasonably priced.

author: apelly
author_rank: Unknown
timestamp: June 05, 2015, 12:12:14 am
content: Thanks for taking the time to reply guys.Quote from: luky315 on June 02, 2015, 08:04:40 amNice. My spec requires 33R termination though.Quote from: jeroen74 on June 04, 2015, 10:03:48 pmExpensive. I like the layout though.Quote from: T3sl4co1l on June 04, 2015, 10:52:28 pmUnderstood, I've read a few app notes by now.Quote from: Howardlong on June 04, 2015, 11:38:53 pmThe CM1213A-02SR doesn't look interesting, and the USB3751 is not stocked by digikey, is expensiveandisn't hand solderable. Nice device though.I hate to be 'that guy' that asks for advice and then does something different, but I found this:http://www.digikey.co.nz/product-detail/en/DT1042-04SO-7/DT1042-04SO-7DICT-ND/4457893It's hand solderable (just) SOT-23-6, as Tim suggested, and about 50c in small quantities over here.

author: c4757p
author_rank: Super Contributor
timestamp: June 05, 2015, 12:16:10 am
content: Quote from: apelly on June 05, 2015, 12:12:14 amwut? it's a QFN...

author: apelly
author_rank: Unknown
timestamp: June 05, 2015, 12:23:39 am
content: Quote from: c4757p on June 05, 2015, 12:16:10 amMaybe I misread the datasheet, I only glanced at it. Hasn't it got a big pad underneath it? Even so, sure you can hand solder it, but why dick around?

author: Howardlong
author_rank: Super Contributor
timestamp: June 05, 2015, 12:37:05 am
content: Quote from: apelly on June 05, 2015, 12:12:14 amThe reason I offered the CM1213A part was because I can testify to its functionality in a real device with a reasonably large volume of production. I am sure there may well be other devices, but I was offering you real evidence and experience of one that works in the field. That may or may not be important to you, so feel free to take it or leave it!Regarding the USB5731, I've hand soldered several, it's really not a big deal, it's just a usual QFN. I understand it if you're reticent if you've not toyed with hand soldering QFNs before, but given enough initial bravado I'm sure you'll take to it like a duck to water and wonder what all the fuss was about. You just need a $100 hot air iron, solder, flux and your usual iron. A steady hand and magnifying capability are also pretty much prereqs, but if you're soldering SOT-23s you prolly already have those.

author: Howardlong
author_rank: Super Contributor
timestamp: June 05, 2015, 12:39:45 am
content: Quote from: apelly on June 05, 2015, 12:23:39 amBecause it has all that extra functionality that otherwise you'd have to use another dozen or so parts for, and it's cheaper. Seriously, don't think a QFN is hard, it isn't.

author: zapta
author_rank: Super Contributor
timestamp: June 05, 2015, 12:46:16 am
content: Quote from: apelly on June 05, 2015, 12:12:14 amThey are 22 ohm. I use them with devices that require 33 (lpc11u35) and everything seems to work just fine. You can add 11R in series.

author: apelly
author_rank: Unknown
timestamp: June 05, 2015, 02:18:41 am
content: Quote from: Howardlong on June 05, 2015, 12:37:05 amSorry, I did understand that. I shouldn't have just glossed over your input like that.Also, re-reading the datasheet indicates this is indeed a fine recommendation. When I first looked I read the datasheet incorrectly. Wrong device.Quote from: Howardlong on June 05, 2015, 12:37:05 amIt was the thermal pad that put me off. But thanks for the encouragement!Quote from: zapta on June 05, 2015, 12:46:16 amInteresting, that's the same MCU as I'm using.Anyway, I've designed in the part I found now. This is a lesson to do my research better. Thanks again guys.

author: zapta
author_rank: Super Contributor
timestamp: June 05, 2015, 05:37:18 am
content: Quote from: apelly on June 05, 2015, 02:18:41 amHere is the schema if it helps. If you are using an ISP button, you can make it a single button operation using D4 and C7. I used it all the time for programming during the edit/run cycle.https://github.com/zapta/arm/raw/master/pro-mini/board/arm-pro-mini-schematic.pdf