change IC pinout voltage - Page 1
Forum section: electronics / beginners

author: alamwte
author_rank: Regular Contributor
timestamp: January 18, 2021, 10:37:20 am
content: Hello,I have a question,I have a programmable IC, that its pinouts have 4.5 to 5.5 volt range(for example) in datasheet .Is it possible that I change the voltage of its pins with changing in programming of IC? I mean can I determine its voltage that be for example 4.9v?Thanks,

author: ledtester
author_rank: Super Contributor
timestamp: January 18, 2021, 10:42:41 am
content: Can you provide a link to the datasheet or upload it as an attachment to your message?

author: alamwte
author_rank: Regular Contributor
timestamp: January 18, 2021, 07:17:56 pm
content: yes, below is its datasheet linkhttps://datasheetspdf.com/pdf-file/837145/Semtech/GN25L95/1

author: golden_labels
author_rank: Super Contributor
timestamp: January 18, 2021, 07:32:34 pm
content: I do not see any mentions of 4.5 or 5.5 (as voltages) in this datasheet. Could you reference a specific page?

author: sahko123
author_rank: Frequent Contributor
timestamp: January 18, 2021, 07:35:50 pm
content: If you mean vary the voltage between 4.5 and 5.5v this wouldnt be possible because the output is most likely digital. This just means that the voltage may vary in that range not that it can be controlled.

author: Zero999
author_rank: Super Contributor
timestamp: January 18, 2021, 10:30:17 pm
content: Quote from: alamwte on January 18, 2021, 07:17:56 pmThe power supply voltage id 3.3V, so no, it won't output 5V. Use another IC, to level shift the outputs to 5V. Any 74HCTxx IC will do, such as the 74HCT08, 74HCT241, of the 74LVC such as the 74LVC17, will do.https://www.onsemi.com/pub/Collateral/74HCT08.REV1.PDFhttps://assets.nexperia.com/documents/data-sheet/74HC_HCT241.pdfhttps://4donline.ihs.com/images/VipMasterIC/IC/PHGL/PHGLS27084/PHGLS27084-1.pdf

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 18, 2021, 11:22:29 pm
content: Not understand the question... This chip is designed for 3.3 V power supply. You can't increase it to 4.9 V. If this chip allows you to configure analog pins for other voltage outputs, which is likely when using internal boosters, then you can do it.

author: alamwte
author_rank: Regular Contributor
timestamp: January 19, 2021, 05:32:07 am
content: Thanks all,Quote from: S. Petrukhin on January 18, 2021, 11:22:29 pmCan you give me more guide? You mean if this output be analog, I can change and control its voltage? with change in its programming?

author: ledtester
author_rank: Super Contributor
timestamp: January 19, 2021, 05:52:37 am
content: You have to ask a more specific question.Tell us which pin on which chip and exactly what you want to do with it.

author: alamwte
author_rank: Regular Contributor
timestamp: January 19, 2021, 07:23:15 am
content: I have a module that use this IC and also a laser diode.The pins number 23 and 28 of IC are connected to laser diode(TX).I want to change the power of laser diode (TX-power).Now I want to know how can I change the power of laser diode?Is it possible that I change the voltage of my IC to have change in laser diode power? Is the voltage of this IC changeable?

author: ledtester
author_rank: Super Contributor
timestamp: January 19, 2021, 08:20:11 am
content: Pins 23 and 28 of the chip in the above datasheet have nothing to do with controlling the transmit power a laser.Pin 23 is an input. Also it is a "current input" - the maximum is 8 mA.Pin 28 is a "+3.3V power supply input" - going above that voltage will damage the chip.

author: Terry Bites
author_rank: Super Contributor
timestamp: January 19, 2021, 08:21:55 am
content: Cryptic?

author: Zero999
author_rank: Super Contributor
timestamp: January 19, 2021, 10:34:54 am
content: Quote from: alamwte on January 19, 2021, 05:32:07 amI thought you wanted to increase the voltage, not reduce it as well?The IC you've linked to runs off 3.3V and you said you wanted 4.5V to 5.5V. The ICs I listed will level shift 3.3V signals up to 5V. If you want to vary the output voltage, then power them from a variable 4.5V to 5V supply.What's the over all goal of your project? It seems like you could be taking the wrong/most difficult path.

author: tooki
author_rank: Super Contributor
timestamp: January 19, 2021, 10:44:51 am
content: Quote from: alamwte on January 18, 2021, 10:37:20 amPlease read and understand this:https://xyproblem.infoThen ask your actual question again, the right way.

author: ledtester
author_rank: Super Contributor
timestamp: January 19, 2021, 11:25:20 am
content: This is a very specialized chip. I don't know how it works, and it's not clear from the datasheet even how LASER+, LASER- and BIAS+, BIAS- are supposed to be connected to the laser.I would contact a support engineer at Semtech for assistance. If you go tohttps://www.semtech.com/design-supportyou'll see helpful links under "Design Support Request".

author: alamwte
author_rank: Regular Contributor
timestamp: January 19, 2021, 05:16:57 pm
content: Quote from: ledtester on January 19, 2021, 11:25:20 amOK, Thanks alot