Large SPI/QSPI DRAM in SOIC8?  - Page 1
Forum section: electronics / general

author: MT
author_rank: Super Contributor
timestamp: November 08, 2019, 02:42:24 am
content: Why isnt there any (large) self refreshing SPI/QSPI DRAM in SOIC8? Technical reasons? To old?

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 08, 2019, 03:07:15 am
content: You may want to take a look at PSRAM chips. Not many vendors make them in SOIC8 packages though, but this one seems to have them:https://www.sramsun.com/list-354-1.html

author: MT
author_rank: Super Contributor
timestamp: November 08, 2019, 03:26:52 am
content: Thanks! 8MByte but no data sheet. I suspect their MOQ is quite high.

author: lucazader
author_rank: Regular Contributor
timestamp: November 08, 2019, 03:40:54 am
content: Espressif seem to produce their own for use in the esp32-wrover modules.Not sure if this is a re-badge of another vendors product or not, or if not where you can buy it from them.but here is the datasheet regardless:https://www.espressif.com/sites/default/files/documentation/esp-psram64_esp-psram64h_datasheet_en.pdfhttp://gamma.spb.ru/images/pdf/esp-psram32_datasheet_en.pdfLyontek seem to do some as wellhttp://www.lyontek.com.tw/en/ddropiram.html

author: PCB.Wiz
author_rank: Super Contributor
timestamp: November 08, 2019, 04:00:55 am
content: Quote from: MT on November 08, 2019, 02:42:24 amWhat does 'large' mean exactly ?Have you looked at these ?SRAM 64Mb (8M x 8 ) SPI/ QPI SOP-8_150mil RAM RoHShttps://lcsc.com/product-detail/RAM_Lyontek-Inc-LY68L6400SLIT_C261881.html

author: MT
author_rank: Super Contributor
timestamp: November 08, 2019, 03:13:08 pm
content: Quote from: PCB.Wiz on November 08, 2019, 04:00:55 am+20Mbyte..QuoteNow i have!. The issue are regular "western" suspects offerings of SPI Sram are small 512k and expensive.Had completely forgot about LCSC!.

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 08, 2019, 04:11:11 pm
content: Those are PSRAM chips as well, with likely very similar specs. Same stuff. This is not SRAM, this is PSRAM, which is DRAM internally, with an easier to deal with interface.You'll have a very hard time finding anything above 64Mbits (8MBytes) in this package.What's your intended use?

author: MT
author_rank: Super Contributor
timestamp: November 08, 2019, 06:32:11 pm
content: High speed collection of data , later sorted processed and stored in flash for later use. SRAM, PSRAM, DRAM, FERAM, whatever , as long its its cheap, small, few pins and meet the requirement of high speed writes, so Flash dont cut.So 3 of e.g LY68L6400SLIT will make 24Mbytes but i can switch to another package if i implement a low profile board connector and some dampening resistors if needed. SOIC8 was for convenience.

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 08, 2019, 06:47:59 pm
content: Alright. At the moment, it's just that PSRAM is your only realistic option regarding cost and density. And yes you'd do ok with 3 of them. They are not expensive at all. Supply may be a bit tricky (you can find them on Aliexpress easily, but as always, I don't know how much you can trust parts bought off Aliexpress... your call!)

author: MT
author_rank: Super Contributor
timestamp: November 08, 2019, 07:20:09 pm
content: Yes, initially i buy in chunks of 100 so it's affordable! With the coming Octa SPI/Hyperbus i have seen better support I/O for memory mapped Octa Flash/RAM, so far STM32L4+, L5 devices that partly support it, somewhat surprised not a single 32H75x did.