Hobbyist WTB: A couple of ATECC608-SSHDA/-SSVDA and LM27951 ICs - Page 1
Forum section: electronics / general

author: Nominal Animal
author_rank: Super Contributor
timestamp: July 07, 2022, 02:43:05 am
content: I'm just an uncle bumblefuck hobbyist residing in Finland, in Northern Europe. I don't have a company, and the suppliers that would actually sell to me, are all completely out of stock. Chipageddon...I'm looking for a couple ofMicrochip ATECC608Bcrypto chips, to use withTeensy 4.1withEthernet. I've been doing software dev for decades, quite a bit of it network/server dev and Linux stuff, and only a couple of days ago found out these chips exist. I'd love to play with one, but since I usually manage to break things I play with, I'd prefer to have a backup too.(The -SSHDA and -SSVDA are the 8-lead SOIC packages with I²C, as opposed to the UFDN or 3-lead packages, and/or with Single Wire interface.)TheTexas Instruments LM27951chips are common cathode LED backlight charge pump drivers, that might be optimally suited for myBuyDisplay 2.8 240x320 IPS display panels. I have a couple of these displays (love'm too), and can use the standard transistor-based constant current source to drive the four backlight leds in parallel (common cathode, 3.2-3.4V forward voltage, 20mA max per LED, max. 80mA total), but I'd like to see if this chip would suit my needs even better. In particular, the forward voltage of the four backlight LEDs is between 3.2V and 3.4V, and this chip might let me run everything off a single 3.3V supply. A couple of extra chips would let me do some testing before committing to a carrier board, plus cater to my sausage fingers inevitably breaking one.

author: thm_w
author_rank: Super Contributor
timestamp: July 07, 2022, 08:56:18 pm
content: https://www.aliexpress.com/item/1005003449618788.htmlFor LM27951 I think you'll be better off finding an alternate part, something more generic.

author: Nominal Animal
author_rank: Super Contributor
timestamp: July 07, 2022, 10:41:18 pm
content: Quote from: thm_w on July 07, 2022, 08:56:18 pmThe M5Stack one (U124) uses a pre-configured and pre-provisioned ATECC608B-TN* with configuration and credentials locked.However, MikroE hasSecure 8 Clickwith one ATECC608B-MAHDA (I2C) and one ATECC608B-MAHCZ (SWI) on it. They are UDFN packages (so you need reflow or hot air to solder these), but since they're already on a board, they're perfectly fine for testing.The question is, does MikroE have any in stock or not?Quote from: thm_w on July 07, 2022, 08:56:18 pmCommon cathode constant current charge pumps for 2.8V-5.5V in, 3.0-3.6V out, four channels, max. 20mA each, with PWM brightness control, seems to be a bit hard to find.Mouser does have a relatively similar LM2794 in stock, but it's a DSBGA with 0.25mm balls at 0.5mm pitch in a hexagonal lattice, and me and BGA ain't friends anyways.It's not the end of anything if I don't get any, since I do have 5V USB available, so I can use a MOSFET and a single transistor to provide the 70-80mA to all four LEDs in parallel.

author: thm_w
author_rank: Super Contributor
timestamp: July 07, 2022, 11:00:00 pm
content: Yeah generic as in just a single output charge pump, run them in parallel, or use a few ICs.https://lcsc.com/product-detail/LED-Drivers_MICRONE-Nanjing-Micro-One-Elec-ME2212AM6G_C84118.htmlhttps://lcsc.com/product-detail/LED-Drivers_KINETIC-KTD2685EUD-TR_C500370.htmlinteresting but i2c and tinyMikroe doesn't care how many you add to cart so no way to tell what they have in stock without asking.