TI BAW oscillator on microcontrollers - Page 1
Forum section: electronics / general

author: rsjsouza
author_rank: Super Contributor
timestamp: February 27, 2019, 11:13:54 pm
content: I haven't seen anything posted about that yet. What do you guys think?https://e2e.ti.com/blogs_/b/thinkinnovate/archive/2019/02/27/tiny-technology-global-impact-ti-baw-breakthrough-creates-new-electronic-heartbeatPerhaps the timenuts could have further comments...

author: PCB.Wiz
author_rank: Super Contributor
timestamp: February 27, 2019, 11:31:38 pm
content: Just been looking at those...Interesting, and the MCU version (48MHz) offers faster startup time than Xtal, (but omits to say if that is inside timing secs within that 8us) - seems to need a running calibrate V-T code stub, to manage the tempcos, but since it is all in one package, that can be done.The Clock Gen device has 435 Bytes of register, so is quite complex. It uses a 2.5GHz +/- 50ppm BAW and a LC VCO too, but gives low jitter...

author: OwO
author_rank: Super Contributor
timestamp: February 28, 2019, 03:51:10 am
content: Isn't BAW essentially the same thing as a crystal? It still requires special packaging and doesn't have the advantages of MEMS. I wonder how they are going to put that into the same package as a microcontroller...I haven't seen any frequency stability numbers quoted so I think I'll stick with SMD TCXOs which are cheap and give you 0.5ppm stability over temperature.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: February 28, 2019, 04:11:23 am
content: Quote from: OwO on February 28, 2019, 03:51:10 amthey already did that...Quote from: OwO on February 28, 2019, 03:51:10 amThey target better than 40ppm for the RF chips, to meet those RF standards.

author: KE5FX
author_rank: Super Contributor
timestamp: February 28, 2019, 04:25:14 am
content: It appears to be several dB noisier than some of their existing LMK-series parts. Not sure what the hype is all about here.

author: mikerj
author_rank: Super Contributor
timestamp: February 28, 2019, 10:26:42 am
content: Quote from: KE5FX on February 28, 2019, 04:25:14 amDid you miss the part about it being integrated into a micro? The LMK parts are all stand alone components AFAIK.

author: OwO
author_rank: Super Contributor
timestamp: February 28, 2019, 01:05:49 pm
content: I checked the eval board and that chip still needs a really complex output balun and impedance matching network. I counted 10 passives in total just for antenna matching. Maybe this is where TI should work on reducing parts count... the ESP32 for example requires NO matching or baluns on the RF port. OTOH a surface mount TCXO is a single part and costs < $0.2, probably way less than the price premium TI wants to add on these parts... I don't see the point of this at all.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: February 28, 2019, 06:42:42 pm
content: Quote from: OwO on February 28, 2019, 01:05:49 pmany links to such parts & a volume reference ?

author: OwO
author_rank: Super Contributor
timestamp: March 01, 2019, 03:01:54 am
content: Quote from: PCB.Wiz on February 28, 2019, 06:42:42 pmhttps://lcsc.com/product-detail/Others_KDS-Daishinku_1XTW26000MAA_KDS-Daishinku-KDS-1XTW26000MAA_C213404.htmlhttps://lcsc.com/product-detail/Others_KDS_DSB221SDN38-400MHZ3-3V0-5PPM-30-85_DSB221SDN-38-4M_C190737.html$0.3 actually, I remembered wrong. The point still stands, TI's price premium over other more commodity transceiver chips is going to be way more than that, and 40ppm is pretty shitty for a frequency reference used for communications.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: March 01, 2019, 07:17:27 pm
content: Quote from: OwO on March 01, 2019, 03:01:54 amAh, ok, I already know of these, so I thought you meant what you said...Quote from: OwO on March 01, 2019, 03:01:54 amPerhaps, but it is what the communication standards TI targets can work within. That is the important thing.USB and UARTs have tolerances that could be called 'pretty shitty' too, but they work fine for communications every day...