16 capacitive touch IC (TTP229-LSF alternatives) - Page 1
Forum section: electronics / projects

author: 3dgeo
author_rank: Frequent Contributor
timestamp: July 28, 2020, 01:58:54 pm
content: Hi,for a long time I was trying to makeTTP229-LSFwork, and in some degree it is – I'm getting inputs, but due to some IO using pullups (850K-1M) for IC settings those IO don't work properly, plus I can't make this IC to work at 400 kHz and It's crucial that I do. Cherry on top that LCSC mark this chip as discontinued, so I need alternatives.What I like about TTP229-LSF:1.Low external component count(have very little space for it).2.Cheap3.I2C (supose to work with 400kHz).I scouted internet for a viable replacement, nothing that fits my needs.

author: OM222O
author_rank: Frequent Contributor
timestamp: July 28, 2020, 02:02:39 pm
content: why do you need I2C? does a single on / off switch not work? they are configurable via traces (connect to GND or connect to VCC) so no external components needed at all.

author: 3dgeo
author_rank: Frequent Contributor
timestamp: July 28, 2020, 02:08:52 pm
content: Quote from: OM222O on July 28, 2020, 02:02:39 pmThis is with no doubt most useless post I've read in this forum... Thanks a lot for spamin for no reason.

author: Renate
author_rank: Super Contributor
timestamp: July 28, 2020, 02:13:49 pm
content: I've used the MPR121 12 input sensor with success.Ok, I use it for capacitive sensing, not touch, but it works well.https://www.ebay.com/itm/MPR121-Breakout-V12-Capacitive-Touch-Sensor-Controller-Module-I2C-keyboard-S3/261996625969Edit: Hmm, it looks like the MPR121 is on its way out also.Plenty of breakout boards on ebay, but might not be a good choice for production.I see that the Azoteq IQS316 looks popular but I can't find it on a breakout to test it.Another edit: DigiKey has breakouts.The fine print confirms that this is 3 boards for the total price of $9.26https://www.digikey.com/products/en?mpart=IQS316EV01-S&v=1790

author: 3dgeo
author_rank: Frequent Contributor
timestamp: July 28, 2020, 03:56:36 pm
content: Oh, it looks promising, it got SPI, not ideal but I'm willing to trade I2C to it and price is OK in quantities. Thanks!EDIT: SPI clock frequency 0.4-0.8MHz, I2C clock frequency 0.1MHz

author: Renate
author_rank: Super Contributor
timestamp: July 28, 2020, 04:32:37 pm
content: Quote from: 3dgeo on July 28, 2020, 03:56:36 pmWell, it has that down as "typical".I mean, if it can shift the SPI at 0.8 MHz, why not I²C at 0.4 MHz?I've seen other devices, other manufacturers quote 400 kHz, but usable up to 1 MHz.Quote from: Other mfr, not AzoteqStill, Azoteq could have made this all clearer.

author: 3dgeo
author_rank: Frequent Contributor
timestamp: July 28, 2020, 11:27:10 pm
content: Azoteq IQS316 looks really nice on paper – shielding, proximity detection. Hope you are right that it can run at 400kHz (TTP229-LSF can't even if datasheet says it can)...It's strange how all touch ICs I found are older that 5 yearsBtw, TTP229-LSF is the last IC on the board that is not QFN

author: 3dgeo
author_rank: Frequent Contributor
timestamp: July 29, 2020, 02:06:53 pm
content: Interesting thing I found with TTP229-LSF – it crashes when data requests are made very often. I mixed this with not working in 400kHz, it works, but data request should be made with delays. I will use INT anyway.

author: girishv
author_rank: Regular Contributor
timestamp: July 29, 2020, 07:54:35 pm
content: I suppose you are looking for a stand alone touch. If you are open to use a MCU in place of standalone touch, checkouthttps://www.ti.com/product/MSP430FR2633MSP430FR2633 comes with touch library embedded into ROM and pc software to optimize the touch.Available in SOP, QFN and BGA packages. Costs about US$1.3 retail.

author: 3dgeo
author_rank: Frequent Contributor
timestamp: July 29, 2020, 08:54:43 pm
content: Quote from: girishv on July 29, 2020, 07:54:35 pmYes, I want stand alone cuz MCU is on the other side of the PCB (touch keys has their own PCB on top of the main PCB).1.3USD is a bit too much, even IQS316 is bit a pricey, but I can live with it cuz it seems I have no choice – I can't find TTP229-LSF on Digikey or Mouser anymore too. Now only left knockoffs on Ali and I don't trust those.Ironically, as I found out that it's data pooling problem, not bus speed I made 229 to work perfectly, even interrupt works...I will make IQS316 test PCB, but for now I think I will continue with 229 cuz integrating new IC might took few tries and I have other things to sort out...I have big metal plate beneath touch buttons, I would like to make it as a proximity sensor with IQS316, but I doubt it will work reliably to detect hand above (5cm).

author: Renate
author_rank: Super Contributor
timestamp: July 30, 2020, 02:31:51 am
content: I ordered those IQS316 eval boards and I should have them next week.

author: Renate
author_rank: Super Contributor
timestamp: September 15, 2020, 06:50:04 pm
content: I received those IQS316 evalutation boards a while ago but finally got around to looking at them.I must say, the little cardboard box that they ship them in is of the highest quality!I wish that I could say that that quality permeates everything.The documentation tells you to just plug in the 20 pin connector on their evaluation programmer.If you are just interested in trying out the evaluation board as a break-out board you are kind of lost to find the pinout in obscure documentation.If you want to use it with I²C then you have to remove an (undocumented) resistor.The pinout of the 20 pin header out the side is:Code:SPI I²C1 Gnd2 /MCLR3 VDD4 -5 ZC6 MOSI A07 MISO SDA8 RDY9 SCK SCL10 /SS /RDY

author: 3dgeo
author_rank: Frequent Contributor
timestamp: October 02, 2020, 01:43:39 pm
content: My apologies for slow reply – I try to juggle a lot of project...I'm not buying that evaluation board, I'm going straight to PCB design. I will have to test it on my specific PCB anyway.But I would appreciate if you post your further experience with it.

author: Renate
author_rank: Super Contributor
timestamp: October 02, 2020, 05:42:04 pm
content: I haven't gotten very far with this.It is one of those I²C that really do need the separate reset line (/MCLR).A straight power up doesn't leave it working.I'm talking to it on 0x74 and I can read the ID back as 0x1b01.