What is this chip's SOT number?? "TA 4c" filtering chip... - Page 1
Forum section: electronics / projects

author: junwoo091400
author_rank: Newbie
timestamp: February 05, 2017, 04:49:40 am
content: Hi, I am currently looking inside a Device called 'M10 GPSonde'. And I ran into... let's say a ProblemI was able to find some part's DATASHEET like 'the MCU (MSP430F23x) ', 'GPS (Trimble 63530)', 'Transmitter (ADF 7012)'.But AFTER that... I got stuck with VERY MYSTERIOUS componentsSo... I'm seeking for a help from people who are interested in my question!!!and since the files are too big... I will give you guys a LINK to my google docs=======================================================================https://docs.google.com/document/d/1cBWyd7TAhw9lC-dlNxIkK_DX0Nfh8_7OSs-B1fA5LMI/edit?usp=sharing========================================================================> 1) What kind of ICs are those ?? I would really appreciate your Suggestions!! (I really just want to know WHAT THEY DO!!!!!)=> 2) If you have seen any of those, then PLEASE tell me their NAME!!!Now, thanks to everyone who helped me out, I am having only ONE component left : written "TA4C" ...color is GOLD and 3 pin on each side. You can see it on Google Docs, and it is IN BETWEEN 'gps antenna' and 'gps RF_IN pin' ...What is it??Wish you have a Nice DayJW HWANG

author: Buriedcode
author_rank: Super Contributor
timestamp: February 07, 2017, 04:27:44 pm
content: Could be dual diodes, single diodes, or more likely transistors, possible 'bias' transistors - ones with built-in resistors to base and emitter.Have you tested them? Use a volt meter to measure diode Vf, then check the voltage between pins. As its in-circuit, this could skew results, so I would desolder one, and test it.

author: junwoo091400
author_rank: Newbie
timestamp: February 07, 2017, 05:51:07 pm
content: Quote from: Buriedcode on February 07, 2017, 04:27:44 pmThank you!! I will search more about measuring diode's Vf. And I should probably desolder them for sure!And it would be really nice if you can give me some advice on where you get those knowledge about Diodes and many others!I have tons of sites to visit, but I can't find a decent one. Maybe you can recommend me any source you know??Thank you so much for replying. I've been waiting for couple of days and you replied!!

author: mikerj
author_rank: Super Contributor
timestamp: February 07, 2017, 06:29:31 pm
content: '1K' may denote it's aBC848 transistor.

author: junwoo091400
author_rank: Newbie
timestamp: February 07, 2017, 06:34:54 pm
content: Quote from: mikerj on February 07, 2017, 06:29:31 pmWow, Thanks!! At least now I know what '1K' stands forThank you so much for helping me out! How did you know that??

author: PA0PBZ
author_rank: Super Contributor
timestamp: February 07, 2017, 07:06:40 pm
content: Quote from: junwoo091400 on February 07, 2017, 06:34:54 pmDid you click the link?The thing to do with these is find the package and find what the marking is. As an example, the "maybe a voltage regulator?". The package is SOT89 and the marking code is probably AL. The first hit when you google "SOT89 marking AL" suggests it is a BCX53-16 PNP transistor. Now check the voltages on the pins and see if it matches.Now for the coil, it's small and has a marking of 22N. Looking at it I guess without a core it is probably 2.2uH, if it has a ferrite core it could also be 22uH. Measure to be sure or since it is in a low pass filter find out the frequency and work from there.The crystal: clearly 8MHz, what else do you want to know?The LA5 one looks like a SOT25, when you google SOT25 marking LA5 you find XC6219A362MR, a look at the datasheet and you find that it is very well possible.One of the possibilities for SH is 2SC4703 RF transistor.Well, enough spoilers for now

author: junwoo091400
author_rank: Newbie
timestamp: February 07, 2017, 07:24:26 pm
content: Quote from: PA0PBZ on February 07, 2017, 07:06:40 pmYes, I did click the link and now, knowing what SOT package specific chip is and finding that marking gives me specific kind of datasheet, I am VERY VERY impressed!I really wanted to click 'say Thanks' twice!! Wow... just THANK you So much!! I will make sure not to scratch my head when finding parts online anymore!!Thank you for teaching me this!!Junwoo HWANG

author: thieringpeti
author_rank: Contributor
timestamp: January 01, 2019, 01:30:13 pm
content: http://radiosonde.eu/RS03/RS03H02.html:-)I have a few of these sondes. Nice hardware with the Texas MCU. Moisture sensor uses a 7555 timer, and the signal frequency represents the humidity value. The temperature sensor is a thermocouple, and also it has a small SMD NTC sensor beside the moisture sensor.THe circuit is very simple. Notice, that the frequency can be changed by sending an infrared transmission to the on-board IR photodiode. One character at 110 baud can re-tune the radio with 100kHz steps.http://keraman.free.fr/m10/m10.htmlSome software mods:http://keraman.free.fr/m10/programateur_usb.htm