Please help identify this component that has a clear number written on it - Page 1
Forum section: electronics / beginners

author: Jay112
author_rank: Regular Contributor
timestamp: November 15, 2017, 04:15:07 pm
content: I attached a picture of the component. It's part of a Vehicle Security Module. I tried searching for the text on the part, but haven't been able to find anything.The letters on the part are: UPL38, and then on the next line: XAZB.Thanks!

author: korbasiewicz
author_rank: Unknown
timestamp: November 15, 2017, 04:39:01 pm
content: Aliexpress has exactly this one:https://goo.gl/CC5Qwm

author: Jay112
author_rank: Regular Contributor
timestamp: November 15, 2017, 05:24:11 pm
content: Thanks, but I'm still having trouble finding a datasheet on it. It looks like we learned from that page (if it's the same component) that it's a "time relay". I tried searching for "UPL38 time relay", but still couldn't find anything relevant.

author: korbasiewicz
author_rank: Unknown
timestamp: November 16, 2017, 10:32:56 am
content: Yeah, me too. Can you say what is it on (what's the circuit) and share photo of full PCB? Maybe we can figure it out somehow.

author: Kjelt
author_rank: Super Contributor
timestamp: November 16, 2017, 11:32:51 am
content: Quote from: Jay112 on November 15, 2017, 04:15:07 pmIf it is connected to a microcontroller (not very visible on your picture) it might well be a security coprocessor / authenticator ic.Infineon, Atmel and others make those and my experience is that their package has no relevance to the manufacturer or partnr. but the buyer can order its own code to be printed on top of these chips after being programmed with for instance their companies "secret" or "private" key.These parts are made to simplify some cryptographic functions such as RSA, ECC or AES for the microcontroller.In case of an authenticator (example Maxim DS28E series), the microcontroller sends a "challenge" (usually a unique random created bytestring aka nonce), they ic performs a signature over this challenge with its private key and sends it back to the microcontroller, which has the public key and verify that the ic is authentic.This is to make sure the module is authentic and not a clone.Only way to find out is monitor the traffic between the two if the data is total random noise/garbage you have more confirmation that it probably is one of the above.

author: Jay112
author_rank: Regular Contributor
timestamp: November 16, 2017, 04:25:50 pm
content: Quote from: korbasiewicz on November 16, 2017, 10:32:56 amThanks! I'll share a picture and description in the next post.Quote from: Kjelt on November 16, 2017, 11:32:51 amThis sounds very relevant, and that would explain why it's the only component on the board that I'm not able to identify. It would also explain why the letters are brighter than the letters on any other component. I haven't checked yet to see if it's connected directly to any microcontroller pins, but I'll do that later. As you can see in the pic below (once I post it), it's very close to the microcontroller.

author: Jay112
author_rank: Regular Contributor
timestamp: November 16, 2017, 04:36:04 pm
content: I wonder what you guys think of this situation:Short description of problem: The VSM is from a 2002 Ford truck. Everything it's supposed to do has stopped working (doesn't toggle car lights, keyfob functions don't work, doesn't toggle door unlock/lock from door buttons). I've checked all the wiring and switches external to the board, and everything else seems okay.These are the problems I could find so far:1) Diagnostic fault output pin on TLE 6220 constantly outputting low, meaning it detects a fault. (this component is also connected to some of the relay coils). I tried to download the specific fault info via SPI according to the datasheet, but accidentally broke the power pin (already have a replacement chip). Chip is currently disconnected from circuit.2) There are constant voltage fluctuations on the board. Every 2 seconds the voltages on most of the 12V side momentarily jump down to 10V, and at the same time most of the 5V side jumps to 4V. Haven't hooked a scope up to it yet to clearly see the patterns. (I already replaced the large 470uF capacitor).2a) I disconnected the input of the 5V LDO regulator, so that I can see what side the voltage fluctuations are happening on. When I power either the 5V or 12V sides alone, the voltages are stable and there are no fluctuations. Only when both sides are powered are there fluctuations. I've tried bypassing the regulator by giving 12V and 5V from separate sources with the regulator disconnected, and still there are fluctuations (which I think means it's not from the regulator).3) "COM" pin on ULN2003A always has seemingly high voltage, around 16V (rest of circuit is 12V and 5V). When 12V side is disconnected from circuit and only 5V side is connected, there is 8V on this pin. Since it's supposed to be switching 12V relays, is it normal for the common pin to receive anything from the 5V side? Could this be a sign of a problem? Plus, how does it get 8V when everything else is 5V?sUsually I would prefer to just replace the VSM by now, but with the voltage fluctuations on the board, I don't think they'll be able to download the programming data from it. The MCU Vin drops to 4V every 2 seconds, which according to the data sheet would cause the MCU to reset.

author: brabus
author_rank: Frequent Contributor
timestamp: November 16, 2017, 06:07:36 pm
content: Quote from: Jay112 on November 16, 2017, 04:36:04 pmThis.I suspect something is badly playing up somewhere else in the vehicle. I would start by measuring the current drawn from the battery: if you see high current spikes you can search from there. If you don't see anything wrong and the current remains stable and fine, it may be something related to the grounding of the ECU. Maybe a ground wire has lifted itself from the chassis, leading to the fault you are seeing.Of course, a closer look with a portable oscilloscope can give you a lot more hints.

author: Jay112
author_rank: Regular Contributor
timestamp: November 16, 2017, 07:29:04 pm
content: Quote from: brabus on November 16, 2017, 06:07:36 pmThanks for the advice.I actually powered it externally with a 12V wall wart, and it was still displaying the exact same behavior (I had all external wires disconnected except for the 12V and GND wires). Would that eliminate the possibility of it being related to something outside the board?