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TPL5110 - not correct working

Other Parts Discussed in Thread: TPL5110


I am using TPL5110 for the first time in my circuit, but behaviour of this IC is strange. I am using basic manufacturer scheme connection as a timer, but for me it is not working. After connection of power supply IC does not start to integrate resistor value at pin 3 (Delay). Resistor value is 77,5 kOhm cca 20 minutes. When I use it in manual mode - pin 3 directly to HIGH (VDD) than it works, but for one time. It is not working in timer mode. Does somebody any experince to help me? I attached part of scheme. Thank you for any idea.

  • I just got on here to post about a similar issue. I've been using the TPL5110DDCT in my design for awhile now and it's been working great. I just built a couple new boards and they're behaving strange. Like you said, it works when manually toggled but the timer function isn't working correctly. I scoped it and the DRV output pulse is only 200us wide, not enough to do anything.

    I know these parts are moisture sensitive and I know the parts I just soldered on have been exposed to normal humidity (here in Florida). Do you remember if your parts were passed it's moisture content spec? I don't have access to an oven to bake them out so I just hoped that it wouldn't be an issue. I guess I was wrong. I'm about to order new parts and solder them immediately after opening the package.

    EDIT: I thought my first batch came in a sealed bag but I must have been mistaken. The part is being shown as not moisture sensitive. Must be losing my mind. 

  • All 5 pcs which I order came in standard endless package like and resistors or capacitors. Soldered after one week since delivery time. I dont think that moisture is reason. I change it by next two and it. Is the same case.

  • I could've sworn that my parts came in a sealed bag but now I can't find it. Still doesn't answer the question as to why these parts are behaving badly.

    Any thoughts on this ? ? ?

  • Tomorrow I will Try alain measure signal at DELAY pin at resitor Text. There should be konstant current. But yesterday I dont see any voltage or current after connection power supply. BTW power supply is stable 5,1 V without peaks or something similar. Each hunt will be great. I spent money for manufacturing PCB and now I am not able to start it.
  • Hi there,

    Can you please provide the waveforms you are seeing at startup for VDD, EN, DRV & DELAY pins? 



  • Hi,

    I pushed little bit forward. Right now I measured at osciloscope that resistor value is integrated about 31 ms for me. Then IC TPL5110 starts wait cca 20 minutes (77,5 kOhm). After this time it opens MOSFET but for very very short time. And I dont know why. I disconnect MCU, because I though that the MCU sends during boot done signal to TPL5110. But the situation is the same with only resistor connected. It starts just for 1 second.

    Manual mode working great, Timer mode is working as I describe above.

    Thank you for reply.

  • Update: I found a reason. IC TPL5110 is working fine. Problem is in MCU especially in NodeMCU (ESP8266), during boot of ESP the ESP8266 toggle with GPIO ports. This is caused closing of FET resp. short opening. I am glad that I found a reason, but I am very sad that I dont know how to manage it. Boot states is not possible set up. I have to do something like delay circuit.
  • , I found the issue. You need a pull-down resistor on your DONE line. A 10k or something. Mine wasn't installed.