I am designing a charging controller using the MP2759A IC. However, I am facing an issue where the STAT LED keeps blinking, indicating an NTC fault. I am using an SMD NTC (NT08104F3435B1F) with a beta value that matches the recommended NTC (103AT-2). However, the voltage at the NTC pin is 2.2V, which causes the device to detect a “HOT TEMP” status.
Do you have any suggestions for solving this issue? Or do you have recommendations for an alternative SMD NTC that I can use?
2,2V is in the normal range for temp sensing isn’t it? Not too hot. What else can cause flashing?
Well how hot is it? Have you tried the recommended NTC? Forgive me for pointing out that you question devolves to essentially , I didn’t do what you suggested and it isn’t working.
Those NTC’s look pretty similar. It looks like the switching point is 45C or so. I do believe that idea of the thermistor was to monitor the pack temperature. Is the NTC well coupled to the pack temp?
Yes, I did not use the recommended NTC (103AT-2) because it is a THT type. I think it is less accurate in measuring the temperature of the heat source (in this case, the PCB). I chose to use the NTC (NT08104F3435B1F) because I think it would be more accurate as it has direct contact with the heat source.
By the way, what do you mean by “pack temperature”? Is it the temperature of the battery pack or the IC MP2759A?
well electronics aren’t harmed by 45C but batteries are it is the battery pack
