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TMP390EVM: When triggle the overtemperture, the logic of outB also effect

Part Number: TMP390EVM
Other Parts Discussed in Thread: TMP390

Hi team, 

this is brandon. 

My customer is facing a problem when used TMP390 as temperature switch;

they were set the overtemperature at 85℃. when this happen, the outA was set low which is normal.However, the outB was also effect, output the waveform as follow:

The blue one is the outB waveform when overtemperature;

i attached the schematic and could you help check the reason?(85℃ for OUTA and 0℃ for OUTB)

温度开关1.pdf

Thank you 

BR

Brandon.

  • Brandon,

    I am a bit confused by the graph, what is represented by the yellow line? Are they conducting this test via the trip test? Could you give more details to the test set up?

    Looking at the schematic, I see there is a value of 22kΩ for the Channel B set resistor. This is not a valid resistance as shown in Table 2 of the datasheet. For a   0℃ undertemperature set point, they should use a 21.5kΩ  resistor.

    Also, the set resistor on channel A needs to be a 1% tolerant resistor to ensure trip point accuracy. Can this also be adjusted?

    Jalen