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Hey folks, I’m working on a custom sensor board and trying to use the EMC1403 temp sensor this one: https://www.kasuo.com/product/emc1403-2-aizl-tr-datasheet-price-pdf/ ) for monitoring three temperature channels via I²C/SMBus. It’s meant to monitor a hot board, a nearby heat sink and ambient air. According to specs, it supports three channels and ±1 °C accuracy. Here’s my snag: I can read the board’s ambient temp fine. But when I try to connect an external diode sensor for the sink, the reading is unstable and jumps ±5 °C under load. I set it up on the same 3.3 V rail as the MCU and other sensors, maybe the shared rail is picking up switching noise. The external diode is soldered a bit far from the EMC1403’s pins (trace length ~30 mm). I wonder if trace length or routing is degrading accuracy. How close the external diode needs to be to maintain accuracy Power decoupling and I²C pull-ups you used to avoid noise. Any layout or routing tricks you found for accurate multi-channel temperature sensing Thanks in advance, your real-world advice would help a lot! |
November 02, 2025 |
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The unstable readings from the external diode temperature sensor are most likely caused by noise interference. |
by Liyapcb November 03, 2025 |
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