Wiznet makers

The SIP chip W55RP20 (W5500 + RP2040 integration) added by our company is a useful product that can be used in various IoT projects. This chip includes the internal temperature sensor of RP2040, which can be useful for monitoring the ambient temperature. However, this temperature sensor may have an error depending on the reference voltage, so we conducted a test to confirm this again.

NOTE section of 4.9.5. Temperature Sensor in RP2040 Datasheet

I was curious to know whether the content is the same as the difference in W55RP20 or if there is a large error in each chip, so I conducted a comparison test using 20EA W55RP20.

Results: The measured temperature values ​​are very different due to the difference in the reference voltage (same as the current supply voltage on the board), and if the reference voltage is not fixed, the temperature sensor error of ADC5 is large and cannot be used.
When the reference voltage is 3.3V, the chip temperature does not rise to 42~44 degrees during the loopback test measured by the onboard temperature sensor (office temperature 25~26 degrees)