A 4-layer PCB with a solid ground plane and a separate power plane is recommended. Keep the analog and digital grounds separate and connect them at a single point. Use a 10uF capacitor between VCC and GND, and a 100nF capacitor between AVCC and AGND.
Use a thermocouple or a thermistor with a high accuracy rating. Ensure good thermal contact between the sensor and the device being measured. Use a low-pass filter to remove noise and ensure the ADC sampling rate is at least 10 times the bandwidth of the signal.
The maximum clock frequency for the ADC is 4MHz. However, it's recommended to use a clock frequency between 1MHz to 2MHz for optimal performance and to minimize noise.
The internal voltage reference is enabled by default. To use an external voltage reference, connect the external reference voltage to the VREF pin and set the VREFEN bit in the ADC control register. Ensure the external reference voltage is stable and within the recommended range.
Power up the device in the following sequence: VCC, AVCC, and then the analog input voltage. Ensure the power supplies are stable and within the recommended range before starting the conversion.
MPY634KU datasheet
