SAR ADC Oscillations | Cypress Semiconductor
SAR ADC Oscillations
Hello, I am trying to use an SAR ADC for an application that requires low power and battery power. I have the SAR input setup from an analog pin(high z). Going into the pin, I have a DC power supply that is supplying 2.5VDC. I have the ADC output reading into a uint16, and then going directly to the LCD.
-100kSPS(tried 60k and 900k with bypass cap)
-vref internal(tried bypass and external vref)
-played around with IMO frequency a bit, but left it at 3MHz and PLL at 24MHz
-software trigger(use startconv and stopconv then read)
I took several readings, delaying 4 seconds between each reading. The max and min decimal values are below. 2154 is 2.5V at my vdd of 4.75VDC.
Why are the outputs oscillating 4 bits? I am really only getting 8 bits of resolution with this setup because of the oscillation..