Datasheet

203
XMEGA A1U [DATASHEET]
Atmel-8385H-AVR-ATxmega64A1U-128A1U-Datasheet–AVR–04/2014
Problem fix/Workaround
Use the ADC in single ended signed mode.
15. ADC has increased linearity error when using the gain stage above 500ksps
The INL error for gain stage is increased to above 20LSB for sampling speed exceeding 500 ksps.
Problem fix/Workaround
None.
16. DAC Offset calibration range too small when using AVCC as reference
If using AVCC as reference, the DAC offset calibration will not totally remove the offset error. Offset could be
up to 100LSB after calibration.
Problem fix/Workaround
Offset adjustment must be partly handled in software.
17. DAC clock noise
The system clock is visible as clock noise on the output of the DAC. Peak to peak noise is in the range 0.7mV
- 1.6mV at 2MHz and 0.05mV to 0.1mV at 32MHz. If external clock is used as system clock, the noise is up to
three times higher.
Problem fix/Workaround
Add external low-pass filter to remove the noise.
18. Internal 1V reference has noise at low temperature
The internal 1.0V reference for the ADC and DAC has increased noise at low temperatures. The noise can
result in INL numbers up to +/- 20 LSB at temperatures below 0C.
Problem fix/Workaround
For the ADC, use oversampling to reduce noise. For the DAC use external filter to reduce the noise.
39.1.2 Rev. A – K
Not sampled.