ATXMEGA256A3B_09 ATMEL [ATMEL Corporation], ATXMEGA256A3B_09 Datasheet - Page 94

• Manufacturer Part Number: ATXMEGA256A3B_09
• Description: 8/16-bit XMEGA A3B Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

8116F–AVR–09/09
4. Bandgap measurement with the ADC is non-functional when V
5. BOD will be enabled after any reset
6.
7.
8. VCC voltage scaler for AC is non-linear
Problem fix/Workaround
If the bandgap is used as reference for either the ADC, DAC and Analog Comparator, the
BOD must not be set in sampled mode.
The ADC cannot be used to do bandgap measurements when V
Problem fix/Workaround
If internal voltages must be measured when V
reference instead of the bandgap.
If any reset source goes active, the BOD will be enabled and keep the device in reset if the
VCC voltage is below the programmed BOD level. During Power-On Reset, reset will not be
released until VCC is above the programmed BOD level even if the BOD is disabled.
Problem fix/Workaround
Do not set the BOD level higher than VCC even if the BOD is not used.
ADC has increased INL error for some operating conditions
Some ADC configurations or operating condition will result in increased INL error.
In differential mode INL is increased to:
– 6 LSB for sample rates above 1 Msps, and up to 8 LSB for 2 Msps sample rate.
– 6 LSB for reference voltage below 1.1V when VCC is above 3.0V.
– 20 LSB for ambient temperature below 0 degree C and reference voltage below 1.3V.
In single ended mode, the INL is increased up to a factor of 3 for the conditions above.
Problem fix/Workaround
None, avoid using the ADC in the above configurations in order to prevent increased INL
error.
DAC has increased INL or noise for some operating conditions
Some DAC configurations or operating condition will result in increased output error.
– INL error is increased up to 35 LSB when VCC < 2.0V
– Enabling Sample and Hold, will increase noise and reduce resolution below 8 bit
Problem fix/Workaround
None, avoid using the DAC in the above configurations in order to prevent increased INL
error.
The 6-bit VCC voltage scaler in the Analog Comparators is non-linear. The typical voltage
output versus the scale factor for different VCC voltages is shown below:
CC
is below 2.7V, measure the internal 1.00V
CC
CC
is below 2.7V.
XMEGA A3B
is below 2.7V
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