Datasheet

366
XMEGA D3 [DATASHEET]
Atmel-8134N-ATxmega32D3-64D3-128D3-192D3-256D3-384D3_datasheet–03/2014
Figure 34-2. Analog comparator voltage scaler vs. scalefac.
T = 25°C.
Problem fix/Workaround
Use external voltage input for the analog comparator if accurate voltage levels are needed.
3. ADC gain stage cannot be used for single conversion
The ADC gain stage will not output correct result for single conversion that is triggered and started from soft-
ware or event system.
Problem fix/Workaround
When the gain stage is used, the ADC must be set in free running mode for correct results.
4. ADC has increased INL error for some operating conditions
Some ADC configurations or operating condition will result in increased INL error.
In signed mode INL is increased to:
6LSB for sample rates above 130ksps, and up to 8LSB for 200ksps sample rate.
6LSB for reference voltage below 1.1V when V
CC
is above 3.0V.
20LSB for ambient temperature below 0°C and reference voltage below 1.3V.
In unsigned mode, the INL error cannot be guaranteed, and this mode should not be used.
Problem fix/Workaround
None, avoid using the ADC in the above configurations in order to prevent increased INL error. Use the ADC
in signed mode also for single ended measurements.
5. ADC gain stage output range is limited to 2.4V
The amplified output of the ADC gain stage will never go above 2.4V, hence the differential input will only
give correct output when below 2.4V/gain. For the available gain settings, this gives a differential input range
of:
3.3V
2.7V
1.8V
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0 5 10 15 20 25 30 35 40 45 50 55 60 65
SCALEFAC
V
SCALE
[V]