ATxmega128A3 Atmel Corporation, ATxmega128A3 Datasheet - Page 118

• Manufacturer Part Number: ATxmega128A3
• Manufacturer: Atmel Corporation

Specifications of ATxmega128A3

• Flash (kbytes): 128 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 50
• Ext Interrupts: 50
• Usb Speed: No
• Usb Interface: No
• Spi: 10
• Twi (i2c): 2
• Uart: 7
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 16
• Adc Resolution (bits): 12
• Adc Speed (ksps): 2000
• Analog Comparators: 4
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 8
• Eeprom (bytes): 2048
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.6 to 3.6
• Operating Voltage (vcc): 1.6 to 3.6
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 7
• Output Compare Channels: 22
• Input Capture Channels: 22
• Pwm Channels: 22
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

8068T–AVR–12/10
Figure 36-5. Analog Comparator Voltage Scaler vs. Scalefac
3.
4. ADC gain stage output range is limited to 2.4 V
Problem fix/Workaround
Use external voltage input for the analog comparator if accurate voltage levels are needed
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 1Msps, and up to 8 LSB for 2Msps sample rate.
– 6LSB for reference voltage below 1.1V when VCC is above 3.0V.
– 20LSB for ambient temperature below 0 degree 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.
The amplified output of the ADC gain stage will never go above 2.4 V, hence the differential
input will only give correct output when below 2.4 V/gain. For the available gain settings, this
gives a differential input range of:
–
–
–
–
–
–
–
16x
32x
64x
3.5
2.5
1.5
0.5
1x
2x
4x
8x
3
2
1
0
0
T = 25°C
gain:
gain:
gain:
gain:
gain:
gain:
gain:
5
10
300
150
2.4
1.2
0.6
75
38
15
V
V
V
mV
mV
mV
mV
20
25
SCALEFAC
30
35
40
45
50
55
XMEGA A3
60
65
3.3 V
2.7 V
1.8 V
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