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7647H–AVR–03/12
Atmel ATmega16/32/64/M1/C1
21. Digital to Analog Converter - DAC
21.1 Features
• 10 bits resolution
• 8 bits linearity
• +/- 0.5 LSB accuracy between 150mV and AVcc-150mV
• Vout = DAC*Vref/1023
• The DAC could be connected to the negative inputs of the analog comparators and/or to a
dedicated output driver.
• The output impedance of the driver is around 100 Ohms. So the driver is able to load a 1nF
capacitance in parallel with a resistor higher than 33K with a time constant around 1us.
The ATmega16/32/64/M1/C1 features a 10-bit Digital to Analog Converter. This DAC can be
used for the analog comparators and/or can be output on the D2A pin of the microcontroller via
a dedicated driver.
The DAC has a separate analog supply voltage pin, AV
CC
. AV
CC
must not differ more than ±0.3V
from V
CC
. See the paragraph “ADC Noise Canceler” on page 237 on how to connect this pin.
The reference voltage is the same as the one used for the ADC, See “Clock Prescaler Register
– CLKPR” on page 38.. These nominally 2.56V Vref or AV
CC
are provided On-chip. The voltage
reference may be externally decoupled at the AREF pin by a capacitor for better noise
performance.
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