Manual

Table Of Contents
265
8209A–AVR–08/09
ATmega16M1/32M1/64M1
25. DAC – Digital to Analog Converter
25.1 Features
10 bits resolution
8 bits linearity
+/- 0.5 LSB accuracy between 100mV and AVcc-100mV
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.
25.2 Overview
The ATmega16M1/32M1/64M1 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 232 on how to connect this
pin.
The reference voltage is the same as the one used for the ADC, See “ADMUX – ADC Multi-
plexer Register” on page 244.. 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.