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. So the driver is able to load a 1nF capacitance in parallel with a
resistor higher than 33k with a time constant around 1µs.
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, AVCC. AVCC must not differ more than ±0.3V from VCC. See Section 18.6
“ADC Noise Canceler” on page 203 on how to connect this pin.
The reference voltage is the same as the one used for the ADC, see Section 5.10.1 “Clock Prescaler Register – CLKPR” on
page 33. These nominally 2.56V Vref or AVCC are provided On-chip. The voltage reference may be externally decoupled at
the AREF pin by a capacitor for better noise performance.
Figure 21-1. Digital to Analog Converter Block Schematic
DAC
Result
D2A Pin
Output
Driver
VRef
DAC
10
0
1
10
10
DAC High bits
DAC Low bits
DACH
DACL
Update DAC
Trigger
Edge
Detector
DAATE DATS2 DATS1 DATS0
DACON
-
DALA
DAOE
DAEN
ATmega16/32/64/M1/C1 [DATASHEET]
233
7647O–AVR–01/15
MICROCHIP [ MICROCHIP ]
