Datasheet

227
7734Q–AVR–02/12
AT90PWM81/161
18. Digital to Analog Converter - DAC
18.1 Features
• 10 bits resolution
• 8 bits linearity
• ±0.5LSB accuracy between 100mV and AV
CC
- 100mV
• V
OUT
= DAC × V
REF
/1023
• The DAC could be connected to the negative inputs of the analog comparators
The AT90PWM81/161 features a 10-bit Digital to Analog Converter. This DAC can be used for
the analog comparators.
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 210 on how to connect this pin.
The reference voltage is the same as the one used for the ADC. See “ADMUX - ADC Multiplexer
Register” on page 217. These nominally 2.56V V
REF
or AV
CC
are provided On-chip. The voltage
reference may be externally decoupled at the A
REF
pin by a capacitor for better noise
performance.
Figure 18-1. Digital to analog converter block schematic.
DAC
DALA DAEN-DAATE DATS2 DATS1 DATS0
10
DACH DACL
DACO N
1010
10
VRef
DAC
Result
Update DAC
Trigger
DAC Low bitsDAC High bits
Edge
Detector
Sources