Datasheet

ATmega48/88/168 Automotive [DATASHEET]
7530K–AVR–07/14
206
21. Analog-to-Digital Converter
21.1 Features
● 10-bit resolution
● 0.5 LSB integral non-linearity
● ±2 LSB absolute accuracy
● 13 - 260µs conversion time
● Up to 15kSPS at maximum resolution
● 6 multiplexed single ended input channels
● 2 additional multiplexed single ended input channels (TQFP and QFN package only)
● Optional left adjustment for ADC result readout
● 0 - V
CC
ADC input voltage range
● Selectable 1.1V ADC reference voltage
● Free running or single conversion mode
● Interrupt on ADC conversion complete
● Sleep mode noise canceler
The Atmel
®
ATmega48/88/168 features a 10-bit successive approximation ADC. The ADC is connected to an 8-channel
analog multiplexer which allows eight single-ended voltage inputs constructed from the pins of port A. The single-ended
voltage inputs refer to 0V (GND).
The ADC contains a sample and hold circuit which ensures that the input voltage to the ADC is held at a constant level
during conversion. A block diagram of the ADC is shown in Figure 21-1 on page 207.
The ADC has a separate analog supply voltage pin, AV
CC
. AV
CC
must not differ more than ±0.3V from V
CC
. See the
Section 21.5 “ADC Noise Canceler” on page 213 on how to connect this pin.
Internal reference voltages of nominally 1.1V 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.
The power reduction ADC bit, PRADC, in Section 7.7.1 “Power Reduction Register - PRR” on page 35 must be disabled by
writing a logical zero to enable the ADC.