Datasheet

28. Analog-to-Digital Converter (ADC)
28.1 Features
• 10-bit Resolution
• 0.5 LSB Integral Non-Linearity
• ±2 LSB Absolute Accuracy
• 13 - 260 μs Conversion Time
• Up to 76.9 kSPS (Up to 15 kSPS at Maximum Resolution)
• Six Multiplexed Single Ended Input Channels
• Two Additional Multiplexed Single Ended Input Channels (TQFP and QFN Package only)
• Temperature Sensor Input Channel
• 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
28.2 Overview
The device 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 below.
The ADC has a separate analog supply voltage pin, AV
CC
. AV
CC
must not differ more than ±0.3V from
V
CC
. See section 28.6 ADC Noise Canceler on how to connect this pin.
The Power Reduction ADC bit in the Power Reduction Register (PRR.PRADC) must be written to '0' in
order to enable the ADC.
The ADC converts an analog input voltage to a 10-bit digital value through successive approximation.
The minimum value represents GND and the maximum value represents the voltage on the AREF pin
minus 1 LSB. Optionally, AV
CC
or an internal 1.1V reference voltage may be connected to the AREF pin
by writing to the REFSn bits in the ADMUX Register. The internal voltage reference must be decoupled
by an external capacitor at the AREF pin to improve noise immunity.
ATmega48PA/88PA/168PA
Analog-to-Digital Converter (ADC)
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40002011A-page 314