Datasheet

132
8183F–AVR–06/12
ATtiny24A/44A/84A
16. Analog to Digital Converter
16.1 Features
• 10-bit Resolution
• 1 LSB Integral Non-linearity
• ±2 LSB Absolute Accuracy
• 13 µs Conversion Time
• 15 kSPS at Maximum Resolution
• Eight Multiplexed Single Ended Input Channels
• Twelve Differential Input Channels with Selectable Gain (1x, 20x)
• Temperature Sensor Input Channel
• Optional Left Adjustment for ADC Result Readout
• 0 - V
CC
ADC Input Voltage Range
• 1.1V ADC Reference Voltage
• Free Running or Single Conversion Mode
• ADC Start Conversion by Auto Triggering on Interrupt Sources
• Interrupt on ADC Conversion Complete
• Sleep Mode Noise Canceler
• Unipolar / Bipolar Input Mode
• Input Polarity Reversal Mode
16.2 Overview
ATtiny24A/44A/84A features a 10-bit, successive approximation Analog-to-Digital Converter
(ADC). The ADC is wired to a nine-channel analog multiplexer, which allows the ADC to mea-
sure the voltage at eight single-ended input pins, or between twelve differential pairs of input
pins, or from one internal, single-ended voltage channel coming from the internal temperature
sensor. Single-ended voltage inputs are referred to 0V (GND), while differential-ended input
pairs are subject to a gain stage with programmable amplification steps of 0 dB (1x) and 26 dB
(20x).
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 16-1
on page 133.
Internal reference voltage of nominally 1.1V is provided on-chip. Alternatively, V
CC
can be used
as reference voltage for single ended channels. There is also an option to use an external volt-
age reference and turn-off the internal voltage reference.