
203
7734Q–AVR–02/12
AT90PWM81/161
17. Analog to Digital Converter - ADC
17.1
Features
 10-bit resolution
 0.5LSB integral non-linearity
 ±2LSB absolute accuracy
 8s - 250s conversion time
 Up to 120kSPS at maximum resolution
 11 multiplexed single ended input channels
 One differential input channels with accurate (5%) programmable gain 5, 10, 20, and 40
 Optional left adjustment for ADC result readout
 0 - V
CC ADC input voltage range
 Selectable 2.56V 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
 Temperature sensor
The AT90PWM81/161 features a 10-bit successive approximation ADC. The ADC is connected
to an 15-channel Analog Multiplexer which allows eleven single-ended input. The single-ended
voltage inputs refer to 0V (GND).
The device also supports 2 differential voltage input combinations which are equipped with a
programmable gain stage, providing amplification steps of 14dB (5×), 20dB (10×), 26dB (20×),
or 32dB (40×) on the differential input voltage before the A/D conversion. On the amplified chan-
nels, 8-bit resolution can be expected.
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 17-1The ADC has a separate analog supply voltage pin, AV
CC. AVCC must not differ more than ±0.3V
from V
Internal reference voltages of nominally 2.56V or AV
CC are provided On-chip. The voltage refer-
ence may be externally decoupled at the AREF pin by a capacitor for better noise performance.