
181
4378C–AVR–09/08
AT90PWM1
19. Analog to Digital Converter - ADC
19.1
Features
10-bit Resolution
0.5 LSB Integral Non-linearity
± 2 LSB Absolute Accuracy
8- 250 s Conversion Time
Up to 120 kSPS at Maximum Resolution
11 Multiplexed Single Ended Input Channels
Two 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 2.56 V 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
The AT90PWM1 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 volt-
age 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 (5x), 20 dB (10x), 26 dB (20x),
or 32dB (40x) 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 19-1.The ADC has a separate analog supply voltage pin, AV
CC. AVCC must not differ more than ±
0.3V from V
pin.
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.