ata5773 ATMEL Corporation, ata5773 Datasheet - Page 192

• Manufacturer Part Number: ata5773
• Description: Microcontroller With Uhf Ask/fsk Transmitter
• Manufacturer: ATMEL Corporation

16.9
16.10 ADC Accuracy Definitions
140
Noise Canceling Techniques
ATtiny24/44/84
Figure 16-8. Analog Input Circuitry
Note:
Digital circuitry inside and outside the device generates EMI which might affect the accuracy of
analog measurements. When conversion accuracy is critical, the noise level can be reduced by
applying the following techniques:
Where high ADC accuracy is required it is recommended to use ADC Noise Reduction Mode, as
described in
is above 1 MHz, or when the ADC is used for reading the internal temperature sensor, as
described in
bypass capacitors does reduce the need for using ADC Noise Reduction Mode
An n-bit single-ended ADC converts a voltage linearly between GND and V
(LSBs). The lowest code is read as 0, and the highest code is read as 2
Several parameters describe the deviation from the ideal behavior:
• Keep analog signal paths as short as possible.
• Make sure analog tracks run over the analog ground plane.
• Keep analog tracks well away from high-speed switching digital tracks.
• If any port pin is used as a digital output, it mustn’t switch while a conversion is in progress.
• Place bypass capacitors as close to V
The capacitor in the figure depicts the total capacitance, including the sample/hold capacitor and
any stray or parasitic capacitance inside the device. The value given is worst case.
ADCn
Section 16.7 on page
Section 16.12 on page
I
IH
139. This is especially the case when system clock frequency
I
IL
144. A good system design with properly placed, external
CC
and GND pins as possible.
1..100 kohm
C
S/H
= 14 pF
n
-1.
V
CC
REF
/2
8006G–AVR–01/08
in 2
n
steps