AT90PWM2B-16SE ATMEL [ATMEL Corporation], AT90PWM2B-16SE Datasheet - Page 241

• Manufacturer Part Number: AT90PWM2B-16SE
• Description: 8-bit Microcontroller with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

21.6.2
4317J–AVR–08/10
Analog Noise Canceling Techniques
Figure 21-8. Analog Input Circuitry
Digital circuitry inside and outside the device generates EMI which might affect the accuracy of
analog measurements. If conversion accuracy is critical, the noise level can be reduced by
applying the following techniques:
Figure 21-9. ADC Power Connections
1. Keep analog signal paths as short as possible. Make sure analog tracks run over the
2. The AV
3. Use the ADC noise canceler function to reduce induced noise from the CPU.
4. If any ADC port pins are used as digital outputs, it is essential that these do not
analog ground plane, and keep them well away from high-speed switching digital
tracks.
an LC network as shown in
switch while a conversion is in progress.
CC
(ADC1) PD4
(ADC0) PE2
pin on the device should be connected to the digital V
GND
VCC
ADCn
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Figure
I
IH
21-9.
I
IL
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
Analog Ground Plane
1..100 kΩ
PB7(ADC4)
PB6 (ADC7)
PB5 (ADC6)
PC7 (D2A)
PB4 (AMP0+)
PB3 (AMP0-)
PC6 (ADC10/ACMP1)
AREF
AGND
AVCC
PC5 (ADC9/AMP1+)
PC4 (ADC8/AMP1-)
PB2 (ADC5)
PD7 (ACMP0)
PD6 (ADC3/ACMPM)
PD5 (ADC2/ACMP2)
AT90PWM2/3/2B/3B
C
S/H
= 14 pF
CC
V
CC
supply voltage via
/2
100nF
241