SAM3X8E Atmel Corporation, SAM3X8E Datasheet - Page 1417

• Manufacturer Part Number: SAM3X8E
• Manufacturer: Atmel Corporation

11057A–ATARM–17-Feb-12
During the tracking phase the ADC needs to track the input signal during the tracking time
shown below:
With t
Two cases must be considered:
Set TRANSFER = 1 and TRACTIM = 0.
In this case, the allowed Zsource can be computed versus the ADC frequency with
the hypothesis of t
Where t
Table 45-35. Source impedance values
Set TRANSFER = 1 and TRACTIM = 0.
In this case, a timer will trigger the ADC in order to set the correct sampling rate according to the
Track time.
f
20.00
16.00
10.67
8.00
6.40
5.33
4.57
4.00
3.56
3.20
2.91
2.67
2.46
2.29
2.13
2.00
1.00
• 10-bit mode: t
• 12-bit mode: t
1. The calculated tracking time (t
2. The calculated tracking time (t
ADC
= ADC clock (MHz)
TRACK
CP_ADC
expressed in ns and Z
= 1/f
TRACK
TRACK
TRACK
ADC
= 0.042 x Zsource + 160
= 0.054 x Zsource + 205
. See
= 15 × t
Table 45-35 on page
CP_ADC
Z
SOURCE
10
14
22
31
40
48
57
66
74
83
92
100
109
118
126
135
274
SOURCE
TRACK
TRACK
:
expressed in Ohms.
(kOhms) for 12 bits
) is lower than 15 t
) is higher than 15 t
1417.
CP_ADC
CP_ADC
Z
14
19
30
41
52
63
74
85
97
108
119
130
141
152
164
175
353
.
SOURCE
.
(kOhms) for 10 bits
SAM3X/A
1417