SAM3SD8B Atmel Corporation, SAM3SD8B Datasheet - Page 1096

• Manufacturer Part Number: SAM3SD8B
• Manufacturer: Atmel Corporation

1096
1096
SAM3S8/SD8
SAM3S8/SD8
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 40-35. 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.
The maximum possible sampling frequency will be defined by t
by the previous formula but with minus 15 × t
Note:
Note:
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
1. The calculated tracking time (t
2. The calculated tracking time (t
• 10 bit mode: 1/f
• 12 bit mode: 1/f
ADC
= ADC clock (MHz)
CP_ADC
Csample and Ron are taken into account in the formulas
1. Input Voltage range can be up to VDDIN without destruction or over-consumption.
If VDDIO < V
= 1/f
TRACK
S
S
ADC
= t
= t
TRACK
TRACK
ADVREF
. See
= 15 × t
- 15 × t
- 15 × t
max input voltage is VDDIO.
Table
CP_ADC
Z
10
14
22
31
40
48
57
66
74
83
92
100
109
118
126
135
274
SOURCE
40-35.
TRACK
TRACK
CP_ADC
CP_ADC
:
(kOhms) for 12 bits
) is lower than 15 t
) is higher than 15 t
+ 5 t
+ 5 t
CP_ADC
CP_ADC
CP_ADC
and plus TRANSFER time.
CP_ADC
CP_ADC
TRACK
Z
14
19
30
41
52
63
74
85
97
108
119
130
141
152
164
175
353
.
SOURCE
.
in nano seconds, computed
(kOhms) for 10 bits
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12