Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet
Product codes
ATSAM4S-WPIR-RD
1161
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
Note:
1. N/A: Not applicable
Track and Hold Time versus Source Output Impedance
shows a simplified acquisition path.
Figure 44-17. Simplified Acquisition Path
In 12-bit mode, during the tracking phase, the ADC needs to track the input signal during the tracking time shown
below:
t
TRACK
= 0.054 x Z
SOURCE
+ 205
with t
TRACK
expressed in ns and Z
SOURCE
expressed in
Ω
.
The ADC already includes a tracking time of 15 t
CP_ADC
Two cases must be considered:
1. If the calculated tracking time (t
TRACK
) is lower than 15 t
CP_ADC
, then TRACTIM can be set to 0 .
2. If the calculated tracking time (t
TRACK
) is higher than 15 t
CP_ADC
, then TRACTIM must be set to the correct
value.
1
2 pF
4 pF
2
2 pF
8 pF
4
4
p
F
N/A
Table 44-53.
Z
IN
Input Impedance
f
S
(MHz)
1
0.5
0.25
0.125
0.0625
0.03125
0.015625
0.007813
C
IN
= 2 pF
Z
IN
(M
Ω)
0.5
1
2
4
8
16
32
64
C
IN
= 4 pF
Z
IN
(M
Ω)
0.25
0.5
1
2
4
8
16
32
C
IN
= 8 pF
Z
IN
(M
Ω)
0.125
0.25
0.5
1
2
4
8
16
Table 44-52.
Input Capacitance Values
Sample & Hold
12-bit ADC Core
C
IN
MUX
R
ON
Z
SOURCE