Product Specs

Table Of Contents
37 SAADC Successive approximation analog-
to-digital converter
Page
390
CH[n].CONFIG.RESP
R
LADDER
ADC
R
SOURCE
PAD
PSEL
TACQ
C
PAD
R
INPUT
R
LADDER
C
SAMPLE
CH[n].CONFIG.RESP
Symbol
Description
Min.
Typ.
Max.
Units
E
G1/6
Error
b
for Gain = 1/6
-3
3
%
E
G1/4
Error
b
for Gain = 1/4
-3
3
%
E
G1/2
Error
b
for Gain = 1/2
-3
4
%
E
G1
Error
b
for Gain = 1
-3
4
%
C
SAMPLE
Sample and hold capacitance at maximum gain
34
2.5
pF
R
INPUT
Input resistance
>1
E
NOB
Effective number of bits, differential mode, 12-bit resolution,
1/1 gain, 3 µs acquisition time, crystal HFCLK, 200 ksps
9
Bit
S
NDR
Peak signal to noise and distortion ratio, differential mode, 12-
bit resolution, 1/1 gain, 3 µs acquisition time, crystal HFCLK, 200
ksps
56
dB
S
FDR
Spurious free dynamic range, differential mode, 12-bit
resolution, 1/1 gain, 3 µs acquisition time, crystal HFCLK, 200
ksps
70
dBc
R
LADDER
Ladder resistance
160
Figure 105: Model of SAADC input (one channel)
Note: SAADC average current calculation for a given application is based on the sample period, conversion
and acquisition time ( t
conv
and t
ACQ
) and conversion and idle current (I
ADC,CONV
and I
ADC,IDLE
). For example,
sampling at 4kHz gives a sample period of 250µs. The average current consumption would then be:
Figure 106: ADC INL vs Output Code
refresh mode will not be allowed, and it will remain in normal mode from the START task to the STOPPED event.
So depending on t
ACQ
and other resources' needs, the appropriate base current needs to be taken into account.
b
Does not include temperature drift
34
Maximum gain corresponds to highest capacitance.
2
1.5
1
0.5
0
-0.5
-1
-1.5
-2
0 64 128 192 256 320 384 448 512 576 640 704 768 832 896 960
Output code
INL [LSB10b]