CMT2380F64
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Rev 0.3 | 30 / 83
2. Send/receive the lowest bit of the previous byte. There is no send/receive at the lowest level until the first byte.
1.22 ADC Characteristic
ADC characteristics
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
V
DDA
Supply voltage
-
2.4
3.3
5.5
V
V
REF+
Positive reference voltage
-
2.4
-
V
DDA
V
f
ADC
ADC clock frequency
-
-
-
18
MHz
f
s
(1)
Sampling rate
-
-
0.89
1.33
Msps
V
AIN
Conversion voltage range (2)
-
0
-
V
REF+
V
R
AIN
(1)
External input impedance
-
See formula 1
Ω
R
ADC
(1)
ADC input resistance
V
DDA
=3.0 v
-
1500
-
Ω
C
ADC
(1)
Internal sample and holding
capacitor
-
-
13
15
pF
SNDR
Signal noise distortion ration
V
DDA
=3.3 v
-
68
-
dB
t
S
(1)
Sampling time
-
6
-
-
1/f
ADC
t
STAB
(1)
Power-on time
-
32
-
-
1/f
ADC
t
CONV
(1)
Conversion time
-
12
1/f
ADC
1.
Guaranteed by design and comprehensive evaluation, not tested in production.
2.
VREF+ is internally connected to VDDA
。
Formula 1
：
maximum RAIN formula
R
AIN
<
T
S
f
ADC
× C
ADC
× ln(2
N+2
)
− R
ADC
The above formula is used to determine the maximum impedence so that the error can be less than 1/4 LSB, where
N=12( representing 12 bit resolution).
ADC Accuracy
(1)(2)
Symbol
Parameter
Conditions
Typ
Max
Unit
EG
Gain error
V
REF+
= 3.3 V
，
T
A
= 25 °C
，
Vin = 0.05 V
DDA
~ 0.95 V
DDA
±2
±5
LSB
EO
Offset error
±0.5
±2.0
ED
Differential linearity error
±0.6
1.5
EL
Integral linearity error
±1.5
2.5
ENOB
Effective number of bits
11
-
Bits
1. DC numerical accuracy of the ADC is measured after internal calibration.
2 .
Relationship between the reverse injection current and ADC accuracy: it is needed to avoid reverse current injected on any
standard analog input pin, as this will significantly reduce conversion accuracy of the other ongoing analog input pin . It is
recommended to add a Schottky diode (between the pin and ground) on the standard analog pin that may produce reverse
injection current.
3. Guaranteed by design and comprehensive evaluation, not tested in production.
