User's Manual

USER MANUAL 1.34
© 2013 EnOcean | www.enocean.com STM 300 / STM 300C / STM 300U User Manual | Page 13/42
STM 300 / STM 300C / STM 300U
10
0x00
0xFF
ideal
real
Offset Error
Gain Error
Code
ADC
U
ADC
U
RVDD
3.3.2 Analog and digital inputs
Parameter
Conditions / Notes
Min
Typ
Max
Units
Analog Input Mode
Measurement range
Single ended
Internal reference RVDD/2
0.067
RVDD-
0.12
V
Input coupling
DC
Measurement bandwidth
1
62.5
kHz
Input impedance
Single ended against
GND @ 1 kHz
10
M
Input capacitance
Single ended against
GND @ 1 kHz
10
pF
Effective measurement resolution
10
Bit
10 bit measurement
Offset error
23
36
LSB
Gain error
32
62
LSB
INL
Code <=200
+3
-14
+6
-23
LSB
Code >200
+3
-4
+6
-10
LSB
DNL
<±0.5
LSB
8 bit measurement
Offset error
6
9
LSB
Gain error
8
16
LSB
INL
Code <=50
+1
-4
+2
-6
LSB
Code >50
+1
-1
+2
-3
LSB
DNL
<±0.125
LSB
Offset Error: Describes the offset between the minimal possible code and
code 0x00.
Gain Error: Describes the offset between maximum possible code and full
scale (e.g. 0x3FF for 10 bit measurements).
Integral Non-Linearity (INL): Describes the difference between the ideal
characteristics and the real characteristics. Only values between minimum and
maximum possible code are considered (excluding offset error and gain error).
Differential Non-Linearity (DNL): Measures the maximum deviation from
the ideal step size of 1 LSB (least significant bit).
Effective resolution: Results from the signal-noise ratio of the ADC and is
given in Bit. The number describes how many bits can be measured stable. The
criterion selected here is that the noise of DNL is <±0.5 LSB.
Measurement Bandwidth: The measurement bandwitdh is internally
limited by filters. A quasi static signal must be applied as long as the filter
needs to settle. SettlingTime= 1/(MeasurementBandwidth)*ln(2^resolution[Bit])
For further details please refer to the Dolphin Core Description.
1
3 dB input bandwidth, resulting in 111 µs settling time to achieve a deviation of an input
signal <1 LSB (<0.098% @ 10 bit resolution).