Datasheet

197
AT8xC51SND1C
4109E–8051–06/03
Analog to Digital Converter
Definition of symbols Table 172. Analog to Digital Converter Timing Symbol Definitions
Characteristics Table 173. Analog to Digital Converter AC Characteristics
V
DD
= 2.7 to 3.3 V, T
A
= -40 to +85°C
Notes: 1. AV
DD
= AV
REFP
= 3.0 V, AV
SS
= AV
REFN
= 0 V. ADC is monotonic with no missing code.
2. The differential non-linearity is the difference between the actual step width and the
ideal step width (see Figure 154).
3. The integral non-linearity is the peak difference between the center of the actual step
and the ideal transfer curve after appropriate adjustment of gain and offset errors
(see Figure 154).
4. The offset error is the absolute difference between the straight line which fits the
actual transfer curve (after removing of gain error), and the straight line which fits the
ideal transfer curve (see Figure 154).
5. The gain error is the relative difference in percent between the straight line which fits
the actual transfer curve (after removing of offset error), and the straight line which
fits the ideal transfer curve (see Figure 154).
Waveforms Figure 153. Analog to Digital Converter Internal Waveforms
Signals Conditions
C Clock H High
E Enable (ADEN bit) L Low
S
Start Conversion
(ADSST bit)
Symbol Parameter Min Max Unit
T
CLCL
Clock Period 4 µs
T
EHSH
Start-up Time 4 µs
T
SHSL
Conversion Time 11·T
CLCL
µs
DLe
Differential non-
linearity error
(1)(2)
1LSB
ILe
Integral non-
linearity errorss
(1)(3)
2LSB
OSe Offset error
(1)(4)
4LSB
Ge Gain error
(1)(5)
4LSB
ADEN Bit
ADSST Bit
T
EHSH
T
SHSL
CLK
T
CLCL