ST10F276Z5 STMicroelectronics, ST10F276Z5 Datasheet - Page 195

• Manufacturer Part Number: ST10F276Z5
• Description: 16-BIT MICROCONTROLLER WITH MAC UNIT, UP TO 832 KBYTES FLASH MEMORY AND UP TO 68 KBYTES RAM
• Manufacturer: STMicroelectronics

Specifications of ST10F276Z5

• Single Voltage Supply: 5V ±10% (embedded regulator for 1.8 V core supply)

ST10F276Z5
23.7.6
Example of external network sizing
The following hypothesis is formulated in order to proceed with designing the external net-
work on A/D converter input pins:
●
●
●
●
●
●
●
●
●
●
●
1.
2.
3.
4.
Now, the three elements of the external circuit R
discussed in the previous paragraphs have been used to size the component; the others
must now be verified. The relation which allows to minimize the accuracy error introduced by
the switched capacitance equivalent resistance is in this case:
So the error due to the voltage partitioning between the real resistive path and C
Analog signal source bandwidth (f
Conversion rate (f
Sampling time (T
Pin input capacitance (C
Pin input routing capacitance (C
Sampling capacitance (C
Maximum input current injection (I
Maximum analog source voltage (V
Analog source impedance (R
Channel switch resistance (R
Sampling switch resistance (R
Supposing to design the filter with the pole exactly at the maximum frequency of the
signal, the time constant of the filter is:
Using the relation between C
it is possible to define C
As a consequence of Step 1 and 2, RC can be chosen:
Considering the current injection limitation and supposing that the source can go up to
12V, the total series resistance can be defined as:
from which is now simple to define the value of R
S
C
): 1µs
): 25 kHz
F
P1
:
S
R L
): 4 pF
): 5 pF
R S
R F
=
F
S
SW
R EQ
AD
V AM
------------ - R F R S
): 100 Ω
and C
I INJ
+
C F
=
R C C F
P2
): 500 Ω
): 200 Ω
R F
-------------------- -
2πf 0 C F
=
0
INJ
): 1 pF
=
):10 kHz
AM)
–
4000 C S
1
+
S
): 3 mA
-------------- -
f C C S
=
R L
and taking some margin (4000 instead of 2048),
: 12 V
1
----------- -
2πf 0
–
=
⋅
=
1
=
995Ω
V AM
------------ -
F
I INJ
, C
=
10MΩ
=
=
16nF
15.9µs
2.9kΩ
F
=
≅
and R
L
4kΩ
:
1kΩ
L
are defined. Some conditions
Electrical characteristics
S
is less
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