ST10F272M-4T3 STMicroelectronics, ST10F272M-4T3 Datasheet - Page 139

• Manufacturer Part Number: ST10F272M-4T3
• Description: MCU 16BIT 256K FLASH 144-LQFP
• Manufacturer: STMicroelectronics
• Series: ST10r

Specifications of ST10F272M-4T3

• Core Processor: ST10
• Core Size: 16-Bit
• Speed: 40MHz
• Connectivity: ASC, CAN, EBI/EMI, I²C, SSC, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 111
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 20K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 24x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 144-MQFP, 144-PQFP
• Processor Series: ST10F27x
• Core: ST10
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

ST10F272M
The considerations above imposes new constraints on the external circuit, to reduce the
accuracy error due to the voltage drop on C
above, it is simple to derive the following relation between the ideal and real sampled
voltage on C
From this formula, in the worst case (when V
assuming to accept a maximum error of half a count (~2.44 mV), a constraint is immediately
evident on C
In the next section an example of how to design the external network is provided, assuming
some reasonable values for the internal parameters and making a hypothesis on the
characteristics of the analog signal to be sampled.
Example of external network sizing
The following hypotheses are formulated in order to proceed in designing the external
network on A/D converter input pins:
●
●
●
●
●
●
●
●
●
●
●
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
S
F
:
value:
S
C
): 1µs
): 25 kHz
P1
S
): 4pF
): 5 pF
-----------
V A2
V A
S
SW
AD
): 100 Ω
=
P2
): 500 Ω
): 200 Ω
C F 2048 C S
0
INJ
------------------------------------------------------------
C P1
): 1 pF
): 10 kHz
AM)
): 3 mA
C P1
>
: 12 V
S
+
A
. From the two charge balance equations
C P2
+
is maximum, that is for instance 5 V),
C P2
⋅
+
C F
+
C F
+
C S
Electrical characteristics
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