F272-BAG-T-TR STMicroelectronics, F272-BAG-T-TR Datasheet - Page 144

• Manufacturer Part Number: F272-BAG-T-TR
• Description: MCU 16BIT 256K FLASH 144-TQFP
• Manufacturer: STMicroelectronics
• Series: ST10r

Specifications of F272-BAG-T-TR

• 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-TQFP, 144-VQFP
• Processor Series: ST10F27x
• Core: ST10
• Data Bus Width: 16 bit
• Data Ram Size: 12 KB
• Interface Type: ASC, CAN, I2C, SSC
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 111
• Number Of Timers: 4
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 24 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: No

Electrical characteristics
144/182
The two transients above are not influenced by the voltage source that, due to the presence
of the R
C
respect to the sampling time (T
Figure
Calling f
the anti-aliasing filter, f
least 2f
the conversion period (T
T
selected (fastest conversion rate at a specific channel): in conclusion it is evident that the
time constant of the filter R
charge level on C
the sampling switch is closed.
Figure 42. Anti-aliasing filter and conversion rate
The considerations above lead to impose new constraints to 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
Anti-Aliasing Filter (f
S
S
, which is just a portion of it, even when fixed channel continuous conversion mode is
Analog Source Bandwidth (V
with respect to the ideal source V
R
Of course, R
combination with R
definitively bigger than C
charge transfer transient) will be much higher than V
respected (charge balance assuming now C
L
42).
0
F
sizing is obtained:
0
; it means that the constant time of the filter is greater than or at least equal to twice
C
the bandwidth of the source signal (and as a consequence the cut-off frequency of
F
filter, is not able to provide the extra charge to compensate the voltage drop on
S
:
f
f
V A2
0
F
S
L
shall be sized also according to the current limitation constraints, in
F
cannot be modified by the analog signal source during the time in which
⋅
= RC Filter pole)
(
Noise
C S C P1 C P2 C F
F
), according to Nyquist theorem the conversion rate f
S
C
10
+
). Again the conversion period T
(source impedance) and R
f
f
F
⋅
C
A
τ 2
P1
F
)
S
+
is definitively much higher than the sampling time T
-----------
V A2
, C
=
). The filter is typically designed to act as anti-aliasing (see
V A
10
P2
A
=
⋅
+
and C
Sampled Signal Spectrum (f
; the time constant R
R
------------------------------------------------------------
C P1
T
f
2 f
F
L
C
= f
0
C P1
)
⋅
≤ 2 R
=
≤ f
S
0
+
(
V A C F
C
, then the final voltage V
C S
(Anti-aliasing Filtering Condition)
C P2
f
(Nyquist)
0
+
F
S
⋅
C
C P2
+
; from the two charge balance equations
F
S
C P1
+
(Conversion Rate vs. Filter Pole)
already charged at V
C F
+
F
+
V A1
(filter resistance). Being C
C F
+
+
C P2
A1
C S
C
⋅
F
. The following equation must be
(
is longer than the sampling time
f
C P1 C P2
C
C
) T S
F
≤
C
of the filter is very high with
+
= conversion Rate)
ST10F272B/ST10F272E
A2
+
(at the end of the
A1
C S
f
):
)
C
must be at
F
S
, so the