F272-BAGE-T-TR STMicroelectronics, F272-BAGE-T-TR Datasheet - Page 141

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

Specifications of F272-BAGE-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
• Data Bus Width: 16 bit
• Data Ram Size: 20 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

ST10F272B/ST10F272E
24.7.4
Figure 39. A/D conversion characteristic
Analog reference pins
The accuracy of the A/D converter depends on how accurate is its analog reference: a noise
in the reference results in at least that much error in a conversion. A low pass filter on the
A/D converter reference source (supplied through pins V
in order to clean the signal, minimizing the noise. A simple capacitive bypassing may be
sufficient in most of the cases; in presence of high RF noise energy, inductors or ferrite
beads may be necessary.
In this architecture, V
circuitry of the A/D converter: there is an effective DC current requirement from the
reference voltage by the internal resistor string in the R-C DAC array and by the rest of the
analog circuitry.
An external resistance on V
reasons, series resistance are not advisable, and more in general any series devices in the
filter network should be designed to minimize the DC resistance.
Analog Input pins
To improve the accuracy of the A/D converter, it is definitively necessary that analog input
pins have low AC impedance. Placing a capacitor with good high frequency characteristics
at the input pin of the device, can be effective: the capacitor should be as large as possible,
ideally infinite. This capacitor contributes to attenuating the noise present on the input pin;
Digital
Out
(HEX)
Offset Error OFS
3FE
3FD
3FC
3FB
3FA
3FF
007
006
005
004
003
002
001
000
1
2
3
AREF
Ideal Characteristic
4
1 LSB (ideal)
and V
AREF
5
(7)
6
V
[LSB
AIN
(4)
AGND
could introduce error under certain conditions: for this
(3)
IDEAL
7
(LSB
(2)
(5)
IDEAL
pins represents also the power supply of the analog
= V
AREF
)
1018
/ 1024]
(6)
1020
(1)
(1) Example of an actual transfer curve
(2) The ideal transfer curve
(3) Differential Non-Linearity Error (DNL)
(4) Integral Non-Linearity Error (INL)
(5) Center of a step of the actual transfer curve
(6) Quantization Error (1/2 LSB)
(7) Total Unadjusted Error (TUE)
Offset Error OFS
AREF
1022
and V
Electrical characteristics
1024
AGND
Bisector Characteristic
Gain Error GE
), is recommended
141/182