ST72F621L4M1 STMicroelectronics, ST72F621L4M1 Datasheet - Page 121

• Manufacturer Part Number: ST72F621L4M1
• Description: IC MCU 8BIT LS 16K 34-SOIC
• Manufacturer: STMicroelectronics
• Series: ST7r

Specifications of ST72F621L4M1

• Core Processor: ST7
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SCI, SPI, USB
• Peripherals: DMA, LVD, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 34-SOIC (7.5mm Width)
• Processor Series: ST72F6x
• Core: ST7
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: SCI, SPI, USB
• Maximum Clock Frequency: 12 MHz
• Number Of Programmable I/os: 23
• Number Of Timers: 2
• Operating Supply Voltage: 4 V to 5.5 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: 0 C
• On-chip Adc: 10 bit
• For Use With: 497-5046 - KIT TOOL FOR ST7/UPSD/STR7 MCU
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: In Transition
• Other names: 497-2112-5

ADC CHARACTERISTICS (Cont’d)
12.12.0.1 Analog Power Supply and Reference
Pins
Depending on the MCU pin count, the package
may feature separate V
er supply pins. These pins supply power to the A/D
converter cell and function as the high and low ref-
erence voltages for the conversion. In some pack-
ages V
to
this case the analog supply and reference pads
are internally bonded to the V
Separation of the digital and analog power pins al-
low board designers to improve A/D performance.
Conversion accuracy can be impacted by voltage
drops and noise in the event of heavily loaded or
badly decoupled power supply lines (see
10.7.3.2 PCB Design
12.12.0.2 General PCB Design Guidelines
To obtain best results, some general design and
layout rules should be followed when designing
the application PCB to shield the noise-sensitive,
analog physical interface from noise-generating
CMOS logic signals.
– Use separate digital and analog planes. The an-
– Filter power to the analog power planes. The
Figure 84. Power Supply Filtering
alog ground plane should be connected to the
digital ground plane via a single point on the
PCB.
best solution is to connect capacitors, with good
Table 1, “Device Pin Description,” on page
DDA
and V
SSA
POWER
SUPPLY
SOURCE
V
Guidelines).
pins are not available (refer
DD
DDA
10μF
and V
DD
and V
ST7
DIGITAL NOISE
FILTERING
SSA
analog pow-
SS
pins.
EXTERNAL
NOISE
FILTERING
Section
8). In
Doc ID 6996 Rev 5
10pF
10pF
0.1μF
0.1μF
– The analog and digital power supplies should be
– Properly place components and route the signal
12.12.0.3
Guidelines
– When a USB transmission is taking place during
– If the USB is used to supply power to the appli-
high frequency characteristics, between the
power and ground lines, placing 0.1µF and 10pF
capacitors as close as possible to the ST7 power
supply pins and a 10µF capacitor close to the
power source (see
connected in a star network. Do not use a resis-
tor, as V
A/D converter and any resistance would cause a
voltage drop and a loss of accuracy.
traces on the PCB to shield the analog inputs.
Analog signals paths should run over the analog
ground plane and be as short as possible. Isolate
analog signals from digital signals that may
switch while the analog inputs are being sampled
by the A/D converter. Do not toggle digital out-
puts on the same I/O port as the A/D input being
converted.
A/D conversion, the noise caused on the analog
power supply by the USB transmission may re-
sult in a loss of ADC accuracy.
cation, this causes noise which may result in a
loss of ADC accuracy.
V
V
V
V
SS
DD
DDA
SSA
DDA
Specific
is used as a reference voltage by the
ST72XXX
Figure
Application
84).
Design
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