ST72361K6 STMicroelectronics, ST72361K6 Datasheet - Page 206

• Manufacturer Part Number: ST72361K6
• Description: 8-bit MCU
• Manufacturer: STMicroelectronics

Specifications of ST72361K6

• Hdflash Endurance: 100 cycles, data retention 40 years at 85°C
• 5 Power Saving Modes: Halt, Auto Wake Up From Halt, Active Halt, Wait and Slow

ST72361
ADC CHARACTERISTICS (Cont’d)
12.13.0.1 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 smaller
packages V
and the analog supply and reference pads are in-
ternally 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
12.13.0.2 "General PCB Design
12.13.0.2 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-
Figure 122. Power Supply Filtering
206/225
alog ground plane should be connected to the
digital ground plane via a single point on the
PCB.
DDA
and V
SSA
DDA
DD
POWER
SUPPLY
SOURCE
and V
pins are not available
and V
V
DD
Guidelines").
SS
SSA
1 to 10μF
pins.
analog pow-
ST7
DIGITAL NOISE
FILTERING
Section
EXTERNAL
NOISE
FILTERING
– Filter power to the analog power planes. It is rec-
– The analog and digital power supplies should be
– Properly place components and route the signal
12.13.0.3
Conversion Results
For EMC performance reasons, it is recommend-
ed to filter A/D conversion outliers using software
filtering techniques.
ommended to connect capacitors, with good high
frequency characteristics, between the power
and ground lines, placing 0.1µF and optionally, if
needed 10pF capacitors as close as possible to
the ST7 power supply pins and a 1 to 10µF ca-
pacitor close to the power source (see
122).
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.
0.1μF
0.1μF
DDA
Software
is used as a reference voltage by the
V
V
V
V
SS
DD
DDA
SSA
ST72XXX
Filtering
of
Spurious
Figure