AT90CAN64-16AUR Atmel, AT90CAN64-16AUR Datasheet - Page 383

• Manufacturer Part Number: AT90CAN64-16AUR
• Description: MCU AVR 64K FLASH 16MHZ 64TQFP
• Manufacturer: Atmel
• Series: AVR® 90CANr

Specifications of AT90CAN64-16AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: CAN, EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

27. Decoupling Capacitors
7679H–CAN–08/08
The operating frequency (i.e. system clock) of the processor determines in 95% of cases the
value needed for microcontroller decoupling capacitors.
The hypotheses used as first evaluation for decoupling capacitors are:
Figure 27-1. Capacitor description
According to the operating frequency of the product, the decoupling capacitances are chosen
considering the frequencies to filter,
The relation between frequencies to cut and decoupling characteristics are defined by:
where:
Then, in normalized value range, the decoupling capacitors become:
Table 27-1.
These decoupling capacitors must to be implemented as close as possible to each pair of power
supply pins:
Nevertheless, a bulk capacitor of 10-47 µF is also needed on the power distribution network of
the PCB, near the power source.
For further information, please refer to Application Notes AVR040 “EMC Design Considerations“
and AVR042 “Hardware Design Considerations“ on the Atmel web site.
• The operating frequency (
• An SMC capacitor connected to 2 micro-vias on a PCB has the following characteristics:
peaks are located at
– 1.5 nH from the connection of the capacitor to the PCB,
– 1.5 nH from the capacitor intrinsic inductance.
– L: the inductance equivalent to the global inductance on the Vcc/Gnd lines.
– C
– 21-22 and 52-53 for logic sub-system,
– 64-63 for analogical sub-system.
f
1
op
& C
, operating frequency
2
Decoupling Capacitors vs. Frequency
: decoupling capacitors (C
16 MHz
12 MHz
10 MHz
8 MHz
6 MHz
4 MHz
f
op
and 2 •
f
op
) supplies itself the maximum peak levels of noise. The main
f
op
f
op
f
op
=
.
and 2 •
---------------------- -
2Π LC
0.75 nH
1
= 4 • C
1
1
f
op
.
2
).
Capacitor
120 nF
220 nF
560 nF
33 nF
56 nF
82 nF
1.5 nH
C
and
1
AT90CAN32/64/128
2
•
0.75 nH
f
op
=
PCB
---------------------- -
2Π LC
1
120 nF
10 nF
15 nF
22 nF
33 nF
56 nF
C
2
2
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