ATtiny43U Atmel Corporation, ATtiny43U Datasheet - Page 44

• Manufacturer Part Number: ATtiny43U
• Manufacturer: Atmel Corporation

Specifications of ATtiny43U

• Flash (kbytes): 4 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 8 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 16
• Ext Interrupts: 16
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 4
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.25
• Eeprom (bytes): 64
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 0.7 to 5.5
• Operating Voltage (vcc): 0.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

8.6.2
8.6.3
8.6.4
44
ATtiny43U
Diode
Input Capacitors
RC Filter
... where D is the duty cycle and T
verter Characteristics” on page 159
follows:
Overall efficiency of the boost converter is also affected by the resistance of the inductor.
It is recommended to use a Schottky diode with forward voltage, V
rent, I
forward voltage of the diode when I
noted that the reverse leakage current easily becomes a dominant factor, especially in Active
Low Current Mode. For reference, see converter current consumption during Low Current Mode
in
The diode is subject to peak currents the same magnitude as the inductor. See
page
It should be noted that reverse leakage current is a highly temperature dependent variable.
A voltage drop occurs between the voltage source and inductor L
not ideal and tracks have a non-zero resistance. The voltage drop is application specific and
depends on the quality of the voltage source, inductor current, track size and track length.
Capacitor C
currents.
The highest inductor peak currents are reached at highest load current and lowest V
application. The input capacitor stabilises the input voltage and guarantees stable operation at
all load currents. The size of the capacitor can be decreased if load currents remain low, or if a
voltage supply with low internal resistance is available. Also, a good low-pass filter design (see
section
A secondary input capacitor, C
they form a Low-Pass Filter (LPF), the purpose of which is to reduce the voltage ripple at the
V
Component values are application specific and depend on the stability of the supply voltage. The
LPF reduces voltage ripple at the V
ally entering Stop Mode.
BAT
Table 20-7 on page
pin. The corner frequency of the filter can be calculated as follows:
43.
R
, values as low as possible. This is because converter efficiency mainly depends on the
“RC Filter”
1
counteracts the voltage drop by providing energy to the inductor during high peak
below) reduces the size requirements of the capacitor.
159.
2
, and a series input resistor, R
S
D
BAT
the switching period of the boost converter. See
f
LOAD
LPF
=
for limits. The steady-state duty cycle is calculated as
pin and helps to prevent the boost converter unintention-
⎛
⎝
------------ -
V
V
is at maximum and V
=
BAT
CC
-------------------------------------- -
2
×
–
π
1
-- -
2
⎞
⎠
×
1
×
R
1
×
I
LOAD
C
2
BAT
1
, are recommended. Together
1
because voltage sources are
is at minimum. It should be
F
, and reverse leakage cur-
8048B–AVR–03/09
“Inductor” on
“Boost Con-
BAT
of the