ATMEGA48A-AU Atmel, ATMEGA48A-AU Datasheet - Page 258

IC MCU AVR 4K FLASH 32TQFP

ATMEGA48A-AU

Manufacturer Part Number
ATMEGA48A-AU
Description
IC MCU AVR 4K FLASH 32TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA48A-AU

Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
23
Program Memory Size
4KB (2K x 16)
Program Memory Type
FLASH
Eeprom Size
256 x 8
Ram Size
512 x 8
Voltage - Supply (vcc/vdd)
1.8 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
32-TQFP, 32-VQFP
Controller Family/series
Atmega
No. Of I/o's
23
Eeprom Memory Size
256Byte
Ram Memory Size
512Byte
Cpu Speed
20MHz
Rohs Compliant
Yes
Processor Series
ATmega
Core
AVR
Data Bus Width
8 bit
Data Ram Size
512 B
Interface Type
TWI, SPI, USART
Maximum Clock Frequency
20 MHz
Number Of Programmable I/os
23
Number Of Timers
3
Operating Supply Voltage
3.3 V
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
Minimum Operating Temperature
- 40 C
Operating Temperature Range
- 40 C to + 85 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATMEGA48A-AU
Manufacturer:
Atmel
Quantity:
10 000
Part Number:
ATMEGA48A-AUR
Manufacturer:
Atmel
Quantity:
10 000
23.6.1
23.6.2
8271C–AVR–08/10
Analog Input Circuitry
Analog Noise Canceling Techniques
The analog input circuitry for single ended channels is illustrated in Figure 23-8. An analog
source applied to ADCn is subjected to the pin capacitance and input leakage of that pin, regard-
less of whether that channel is selected as input for the ADC. When the channel is selected, the
source must drive the S/H capacitor through the series resistance (combined resistance in the
input path).
The ADC is optimized for analog signals with an output impedance of approximately 10 kΩ or
less. If such a source is used, the sampling time will be negligible. If a source with higher imped-
ance is used, the sampling time will depend on how long time the source needs to charge the
S/H capacitor, with can vary widely. The user is recommended to only use low impedance
sources with slowly varying signals, since this minimizes the required charge transfer to the S/H
capacitor.
Signal components higher than the Nyquist frequency (f
kind of channels, to avoid distortion from unpredictable signal convolution. The user is advised
to remove high frequency components with a low-pass filter before applying the signals as
inputs to the ADC.
Figure 23-8. Analog Input Circuitry
Digital circuitry inside and outside the device generates EMI which might affect the accuracy of
analog measurements. If conversion accuracy is critical, the noise level can be reduced by
applying the following techniques:
ATmega48A/48PA/88A/88PA/168A/168PA/328/328
a. Keep analog signal paths as short as possible. Make sure analog tracks run over the
b. The AV
c. Use the ADC noise canceler function to reduce induced noise from the CPU.
d. If any ADC [3...0] port pins are used as digital outputs, it is essential that these do not
analog ground plane, and keep them well away from high-speed switching digital
tracks.
an LC network as shown in
switch while a conversion is in progress. However, using the 2-wire Interface (ADC4
ADCn
CC
pin on the device should be connected to the digital V
I
IH
I
Figure
IL
23-9.
1..100 kΩ
ADC
/2) should not be present for either
C
S/H
= 14 pF
CC
supply voltage via
V
CC
/2
258

Related parts for ATMEGA48A-AU