ATMEGA48A-PU Atmel, ATMEGA48A-PU Datasheet - Page 251

• Manufacturer Part Number: ATMEGA48A-PU
• Description: IC MCU AVR 4K FLASH 28PDIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA48A-PU

• 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 6x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Controller Family/series: Atmega
• No. Of I/o's: 23
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 512Byte
• Cpu Speed: 20MHz
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

23. Analog-to-Digital Converter
23.1
23.2
8271C–AVR–08/10
Features
Overview
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The ATmega48A/48PA/88A/88PA/168A/168PA/328/328P features a 10-bit successive approxi-
mation ADC. The ADC is connected to an 8-channel Analog Multiplexer which allows eight
single-ended voltage inputs constructed from the pins of Port A. The single-ended voltage inputs
refer to 0V (GND).
The ADC contains a Sample and Hold circuit which ensures that the input voltage to the ADC is
held at a constant level during conversion. A block diagram of the ADC is shown in
on page
The ADC has a separate analog supply voltage pin, AV
from V
Internal reference voltages of nominally 1.1V or AV
ence may be externally decoupled at the AREF pin by a capacitor for better noise performance.
The Power Reduction ADC bit, PRADC, in
be disabled by writing a logical zero to enable the ADC.
The ADC converts an analog input voltage to a 10-bit digital value through successive approxi-
mation. The minimum value represents GND and the maximum value represents the voltage on
the AREF pin minus 1 LSB. Optionally, AV
nected to the AREF pin by writing to the REFSn bits in the ADMUX Register. The internal
voltage reference may thus be decoupled by an external capacitor at the AREF pin to improve
noise immunity.
ATmega48A/48PA/88A/88PA/168A/168PA/328/328
10-bit Resolution
0.5 LSB Integral Non-linearity
± 2 LSB Absolute Accuracy
13 - 260 µs Conversion Time
Up to 76.9 kSPS (Up to 15 kSPS at Maximum Resolution)
6 Multiplexed Single Ended Input Channels
2 Additional Multiplexed Single Ended Input Channels (TQFP and QFN/MLF Package only)
Temperature Sensor Input Channel
Optional Left Adjustment for ADC Result Readout
0 - V
Selectable 1.1V ADC Reference Voltage
Free Running or Single Conversion Mode
Interrupt on ADC Conversion Complete
Sleep Mode Noise Canceler
CC
CC
252.
ADC Input Voltage Range
. See the paragraph
”ADC Noise Canceler” on page 257
CC
”Minimizing Power Consumption” on page 42
or an internal 1.1V reference voltage may be con-
CC
CC
are provided On-chip. The voltage refer-
. AV
CC
must not differ more than ±0.3V
on how to connect this pin.
Figure 23-1
must
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