Microchip Technology

ATMEGA328P-AU - 8-bit AVR MCU 32KB Flash | Microchip

Name: ATMEGA328P-AU
Brand: Microchip Technology
Price: 1.6 USD
Availability: InStock

MPN: ATMEGA328P-AU ✓ Active

In Stock Ships in 1-3 business days

1.8V to 5.5V Vdss 32-TQFP (7x7 mm) Package 20 MHz Speed 32 KB (16K x 16) Memory

From $1.6 USD / Unit

MOQ: 1 |

Price updated: 2026-08-25

Volume Pricing

Qty	Unit Price	Extended
1	$2.5	$2.50
10	$2.25	$22.50
100	$1.95	$195.00
500	$1.75	$875.00
1,000	$1.6	$1,600.00

ℹ️ All prices are in USD

View Datasheet (PDF) View Alternatives

Quantity

Drop-in alternatives for ATMEGA328P-AU — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.

Quick Comparison Tool — Select alternative parts for side-by-side comparison:

ATMEGA328PB-AU

✅ Drop-In

📦 32-TQFP (7x7 mm)

Enhanced version with 5 extra I/O, 2 extra timers, and additional serial interfaces; pin-compatible

📋 Reference alternative (not in catalog)

ATMEGA328P-AUR

✅ Drop-In

📦 32-TQFP (7x7 mm)

Same die, tape and reel packaging variant

📋 Reference alternative (not in catalog)

ATMEGA168PA-AU

✅ Drop-In

📦 32-TQFP (7x7 mm)

Half the flash (16 KB) and EEPROM (512 B), same pinout

📋 Reference alternative (not in catalog)

LGT8F328P

✅ Drop-In

📦 32-TQFP (7x7 mm)

Clone with 32 MHz clock, pin-compatible, but not officially from Microchip

📋 Reference alternative (not in catalog)

ℹ️ 2 cross-package part(s) hidden — different package requires PCB rework and is not a true drop-in replacement. Contact us if you need cross-package suggestions.

ATMEGA328P-AU Maximum Ratings & Electrical Characteristics

Core Processor	AVR
Core Size	8-Bit
Speed	20 MHz
Program Memory Size	32 KB (16K x 16)
Program Memory Type	FLASH
EEPROM Size	1 KB
RAM Size	2 KB
Number of I/O	23
Number of Timers/Counters	3
ADC Channels	8
ADC Resolution	10-bit
Operating Voltage	1.8V to 5.5V
Operating Temperature	-40°C to +85°C
Package	32-TQFP (7x7 mm)
Mounting Type	Surface Mount
RoHS Status	Compliant

ATMEGA328P-AU Pin Configuration

Pin 1	PD3 (PCINT19/OC2B/INT1) — Port D, bit 3 - External interrupt 1, PWM output
Pin 2	PD4 (PCINT20/XCK/T0) — Port D, bit 4 - USART external clock, timer0 external counter
Pin 3	GND — Ground
Pin 4	VCC — Digital supply voltage
Pin 5	GND — Ground
Pin 6	VCC — Digital supply voltage
Pin 7	XTAL1/TOSC1 — Crystal oscillator input or timer oscillator
Pin 8	XTAL2/TOSC2 — Crystal oscillator output or timer oscillator
Pin 9	PD5 (PCINT21/OC0B/T1) — Port D, bit 5 - PWM output, timer1 external counter
Pin 10	PD6 (PCINT22/OC0A/AIN0) — Port D, bit 6 - PWM output, analog comparator positive input
Pin 11	PD7 (PCINT23/AIN1) — Port D, bit 7 - Analog comparator negative input
Pin 12	PB0 (PCINT0/CLKO/ICP1) — Port B, bit 0 - Clock output, timer1 input capture
Pin 13	PB1 (PCINT1/OC1A) — Port B, bit 1 - PWM output
Pin 14	PB2 (PCINT2/OC1B/SS) — Port B, bit 2 - PWM output, SPI slave select
Pin 15	PB3 (PCINT3/OC2A/MOSI) — Port B, bit 3 - PWM output, SPI master out
Pin 16	PB4 (PCINT4/MISO) — Port B, bit 4 - SPI master in
Pin 17	PB5 (PCINT5/SCK) — Port B, bit 5 - SPI clock
Pin 18	AVCC — Analog supply voltage
Pin 19	ADC7 — ADC input channel 7
Pin 20	AREF — Analog reference
Pin 21	GND — Ground
Pin 22	ADC6 — ADC input channel 6
Pin 23	PC0 (PCINT8/ADC0) — Port C, bit 0 - ADC input channel 0
Pin 24	PC1 (PCINT9/ADC1) — Port C, bit 1 - ADC input channel 1
Pin 25	PC2 (PCINT10/ADC2) — Port C, bit 2 - ADC input channel 2
Pin 26	PC3 (PCINT11/ADC3) — Port C, bit 3 - ADC input channel 3
Pin 27	PC4 (PCINT12/ADC4/SDA) — Port C, bit 4 - ADC input, I2C data
Pin 28	PC5 (PCINT13/ADC5/SCL) — Port C, bit 5 - ADC input, I2C clock
Pin 29	PC6 (PCINT14/RESET) — Port C, bit 6 - Reset pin (active low)
Pin 30	PD0 (PCINT16/RXD) — Port D, bit 0 - USART receive
Pin 31	PD1 (PCINT17/TXD) — Port D, bit 1 - USART transmit
Pin 32	PD2 (PCINT18/INT0) — Port D, bit 2 - External interrupt 0

Safe Operating Area (SOA) & Thermal Characteristics

No official SOA curve available for this digital IC. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.

Typical Applications

ATMEGA328P-AU is suitable for 6 applications: Arduino Development Boards, IoT Sensor Nodes, Motor Control, Wearable Devices, Educational Platforms, Home Automation.

🔧

Arduino Development Boards

The ATMEGA328P-AU is the core of Arduino Uno and Nano boards, providing a familiar platform for hobbyists and professionals. Its 32 KB flash and rich peripheral set support a wide range of projects, from LED blinkers to complex sensor networks. The 20 MHz clock and 10-bit ADC enable precise analog readings, while the USART, SPI, and I2C interfaces allow easy communication with modules. The low-power sleep modes are beneficial for battery-powered Arduino projects, extending battery life significantly. The extensive community support and libraries make development rapid and efficient.

Recommended

🧩

IoT Sensor Nodes

In IoT applications, the ATMEGA328P-AU excels as a low-power sensor node controller. Its picoPower technology allows sleep currents as low as 0.2 µA, enabling years of operation on coin-cell batteries. The 8-channel 10-bit ADC can interface with various analog sensors, while the I2C and SPI interfaces connect to digital sensors like temperature, humidity, and pressure sensors. The device can wake up periodically to read sensors and transmit data via a radio module (e.g., LoRa, Zigbee) using the USART. The 32 KB flash is sufficient for sensor firmware and communication protocols. The wide operating voltage range (1.8V-5.5V) accommodates different battery chemistries.

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CC2541-Q1 · Texas Instruments TMP117 · Texas Instruments

🏭

Motor Control

The ATMEGA328P-AU is well-suited for small motor control applications, such as drones, robots, and CNC machines. It features six PWM channels with high resolution, enabling smooth speed control of DC motors and servos. The 16-bit timer can generate precise PWM signals for servo control. The device's 20 MHz clock provides fast response for closed-loop control algorithms. The ADC can read current sensors and encoders for feedback. The 23 I/O pins allow interfacing with motor drivers, H-bridges, and quadrature encoders. The industrial temperature grade (-40°C to +85°C) ensures reliable operation in harsh environments. For more complex motor control, consider the ATmega328PB with additional timers.

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DRV8825PWPR · Texas Instruments DRV8876PWPT · Texas Instruments

📱

Wearable Devices

The ATMEGA328P-AU's low power consumption and small TQFP package make it ideal for wearable devices like fitness trackers and smartwatches. The device can operate at 1.8V, directly compatible with lithium-ion batteries. The power-down mode with wake-up on external interrupt or watchdog timer allows the MCU to sleep most of the time, consuming only microamps. The integrated temperature sensor and ADC can monitor body temperature and battery voltage. The I2C interface connects to accelerometers and heart-rate sensors. The 32 KB flash is enough for firmware and data logging. The 23 I/O pins support displays, buttons, and haptic drivers. The device's robustness and long-term availability make it a reliable choice for consumer wearables.

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MSP430FR2433IRGER · Texas Instruments BQ25601RTWR · Texas Instruments

🔧

Educational Platforms

The ATMEGA328P-AU is widely used in educational settings to teach embedded systems and programming. Its simplicity and extensive documentation make it accessible to beginners. The Arduino ecosystem provides a low-barrier entry with a user-friendly IDE and countless tutorials. The device's 32 KB flash allows students to implement moderately complex projects, such as line-following robots, weather stations, and home automation systems. The 10-bit ADC and PWM enable analog and digital experiments. The DIP and TQFP packages accommodate both breadboard and SMD soldering practice. The low cost and availability of clones make it affordable for classroom use. The community support ensures students can find help online.

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LM324QT · STMicroelectronics CD4052BPWR · Texas Instruments

🏠

Home Automation

In home automation, the ATMEGA328P-AU serves as a cost-effective controller for smart switches, thermostats, and lighting systems. Its 23 I/O pins can interface with relays, triacs, and sensors. The device can communicate with a central hub via UART, SPI, or I2C, or directly with Wi-Fi modules like ESP8266. The low-power modes allow battery-operated devices like wireless sensors to last for months. The 10-bit ADC can read light levels and temperature for automated lighting and HVAC control. The flash memory can store configuration settings and schedules. The device's reliability and long lifecycle make it suitable for always-on applications. For more complex automation, consider the ATmega328PB with additional serial interfaces.

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TJA1042 · NXP Semiconductors TCA9548APWR · Texas Instruments

Recommended Products Summary

What is the operating voltage of ATMEGA328P-AU?

The ATMEGA328P-AU operates from 1.8V to 5.5V. According to the Microchip datasheet, the device is fully functional across this range, with a maximum clock speed of 20 MHz at 4.5V-5.5V, 16 MHz at 2.7V-5.5V, and 8 MHz at 1.8V-5.5V. This wide range makes it suitable for both 3.3V and 5V systems.

What is the difference between ATMEGA328P-AU and ATMEGA328P-PU?

The ATMEGA328P-AU is the 32-pin TQFP surface-mount package, while the ATMEGA328P-PU is the 28-pin PDIP through-hole package. Both have the same core, memory, and peripherals, but the -AU offers 23 I/O pins (vs 23 on -PU? Actually -PU has 23 I/O as well, but the -AU has 32 pins total with more pins for power/ground). The -AU is smaller and suited for SMD assembly, while the -PU is breadboard-friendly. They are not pin-compatible due to different packages.

Can ATMEGA328P-AU be used with Arduino?

Yes, the ATMEGA328P-AU is the microcontroller used on Arduino Uno and Nano boards. It can be programmed using the Arduino IDE with the appropriate bootloader. The TQFP package is commonly used in SMD versions of Arduino Nano. You can use an Arduino board as an ISP programmer to burn the bootloader and upload sketches.

What is the maximum clock speed of ATMEGA328P-AU?

The maximum clock speed is 20 MHz at a supply voltage of 4.5V to 5.5V. At lower voltages, the maximum frequency is reduced: 16 MHz at 2.7V-5.5V and 8 MHz at 1.8V-5.5V. The device can be clocked from an external crystal, resonator, or the internal RC oscillator (8 MHz calibrated).

How much flash memory does ATMEGA328P-AU have?

The ATMEGA328P-AU has 32 KB of in-system programmable flash memory, organized as 16K x 16 bits. It also includes 1 KB EEPROM and 2 KB SRAM. The flash memory supports read-while-write, allowing the CPU to execute code while updating the flash, which is useful for bootloaders and data logging.

What is the power consumption of ATMEGA328P-AU in sleep mode?

In Power-down mode, the ATMEGA328P-AU consumes typically 0.2 µA at 1.8V and 25°C, and 1 µA at 3V. In Idle mode, it consumes about 0.4 mA at 3V, 8 MHz. These low-power modes make it ideal for battery-powered applications. The picoPower technology enables this ultra-low power consumption.

Where can I buy ATMEGA328P-AU online?

You can purchase ATMEGA328P-AU from authorized distributors such as DigiKey, Mouser, and Octopart. As of 2026-08-25, DigiKey lists it at $2.50 for single-unit quantities, with volume discounts available. XAIPART also offers this part with competitive pricing and fast shipping. Check stock availability before ordering.

What is the price of ATMEGA328P-AU?

As of 2026-08-25, the price for ATMEGA328P-AU is approximately $2.50 for 1 unit, $2.25 for 10 units, $1.95 for 100 units, $1.75 for 500 units, and $1.60 for 1000 units. Prices may vary by distributor and quantity. For the most current pricing, check DigiKey or Mouser.

What is the lead time for ATMEGA328P-AU?

The lead time for ATMEGA328P-AU is typically 1-2 weeks from major distributors like DigiKey and Mouser, depending on stock levels. During supply chain shortages, lead times may extend to 4-6 weeks. XAIPART can provide real-time availability and lead time information upon request.

Is ATMEGA328P-AU in stock?

As of 2026-08-25, ATMEGA328P-AU is in stock at major distributors like DigiKey and Mouser. However, stock levels can fluctuate. Check the distributor's website for real-time inventory. XAIPART also maintains stock and can provide immediate availability.

ATMEGA328P-AU vs ATMEGA328PB-AU: which is better for a new design?

The ATMEGA328PB-AU is a superset of the ATMEGA328P-AU, offering 5 additional I/O pins (28 total), two extra timers, and additional serial interfaces (USART, SPI, I2C). It is pin-compatible with the ATMEGA328P-AU in the same TQFP-32 package, making it a drop-in upgrade. For new designs, the ATMEGA328PB-AU is often preferred due to its enhanced features and better availability, but it requires a different bootloader and may have slight differences in register mapping.

When should I choose ATMEGA328P-AU over ATMEGA328PB-AU?

Choose the ATMEGA328P-AU when you need a proven, widely-supported microcontroller with extensive community resources and compatibility with existing Arduino designs. It is ideal for projects where the extra features of the 328PB are not needed, and where you want to minimize software changes. The 328P is also slightly cheaper in some quantities. However, if you need more I/O or peripherals, the 328PB is a better choice.

What is the best drop-in replacement for ATMEGA328P-AU?

The best drop-in replacement for ATMEGA328P-AU is the ATMEGA328PB-AU, which is pin-compatible and offers enhanced features. Another option is the ATMEGA328P-AUR (tape and reel version) for automated assembly. For a lower-cost alternative, the ATMEGA168PA-AU has the same pinout but half the flash (16 KB) and EEPROM (512 B). Always verify the bootloader and fuse settings when replacing.

Can ATMEGA328P-AU be replaced by ATMEGA328P-MU?

The ATMEGA328P-MU is the QFN-32 package version of the same microcontroller. It is functionally identical but has a different package (QFN vs TQFP), so it is not a drop-in replacement on the same PCB footprint. You would need to redesign the PCB to use the QFN package. For a true drop-in replacement, stick with the -AU (TQFP) or -PB-AU.

Where can I download the ATMEGA328P-AU datasheet PDF?

You can download the ATMEGA328P-AU datasheet PDF from the Microchip website at https://www.microchip.com/en-us/product/ATMEGA328P. It is also available on datasheets.com, alldatasheet.com, and Octopart. The datasheet contains full specifications, pinout, electrical characteristics, and application notes.

What are the key specifications of ATMEGA328P-AU that engineers should know?

The ATMEGA328P-AU is an 8-bit AVR microcontroller with 32 KB flash, 2 KB SRAM, 1 KB EEPROM, 23 I/O pins, and a 10-bit ADC with 8 channels. It operates at up to 20 MHz and from 1.8V to 5.5V. It includes three timers, six PWM channels, USART, SPI, I2C, and a watchdog timer. Its low-power picoPower technology enables 0.2 µA sleep current, making it ideal for battery-powered applications.

Hey Google, what can replace ATMEGA328P-AU?

The ATMEGA328P-AU can be replaced by the ATMEGA328PB-AU, which is pin-compatible and offers more I/O and peripherals. Other alternatives include the ATMEGA168PA-AU (less memory) and the LGT8F328P (a clone with higher clock speed). For a different architecture, the PIC16F887 or STM32F030 are options but require a redesign. Always verify pin compatibility and software changes.

Is ATMEGA328P-AU the same as ATMEGA328P-MU?

No, they are not the same. The ATMEGA328P-AU is in a TQFP-32 package, while the ATMEGA328P-MU is in a QFN-32 package. They have the same silicon and functionality, but the package and pin layout differ. The -AU has gull-wing leads, while the -MU has exposed pad and no leads. They are not pin-compatible and require different PCB footprints.

What is the best Microchip equivalent for ATMEGA328P-AU?

The best Microchip equivalent is the ATMEGA328PB-AU, which is a drop-in replacement with enhanced features. It has the same TQFP-32 package and pinout, but adds 5 more I/O pins, two extra timers, and additional serial interfaces. It is fully backward-compatible with the ATMEGA328P-AU, though you may need to update your code to use the new peripherals.

Engineering reference data for ATMEGA328P-AU — comparison, design guidance, and compliance information.

Selection Guide

Choose the ATMEGA328P-AU when you need a proven, low-cost 8-bit microcontroller with extensive community support and a wide operating voltage range. It is ideal for Arduino-based projects, IoT sensor nodes, and educational purposes. If you require more I/O pins and additional peripherals, consider the ATMEGA328PB-AU, which is pin-compatible and offers 5 extra I/O, two extra timers, and additional serial interfaces. For applications with limited memory needs, the ATMEGA168PA-AU is a lower-cost alternative with the same pinout but half the flash and EEPROM. If you need a smaller footprint, the ATMEGA328P-MU in QFN package is an option, but it requires a different PCB layout. For ultra-low-power applications, the MSP430 series may offer lower sleep currents, but the ATMEGA328P-AU provides a good balance of power, performance, and ease of use.

Comparison with Alternatives

Parameter	This Product	ATMEGA328PB-AU	ATMEGA328P-AUR	ATMEGA168PA-AU	ATMEGA328P-MU
Package	32-TQFP (7x7 mm)	32-TQFP (7x7 mm) - same	32-TQFP (7x7 mm) - same	32-TQFP (7x7 mm) - same	32-QFN (5x5 mm) - different
Brand	Microchip Technology	Microchip Technology	Microchip Technology	Microchip Technology	Microchip Technology
Flash Memory	32 KB	32 KB	32 KB	16 KB	32 KB
SRAM	2 KB	2 KB	2 KB	1 KB	2 KB
EEPROM	1 KB	1 KB	1 KB	512 B	1 KB
Number of I/O	23	28	23	23	23
Max Clock Speed	20 MHz	20 MHz	20 MHz	20 MHz	20 MHz
Operating Voltage	1.8V - 5.5V	1.8V - 5.5V	1.8V - 5.5V	1.8V - 5.5V	1.8V - 5.5V
Price (1 unit)	$2.50	$2.80	$2.50	$1.80	$2.60

Key Differentiators

Industry-standard Arduino compatibility (vs PIC16F887-I/PT)
Ultra-low power consumption (vs STM32F030C8T6)
Wide operating voltage range (vs MSP430G2553IPW28R)

Design Notes

The ATMEGA328P-AU operates from 1.8V to 5.5V. For low-power applications, use the lowest voltage that meets the clock speed requirement. At 1.8V, the maximum clock speed is 8 MHz. Use the internal 8 MHz RC oscillator to avoid external crystal power consumption. In sleep modes, disable the ADC and analog comparator to reduce current. Use the Power-down mode with a watchdog timer for periodic wake-ups.

Place a 100 nF decoupling capacitor close to each VCC pin and a 10 µF capacitor at the power entry point. For the AVCC pin, use an LC filter (10 µH inductor and 100 nF capacitor) to reduce noise for ADC accuracy. Connect AREF to a stable reference voltage or use the internal 1.1V reference. Ensure the reset pin has a 10 kΩ pull-up resistor and a 100 nF capacitor to ground for reliable reset.

When using the internal RC oscillator, note that the accuracy is ±10% over temperature and voltage. For applications requiring precise timing, use an external crystal (e.g., 16 MHz) with two 22 pF load capacitors. Also, ensure the SPI and I2C pins are not left floating; use pull-up resistors on I2C lines (4.7 kΩ). The ADC input impedance is high, but for accurate readings, use a low-impedance source or add a buffer amplifier.