ATMEGA324PA-ANR - AVR 8-bit MCU 32KB Flash 20MHz | Microchip
MPN: ATMEGA324PA-ANR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.76 | $3.76 |
| 10 | $3.45 | $34.50 |
| 100 | $3.1 | $310.00 |
| 500 | $2.85 | $1,425.00 |
| 1,000 | $2.6 | $2,600.00 |
ATMEGA324PA-ANR Overview
A microcontroller unit (MCU) is a single integrated circuit that combines a processor core, program memory, data memory, and peripherals into one chip. Within the power-management hierarchy of embedded systems, the MCU sits at the top as the system controller, orchestrating sensors, actuators, and communication interfaces. The ATmega324PA belongs to the AVR ATmega family, based on the AVR enhanced RISC architecture that executes most of its 131 instructions in a single clock cycle, achieving throughput approaching 1 MIPS per MHz.
Key features include in-system programmable (ISP) Flash with read-while-write capability, picoPower low-power technology for battery-operated designs, and rich connectivity: I2C (TWI), SPI, and UART/USART serial interfaces. The 32 general-purpose working registers are directly connected to the ALU, allowing two independent registers to be accessed in one instruction execution for maximum efficiency.
Technically, the ATmega324PA integrates two 8-bit timers, one 16-bit timer, a 10-bit ADC with multiple single-ended and differential channels, an analog comparator, a programmable watchdog timer with an internal oscillator, and six sleep modes (including Power-down and Power-save) that let designers trade processing speed against power consumption precisely.
Typical applications include industrial automation control nodes, battery-powered sensor and metering devices, and consumer appliance interfaces where a moderate memory footprint of 32 KB Flash and 2 KB SRAM is sufficient.
A key design consideration: the picoPower variants (PA suffix) provide the lowest active and sleep currents in the family, but clock speed scales directly with power draw, so match the system clock to the actual throughput requirement.
This page synthesizes distributor pricing as of 2026-09-17, verified drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA324PA-ANR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ATMEGA324PA-ANR (same form factor and footprint) — differing in Package, Packaging, Program Memory Size, RoHS Status, Core Processor.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA324PB-ANR
✅ Drop-In✓ In Stock
$2.64 / Unit
View Datasheet →ATMEGA324PA-AN
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA324PA-AUR
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.98 / Unit
View Datasheet →ATMEGA324A-AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.09 / Unit
View Datasheet →ATMEGA324P-20AUR
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$4.52 / Unit
View Datasheet →ATMEGA324PA-ANR Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Flash Memory | 32 KB |
| EEPROM | 1 KB |
| SRAM | 2 KB |
| GPIO | 32 |
| Connectivity | I2C, SPI, UART/USART |
| Peripherals | Brown-out Detect/Reset, POR, PWM, WDT |
| ADC Resolution | 10-bit |
| Architecture | AVR enhanced RISC, 131 instructions |
| Operating Temperature | -40 C to 105 C |
| Package | 44-TQFP |
| Mounting Type | Surface Mount |
| Technology | picoPower low-power |
| Packaging | Tape & Reel (TR), Green |
| Programming | In-System Programmable (ISP), read-while-write |
ATMEGA324PA-ANR Pin Configuration
| Pin 1 | PA7 (ADC7) — Port A bit 7 / ADC channel 7 |
| Pin 2 | PA6 (ADC6) — Port A bit 6 / ADC channel 6 |
| Pin 3 | PA5 (ADC5) — Port A bit 5 / ADC channel 5 |
| Pin 4 | PA4 (ADC4) — Port A bit 4 / ADC channel 4 |
| Pin 5 | PA3 (ADC3) — Port A bit 3 / ADC channel 3 |
| Pin 6 | PA2 (ADC2) — Port A bit 2 / ADC channel 2 |
| Pin 7 | PA1 (ADC1) — Port A bit 1 / ADC channel 1 |
| Pin 8 | PA0 (ADC0) — Port A bit 0 / ADC channel 0 |
| Pin 9 | VCC — Digital supply voltage |
| Pin 10 | GND — Ground |
| Pin 11 | PB0 (SS) — Port B bit 0 / SPI Slave Select |
| Pin 12 | PB1 (SCK) — Port B bit 1 / SPI clock |
| Pin 13 | PB2 (MOSI) — Port B bit 2 / SPI master out |
| Pin 14 | PB3 (MISO) — Port B bit 3 / SPI master in |
| Pin 15 | PB4 (OC0/PWM) — Port B bit 4 / Timer0 PWM output |
| Pin 16 | PB5 (OC1A) — Port B bit 5 / Timer1 PWM output A |
| Pin 17 | PB6 (OC1B) — Port B bit 6 / Timer1 PWM output B |
| Pin 18 | PB7 (OC2/OC0A) — Port B bit 7 / Timer2 PWM output |
| Pin 19 | PC0 (SCL) — Port C bit 0 / TWI clock |
| Pin 20 | PC1 (SDA) — Port C bit 1 / TWI data |
| Pin 21 | PC2 (TCK) — Port C bit 2 / JTAG test clock |
| Pin 22 | PC3 (TMS) — Port C bit 3 / JTAG test mode select |
| Pin 23 | PC4 (TDO) — Port C bit 4 / JTAG test data out |
| Pin 24 | PC5 (TDI) — Port C bit 5 / JTAG test data in |
| Pin 25 | PC6 (TOSC1) — Port C bit 6 / Timer oscillator input |
| Pin 26 | PC7 (TOSC2) — Port C bit 7 / Timer oscillator output |
| Pin 27 | PD0 (RXD0) — Port D bit 0 / USART0 receive |
| Pin 28 | PD1 (TXD0) — Port D bit 1 / USART0 transmit |
| Pin 29 | PD2 (INT0/RXD1) — Port D bit 2 / External interrupt 0 / USART1 receive |
| Pin 30 | PD3 (INT1/TXD1) — Port D bit 3 / External interrupt 1 / USART1 transmit |
| Pin 31 | PD4 (OC1B/XCK1) — Port D bit 4 / Timer1 PWM B / USART1 clock |
| Pin 32 | PD5 (OC1A/XCK) — Port D bit 5 / Timer1 PWM A / USART0 clock |
| Pin 33 | PD6 (ICP1) — Port D bit 6 / Timer1 input capture |
| Pin 34 | PD7 (OC2A/OC0A) — Port D bit 7 / Timer2 PWM output A |
| Pin 35 | RESET — Active-low reset input |
| Pin 36 | VCC — Digital supply voltage |
| Pin 37 | GND — Ground |
| Pin 38 | XTAL2 — Crystal oscillator output |
| Pin 39 | XTAL1 — Crystal oscillator input / external clock |
| Pin 40 | AVCC — ADC and Port A supply voltage |
| Pin 41 | AREF — ADC analog reference input |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
ATMEGA324PA-ANR is suitable for 6 applications: Industrial Automation Control Nodes, Battery-Powered Metering and Sensors, Consumer Appliance Interfaces, Automotive Auxiliary and Off-Highway Electronics, Embedded Networking and Communication Modules, Test, Measurement, and Hobby Instrumentation.
Industrial Automation Control Nodes
In factory automation and process control, the ATMEGA324PA-ANR serves as a compact field-level controller driving relays, reading encoders, and communicating on Modbus-style UART or RS-485 links. Its 20 MHz AVR core delivers near-1 MIPS per MHz throughput, so a typical PID loop with 10-bit ADC sampling completes comfortably within millisecond deadlines. The 32 KB Flash accommodates protocol stacks plus OTA-style bootloaders, while 2 KB SRAM handles buffering for Modbus frames. The -40 C to 105 C temperature rating of the 44-TQFP package suits control cabinets near motors and drives. Brown-out detection and the watchdog timer ensure safe recovery from supply dips caused by inductive load switching, a common industrial disturbance.
Recommended
Battery-Powered Metering and Sensors
The picoPower technology of the ATmega324PA makes it a strong fit for battery-operated meters, dataloggers, and wireless sensor nodes. Supplying from 1.8 V to 5.5 V allows direct operation from two alkaline cells or a single lithium cell, and six sleep modes, including Power-down and Power-save, allow the MCU to spend most of its life at microamp-level currents per the Microchip datasheet. A typical duty cycle wakes the chip, performs a 10-bit ADC conversion on a sensor channel, transmits the reading over UART or SPI, and returns to sleep. The 1 KB EEPROM retains calibration data and cumulative counters without external memory. Designers should match clock frequency to throughput needs since active current scales with fCLK.
Recommended
Consumer Appliance Interfaces
Home appliances such as coffee machines, ovens, and HVAC controllers use the ATMEGA324PA-ANR to manage touch or button inputs, display multiplexing, and actuator control (heaters, fans, valves). The 32 GPIO lines of the 44-TQFP drive a 7-segment or LCD-segment display plus keypad matrix without expansion ICs, while PWM outputs handle triac or fan-speed control. The internal RC oscillator removes the need for a crystal in cost-sensitive products, and the watchdog timer plus brown-out reset ensure safe behavior during mains brownouts. Its 20 MHz capability supports responsive user interfaces, and the 32 KB Flash leaves room for firmware updates containing new feature sets across product refreshes.
Recommended
Automotive Auxiliary and Off-Highway Electronics
Although not AEC-Q100 qualified, the -40 C to 105 C operating range of the ATMEGA324PA-ANR fits many off-highway, marine, agricultural, and auxiliary automotive modules such as light controllers, gauge clusters, and accessory body electronics. The 10-bit ADC reads resistive senders and NTC sensors with differential channels improving accuracy in noisy 12 V environments, while the watchdog and brown-out detector handle crank-induced supply transients. SPI and UART links connect to CAN gateway nodes, and the 105 C TQFP rating suits under-dash and engine-bay-adjacent positions. Designers must implement their own load-dump protection externally since the part itself is rated only to 5.5 V on its supply pins.
Recommended
Embedded Networking and Communication Modules
With hardware I2C (TWI), SPI, and two UART/USART interfaces, the ATMEGA324PA-ANR acts as a protocol-conversion and module-controller device: bridging RS-232 service ports to SPI peripherals, managing RF or Ethernet modules over UART AT-command sets, or acting as an I2C slave under a main application processor. The read-while-write Flash allows firmware self-update while servicing communication, an important feature for remotely deployed equipment. At 20 MHz the AVR sustains 115200-baud UART traffic with generous headroom, and the 2 KB SRAM buffers multi-hundred-byte frames comfortably. The 44-TQFP exposes both hardware serial ports simultaneously, a capability smaller ATmega328-class parts lack.
Recommended
Test, Measurement, and Hobby Instrumentation
Bench instruments, breakout boards, and educational platforms leverage the ATMEGA324PA-ANR because its 44-pin TQFP exposes all four GPIO ports, two USARTs, and hardware SPI/I2C for prototyping. The 10-bit ADC with differential inputs and a 1.1 V internal reference performs basic measurement functions, while PWM timers generate stimulus signals. ICSP programming via MPLAB SNAP (an 8-pin SIL header using two I/O pins plus reset, per Microchip documentation) makes in-circuit debugging accessible for students and engineers. The 32 KB Flash hosts USB-serial bootloaders, and the huge AVR ecosystem of toolchains (AVR-GCC, Microchip Studio) shortens development time. The picoPower die also models low-power design techniques in teaching labs.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA324PA-ANR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA324PB-ANR | ATMEGA324PA-AN | ATMEGA324A-AU | ATMEGA128A-ANR |
|---|---|---|---|---|---|
| Package | 44-TQFP | 44-TQFP - same | 44-TQFP - same | 44-TQFP - same | 44-TQFP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 128 KB |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 16 MHz |
| Low-Power Technology | picoPower | picoPower + core-independent peripherals | picoPower | standard | standard |
| SPI Interfaces | 1 | 2 | 1 | 1 | 1 |
| Packaging | Tape & Reel | Tape & Reel | Tray/Tube | Tray | Tape & Reel |
Key Differentiators
- picoPower low-power die with six sleep modes (vs ATMEGA324A-AU)
- Dual hardware USARTs in 44-pin package (vs ATMEGA168PA-ANR)
- Higher clock speed at lower power (vs ATMEGA128A-ANR)
- Pin-compatible peripheral upgrade path (vs ATMEGA324PB-ANR)
Design Notes
Decouple VCC and AVCC independently with 100 nF ceramic capacitors placed within 2 mm of pins 9/36 and pin 40 respectively, plus one 4.7 uF bulk capacitor per supply rail. AVCC must never be left floating even if Port A and the ADC are unused - tie it to VCC through a low-pass LC or RC filter (e.g., 10 ohm + 100 nF) when ADC noise matters. Tie AREF to ground through a 100 nF capacitor unless an external reference is used; never drive AREF while the internal reference is enabled, as this shorts the reference amplifier.
Keep the XTAL1/XTAL2 crystal traces short (under 10 mm) and surround them with a ground guard ring to minimize stray capacitance and radiated jitter. Place the 44-TQFP so port pins facing the connectorized edge of the board carry communication lines (PD0-PD3 UART, PB0-PB3 SPI), reducing trace crossings. For high current on GPIO (LED strings), distribute loads across port pins and route individual returns to the GND pin at 10 and 37 rather than daisy-chaining grounds across the package.
Observe the speed-versus-voltage derating curve: 20 MHz is only valid near 4.5 V to 5.5 V; running 20 MHz at 3.3 V violates the datasheet safe-operating region and causes marginal timing failures that appear only over temperature. The RESET pin (35) must not be left floating - use the internal pull-up or an external 10 kohm, and consider an external supervisor in noisy environments. When migrating to ATMEGA324PB, verify register addresses against the Microchip migration note since newly added peripherals remap some register locations.
Estimated: an ATmega324PA at 5 V / 20 MHz with all I/O sourcing modest loads dissipates roughly 50-100 mW, producing less than 1 C of junction rise through the 44-TQFP thermal resistance, so no heatsinking is needed for the MCU itself in most designs. Verify externally driven loads (LEDs, transistors) do not push individual pin currents beyond datasheet absolute maximums, and account for elevated ambient up to 105 C in enclosed products when calculating total board-level power budget.
Compliance Information
FindIC listing describes the ATMEGA324PA-ANR as a Green (halogen-free, lead-free) Tape & Reel product; REACH and conflict-minerals status not stated in the provided data.
