ATMEGA323-8AC - 8MHz AVR MCU 32KB Flash TQFP-44 | Microchip
MPN: ATMEGA323-8AC ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.5 | $6.50 |
| 10 | $5.85 | $58.50 |
| 100 | $5.2 | $520.00 |
| 500 | $4.6 | $2,300.00 |
| 1,000 | $4.1 | $4,100.00 |
ATMEGA323-8AC Overview
An 8-bit AVR microcontroller is a Harvard-architecture RISC processor in which program memory and data memory occupy separate address spaces, allowing most instructions to execute in a single clock cycle. Within the power-management hierarchy, an MCU of this class combines CPU, program memory, data memory, timers, communication peripherals, and an ADC in a single integrated circuit, replacing multi-chip discrete designs.
Key features include the advanced AVR RISC architecture with 131 powerful instructions, most executing in a single clock cycle; eight 8-bit general-purpose working registers; and fully static operation delivering throughput approaching 1 MIPS per MHz. Connectivity is versatile, with I2C, SPI, and UART/USART interfaces supporting a wide range of peripheral and communication designs. In-system programmable Flash allows firmware updates without removing the device from the board.
The ATmega323 achieves throughput approaching 1 MIPS per MHz by executing powerful instructions in a single clock cycle, letting system designers optimize power consumption versus processing speed. The 32KB self-programmable Flash supports boot-loader-based firmware updates, while the separate 1KB EEPROM retains calibration and configuration data through power cycles and Flash reprogramming cycles.
Typical applications include industrial control panels, embedded instrumentation, communication bridges using the I2C/SPI/UART peripherals, and legacy designs requiring ATmega323-family compatibility. The 8MHz grade suits standard 4-5V systems where moderate processing throughput is sufficient.
Design consideration: as the ATmega323 family has been superseded by newer AVR parts, plan firmware and board strategy around the ATmega32 pin-compatible successor for new designs. The -8AC suffix denotes an 8MHz commercial temperature grade.
This page synthesizes distributor availability data, drop-in alternatives, and practical design notes not consolidated in the manufacturer datasheet, as of 2026-09-17.
Drop-in alternatives for ATMEGA323-8AC — 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 ATMEGA323-8AC (same form factor and footprint) — differing in Package, SRAM, Flash Program Memory, EEPROM, Maximum Clock Frequency.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA32-16AC
✅ Drop-In✓ In Stock
$4.48 / Unit
View Datasheet →ATMEGA32-16AUR
✅ Drop-In✓ In Stock
$3.41 / Unit
View Datasheet →ATMEGA323L-4AI
✅ Drop-In✓ In Stock
$3.72 / Unit
View Datasheet →ATMEGA16A-AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.05 / Unit
View Datasheet →ATMEGA16L-8AJ
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.82 / Unit
View Datasheet →ATMEGA323-8AC Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR 8-bit RISC |
| Instruction Count | 131 instructions |
| Flash Program Memory | 32KB (16K x 16), in-system programmable |
| SRAM | 2KB (2K x 8) |
| EEPROM | 1KB (1K x 8) |
| Maximum Clock Frequency | 8 MHz |
| Throughput | up to 8 MIPS at 8 MHz (approx. 1 MIPS per MHz) |
| General Purpose Registers | 8 x 8-bit |
| Communication Interfaces | I2C, SPI, UART/USART |
| Package | 44-TQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| Operation Mode | Fully static |
ATMEGA323-8AC 44-tqfp (10x10 mm) Pin Configuration Guide
Pin configuration for ATMEGA323-8AC (44-tqfp (10x10 mm) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for ATMEGA323-8AC.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA323-8AC is suitable for 6 applications: Industrial Control Panels, Embedded Instrumentation, Communication Bridges and Protocol Converters, Legacy Product Line Maintenance, Smart Home and IoT Nodes, Automotive Aftermarket and Non-Safety Modules.
Industrial Control Panels
The ATMEGA323-8AC fits industrial control panels where 32KB of Flash is sufficient for state-machine and protocol logic and 2KB SRAM handles buffering for sensor and actuator I/O. Running at up to 8MHz with roughly 1 MIPS per MHz throughput, the AVR core executes control loops deterministically without an RTOS. The integrated I2C, SPI, and UART/USART peripherals interface directly with EEPROMs, real-time clocks, displays, and field modules, eliminating external communication controllers. Because it is fully static, the clock can be slowed for low-power standby modes between control cycles. For legacy panel maintenance, the pin-compatible ATmega32 in the same TQFP-44 footprint provides a migration path.
Recommended
Embedded Instrumentation
In bench and field instrumentation, the ATMEGA323-8AC provides a self-contained measurement and control engine: the 1KB EEPROM stores calibration constants that survive power cycles and firmware updates, while 32KB Flash holds lookup tables and measurement firmware. The AVR's single-cycle instruction execution supports bit-banged protocols and precise timing routines at the 8MHz grade. The SPI peripheral connects high-resolution ADCs, and the UART streams results to a PC or display. The 44-TQFP (10x10 mm) surface-mount package offers 32 GPIO-class pins for switches, encoders, and indicator outputs in a compact footprint suitable for handheld instruments.
Recommended
Communication Bridges and Protocol Converters
The ATMEGA323-8AC is well suited to protocol conversion nodes, since the I2C, SPI, and UART/USART peripherals operate independently of the CPU core. A typical bridge implements UART-to-SPI translation for modem or sensor integration: incoming UART frames are buffered in the 2KB SRAM while SPI transfers run under interrupt control. At 8MHz, the core sustains serial rates typical of industrial links with ample margin. In-system programmable Flash enables firmware field updates to add new protocol handlers without desoldering the device. The 44-pin TQFP exposes enough I/O for status LEDs, flow-control lines, and configuration jumpers.
Recommended
Legacy Product Line Maintenance
Designs originally qualified around ATmega323 silicon are the primary ongoing use case for the ATMEGA323-8AC. Since the part is obsolete, service organizations keep board-level stock to avoid requalification of released products. Where stock runs out, the ATMEGA32-16AC provides the same 44-TQFP footprint and compatible AVR instruction set, requiring only firmware revalidation against the ATmega32 register map. The -8AC commercial grade's 8MHz rating matches most original legacy clock configurations, so board crystals and timing-derived baud rates can remain unchanged during repair production runs.
Recommended
Smart Home and IoT Nodes
For wired smart-home nodes, the ATMEGA323-8AC combines sufficient program memory for sensor drivers and messaging stacks with the low-power characteristics of the AVR family. The 1KB EEPROM stores device addresses and configuration locally, while the I2C bus reads environmental sensors and the UART links to a wired gateway module. Fully static operation allows clock-gated idle operation between wake-up events, and the 8MHz grade keeps switching losses low in always-on nodes. The 44-pin TQFP (10x10 mm) suits compact wall-mounted modules, and in-system Flash programming supports feature updates during installation and commissioning.
Recommended
Automotive Aftermarket and Non-Safety Modules
In non-safety automotive aftermarket products such as alarm systems, lighting controllers, and gauge clusters, the ATMEGA323-8AC supplies the timing, communication, and control functions at low cost. The AVR core's deterministic execution supports periodic tasks like PWM generation and debouncing without jitter, and the 32KB Flash accommodates feature-rich firmware including diagnostics logging to the 1KB EEPROM. SPI and UART link to CAN-bridge or telematics daughter boards. Designers should validate the commercial temperature grade against the installed environment, or select the industrial-grade ATMEGA323L-4AI from the same family where extended temperature ranges are required.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA323-8AC — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA32-16AC | ATMEGA32-16AUR | ATMEGA323L-4AI | ATMEGA16A-AU |
|---|---|---|---|---|---|
| Package | 44-TQFP (10x10 mm) | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same |
| Brand | Microchip Technology (Atmel) | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max Clock Frequency | 8 MHz | 16 MHz | 16 MHz | 4 MHz | 16 MHz |
| Flash Memory | 32KB | 32KB | 32KB | 32KB | 16KB |
| SRAM | 2KB | 2KB | 2KB | 2KB | 1KB |
| EEPROM | 1KB | 1KB | 1KB | 1KB | 512B |
| Communication Interfaces | I2C, SPI, UART/USART | I2C, SPI, UART/USART + JTAG | I2C, SPI, UART/USART + JTAG | I2C, SPI, UART/USART | I2C, SPI, UART/USART |
| Lifecycle Status | Obsolete | Active | Active | Obsolete | Active |
Key Differentiators
- 32KB Flash in a legacy-proven AVR platform (vs ATMEGA16A-AU)
- 8MHz commercial grade matched to legacy clock designs (vs ATMEGA32-16AC)
- Obsolescence is the decisive drawback (vs ATMEGA32-16AC)
Design Notes
The ATMEGA323-8AC is an obsolete part: no new production is scheduled, so any design-in is a supply-chain risk. For repairs, buy at least a full service-lifetime quantity; for new layouts, use the pin-compatible ATMEGA32-16AC instead. When substituting ATmega32 silicon on an ATmega323 board, recompile and revalidate firmware because register addresses and added peripherals (e.g., JTAG, OC0 PWM) differ slightly between the two die.
Verify the supply voltage against the datasheet for the commercial -8AC grade before powering legacy boards; the ATmega323 family spans different voltage classes across speed grades (the 323L variants are low-voltage). Decouple VCC and AVCC separately with 100nF ceramic capacitors placed within a few millimeters of the pins, and tie AREF through an RC network if the ADC path is used. Estimated: keep total supply current within the datasheet maximum at 8MHz by counting peripheral loads.
The 44-TQFP (10x10 mm) land pattern requires a 0.5mm pitch footprint; use solder-mask-defined pads and a no-clean flux profile with a convection reflow profile per the JEDEC moisture-sensitivity guidance printed on the packing label. Because this part is sourced as residual stock, check MSL rating and dry-bake parts that have exceeded floor-life before reflow to avoid popcorn cracking of the package.
Compliance Information
Compliance status not stated in the provided verified data for this obsolete Atmel-era part; confirm with the supplier, as early ATmega323 production lots may predate current RoHS definitions.