ATMEGA328-MU - 8-bit AVR MCU 32KB Flash 20MHz | Microchip
部品番号: ATMEGA328-MU ✓ 生産中| 数量 | 単価 | 小計 |
|---|---|---|
| 1 | $3.5 | $3.50 |
| 10 | $3.15 | $31.50 |
| 100 | $2.78 | $278.00 |
| 500 | $2.45 | $1,225.00 |
| 1,000 | $2.2 | $2,200.00 |
ATMEGA328-MU 概要
An 8-bit microcontroller (MCU) is a single-chip computer built around an 8-bit data path, integrating a CPU core, program memory (Flash), working RAM, non-volatile EEPROM, and a set of peripherals. The AVR family used by the ATmega328 implements a Modified Harvard RISC architecture with 131 instructions, most of which complete in a single clock cycle, giving the ATMEGA328-MU an effective throughput of up to 20 MIPS at 20 MHz. Within the broader taxonomy, the part belongs to the hierarchy: AVR 8-bit MCU -> Microcontroller -> Embedded Processor -> Semiconductor.
Key features include the debugWIRE on-chip debug interface (eliminating the need for a full JTAG header), an internal calibrated oscillator, six sleep modes with power-down currents under 1 uA, and a 10-bit successive-approximation ADC capable of 15 kSPS at full resolution. The integrated brown-out detector and watchdog timer simplify firmware safety, while the peripheral event system and programmable serial USART support industrial bus protocols.
Architecturally, the ATmega328 combines an 8-bit ALU with 32 general-purpose working registers that are directly accessible by the instruction set, eliminating accumulator bottlenecks. The 32 KB Flash is organized as 16K x 16 to optimize code density and enable on-chip self-programming via a bootloader, the same mechanism that allows Arduino Uno compatibility and ISP (In-System Programming) through the SPI pins.
Typical applications include Arduino-compatible boards, sensor hubs, low-power battery nodes, and small industrial controllers. The wide 1.8 V to 5.5 V supply range supports both 3.3 V and 5 V rails, and the low-power sleep modes make the device suitable for solar-powered or energy-harvesting designs.
When designing with this part, observe the maximum 20 MHz clock at 4.5 V to 5.5 V supply; at lower Vcc the maximum frequency is derated per the datasheet DC characteristics. Decouple VCC and AVCC with 100 nF plus 10 uF bulk capacitors placed within 5 mm of the pins.
This page synthesizes DigiKey/Mouser distributor pricing, drop-in alternatives (ATmega328P-MU family variants and ATMEGA328PB-MU), and practical PCB/layout design notes that complement the manufacturer datasheet.
ドロップイン代替品: ATMEGA328-MU — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
このシリーズのバリエーション
同一シリーズでドロップイン互換のモデル: ATMEGA328-MU （同一形状・フットプリント） — 相違点: Package, Communication Interfaces, Operating Temperature, Timers, RoHS Status.
クイック比較ツール — 並列比較する代替部品を選択:
ATMEGA328P-MU
✅ ドロップイン✓ 在庫あり
$2.85 / 個
データシートを見る →ATMEGA328PB-MU
✅ ドロップイン✓ 在庫あり
$1.19 / 個
データシートを見る →ATMEGA328-MUR
✅ ドロップイン✓ 在庫あり
$1.84 / 個
データシートを見る →ATMEGA328-MU 最大定格＆電気的特性
| Core Architecture | AVR 8-bit RISC |
| Flash Program Memory | 32 KB (16K x 16) |
| SRAM | 2 KB |
| EEPROM | 1 KB |
| Maximum CPU Speed | 20 MHz (20 MIPS) |
| 電源電圧 | 1.8 V to 5.5 V |
| Operating Temperature (Industrial) | -40C to +85C |
| I/O Pins | 23 general-purpose |
| ADC | 10-bit, 8 channels, up to 15 kSPS |
| Timers | 2 x 8-bit + 1 x 16-bit |
| Communication Interfaces | 1x USART, 1x SPI, 1x I2C (TWI) |
| パッケージ | 32-pin VQFN (5x5 mm) with EP |
| 実装タイプ | Surface Mount |
| On-chip Debug | debugWIRE |
| Instruction Set | 131 instructions, mostly single-cycle |
| Power-down Mode Current | < 1 uA (typical, datasheet) |
| MSLレベル | MSL3 (per JEDEC J-STD-020, typical for VQFN) |
ATMEGA328-MU ピン構成
| ピン 1 | PC6/RESET — Reset input (active low) or GPIO PC6 |
| ピン 2 | PD0/RXD — Digital I/O PD0 / USART RXD |
| ピン 3 | PD1/TXD — Digital I/O PD1 / USART TXD |
| ピン 4 | PD2/INT0 — Digital I/O PD2 / External Interrupt 0 |
| ピン 5 | PD3/INT1/OC2B — Digital I/O PD3 / External Interrupt 1 / Timer2 PWM B |
| ピン 6 | PD4/T0/XCK — Digital I/O PD4 / Timer0 Clock / USART XCK |
| ピン 7 | VCC — Digital supply voltage (1.8 V to 5.5 V) |
| ピン 8 | GND — Ground |
| ピン 9 | PB6/XTAL1/TOSC1 — XTAL1 or GPIO PB6 |
| ピン 10 | PB7/XTAL2/TOSC2 — XTAL2 or GPIO PB7 |
| ピン 11 | PD5/T1/OC0B — Digital I/O PD5 / Timer1 Clock / Timer0 PWM B |
| ピン 12 | PD6/AIN0/OC0A — Digital I/O PD6 / Analog Comparator + / Timer0 PWM A |
| ピン 13 | PD7/AIN1 — Digital I/O PD7 / Analog Comparator - |
| ピン 14 | PB0/ICP1/CLKO — Digital I/O PB0 / Timer1 Input Capture / System Clock Out |
| ピン 15 | PB1/OC1A — Digital I/O PB1 / Timer1 PWM A |
| ピン 16 | PB2/SS/OC1B — Digital I/O PB2 / SPI SS / Timer1 PWM B |
| ピン 17 | PB3/MOSI/OC2A — Digital I/O PB3 / SPI MOSI / Timer2 PWM A |
| ピン 18 | PB4/MISO — Digital I/O PB4 / SPI MISO |
| ピン 19 | PB5/SCK — Digital I/O PB5 / SPI SCK |
| ピン 20 | AVCC — Analog supply voltage (connect to VCC) |
| ピン 21 | AREF — ADC reference voltage |
| ピン 22 | GND — Ground (analog) |
| ピン 23 | PC0/ADC0 — Analog input ADC0 / GPIO PC0 |
| ピン 24 | PC1/ADC1 — Analog input ADC1 / GPIO PC1 |
| ピン 25 | PC2/ADC2 — Analog input ADC2 / GPIO PC2 |
| ピン 26 | PC3/ADC3 — Analog input ADC3 / GPIO PC3 |
| ピン 27 | PC4/ADC4/SDA — Analog ADC4 / I2C SDA / GPIO PC4 |
| ピン 28 | PC5/ADC5/SCL — Analog ADC5 / I2C SCL / GPIO PC5 |
| ピン 29 | ADC6 — Analog input ADC6 (VQFN only) |
| ピン 30 | ADC7 — Analog input ADC7 (VQFN only) |
| ピン 31 | VCC — Digital supply voltage |
| ピン 32 | GND — Ground |
主な用途
ATMEGA328-MU の用途: 7 件s: Arduino-Compatible Embedded Boards, Low-Power Battery Sensor Nodes, Industrial Control and Monitoring, USB HID / Consumer Devices, Home Automation and IoT Gateways, Educational and Hobbyist Robotics, Automotive Aftermarket Accessories.
Arduino-Compatible Embedded Boards
The ATMEGA328-MU is the VQFN-32 (5x5 mm) SMD equivalent of the ATmega328P used on the Arduino Uno, making it ideal for compact Arduino-compatible designs. Its 32 KB Flash, 2 KB SRAM, and 1 KB EEPROM match the Uno memory map exactly, so existing Arduino sketches and bootloaders (optiboot) run without modification. The 20 MHz clock and 20 MIPS throughput support typical AVR workloads - GPIO toggling, ADC sampling, and serial I/O - while the VQFN package saves roughly 70% board area versus the TQFP-32 variant, enabling small-form-factor boards such as the Arduino Pro Mini SMD edition. Use the debugWIRE interface for in-circuit debugging without occupying the SPI pins.
おすすめ
Low-Power Battery Sensor Nodes
The ATMEGA328-MU's six software-selectable sleep modes and sub-1 uA power-down current make it suitable for battery-powered wireless sensor nodes running on 2xAA or coin-cell batteries. The 1.8 V minimum supply supports direct Li-ion / 3.6 V Li-SOCl2 chemistries, while the internal 8 MHz calibrated oscillator eliminates the standby current of an external crystal. Combined with sub-1 uA sleep current, a node that wakes every 60 seconds for a 5 ms ADC read and transmit cycle can achieve average current under 10 uA, giving multi-year battery life on 2xAA. Use the watchdog timer for periodic wake-up and the ADC's internal 1.1 V bandgap reference for ratiometric battery monitoring.
おすすめ
Industrial Control and Monitoring
The ATMEGA328-MU's -40C to +85C industrial temperature range, integrated 10-bit ADC, and USART/SPI/I2C peripherals make it suitable for industrial controllers, motor drivers, and PLC-style I/O modules. The 8-channel ADC with 15 kSPS throughput supports 4-20 mA loop sensing, thermocouple cold-junction compensation, and bridge sensor excitation. The two 8-bit timers plus one 16-bit timer provide PWM outputs for LED dimming, valve actuation, and small DC motor speed control. Hardware peripherals like the watchdog timer and brown-out detector ensure safe recovery from fault conditions in unattended installations.
おすすめ
USB HID / Consumer Devices
Pair the ATMEGA328-MU with an external USB-to-serial bridge (e.g., ATmega16U2 or CH340) to build USB Human Interface Devices (HID) such as keyboards, mice, macro pads, and custom game controllers. The 23 GPIO pins directly drive mechanical key matrices up to 8x8 without additional scan logic, while the 32 KB Flash holds USB HID report descriptors and macro profiles. The on-chip USART provides bootloading/debug output, and the SPI port supports fast peripheral expansion for OLED displays or rotary encoders. The VQFN-32 package fits inside compact enclosures.
おすすめ
Home Automation and IoT Gateways
The ATMEGA328-MU serves as a low-cost peripheral controller in home automation systems, handling local sensor aggregation, relay switching, and edge logic before forwarding data to a Wi-Fi/BLE gateway MCU such as the ESP32. Its I2C interface supports multiple environmental sensors (temperature, humidity, lux, PIR), while the USART can drive RS-485 Modbus for legacy HVAC equipment. The 32 KB Flash is ample for rule-based automation firmware, and the <1 uA sleep current supports battery-powered door/window sensors that last years on a coin cell. The exposed thermal pad on the VQFN-32 package simplifies thermal management in always-on wall-mounted installations.
おすすめ
Educational and Hobbyist Robotics
The ATMEGA328-MU is widely used in hobbyist robotics kits - line-following robots, sumo bots, and educational STEM platforms - because it combines ample processing for PID control loops with simple Arduino IDE programming. The 16-bit Timer1 provides hardware PWM for precise servo control, while the 8-bit timers drive DC motor H-bridges. The integrated ADC reads line-follower IR sensors, sonar echoes, and battery voltage, and the debugWIRE port allows students to step through firmware in real time. The 32-pin VQFN (5x5 mm) package is small enough to fit on 50x50 mm robot PCBs alongside motor drivers and sensor arrays.
おすすめ
Automotive Aftermarket Accessories
The ATMEGA328-MU's -40C to +85C industrial temperature range and robust AVR core support automotive aftermarket accessories such as OBD-II dongles, gauge clusters, and lighting controllers. While not AEC-Q100 qualified (use ATmega328P-AU-Q1 for OEM automotive), the industrial-grade ATMEGA328-MU handles the underhood thermal environment with adequate derating. The 8-channel ADC reads MAP, MAF, and O2 sensor signals, while the PWM timers drive LED tail-light controllers and headlight modulators. The hardware watchdog and brown-out detector recover the device from load-dump voltage transients common in 12 V automotive systems.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: ATMEGA328-MU — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 | ATMEGA328P-MU | ATMEGA328PB-MU | ATMEGA328-MUR |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | VQFN-32 (5x5 mm) | VQFN-32 (5x5 mm) - same | VQFN-32 (5x5 mm) - same | VQFN-32 (5x5 mm) - same |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB |
| EEPROM | 1 KB | 1 KB | 1 KB | 1 KB |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
| USART / I2C / SPI Count | 1 / 1 / 1 | 1 / 1 / 1 | 2 / 2 / 2 (improved) | 1 / 1 / 1 |
| Power-Down Current | < 1 uA | < 1 uA (Pico-Power) | < 1 uA | < 1 uA |
主な差別化要因
- Compact VQFN-32 (5x5 mm) package with exposed thermal pad （vs ATMEGA328P-AU (TQFP-32, 7x7 mm))
- Pin-compatible with enhanced ATmega328PB-MU （vs ATMEGA328PB-MU)
- Standard industrial temperature range with full 20 MHz throughput （vs ATMEGA328P-MU (Pico-Power variant))
設計ノート
Decouple VCC and AVCC with a 100 nF ceramic capacitor placed within 5 mm of each supply pin, plus a bulk 10 uF tantalum or ceramic capacitor on the VCC rail. Connect AVCC to VCC via a ferrite bead or 10 ohm resistor and bypass AREF with a 100 nF capacitor to suppress ADC switching noise. The ATMEGA328-MU's ADC performance is highly sensitive to analog supply noise; failure to decouple AVCC separately from VCC typically degrades ADC SNR by 6-10 dB.
Solder the exposed thermal pad (EP) on the VQFN-32 package to a continuous ground copper pour, stitched with at least 9 thermal vias (0.3 mm drill, 0.6 mm pad) to an inner ground plane. This provides the primary thermal dissipation path and reduces junction-to-ambient thermal resistance (theta_JA) from ~50 C/W to ~30 C/W. Missing EP soldering increases thermal resistance and can cause thermal shutdown in 20 MHz applications with sustained GPIO switching loads.
Do not exceed 20 MHz at VCC below 4.5 V - the device enters unreliable operation outside the datasheet DC characteristics. When running from a 3.3 V rail, derate the clock to 10 MHz maximum, or use the internal 8 MHz calibrated oscillator. Also, the brown-out detector (BOD) fuse must be programmed for the specific VCC range, or the MCU may brown-out repeatedly at low battery voltages. Source: ATmega328P family datasheet Electrical Characteristics section.
Keep I2C bus capacitance below 400 pF (fast mode) or 100 pF (high-speed mode) by limiting pull-up resistor values to 2.2 kohm minimum at 5 V. The ATMEGA328-MU's TWI (I2C) peripheral has limited drive strength; external pull-ups are required even with the internal 20 kohm weak pull-ups enabled. Place the I2C pull-ups close to the MCU side, not at the bus end, to minimize ringing on long cable runs.
コンプライアンス情報
RoHS and REACH compliant per Microchip product page. Industrial temperature grade -40C to +85C. Not AEC-Q100 qualified - for automotive OEM applications use the ATmega328P-AU-Q1 automotive variant. Halogen-free and lead-free per Microchip material declaration.
