ATMEGA128-16MU - 8-Bit AVR MCU 16MHz 128KB Flash | Microchip
MPN: ATMEGA128-16MU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.85 | $9.85 |
| 10 | $8.86 | $88.60 |
| 100 | $7.88 | $788.00 |
| 500 | $7.09 | $3,545.00 |
| 1,000 | $6.4 | $6,400.00 |
ATMEGA128-16MU Overview
An 8-bit AVR microcontroller is a Harvard-architecture RISC processor that executes most instructions in a single clock cycle, placing it in the broader hierarchy of microcontrollers (MCU) -> embedded processors -> integrated circuits. MCUs integrate CPU, memory, and peripherals on one die, making them the workhorse of embedded control systems.
Key features of the ATMEGA128-16MU include 128 KB (64K x 16) Flash with Read-While-Write capability, 4 KB EEPROM, 4 KB SRAM, and an 8-channel 10-bit ADC. Its single-cycle RISC core delivers up to 16 MIPS at 16 MHz, providing deterministic execution for real-time control.
The technical architecture includes four flexible Timer/Counters with compare modes and PWM, two USARTs, a byte-oriented Two-Wire Interface (I2C-compatible TWI), a SPI serial interface, a Real Time Counter with separate oscillator, and a JTAG (IEEE 1149.1-compliant) interface for on-chip debug and boundary scan. The device is 100% pin compatible with the ATmega103 and can replace it on existing PCBs.
Typical applications include industrial control systems, consumer electronics, building automation, and instrumentation where the 128 KB Flash accommodates larger firmware images than smaller ATmega parts.
Design consideration: select the M-version (MLF/QFN) when board height and thermal pad grounding matter, and remember the 10-bit ADC requires a clean AVCC supply and stable AREF reference for full accuracy.
This page synthesizes distributor data, drop-in alternatives, and practical design notes not found in a single manufacturer datasheet.
Drop-in alternatives for ATMEGA128-16MU β 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 ATMEGA128-16MU (same form factor and footprint) β differing in Package, Throughput, Timers, Communication Interfaces, ADC.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA128A-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
AT90CAN128-16MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA1281-16MUR
β Drop-Inβ In Stock
$8.78 / Unit
View Datasheet βATMEGA2561-16MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA64A-MU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA128-16MU Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| CPU Speed | 16 MHz |
| Flash Memory | 128 KB (64K x 16) In-System Programmable |
| EEPROM | 4 KB |
| SRAM | 4 KB |
| GPIO Count | 53 I/O lines |
| ADC | 8-channel 10-bit |
| Timers/Counters | 4 with compare modes and PWM |
| USART | 2 |
| TWI (I2C) | Yes, byte-oriented Two-Wire Interface |
| SPI | Yes |
| JTAG | Yes, on-chip debugging and boundary scan |
| Package | 64-QFN (9x9 mm, MLF) |
| Mounting Type | Surface Mount |
| Compatibility | 100% pin compatible with ATmega103 |
ATMEGA128-16MU 64-qfn (9x9 mm, mlf) Pin Configuration Guide
Pin configuration for ATMEGA128-16MU (64-qfn (9x9 mm, mlf) 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 ATMEGA128-16MU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA128-16MU is suitable for 6 applications: Industrial Control Systems, Building Automation Nodes, Consumer Electronics Control, Instrumentation and Data Loggers, Motor Control Applications, Embedded Networking Gateways.
Industrial Control Systems
The ATMEGA128-16MU fits industrial control nodes where 128 KB Flash accommodates communication stacks and HMI logic, and 53 I/O lines drive relays, sensors, and indicators directly. Its deterministic single-cycle RISC core at 16 MHz (up to 16 MIPS) provides real-time response for sequencing and interlocks, while the two USARTs support Modbus RTU links and the TWI interface reads I2C sensors. Placed as the main controller with a 16 MHz crystal, watchdog enabled, and industrial-grade temperature rating verified, it runs 24/7 control loops; unlike smaller ATmega64 parts, its 128 KB program space leaves headroom for OTA firmware growth in the field.
Recommended
Building Automation Nodes
Building automation controllers benefit from the ATMEGA128-16MU's combination of TWI, SPI, and two USARTs, enabling daisy-chained sensor networks, RS-485 fieldbus bridges, and local actuator control from a single MCU. The 4 KB EEPROM stores calibration constants, node addresses, and schedules that survive power loss, while the 8-channel 10-bit ADC digitizes temperature, humidity, and current sensors at 0.1% class resolution adequate for HVAC monitoring. The 64-QFN (9x9 mm) compact footprint suits dense distributed I/O modules, and the JTAG interface supports field development without removing the device from the board.
Recommended
Consumer Electronics Control
In consumer products such as small appliances, remote controllers, and gaming peripherals, the ATMEGA128-16MU provides a cost-effective 8-bit control core where 16 MHz performance handles menu-driven UIs, PWM dimming, and infrared protocol decoding without an RTOS. Four Timer/Counters with PWM outputs generate motor speed control and LED brightness control channels, while the 128 KB Flash supports multilingual menus and graphical LCD drivers that smaller ATmega parts cannot fit. The MLF package's low profile suits slim enclosures, and its exposed die pad bonded to ground improves EMI behavior in cost-sensitive plastic-housed products.
Recommended
Instrumentation and Data Loggers
Portable instrumentation and data loggers use the ATMEGA128-16MU's 8-channel 10-bit ADC to sample multi-sensor inputs, its 4 KB EEPROM plus external SPI Flash to store records, and its USARTs to upload data over RS-232 or radio modules. The Real Time Counter with a separate 32.768 kHz oscillator maintains timestamps during sleep, and AVR power-down modes extend battery life in duty-cycled designs. The 16 MHz core executes digital filtering and linearization math quickly enough for 1 kSPS-class logging, and JTAG on-chip debugging shortens development cycles when calibrating measurement front-ends.
Recommended
Motor Control Applications
The ATMEGA128-16MU suits small DC and stepper motor controllers: its four Timer/Counters with compare modes and PWM outputs generate complementary drive signals, while the ADC reads current-shunt feedback and the analog comparator supports cycle-by-cycle current limiting. At 16 MHz, PWM resolution reaches 8-10 bits at audible-suppression frequencies suitable for fan, pump, and actuator drives. The 53 I/O lines handle limit switches, encoders, and H-bridge gate control without external logic, and the watchdog timer ensures safe shutdown on firmware faults - critical in motorized consumer and light-industrial equipment.
Recommended
Embedded Networking Gateways
Serial-to-Ethernet bridges and small protocol gateways leverage the ATMEGA128-16MU's two independent USARTs to translate between RS-232/RS-485 field devices and an external network co-processor over SPI. The 128 KB Flash holds dual protocol stacks plus a bootloader, and Read-While-Write Flash enables firmware updates while the application monitors communications - important for remotely deployed units. Its JTAG boundary scan supports production test of dense multi-chip boards, and the 64-QFN (9x9 mm) package keeps gateway PCBs compact. Deterministic interrupt latency ensures wire-speed serial bridging without dropped characters at 115.2 kbaud.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA128-16MU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA128A-MU | AT90CAN128-16MU | ATMEGA1281-16MUR | ATMEGA64A-MU |
|---|---|---|---|---|---|
| Package | 64-QFN (9x9 mm, MLF) | 64-QFN (9x9 mm, MLF) - same | 64-QFN (9x9 mm, MLF) - same | 64-QFN (9x9 mm, MLF) - same | 64-QFN (9x9 mm, MLF) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 128 KB | 128 KB | 128 KB | 128 KB | 64 KB |
| CPU Speed | 16 MHz | 16 MHz | 16 MHz | 16 MHz | 16 MHz |
| CAN Controller | No | No | Yes, CAN 2.0A/B | No | No |
| SRAM | 4 KB | 4 KB | 4 KB | 8 KB | 4 KB |
| Firmware Compatibility with ATmega128 | Native | Direct, code-compatible successor | Partial - peripheral registers differ | Partial - register map differs | Partial - must fit in 64 KB |
Key Differentiators
- Largest AVR program memory in the classic 64-MLF footprint at launch (vs ATMEGA64A-MU)
- 100% ATmega103 pin compatibility for legacy board reuse (vs ATMEGA1281-16MUR)
- Deterministic single-cycle RISC core vs needing a CAN coprocessor (vs AT90CAN128-16MU)
- Honest trade-off: higher power than successor die (vs ATMEGA128A-MU)
Design Notes
The 64-QFN (9x9 mm MLF) package has a large exposed die pad under the device. Solder this pad to a grounded copper pour via an array of thermal vias (typically 5x5 pattern of 0.3 mm vias) - it is the main ground return and heat conduction path. Since [DATA_NEEDED] applies to exact theta_JA, verify the thermal figures in the Microchip package drawing before high-temperature designs. Note that X-ray inspection is recommended to confirm void-free pad soldering on production boards.
Decouple every VCC pin pair with 100 nF ceramic capacitors placed within 3 mm of the pins, plus 10 uF bulk capacitance near the device. AVCC powers the ADC - feed it through an RC or LC filter (e.g., 10 ohm resistor plus 100 nF/10 uF) from the digital rail, and connect AREF to a clean reference with a 100 nF bypass for full 10-bit accuracy. Keep the JTAG-enabled fuse in mind: PF4-PF7 default to JTAG after reset, so ADC channels 4-7 are unavailable unless JTAG is fused off.
Three frequent ATmega128 pitfalls: (1) The PC7 pin doubles as TOSC2 for the RTC - using an external 32.768 kHz RTC crystal on PC6/PC7 removes two address lines from external-memory mode. (2) External memory interface pins (PA/PC ports) default to general I/O only when the XMEM fuse is set correctly; verify MCUCR/SFIOR settings. (3) Migrating code from ATmega103 requires reviewing the Microchip application note 'Replacing ATmega103 by ATmega128' because register addresses and boot features differ despite 100% pin compatibility.
Compliance Information
Compliance certificates not present in the verified web data. Microchip supplies RoHS/REACH declarations for ATmega128 family parts on request via its product page - confirm against the certificate of conformity for your date code.
