ATMEGA128A-MUR - 8-bit AVR MCU 128KB 16MHz 64-QFN | Microchip
MPN: ATMEGA128A-MUR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.21 | $7.21 |
| 10 | $6.7 | $67.00 |
| 100 | $6.05 | $605.00 |
| 500 | $5.6 | $2,800.00 |
| 1,000 | $5.2 | $5,200.00 |
ATMEGA128A-MUR Overview
An 8-bit AVR microcontroller is a single-chip computer that integrates a RISC processor core, program flash, data SRAM, EEPROM, and peripheral functions such as timers, UARTs, and SPI on one die. Within the embedded systems hierarchy, it sits under the microcontroller family, which belongs to the broader class of integrated circuits and semiconductor devices used for embedded control.
Key differentiating features include 133 powerful instructions, most executing in a single clock cycle; 32 general-purpose working registers directly connected to the ALU; read-while-write flash for in-system self-programming; four flexible timer/counters with compare modes and PWM; two USARTs; and a byte-oriented Two-Wire Interface (I2C-compatible) plus SPI and EBI/EMI connectivity.
Architecturally, the ATmega128A uses the AVR enhanced RISC Harvard architecture with separate instruction and data buses, allowing single-cycle instruction fetch and execution. The advanced architecture achieves near-1 MIPS/MHz efficiency, letting designers optimize power consumption versus processing speed, aided by multiple sleep modes and an on-chip real-time counter.
Typical applications include industrial control and embedded automation, motor control, metering, IoT end nodes, and low-power board-level designs where 128KB of flash supports larger C code bases without external memory.
A key design consideration: the 64-QFN (9x9 mm) exposed pad must be soldered to a grounded thermal land pattern for reliable operation, and the 16MHz clock should be supplied via the on-chip oscillator or an external crystal per the datasheet clock configuration options.
This page synthesizes distributor pricing, drop-in alternatives such as ATMEGA128A-MU and ATMEGA1284P-MUR, pinout guidance, and practical design notes not found in the manufacturer datasheet, adding value for sourcing and selection engineers. Pricing data is current as of 2026-09-16.
Drop-in alternatives for ATMEGA128A-MUR — 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 ATMEGA128A-MUR (same form factor and footprint) — differing in Package, Supply Voltage Range, SRAM, Serial Interfaces, Timers/Counters.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA128A-MU
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA128-16MUR
✅ Drop-In✓ In Stock
$8.4 / Unit
View Datasheet →ATMEGA1281V-8MUR
✅ Drop-In✓ In Stock
$4.02 / Unit
View Datasheet →ATMEGA1281-16MUR
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$8.78 / Unit
View Datasheet →ATMEGA1284P-MUR
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →ATMEGA128A-MUR Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Maximum Clock Speed | 16 MHz |
| Flash Memory | 128 KB (64K x 16) |
| EEPROM | 4 KB |
| SRAM | 4 KB |
| Supply Voltage Range | 2.7 V to 5.5 V |
| General Purpose I/O | 53 lines |
| Working Registers | 32 general purpose |
| Instructions | 133 powerful instructions, most single-cycle |
| Timer/Counters | 4 flexible timer/counters with compare modes and PWM |
| Connectivity | EBI/EMI, I2C (Two-Wire Interface), SPI, UART/USART (2x USART) |
| Real-Time Counter | Yes |
| Package | 64-VFQFN Exposed Pad (9x9 mm) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (TR) |
| Lifecycle Status | Active |
ATMEGA128A-MUR 64-vfqfn exposed pad (9x9 mm) Pin Configuration Guide
Pin configuration for ATMEGA128A-MUR (64-vfqfn exposed pad (9x9 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 ATMEGA128A-MUR.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA128A-MUR is suitable for 6 applications: Industrial Control and Automation, Motor Control, Metering and Smart Instruments, IoT End Nodes, Legacy ATmega103 Board Upgrade, Embedded Educational and Prototyping Boards.
Industrial Control and Automation
The ATMEGA128A-MUR fits industrial control because its 128KB flash accommodates large control firmware, 53 GPIO lines interface PLC-style inputs and outputs, and two USARTs plus SPI and I2C support Modbus and sensor buses. Operating from 2.7V to 5.5V allows direct connection to 5V industrial logic levels, providing robust noise margins on factory floors. Four timer/counters with compare modes and PWM drive actuators and generate precise timing sequences, while the external memory interface (EBI/EMI) expands RAM for data logging when 4KB internal SRAM is insufficient. Typical deployments place the MCU on a 5V rail with a 16MHz crystal, using watchdog and brown-out fuses for fail-safe operation in embedded automation nodes.
Recommended
Motor Control
For motor control, the ATMEGA128A-MUR leverages four flexible timer/counters with compare modes and hardware PWM to drive DC, stepper, and brushless motor stages directly. The 16MHz AVR RISC core delivers roughly 16 MIPS at 5V, sufficient for closed-loop control loops sampled at several kilohertz, while the 53 GPIO lines connect encoders, limit switches, and gate drivers. Dual USARTs support command interfaces, and SPI links to external ADCs for current sensing. The 2.7V to 5.5V supply range matches common 5V gate-driver rails. Designs typically gate MOSFET bridges such as IR2110-based drivers from the PWM outputs, with the MCU supervising fault feedback inputs for safe shutdown.
Recommended
Metering and Smart Instruments
Energy and utility metering benefits from the ATMEGA128A-MUR's 128KB flash, which stores calibration tables, communication stacks, and multi-tariff logic without external memory. The 4KB EEPROM retains metering constants and consumption registers across power cycles, a critical requirement for billing-grade instruments. Its real-time counter supports timestamping with an external 32.768kHz crystal, while USART connectivity handles RS-485 or infrared communication heads. The low-power architecture and sleep modes suit battery-assisted meter operation. According to GlobalSpec's product overview, metering is a target application for this MCU; typical designs pair it with current-sensing front ends and isolate the communication bus with optocouplers for compliance and safety.
Recommended
IoT End Nodes
In IoT end nodes, the ATMEGA128A-MUR balances capability and cost: 128KB flash hosts protocol stacks and OTA-style update loaders, SPI and I2C interfaces connect radio modules and sensors, and sleep modes extend battery life in duty-cycled designs. The byte-oriented Two-Wire Interface links environmental sensors, while SPI addresses faster peripherals such as flash and ADCs. Operating at 3.3V at reduced clock speed lowers dynamic power; at 5V and 16MHz it delivers about 16 MIPS for edge preprocessing. Because the node firmware often evolves, the read-while-write flash supports in-system self-programming for field updates. Gateway-style designs pair the MCU with wireless modules through a UART link.
Recommended
Legacy ATmega103 Board Upgrade
The ATMEGA128A-MUR is the sanctioned upgrade path for ATmega103-based PCBs: per the Microchip ATmega128A datasheet, the ATmega128A is 100% pin compatible with the ATmega103 and can replace it on current printed circuit boards. Microchip's application note 'Replacing ATmega103 by ATmega128A' details the few software considerations, including fuse differences and relocated peripheral functions. Existing boards gain doubled flash (128KB vs 103's 128KB equivalent architecture with modern process support), continued supply availability, and full compatibility with current programming tools. Procurement teams facing ATmega103 end-of-life shortages can drop this part onto legacy land patterns with minimal redesign effort.
Recommended
Embedded Educational and Prototyping Boards
The ATMEGA128A-MUR is a popular choice for development and educational platforms because the AVR architecture is extensively documented, tools such as AVR-GCC, AVR Studio, and Arduino-compatible cores are free, and in-system programming requires only a SPI header. The 128KB flash removes compile-size anxiety for student projects, and 53 GPIO lines support rich peripheral experiments from LCDs to motor shields. The 2.7V to 5.5V supply tolerance makes boards tolerant of USB 5V or battery 3.7V inputs with simple regulation. Prototypers typically run the internal RC oscillator at 8MHz for minimal component count, then switch to a 16MHz external crystal for final designs, keeping the same PCB population options.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA128A-MUR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA128A-MU | ATMEGA128-16MUR | ATMEGA1284P-MUR | ATMEGA1281V-8MUR |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 64-QFN (9x9 mm) Exposed Pad | 64-QFN (9x9 mm) Exposed Pad - same | 64-QFN (9x9 mm) Exposed Pad - same | 64-QFN | 64-QFN (9x9 mm) |
| Flash Memory | 128 KB | 128 KB | 128 KB | 128 KB | 128 KB |
| SRAM | 4 KB | 4 KB | 4 KB | 16 KB | 8 KB |
| External Memory Interface (EBI/EMI) | Yes | Yes | Yes | No | No |
Key Differentiators
- External memory interface (EBI/EMI) for RAM expansion (vs ATMEGA1284P-MUR)
- 16MHz operation vs reduced-speed family variant (vs ATMEGA1281V-8MUR)
- 100% pin compatibility with legacy ATmega103 (vs ATMEGA128-16MUR)
Design Notes
The 64-QFN (9x9 mm) exposed pad on the ATMEGA128A-MUR must be connected to a solid ground land pattern. Extend multiple thermal vias from the exposed pad to internal ground planes to improve heat dissipation and electrical grounding. Follow the datasheet land-pattern dimensions; oversized pads cause solder wicking onto the perimeter pins during reflow, while undersized pads weaken joints. Inspect with X-ray or AOI since the perimeter pads sit under the package body.
Decouple VCC and AVCC independently: place a 100nF ceramic capacitor within 5 mm of each supply pin, plus bulk 10uF per rail. When running the ADC, power AVCC through an LC filter (ferrite bead plus 100nF) from the digital rail to reduce noise coupling. Keep the ADC reference (AREF) capacitor close to the pin. The MCU tolerates 2.7V to 5.5V, but ensure brown-out detection fuses are set appropriately for your chosen rail to prevent corrupted EEPROM writes during supply dips.
When migrating from ATmega103, do not copy fuse bytes directly: the ATmega128A fuse map differs, and Microchip's application note 'Replacing ATmega103 by ATmega128A' lists relocated peripherals and configuration changes. Also confirm clock source fuses - enabling CKOPT or the wrong clock settings can render the device unresponsive to SPI programming. Always verify the clock fuse settings and use a slow external clock for recovery of misfused devices.
Compliance Information
Compliance details were not present in the provided verified web data; consult Microchip's product page or distributor RoHS certificates.
