ATMEGA128-16AU - 8-Bit AVR MCU, 128KB Flash, 16MHz | Microchip
MPN: ATMEGA128-16AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $17.04 | $17.04 |
| 10 | $16.2 | $162.00 |
| 100 | $15.5 | $1,550.00 |
| 500 | $14.9 | $7,450.00 |
| 1,000 | $14.3 | $14,300.00 |
ATMEGA128-16AU Overview
An 8-bit AVR microcontroller is a single-chip processor built on the AVR enhanced RISC architecture, in which most instructions execute in a single clock cycle. Within the power-management and embedded-control hierarchy, it functions as the central computing element of a system, replacing discrete logic and analog control circuitry while offering flash-based field reprogrammability.
Key features include 128KB self-programmable Flash with a boot section for in-application programming, 4KB internal SRAM, 4KB EEPROM for non-volatile parameter storage, and throughput approaching 16 MIPS at 16 MHz, allowing designers to optimize power consumption versus processing speed.
Technically, the ATmega128 combines an 8-channel 10-bit A/D converter with an external-memory interface (up to 64KB external data space via PORTA/PORTC multiplexed addressing), two 8-bit and two 16-bit timers with PWM outputs, two USARTs, SPI, and a Two-Wire Interface, plus a JTAG boundary-scan and debug port. The AVR Harvard architecture with 32 general-purpose registers enables efficient C-compiled code execution.
Typical applications include industrial control and automation nodes, general embedded systems, data loggers, and legacy ATmega103 upgrades, since the ATmega128 is 100% pin compatible with ATmega103 and can replace it on existing PCBs.
A key design consideration is supply voltage: the 16 MHz -16AU speed grade requires 4.5V to 5.5V operation; the ATmega128L variant is needed for 2.7V-5.5V low-voltage designs. Provide decoupling capacitors on all VCC/AVCC pins and use the internal RC or external crystal clock option accordingly.
This page synthesizes distributor pricing, verified drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA128-16AU 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 ATMEGA128-16AU (same form factor and footprint) β differing in Operating Temperature, Package, Flash Memory, Timers/Counters, Program Memory Size.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA128A-AU
β Drop-Inβ In Stock
$4.3 / Unit
View Datasheet βATMEGA128-16AN
β Drop-Inβ In Stock
$7.44 / Unit
View Datasheet βATMEGA128-16AI
β Drop-Inβ In Stock
$5.9 / Unit
View Datasheet βATMEGA1281-16MUR
β Drop-Inβ In Stock
$8.78 / Unit
View Datasheet βAT90CAN128-16AUR
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA128-16AU Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Flash Memory | 128 KB (64K x 16) In-System Programmable |
| SRAM | 4 KB |
| EEPROM | 4 KB |
| Maximum Clock Frequency | 16 MHz |
| Throughput | 16 MIPS at 16 MHz (approx. 1 MIPS per MHz) |
| Supply Voltage Range | 4.5 V to 5.5 V (16 MHz speed grade) |
| ADC | 8-channel 10-bit |
| Debug Interface | JTAG for on-chip debugging |
| Package | 64-TQFP (14x14 mm) |
| Mounting Type | Surface Mount |
| Temperature Grade | Industrial (IND TEMP) |
| External Memory Interface | Supported (up to 64 KB external data memory) |
| Serial Interfaces | 2x USART, SPI, Two-Wire Interface (I2C-compatible) |
| RoHS Status | Compliant (RoHS Y) |
ATMEGA128-16AU 64-tqfp (14x14 mm) Pin Configuration Guide
Pin configuration for ATMEGA128-16AU (64-tqfp (14x14 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 ATMEGA128-16AU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA128-16AU is suitable for 6 applications: Industrial Control and Automation, Data Acquisition and Logging Systems, General Purpose Embedded Systems, Legacy ATmega103 Board Upgrade, Motor Control and Actuation, Instrumentation Front Panels and HMI.
Industrial Control and Automation
The ATMEGA128-16AU fits industrial control nodes where deterministic 8-bit control, moderate code size, and rugged I/O matter. Its 128KB Flash accommodates state machines, communication stacks, and bootloaders, while the industrial temperature grade and 4.5V-5.5V supply suit noisy 5V plant environments. Two USARTs handle Modbus RTU links and diagnostics simultaneously, and the external memory interface extends RAM for buffering. With throughput of 16 MIPS at 16 MHz, closed-loop control at kilohertz rates is practical, and JTAG enables in-circuit debugging during commissioning of automated machinery.
Recommended
Data Acquisition and Logging Systems
In data loggers, the ATmega128's 8-channel 10-bit ADC multiplexes multiple analog sensors without external front ends, and 4KB EEPROM retains calibration and configuration across power cycles. The 128KB Flash supports substantial logging firmware and file-system code, while the external memory interface addresses external SRAM when 4KB internal SRAM is insufficient for long sample buffers. Two USARTs allow simultaneous sensor-network capture and telemetry output. The 16 MHz clock provides 16 MIPS for real-time filtering, and the ADC interrupt-driven sampling keeps CPU load low during continuous acquisition campaigns.
Recommended
General Purpose Embedded Systems
For general embedded products such as controllers, meters, and interface converters, the ATMEGA128-16AU offers a balanced feature set: 32 general-purpose registers, rich timer/PWM resources, SPI and Two-Wire Interface for peripherals, and a JTAG port that simplifies production debugging. The AVR architecture executes most instructions in a single cycle, delivering approximately 1 MIPS per MHz, so a 16 MHz system behaves like far slower-cycle-count competitors. Long-term availability and extensive community code make it low-risk for products with multi-year service lives, and the boot-section Flash supports field firmware updates.
Recommended
Legacy ATmega103 Board Upgrade
The ATmega128 is 100% pin compatible with the ATmega103 and can replace it on existing printed circuit boards, as stated in the Microchip datasheet. Designs built around the ATmega103's 4MHz-era performance gain a 16 MHz clock, 128KB self-programmable Flash with boot section, JTAG debugging, and revised peripherals without PCB respin. Microchip's application note 'Replacing ATmega103 by ATmega128' documents the register-level and fuse differences engineers must address in firmware. This makes the ATMEGA128-16AU the sanctioned drop-in path for sustaining legacy 5V industrial and telecom hardware.
Recommended
Motor Control and Actuation
With two 8-bit and two 16-bit timers providing multiple PWM channels, the ATMEGA128-16AU drives DC and stepper motors with modest gate-driver overhead. The 16 MHz clock yields PWM resolutions in the kilohertz carrier range appropriate for motor control, while external interrupt pins INT0-INT7 accept quadrature or Hall-feedback signals. The 10-bit ADC reads current-sense amplifiers for closed-loop torque control. Because all PWM and feedback functions are on-chip, the surrounding BOM stays small, and the 5V industrial supply range simplifies interfacing with standard driver ICs in actuator assemblies.
Recommended
Instrumentation Front Panels and HMI
Human-machine interface boards benefit from the ATmega128's combination of ADC inputs for keypads and potentiometers, TWI for driving character LCD controllers, and ample Flash for menu systems and multilingual strings. The JTAG interface enables boundary-scan testing of assembled display boards, improving production quality. External memory expansion supports graphics buffers for small displays beyond what 4KB SRAM allows, and the dual USART bridges an RS-485 supervisory link with a local RS-232 service port. The 14x14 mm TQFP fits compact panel controllers while remaining hand-solderable and reworkable.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA128-16AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA128A-AU | ATMEGA1281-16MUR | AT90CAN128-16AUR |
|---|---|---|---|---|
| Package | 64-TQFP (14x14 mm) | 64-TQFP (14x14 mm) - same | 64-TQFP - same footprint | 64-TQFP - same footprint |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 128 KB | 128 KB | 128 KB | 128 KB |
| Max Clock Frequency | 16 MHz | 16 MHz | 16 MHz | 16 MHz |
| Special Peripherals | JTAG, 2x USART, SPI, TWI, ext. memory interface | Same set (refreshed die) | Added USARTs / revised peripheral set | Adds CAN 2.0A/B controller |
| RoHS | Compliant ('U' suffix, green) | Compliant | Compliant ('R' reel, green) | Compliant |
Key Differentiators
- External memory expansion interface (vs ATMEGA64A-AU)
- Refreshed-die continuity option (vs ATMEGA128A-AU)
- CAN-fieldbus-ready pin-compatible path (vs AT90CAN128-16AUR)
Design Notes
The -16AU speed grade requires a 4.5V to 5.5V supply; do not power it from a 3.3V rail expecting 16 MHz operation. Decouple every VCC pin and AVCC with 100 nF ceramics placed within a few millimeters of the pins, plus bulk 10 uF per board. Tie AVCC to VCC through an LC filter when ADC accuracy matters, and keep AGND/AREF routing quiet. Estimated: at 16 MHz with I/O loaded, active current is typically in the tens of milliamps per the datasheet current-consumption tables.
The 64-TQFP (14x14 mm) exposes JTAG on PF7-PF4 (TDI/TDO/TMS/TCK). Reserve the 10-pin JTAG header footprint even if unused, because JTAG is enabled by default fuse settings and doubles as boundary-scan for production test. Route the external memory bus (PORTA multiplexed address/data, PORTC high address, PG2 ALE, PG0/PG1 WR/RD) with matched-ish lengths and series termination on ALE if long. Keep the crystal within 10 mm of XTAL pins with appropriate load capacitors.
Migrating from ATmega103: the ATmega128 changes several register locations and default fuse behavior; follow Microchip's 'Replacing ATmega103 by ATmega103/128' guidance and re-check WDTCR, MCUCR, and interrupt vector mapping. Also note the boot-loader section requires correct BOOTRST fusing, and EEPROM operation has a timed write sequence that must not be interrupted by power loss - add brown-out detection. Verify the exact operating temperature limits against the full datasheet before qualification.
Compliance Information
RoHS Y and green packaging indicated by the 'U' suffix and distributor compliance data (PartGenie: RoHS Y). REACH, halogen-free, and conflict-minerals statuses were not specified in the provided data - consult Microchip's official product compliance documentation.