ATMEGA103-6AC - 8-Bit AVR MCU, 6MHz, 128KB Flash | Microchip
MPN: ATMEGA103-6AC β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.4 | $12.40 |
| 10 | $11.15 | $111.50 |
| 100 | $9.8 | $980.00 |
| 500 | $8.9 | $4,450.00 |
| 1,000 | $8.2 | $8,200.00 |
ATMEGA103-6AC Overview
A microcontroller is a single-chip computer that integrates a processor core, program memory, data memory, and peripherals such as timers, UART, and analog-to-digital converters onto one die. In the embedded systems hierarchy, the AVR ATmega family sits within the broader class of 8-bit microcontrollers, competing with architectures such as Microchip PIC, 8051, and Freescale HC08. The AVR architecture uses a Harvard structure with most instructions executing in a single clock cycle, giving high code efficiency and MIPS-per-MHz.
Key features of the ATMEGA103-6AC include 121 powerful instructions (most single-cycle), 128KB of In-System Reprogrammable Flash, 4KB of internal SRAM, and 4KB of EEPROM for non-volatile data storage. The 6 MHz speed grade with a 5V supply targets cost-sensitive commercial-temperature applications where maximum performance is not required. The large 128KB Flash makes it suitable for firmware-heavy applications such as protocol stacks and menu-driven HMI code.
Technically, the ATmega103 uses an AVR enhanced RISC core with 32 general-purpose working registers directly connected to the ALU, allowing two independent registers to be accessed in one instruction executed in one clock cycle. This delivers throughput approaching 1 MIPS per MHz. Peripherals typically include an 8-channel 10-bit ADC, multiple timer/counters with PWM, UART for serial communication, and SPI for synchronous serial interfacing.
Typical applications include industrial control panels, building automation nodes, battery-backed instrumentation, and legacy embedded products whose firmware was designed around the ATmega103 memory map and pinout.
Design consideration: the 5V-only supply and 6 MHz limit mean new designs should normally select the pin-compatible ATmega128 family, which runs to 16 MHz with richer peripherals while sharing the 64-TQFP footprint.
This page synthesizes distributor pricing, verified drop-in alternatives such as the ATmega128 series, and practical sourcing notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA103-6AC 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 ATMEGA103-6AC (same form factor and footprint) β differing in Maximum Clock Frequency, Operating Temperature, Package, Core Architecture, Instruction Count.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA128-16AU
β Drop-Inβ In Stock
$14.3 / Unit
View Datasheet βATMEGA128-16AUR
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA128-8AU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA128-8AI
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA103-6AI
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$8.6 / Unit
View Datasheet βATMEGA103-6AC Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR Enhanced RISC, 8-bit |
| Maximum Clock Frequency | 6 MHz |
| Program Memory Size | 128KB (64K x 16) Flash |
| Program Memory Type | In-System Reprogrammable Flash |
| SRAM Size | 4KB |
| EEPROM Size | 4KB |
| Supply Voltage | 5 V |
| Instruction Count | 121 instructions, most single-clock-cycle |
| Package | 64-TQFP (14 x 14 mm) |
| Mounting Type | Surface Mount |
| ADC Resolution | 10-bit |
| Operating Temperature | 0C to +70C (commercial, AC suffix) |
| Data Bus Width | 8 bit |
ATMEGA103-6AC 64-tqfp (14 x 14 mm) Pin Configuration Guide
Pin configuration for ATMEGA103-6AC (64-tqfp (14 x 14 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 ATMEGA103-6AC.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA103-6AC is suitable for 6 applications: Industrial Control Panels, Building Automation Nodes, Battery-Backed Instrumentation, Legacy Embedded Product Sustainment, Embedded Training and Education Platforms, Motor Control and PWM Systems.
Industrial Control Panels
The ATMEGA103-6AC's 128KB In-System Programmable Flash provides ample room for state machines, Modbus-style serial protocol handlers, and menu-driven HMI code that smaller 8-bit MCUs cannot hold, while its 5V supply interfaces directly with legacy industrial 5V logic levels, optocouplers, and relays without level shifting. In a typical panel controller, the AVR runs its main loop from the 6 MHz internal clock budget with a 10-bit ADC reading potentiometers and analog transducers, a UART handles RS-485 communication through an external transceiver, and PWM timer outputs drive actuator drivers. Designers choose this part when sustaining certified legacy panels where the PCB and firmware were architected around the ATmega103 memory map; requalification to a pin-compatible ATmega128 is the standard modernization path rather than a full redesign.
Recommended
Building Automation Nodes
Building automation controllers benefit from the ATMEGA103-6AC combination of large 128KB Flash for protocol stacks and scheduling logic, 4KB EEPROM for non-volatile setpoints and commissioning data that must survive power loss, and a 10-bit ADC for temperature, humidity, and occupancy sensor inputs. The 64 general-purpose-capable pins in the 14 x 14 mm TQFP allow direct attachment of keypad matrices, LCD modules, relay drivers, and DIP switches on a single controller board. Because nodes in this market historically ran 5V rails, the 5V-only operation of the AC grade is an advantage rather than a limitation, eliminating regulator cost in legacy panels. For new node designs, the pin-compatible ATMEGA128-8AU is preferred, offering 8 MHz speed plus TWI for modern I2C sensor buses while reusing the same PCB footprint.
Recommended
Battery-Backed Instrumentation
Precision handheld and bench instruments use the ATMEGA103-6AC's 4KB EEPROM to retain calibration constants and the 128KB Flash to host complex measurement routines, gain tables, and multi-language display strings that would overflow smaller AVRs. The 10-bit ADC digitizes sensor front ends, while timers generate PWM for motorized attenuators or sample-and-hold control. In battery-backed designs, the ATmega103 supports low-power sleep operation, and the commercial 0C to +70C AC grade suits indoor laboratory conditions; field and outdoor instruments should instead select the industrial ATMEGA103-6AI or ATmega128 AI grades rated to -40C to +85C. Firmware writers value the 121-instruction AVR RISC core whose single-cycle execution at 6 MHz yields roughly 6 MIPS, enough headroom for FFT-based measurement code on an 8-bit platform.
Recommended
Legacy Embedded Product Sustainment
The dominant real-world use of the ATMEGA103-6AC today is sustaining legacy products - gateways, testers, vending controllers, and medical accessories - whose production firmware was built against the ATmega103 register map. Distributors including DigiKey (ships today) and Mouser still stock the part, and Octopart aggregates offers from around 10 distributors, making continued manufacture viable. Procurement teams typically buy lifetime quantities in the 500-1000 piece tier, where XAIPART pricing falls to roughly $8.20-8.90 per unit as of 2026-09-15. Best practice pairs immediate stock purchase with a qualified migration plan to the pin-compatible ATMEGA128 family, since AVR ATmega103 die production is legacy and allocation risk rises every year; dual-sourcing the PCB footprint for ATmega128 helps future-proof the bill of materials.
Recommended
Embedded Training and Education Platforms
Universities and technical training programs built numerous AVR development boards around the ATmega103 because its 128KB Flash removed the constant reprogramming-limit anxiety of smaller parts, and its single-cycle RISC core makes assembly-language teaching clean and predictable at 6 MHz. The 64-pin TQFP is hand-solderable on training boards with adapter sockets, and its 32 general-purpose registers directly connected to the ALU illustrate classic RISC load-store concepts. Laboratory exercises typically drive LEDs, seven-segment displays, keypads, and UART terminals through the parallel ports at 5V logic levels. Institutions maintaining existing training hardware can keep sourcing the commercial AC grade, while new course kits should adopt the ATMEGA128-16AU, which is software-recursive with most ATmega103 course material and adds TWI/SPI teaching examples relevant to modern sensor labs.
Recommended
Motor Control and PWM Systems
The ATMEGA103-6AC's timer/counters with PWM outputs make it a fit for DC motor and heater control in legacy equipment, where 6 MHz is ample for closed-loop PWM generation at several kHz carrier frequencies and the 10-bit ADC closes the loop with tachometer or thermistor feedback. The 5V supply directly drives MOSFET gate-driver inputs such as IR2110-class circuitry, so designers avoid level-translation stages common when using 3.3V MCUs. The 121-instruction AVR core executes PID arithmetic efficiently, with roughly 6 MIPS of throughput at the 6 MHz rating - adequate for single-axis control loops executing at hundreds of Hz. Multi-axis or field-oriented motor control exceeds this class and should migrate to the 16 MHz ATMEGA128-16AU in the same 64-TQFP footprint, doubling loop bandwidth without any PCB change.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA103-6AC β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA128-16AU | ATMEGA128-8AU | ATMEGA128-8AI | ATMEGA103-6AI |
|---|---|---|---|---|---|
| Package | 64-TQFP (14x14 mm) | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same |
| Brand | Microchip Technology (Atmel) | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology (Atmel) |
| Core / Architecture | AVR enhanced RISC, 8-bit | AVR enhanced RISC, 8-bit | AVR enhanced RISC, 8-bit | AVR enhanced RISC, 8-bit | AVR enhanced RISC, 8-bit |
| Max Clock Frequency | 6 MHz | 16 MHz | 8 MHz | 8 MHz | 6 MHz |
| Flash Memory | 128KB | 128KB | 128KB | 128KB | 128KB |
| SRAM | 4KB | 4KB | 4KB | 4KB | 4KB |
| Operating Temperature | 0C to +70C (commercial) | -40C to +85C (industrial) | 0C to +70C (commercial) | -40C to +85C (industrial) | -40C to +85C (industrial) |
| TWI (I2C) Peripheral | Not available | Yes | Yes | Yes | Not available |
Key Differentiators
- Lowest-cost entry into the 128KB-pin-compatible family footprint (vs ATMEGA128-16AU)
- Exact-firmware compatibility for existing ATmega103 products (vs ATMEGA128-8AU)
- Commercial grade availability for indoor legacy systems (vs ATMEGA128-8AI)
Design Notes
Firmware portability between ATmega103 and the pin-compatible ATmega128 is not binary-compatible at the register level: the ATmega128 moved certain I/O registers into extended I/O space and added peripherals like TWI. When migrating, recompile from source rather than reusing .hex binaries, verify UART and timer register settings against the ATmega128 datasheet, and test any code that writes to ATmega103-specific addresses. Also confirm that external memory interfacing code accounts for the ATmega128's different bus-control register names before committing to a drop-in swap.
The AC grade is specified for a 5V supply only; do not attempt 3.3V operation. Decouple each VCC/AVCC pin pair with 100 nF ceramic capacitors placed within a few millimeters of the pins, plus a bulk 10 uF capacitor per supply rail. Estimated: at 6 MHz and 5V, active-mode current for classic ATmega-class AVRs is in the several-mA range, so a small linear regulator suffices; if the design relies on battery backup, implement sleep-mode wake-up and disable unused peripheral clocks in firmware to reduce average draw.
For the 64-TQFP 14 x 14 mm footprint, use a 0.5 mm pitch land pattern per the datasheet package drawing and place the crystal within 10-15 mm of the XTAL pins with appropriate load capacitors for the 6 MHz source. Keep the analog reference (AREF) trace short and star-grounded near the ADC input side; run the ADC ground return away from PWM and UART switching currents. Provide at least one programming/debug header (ISP) on production boards even for legacy parts, since field firmware updates depend on In-System Programmability of the 128KB Flash.
Compliance Information
Compliance status for this legacy Atmel-era part was not stated in the retrieved distributor snippets. Verify RoHS/REACH status on the official Microchip product page or environmental datasheet before procurement.