ATMEGA64A-AUR - 8-bit AVR MCU 64KB Flash 16MHz TQFP-64 | Microchip
MPN: ATMEGA64A-AUR β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.12 | $6.12 |
| 10 | $5.55 | $55.50 |
| 100 | $4.95 | $495.00 |
| 500 | $4.48 | $2,240.00 |
| 1,000 | $4.1 | $4,100.00 |
ATMEGA64A-AUR Overview
A microcontroller unit (MCU) is a single integrated circuit that combines a processor core, memory, and programmable peripherals into one chip, forming the lowest level of the embedded computing hierarchy (MCU -> embedded processor -> computing system). The AVR ATmega family uses an advanced RISC architecture with 130 powerful instructions, most executed in a single clock cycle, giving roughly 16 MIPS throughput at 16MHz.
Key features include read-while-write ISP Flash for self-programming, two USARTs, four flexible timer/counters with compare modes and PWM, an 8-channel 10-bit ADC, byte-oriented Two-Wire Serial Interface (TWI/I2C), SPI, JTAG for boundary scan and on-chip debugging, and an internal oscillator option that reduces external component count.
Technically, the device provides 32 general purpose working registers directly connected to the ALU, allowing one-cycle instruction execution and C-compiler-friendly code density. The ATmega64A is 100% pin compatible with the legacy ATmega103, and the ATmega64A summary datasheet documents migration paths to and from ATmega128 parts, protecting long-term PCB investments.
Typical applications include industrial control and automation nodes, HVAC and building controllers, motor-adjacent sensing boards, and instrumentation front ends where the 10-bit ADC, dual USART, and PWM channels cover most interface needs from a single chip.
Design considerations: for UART or precise timing, prefer a crystal on XTAL1/XTAL2 because the internal RC oscillator trades accuracy (Β±2% after calibration) for board space; budget the 4KB SRAM carefully when using large frame buffers or protocol stacks.
This page synthesizes verified distributor listings, pinout data, drop-in alternatives, and practical design guidance not consolidated in the manufacturer datasheet.
Drop-in alternatives for ATMEGA64A-AUR 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 ATMEGA64A-AUR (same form factor and footprint) β differing in EEPROM, Package, ADC, Communication Interfaces, Operating Voltage.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA64A-AU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA64-16AU
β Drop-Inβ In Stock
$7.23 / Unit
View Datasheet βATMEGA128A-AU
β Drop-Inβ In Stock
$4.3 / Unit
View Datasheet βATMEGA64L-16AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA103-8AU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA64A-AUR Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Program Memory Size | 64KB (32K x 16) ISP Flash |
| EEPROM Size | 2KB |
| SRAM Size | 4KB |
| Maximum CPU Speed | 16MHz |
| General Purpose I/O | 53 lines |
| Working Registers | 32 general purpose |
| Timers/Counters | 4 flexible timer/counters with compare modes and PWM |
| ADC | 8-channel, 10-bit (from manufacturer product summary) |
| Communication Interfaces | 2x USART, SPI, TWI (I2C compatible) |
| Oscillator Type | Internal |
| Debug / Test | JTAG for on-chip debug and boundary scan |
| Package | 64-TQFP (14x14mm) |
| Mounting Type | Surface Mount |
| Operating Temperature Range | Industrial (-40C to +85C) |
| Packaging | Tape & Reel (TR) |
| RoHS Status | Compliant (GREEN per FindIC listing) |
| Pin Compatibility | 100% pin compatible with ATmega103 |
ATMEGA64A-AUR Pin Configuration
| Pin 1 | PB0 (SS) β Port B bit 0 / SPI Slave Select |
| Pin 2 | PB1 (SCK) β Port B bit 1 / SPI Serial Clock |
| Pin 3 | PB2 (MOSI) β Port B bit 2 / SPI Master Out Slave In |
| Pin 4 | PB3 (MISO) β Port B bit 3 / SPI Master In Slave Out |
| Pin 5 | PB4 (OC0) β Port B bit 4 / Timer0 Output Compare |
| Pin 6 | PB5 (OC1A) β Port B bit 5 / Timer1 Output Compare A |
| Pin 7 | PB6 (OC1B) β Port B bit 6 / Timer1 Output Compare B |
| Pin 8 | PB7 (OC2) β Port B bit 7 / Timer2 Output Compare |
| Pin 9 | RESET β Reset input (active low) |
| Pin 10 | VCC β Digital supply voltage |
| Pin 11 | GND β Digital ground |
| Pin 12 | XTAL2 β Crystal oscillator output 2 |
| Pin 13 | XTAL1 β Crystal oscillator input 1 / external clock |
| Pin 14 | PD0 (RXD0) β Port D bit 0 / USART0 receive |
| Pin 15 | PD1 (TXD0) β Port D bit 1 / USART0 transmit |
| Pin 16 | PD2 (INT0) β Port D bit 2 / External interrupt 0 |
| Pin 17 | PD3 (INT1) β Port D bit 3 / External interrupt 1 |
| Pin 18 | PD4 (IC1) β Port D bit 4 / Timer1 input capture |
| Pin 19 | PD5 (XCK0) β Port D bit 5 / USART0 external clock |
| Pin 20 | PD6 (T1) β Port D bit 6 / Timer1 external counter input |
| Pin 21 | PD7 (T2) β Port D bit 7 / Timer2 external counter input |
| Pin 22 | VCC β Digital supply voltage |
| Pin 23 | GND β Digital ground |
| Pin 24 | PE0 (RXD1) β Port E bit 0 / USART1 receive |
| Pin 25 | PE1 (TXD1) β Port E bit 1 / USART1 transmit |
| Pin 26 | PE2 β Port E bit 2 |
| Pin 27 | PE3 β Port E bit 3 |
| Pin 28 | PE4 β Port E bit 4 |
| Pin 29 | PE5 β Port E bit 5 |
| Pin 30 | PE6 β Port E bit 6 |
| Pin 31 | PE7 β Port E bit 7 |
| Pin 32 | VCC β Digital supply voltage |
| Pin 33 | GND β Digital ground |
| Pin 34 | PF0 (ADC0) β Port F bit 0 / ADC channel 0 |
| Pin 35 | PF1 (ADC1) β Port F bit 1 / ADC channel 1 |
| Pin 36 | PF2 (ADC2) β Port F bit 2 / ADC channel 2 |
| Pin 37 | PF3 (ADC3) β Port F bit 3 / ADC channel 3 |
| Pin 38 | PF4 (ADC4) β Port F bit 4 / ADC channel 4 |
| Pin 39 | PF5 (ADC5) β Port F bit 5 / ADC channel 5 |
| Pin 40 | PF6 (ADC6) β Port F bit 6 / ADC channel 6 |
| Pin 41 | PF7 (ADC7) β Port F bit 7 / ADC channel 7 |
| Pin 42 | AREF β ADC analog reference |
| Pin 43 | AGND β Analog ground |
| Pin 44 | AVCC β Analog supply for ADC / Port F |
| Pin 45 | PA0 (AD0) β Port A bit 0 / External memory address/data line 0 |
| Pin 46 | PA1 (AD1) β Port A bit 1 / External memory address/data line 1 |
| Pin 47 | PA2 (AD2) β Port A bit 2 / External memory address/data line 2 |
| Pin 48 | PA3 (AD3) β Port A bit 3 / External memory address/data line 3 |
| Pin 49 | PA4 (AD4) β Port A bit 4 / External memory address/data line 4 |
| Pin 50 | PA5 (AD5) β Port A bit 5 / External memory address/data line 5 |
| Pin 51 | PA6 (AD6) β Port A bit 6 / External memory address/data line 6 |
| Pin 52 | PA7 (AD7) β Port A bit 7 / External memory address/data line 7 |
| Pin 53 | PC0 (A8) β Port C bit 0 / External memory address line 8 / JTAG TCK |
| Pin 54 | PC1 (A9) β Port C bit 1 / Address line 9 / JTAG TDO |
| Pin 55 | PC2 (A10) β Port C bit 2 / Address line 10 / JTAG TMS |
| Pin 56 | PC3 (A11) β Port C bit 3 / Address line 11 / JTAG TDI |
| Pin 57 | PC4 (A12) β Port C bit 4 / Address line 12 |
| Pin 58 | PC5 (A13) β Port C bit 5 / Address line 13 |
| Pin 59 | PC6 (A14) β Port C bit 6 / Address line 14 |
| Pin 60 | PC7 (A15) β Port C bit 7 / Address line 15 |
| Pin 61 | PG0 (WR) β Port G bit 0 / External memory write strobe |
| Pin 62 | PG1 (RD) β Port G bit 1 / External memory read strobe |
| Pin 63 | PG2 (TOSC1) β Port G bit 2 / Timer oscillator input (32.768kHz RTC crystal) |
| Pin 64 | PG3 (TOSC2) β Port G bit 3 / Timer oscillator output |
Typical Applications
ATMEGA64A-AUR is suitable for 6 applications: Industrial Automation Control Nodes, Building Automation and HVAC Controllers, Instrumentation and Data Acquisition Front Ends, Legacy ATmega103 Board Refresh, Motor Control and PWM Actuator Drive, Security and Access Control Terminals.
Industrial Automation Control Nodes
The ATMEGA64A-AUR fits industrial control nodes because its industrial -40C to +85C temperature rating, dual USARTs for MODBUS RTU links, and four PWM timer channels cover the full sensor-actuator interface of a typical control board. The 64KB Flash (32K x 16) accommodates protocol stacks plus control logic with headroom, while 4KB SRAM buffers communication frames. In use, the chip sits as the main controller, reading analog sensors through the 8-channel 10-bit ADC and driving relays or actuators via PWM outputs; the industrial rating and active lifecycle status make it safe for long deployment cycles that consumer-grade MCUs cannot guarantee.
Recommended
Building Automation and HVAC Controllers
HVAC and building controllers benefit from the ATmega64A's combination of 53 GPIO lines, 10-bit ADC for temperature and pressure sensors, and TWI (I2C) bus for interfacing RTCs and EEPROM expansion. The 16MHz AVR core delivers roughly 16 MIPS, sufficient for PID control loops and BACnet-style serial communication over one of the two USARTs. Because the part offers read-while-write ISP Flash, firmware and logged setpoints can be updated in the field without removing the board. Its external memory interface on PORTA/PORTC also allows RAM expansion if logging requirements grow, making it a durable backbone for thermostat and air-handler boards.
Recommended
Instrumentation and Data Acquisition Front Ends
The 8-channel 10-bit ADC, precise timer capture capability (IC1 input capture on PD4), and JTAG on-chip debug make the ATmega64A a practical acquisition front end for bench instruments and dataloggers. Four timer/counters enable frequency measurement, PWM stimulus generation, and timestamped event capture simultaneously. With 64KB of self-programmable Flash, the firmware can store calibration tables and even reflash itself from a bootloader. Per designs referenced in Microchip application literature, sampling loops over the ADC at moderate rates are easily scheduled, and the 2KB EEPROM retains calibration data across power cycles without external nonvolatile memory.
Recommended
Legacy ATmega103 Board Refresh
According to the official ATmega64A summary datasheet, the ATmega64A is 100% pin compatible with ATmega103 and can replace it on current printed circuit boards, with Microchip's application note 'Replacing ATmega103 by ATmega64A' documenting the migration details. This makes ATMEGA64A-AUR the designated refresh path for the large installed base of ATmega103-based industrial and telecom boards that face ATmega103 end-of-life. Because the footprint, supply pins, and port mapping are identical, requalification is limited to firmware recompilation and verification, dramatically reducing redesign cost versus a re-layout onto a modern MCU package.
Recommended
Motor Control and PWM Actuator Drive
The ATmega64A's four timer/counters with compare modes and PWM outputs (OC0, OC1A, OC1B, OC2 on PORTB) directly generate multi-channel PWM for DC motor drivers, LED dimming, and heater control. The input capture feature provides rotational speed feedback from encoders, closing the control loop in firmware. At 16MHz the single-cycle AVR core executes control ISR routines deterministically, while the 10-bit ADC reads current-sense shunts for overload protection. Designs pair the MCU with external MOSFET gate drivers; the MCU's 5V tolerant industrial I/O and abundant 53 GPIO leave routing margin for direction, enable, and fault-handling signals on dense boards.
Recommended
Security and Access Control Terminals
Access-control terminals exploit the ATmega64A's balance of memory and interfaces: 64KB Flash holds cryptography-light access tables and event logs, 2KB EEPROM stores credential keys that survive power loss, and 4KB SRAM buffers keypad input and RS-485 traffic over a USART. The TWI bus reads real-time clocks and RFID reader front ends, while ample GPIO drives relays and status indicators directly. The JTAG interface supports production debugging and boundary-scan board test, and the industrial temperature range suits outdoor reader cabinets. Its active lifecycle status ensures continued availability for security products with multi-year service commitments.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA64A-AUR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA64A-AU | ATMEGA64-16AU | ATMEGA128A-AU | ATMEGA103-8AU |
|---|---|---|---|---|---|
| Package | 64-TQFP (14x14mm) | 64-TQFP (14x14mm) - same | 64-TQFP (14x14mm) - same | 64-TQFP (14x14mm) - same | 64-TQFP (14x14mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology (Atmel) |
| Flash Memory | 64KB (32K x 16) | 64KB (32K x 16) | 64KB (32K x 16) | 128KB (64K x 16) | 128KB |
| SRAM | 4KB | 4KB | 4KB | 8KB | 4KB |
| Max Clock Speed | 16MHz | 16MHz | 16MHz | 16MHz | 8MHz |
| GPIO Count | 53 | 53 | 53 | 53 | 48 |
| Lifecycle Status | Active | Active | Active (legacy die) | Active | Obsolete / EOL |
| Pin Compatibility | 100% compatible with ATmega103 | Identical (same die) | 100% pin-to-pin | 100% pin-to-pin (documented migration) | 100% pin-to-pin (legacy reference) |
Key Differentiators
- Current-generation 'A' die with active lifecycle (vs ATMEGA103-8AU)
- Headroom upgrade path on the same PCB (vs ATMEGA64-16AU)
- External memory bus plus dual USART (vs ATMEGA48PA-AUR)
Design Notes
Decouple all VCC pins (10, 22, 32) with 100nF ceramic capacitors placed within 5mm of each pin, plus one bulk 10uF capacitor near the supply entry. AVCC (pin 44) should be connected to VCC through a low-pass LC filter (10uH + 10uF) when ADC accuracy matters, and AREF (pin 42) should be decoupled with 100nF to AGND - never drive AREF from a low-impedance source when the internal reference is enabled. Estimated: with a typical 30mA active current at 5V, total dissipation is roughly 0.15W, requiring no heatsink.
Keep the analog island (pins 34-44: ADC inputs, AREF, AGND, AVCC) physically separated from the digital switching area and route a solid ground return to AGND. Place the JTAG header (PC0-PC3, pins 53-56) close to the connector and include the standard 10-pin AVR JTAG layout so on-chip debugging stays possible in production housings. Leave probe pads on XTAL1/XTAL2 and RESET for production programming and clock measurement.
Do not rely on the internal RC oscillator for USART communication: its accuracy is only a few percent even after calibration, while UART needs about 2% total budget - use a crystal when either USART is active. When migrating from ATmega103, note that fuse defaults, register maps, and peripheral features differ; follow Microchip's 'Replacing ATmega103 by ATmega64A' application note rather than assuming binary compatibility. Also verify that PG2/PG3 are configured for the timer oscillator only if a 32.768kHz crystal is actually fitted.
Compliance Information
Listed as 'GREEN' (RoHS-compliant, lead-free Matte Tin per 'U' suffix) in the FindIC distributor data. REACH, halogen-free and conflict-minerals declarations not stated in provided data.
