ATMEGA64A-MNR - 8-bit AVR MCU 64KB Flash 16MHz | Microchip
MPN: ATMEGA64A-MNR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.2 | $6.20 |
| 10 | $5.58 | $55.80 |
| 100 | $4.95 | $495.00 |
| 500 | $4.46 | $2,230.00 |
| 1,000 | $4.02 | $4,020.00 |
ATMEGA64A-MNR Overview
An 8-bit AVR microcontroller is a Harvard-architecture processor that executes most instructions in a single clock cycle, sitting at the entry level of the embedded processor hierarchy (MCU -> embedded processor -> system-on-chip). MCUs integrate CPU, program memory, data memory, timers, and peripherals on a single die, making them the workhorse of embedded control systems in industrial, consumer, and automotive electronics.
The ATmega64A combines 64KB of self-programmable Flash with read-while-write support, 53 general-purpose I/O lines, and 32 general-purpose working registers, all directly connected to the ALU for fast single-cycle operation. Its peripheral set includes 8-channel 10-bit ADC, two 8-bit and two 16-bit timers with PWM, two USARTs, TWI (I2C), SPI, analog comparator, and an on-chip JTAG boundary-scan/debug interface. The improved -A variant is a functionally identical, drop-in replacement for the original ATmega64 with reduced current consumption, per Microchip application note AVR524.
Architecturally, the AVR core uses a two-stage pipeline with fast register file access, achieving throughputs close to 1 MIPS per MHz. Operating from 2.7V to 5.5V, the device supports six sleep modes including power-down and standby for aggressive energy budgets in battery-operated systems. In-system programming (ISP) via SPI and boot-section self-programming enable field firmware updates without removing the device from the PCB.
Typical applications include industrial automation controllers, HVAC and building-control nodes, motor-control and inverter boards, battery-powered instrumentation, and embedded communication bridges using the dual USART or I2C/SPI links.
When designing with the 64-QFN package, pay particular attention to the exposed thermal pad, which must be soldered to a solid ground pour for both electrical grounding and heat dissipation, and to JTAG pin sharing with PC2-PC7 which must be disabled via fuse if those pins are needed as GPIO.
This page synthesizes verified distributor data, drop-in same-package alternatives, and practical layout guidance not found in the manufacturer datasheet. Pricing shown is as of 2026-09-18 and reflects typical distributor tiers; availability and lead time should be confirmed at order time.
Drop-in alternatives for ATMEGA64A-MNR — 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-MNR (same form factor and footprint) — differing in Package, ADC Resolution, Debug Interface, General Purpose I/O, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA64-16MI
✅ Drop-In✓ In Stock
$4.48 / Unit
View Datasheet →ATMEGA649P-MU
✅ Drop-In✓ In Stock
$3.91 / Unit
View Datasheet →ATMEGA645-16MUR
✅ Drop-In✓ In Stock
$3.35 / Unit
View Datasheet →ATMEGA649A-MU
✅ Drop-In✓ In Stock
$4.42 / Unit
View Datasheet →ATMEGA64A-MNR Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Program Memory Size | 64KB (32K x 16) Flash |
| EEPROM Size | 2KB |
| SRAM Size | 4KB (4K x 8) |
| Maximum Clock Frequency | 16MHz |
| Number of I/O | 53 |
| Package / Case | 64-VFQFN Exposed Pad (9x9 mm) |
| Operating Temperature | -40C to +105C |
| Supply Voltage Range | 2.7 V to 5.5 V |
| Interfaces | I2C (TWI), SPI, UART, USART |
| ADC Resolution | 10-bit, 8-channel |
| Timers / Counters | 2 x 8-bit, 2 x 16-bit with PWM |
| Debug / Scan | JTAG boundary-scan and on-chip debug |
| Mounting Type | Surface Mount |
| Packaging | Tape and Reel |
| RoHS Status | Compliant (Green) |
| General Purpose Working Registers | 32 |
ATMEGA64A-MNR 64-vfqfn exposed pad (9x9 mm) Pin Configuration Guide
Pin configuration for ATMEGA64A-MNR (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 ATMEGA64A-MNR.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA64A-MNR is suitable for 6 applications: Industrial Automation Controllers, HVAC and Building Automation, Battery-Powered Portable Instruments, Motor Control and Inverter Boards, Embedded Communication Bridges, Security and Access Control Panels.
Industrial Automation Controllers
The ATMEGA64A-MNR suits industrial control nodes that need substantial code space and robust serial connectivity. Its 64KB flash accommodates state machines, PID loops, and communication stacks, while the dual serial ports (UART plus USART) allow simultaneous PLC-fieldbus and HMI links. The -40C to +105C rating covers control cabinets near heat sources such as motor drives, where ordinary 85C-grade MCUs derate. With 53 GPIO lines, one device can drive relay banks, read limit switches, and manage status LEDs without port expanders. The 10-bit ADC reads potentiometers, 4-20mA-conditioned sensor signals, and supply monitors directly. Designers typically run the TWI bus for I/O expanders and EEPROM, keeping the hardware UARTs free for deterministic communication. JTAG debug shortens commissioning cycles on DIN-rail controller boards.
Recommended
HVAC and Building Automation
Building-control boards mix sensor acquisition, actuator driving, and network communication, and the ATMEGA64A-MNR covers all three. The 8-channel 10-bit ADC digitizes temperature sensors, humidity elements, and damper feedback, while timer-based PWM drives triac or SSR fan controls with precise phase control. The TWI (I2C) interface chains multiple environmental sensor ICs and RTCs on two wires, and the hardware UART connects to RS-485 transceivers for Modbus RTU networks. Six sleep modes allow the controller to idle between polling cycles in battery-backed thermostats, extending reserve-power runtime during outages. The 105C ambient ceiling matters for rooftop-unit enclosures exposed to solar gain. At 16MHz, scan-cycle execution of HVAC algorithms completes well within typical 100ms control-loop budgets, leaving headroom for future feature additions.
Recommended
Battery-Powered Portable Instruments
Portable measurement instruments benefit from the ATMEGA64A-MNR balance of flash capacity and low idle power. Per the ATmega64A datasheet, the optimized -A process reduces current consumption versus the original ATmega64, and six software-selectable sleep modes, including power-down at microamp-level currents, allow aggressive duty-cycling. The 4KB SRAM buffers waveform samples from the 10-bit ADC between radio or USB transfers, and 64KB flash holds complex measurement libraries, calibration tables, and multi-language UI strings. Operation from 2.7V permits direct use of two alkaline cells through a boost converter or three-cell stacks. Designers exploit timer PWM for display backlight dimming and buzzer tones. Because the device sustains read-while-write self-programming, field-updatable calibration and firmware are practical without external memory.
Recommended
Motor Control and Inverter Boards
Small inverter and motor-control boards use the ATMEGA64A-MNR as the supervisory MCU alongside gate-driver hardware. Two 16-bit timers with output-compare PWM generate complementary drive waveforms for DC motor H-bridges or single-phase inverters, and the analog comparator plus ADC support overcurrent and bus-voltage fault detection in software. The 105C rating suits enclosures mounted near power stages, and the 64KB flash holds field-oriented or sensorless startup algorithms with margin for diagnostics and logging. The USART connects to a host controller or touch panel over RS-485, while SPI links external flash for parameter storage. JTAG boundary scan eases ICT fixture development on multi-layer boards. Dead-time insertion is handled in firmware with output-compare units, sufficient for frequencies typical of hobby-size drives.
Recommended
Embedded Communication Bridges
Protocol-conversion nodes map naturally onto the ATMEGA64A-MNR because it carries two independent hardware serial ports plus SPI and TWI simultaneously. A typical bridge forwards Modbus RTU on one USART to a proprietary TTL link on the second, while TWI gathers local sensor data and SPI services external flash or an RF module. The 4KB SRAM sustains multi-frame buffering with retransmission queues that smaller AVRs cannot hold, and 64KB flash leaves ample room for several protocol stacks plus a web-style configuration layer. Hardware flow control on the USARTs, combined with the fast single-cycle AVR core at 16MHz, keeps line turnaround under industrial timing limits. The exposed-pad QFN package provides a low-impedance ground return that benefits signal integrity on unshielded field buses.
Recommended
Security and Access Control Panels
Access-control and alarm panels require reliable keypads, readers, tamper sensing, and reporting links, all within a single MCU. The ATMEGA64A-MNR scans large key matrices on Ports B through D, communicates with Wiegand or RFID reader front-ends on interrupt-capable pins, and logs events to I2C EEPROM or SPI flash. Its 64KB flash supports cryptographic card handling and multi-thousand-user local databases, while the 10-bit ADC monitors backup-battery voltage and enclosure tamper switches. The real-time counter structure with asynchronous operation keeps time-of-day accuracy through a 32.768kHz crystal when the main clock stops. The 105C rating covers outdoor gate controllers in hot climates, and in-system programming allows credential-format updates in the field without recalling installed panels.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA64A-MNR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA64-16MI | ATMEGA649P-MU | ATMEGA645-16MUR | ATMEGA649A-MU |
|---|---|---|---|---|---|
| Package | 64-QFN/MLF (9x9 mm) | 64-MLF (9x9 mm) - same footprint | 64-MLF (9x9 mm) - same footprint | 64-MLF (9x9 mm) - same footprint | 64-MLF (9x9 mm) - same footprint |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 64KB | 64KB | 64KB | 64KB | 64KB |
| LCD Controller | No | No | Yes (segment LCD) | Yes (segment LCD) | Yes (segment LCD) |
| Drop-in Status | Reference part | Pin-to-pin, verify temp derating | Pin-compatible, LCD pin muxing changes | Pin-compatible, peripheral remap required | Pin-compatible, LCD pin muxing changes |
Key Differentiators
- 105C industrial temperature rating (vs ATMEGA64-16MI)
- Optimized -A process with lower current (vs ATMEGA64-16MI)
- Full general-purpose I/O without LCD pin sharing (vs ATMEGA649P-MU)
Design Notes
The 64-QFN exposed pad is the primary ground connection for the die. Solder it to a solid ground pour using an array of thermal vias (typically 5x5 via field); skipping this connection causes both floating-ground erratic behavior and elevated junction temperature. QFN center pads often suffer from solder voids - use a segmented stencil apertures pattern (50-60% coverage) rather than a full-open aperture to reduce voiding, per standard QFN assembly practice.
JTAG shares pins PC2-PC7 (including TCK, TMS, TDO, TDI). The JTAGEN fuse is factory-programmed, so PC2-PC7 will not function as GPIO until JTAG is disabled via fuse programming. Additionally, PC1 (XCK/...) and alternate-function conflicts on PG pins must be checked against the port-function tables in the ATmega64A datasheet before routing. Brown-out detection should be enabled via fuse for 5V designs, since flash writes below minimum VCC can corrupt EEPROM contents.
Decouple each VCC pin and AVCC with 100nF ceramic capacitors placed within a few millimeters of the pins, plus one bulk 10uF per supply domain. AVCC must be connected even if the ADC is unused - the datasheet requires it within 0.3V of VCC. When using the ADC, filter AVCC through an LC network (10uH + 10uF) and route analog traces away from the 16MHz clock. These are estimated layout practices consistent with the ATmega64A datasheet power-supply guidance.
Compliance Information
Distributor and Microchip listings mark the ATMEGA64A-MNR as RoHS compliant and Green (halogen-free per Microchip green packaging definition). REACH and conflict-minerals declarations were not stated in the provided data.
