ATMEGA645P-AUR - 8-bit AVR MCU, 64KB Flash, 16MHz | Microchip
MPN: ATMEGA645P-AUR β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.29 | $6.29 |
| 10 | $5.85 | $58.50 |
| 100 | $5.4 | $540.00 |
| 500 | $4.95 | $2,475.00 |
| 1,000 | $4.5 | $4,500.00 |
ATMEGA645P-AUR Overview
An 8-bit microcontroller is a complete computing system on a single chip, combining a processor core, program memory, data memory, and peripherals such as timers, UARTs, and ADCs. Within the Microchip (formerly Atmel) hierarchy, the ATmega family sits above the ATtiny series and below the 32-bit AVR/ARM lines, addressing mid-range embedded control tasks where rich peripherals and large flash matter.
Key features include 64 general-purpose working registers directly connected to the ALU, 53 general-purpose I/O lines, in-system programmable flash supporting ICSP via debugWIRE-style programming tools, and operation across industrial temperature ranges in the TQFP-64 footprint. The P-suffix denotes the picoPower-optimized die, an upwards-compatible drop-in improvement over the ATmega645A per Atmel application note AVR534.
Technically, the AVR architecture achieves code efficiency through a rich instruction set executing mostly in single clock cycles, while the 4KB SRAM accommodates stack-heavy C code and the 2KB EEPROM retains calibration data through power cycles. Supply voltage for the -AU industrial speed grade is specified at 4.5V to 5.5V at 16 MHz operation.
Typical applications include industrial automation controllers, consumer appliance interfaces with segment-LCD-adjacent sibling parts, metering systems, and hobby/education platforms where the large flash permits bootloader-based field updates.
When designing, decouple VCC/AVCC with 0.1uF ceramics close to the package and reserve the ICSP header (MOSI/MISO/SCK/RESET) for field programming.
This page synthesizes distributor pricing, drop-in alternatives, pin-compatibility guidance, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA645P-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 ATMEGA645P-AUR (same form factor and footprint) β differing in Operating Temperature, Core Architecture, EEPROM, Package, SRAM.
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No drop-in alternatives available for this product.
Request AlternativesATMEGA645P-AUR Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR 8-bit RISC |
| Data Bus Width | 8 Bit |
| Flash Memory | 64KB (32K x 16) In-System Programmable |
| EEPROM | 2KB |
| SRAM | 4KB |
| Maximum Clock Frequency | 16 MHz |
| Supply Voltage | 4.5 V to 5.5 V (16 MHz industrial speed grade) |
| I/O Ports | 53 I/O lines |
| Package | 64-TQFP (14x14 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (A = industrial grade) |
| Programming Interface | ICSP (In-Circuit Serial Programming) |
| General Purpose Registers | 32 directly connected to ALU |
| Lifecycle Stage | Active |
| Packaging | Tape & Reel (R suffix) |
ATMEGA645P-AUR 64-tqfp (14x14 mm) Pin Configuration Guide
Pin configuration for ATMEGA645P-AUR (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 ATMEGA645P-AUR.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA645P-AUR is suitable for 6 applications: Industrial Automation Controllers, Metering and Measurement Instruments, Consumer Appliance Control Boards, Embedded Education and Prototyping Platforms, Data Acquisition Front Ends, Building Automation and Security Panels.
Industrial Automation Controllers
The ATMEGA645P-AUR fits industrial automation nodes where 53 I/O lines drive relays, optocoupled inputs, and status LEDs without an external port expander. Its 64KB In-System Programmable Flash holds protocol stacks (Modbus-RTU over the built-in USART) and bootloader code simultaneously, while 4KB SRAM buffers network frames and 2KB EEPROM stores node addresses and calibration constants across power cycles. Operating from a 5V industrial rail (4.5V to 5.5V supply) at 16 MHz delivers near 1 MIPS per MHz throughput with single-cycle ALU access to 32 registers, keeping control-loop latency deterministic. The industrial -40C to +85C temperature grade and ICSP field-update path suit factory-floor deployments.
Recommended
Metering and Measurement Instruments
Utility meters and panel instruments benefit from the ATMEGA645P-AUR's 2KB EEPROM for tamper-event logging and rolling accumulation registers, plus 64KB flash for metrology firmware and display drivers. The picoPower P die reduces average consumption in sleep-based sampling loops, extending battery-backed operation between mains events. With 53 I/O lines, one chip can scan a keypad matrix, drive segment indicators through port expansion, and bit-bang communication, reducing BOM count versus smaller AVRs like the ATMEGA328P (23 I/O). The 16 MHz core processes ADC-scaled readings and applies linearization tables held in SRAM, while the 64-TQFP 14x14 mm package provides the pin count for multi-board connectors.
Recommended
Consumer Appliance Control Boards
Appliance controllers - washers, ovens, HVAC boards - use the ATMEGA645P-AUR where large flash (64KB) accommodates UI state machines, fault-logging code, and field-updatable firmware via ICSP bootloaders. The 5V operating range (4.5V to 5.5V) interfaces directly with relay coils through driver transistors and triacs via optocouplers without level shifting, and the 53 GPIO lines handle touch-key matrices, buzzer, fan, and sensor inputs concurrently. The AVR's single-cycle instruction set gives predictable button-debounce and PWM timing without RTOS overhead, and the industrial temperature grade tolerates enclosed, warm compartments. Tape-and-reel delivery supports high-volume SMT assembly lines.
Recommended
Embedded Education and Prototyping Platforms
The ATmega645 family is a staple of university embedded-systems courses because the AVR architecture pairs a simple RISC instruction set with 32 registers directly wired to the ALU, letting students reason about cycle-accurate behavior. The ATMEGA645P-AUR's 64KB flash removes the code-size ceiling that frustrates projects using ATmega328-class parts, supporting full C programs with floating-point math, FAT file fragments, and a bootloader for ICSP reprogramming via the MPLAB SNAP or legacy AVRISP tools. The 53 I/O lines drive LCDs, keypads, motors, and breadboard experiments simultaneously, and the standard 64-TQFP footprint appears on many through-adapter breakout boards for lab use.
Recommended
Data Acquisition Front Ends
Distributed acquisition nodes use the ATMEGA645P-AUR as a concentrator MCU: its 16 MHz core and 4KB SRAM timestamp and frame data from external ADCs over SPI, while the 2KB EEPROM holds channel calibration coefficients that survive recalibration cycles. The 53 I/O lines multiplex sensor banks, chip-select lines, and IEEE-style status outputs without glue logic, and the USART forwards framed data over RS-485 to a supervisory PLC. The picoPower die cuts idle consumption between polling windows, important for nodes on switched industrial rails, and the industrial -40C to +85C rating covers uncontrolled cabinets. Flash-based firmware allows protocol updates through the same ICSP header used at manufacture.
Recommended
Building Automation and Security Panels
Zone controllers and access panels exploit the ATMEGA645P-AUR's combination of 64KB flash for encrypted credential tables and communication stacks, plus 53 GPIO lines to read door sensors, drive locks, and control annunciators from one device. The 2KB EEPROM safely stores event logs and site codes through brownouts, and the 4.5V to 5.5V supply range rides through battery-backed 5V rail sags common in buildings. The picoPower generation reduces standby draw in mains-failure monitoring loops, and the ICSP interface enables on-site firmware updates without desoldering. The 64-TQFP package gives the pad count for keypad, reader, and relay board connectors in a compact 14x14 mm footprint.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA645P-AUR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA645A-AUR | ATMEGA649P-AUR | ATMEGA3290P-20AUR | ATMEGA645-16AI |
|---|---|---|---|---|---|
| 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 | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 64KB (32K x 16) | 64KB | 64KB | 32KB | 64KB |
| Maximum Clock Frequency | 16 MHz | 16 MHz | 16 MHz | 20 MHz | 16 MHz |
| LCD Controller | No | No | Yes (segment LCD) | Yes (segment LCD) | No |
| Power Generation | picoPower (P die) | Standard (non-P) | picoPower (P die) | picoPower (P die) | Standard (non-P) |
Key Differentiators
- picoPower P-generation die in a proven footprint (vs ATMEGA645A-AUR)
- Double the program memory of the smaller-footprint peer (vs ATMEGA3290P-20AUR)
- Pure general-purpose I/O without LCD pin sharing (vs ATMEGA649P-AUR)
Design Notes
Decouple VCC and AVCC each with a 0.1uF ceramic capacitor placed within 2-3 mm of the corresponding TQFP-64 pins, and add a 10uF bulk capacitor near the supply entry. Tie AVCC to VCC through an LC filter (ferrite bead plus 0.1uF) when the ADC is used, since digital switching noise on AVCC directly degrades conversion accuracy. Provide an ICSP header (MOSI, MISO, SCK, RESET, VCC, GND) so the MPLAB SNAP tool can reprogram the device in-circuit without removal.
Do not run the part below 4.5V at 16 MHz: the verified supply range for this speed grade is 4.5V to 5.5V, and undervoltage operation at full clock violates the speed-versus-voltage derating in the manufacturer datasheet. Also verify RESET has a 10k pull-up if the ICSP line is long, and avoid driving unused pins as outputs against external pull-ups. When migrating from the non-P ATmega645, review application note AVR534 (doc8421) because some electrical characteristics differ between generations.
The picoPower P die reduces sleep-mode consumption versus the ATmega645A, so design the power budget around sleep-based duty cycling: keep the AVR in power-down between sampling events and wake via watchdog or external interrupt to exploit the P-generation advantage. Estimated: at 5V and 16 MHz active operation, consumption is in the tens of milliamps range per typical ATmega family behavior, so a 5V/500mA rail comfortably supports the MCU plus LED and relay driver loads.
Compliance Information
Compliance certificates were not included in the verified data. Microchip current-production ATmega parts are generally RoHS-compliant, but confirm via the official Microchip product page certificate of conformance for ATMEGA645P-AUR before export or automotive use.
