ATMEGA645A-AU - 8-bit AVR MCU 64KB Flash 16MHz TQFP-64 | Microchip
N.º de pieza: ATMEGA645A-AU ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $5.9 | $5,90 |
| 10 | $5.4 | $54,00 |
| 100 | $4.85 | $485,00 |
| 500 | $4.4 | $2.200,00 |
| 1.000 | $3.95 | $3.950,00 |
ATMEGA645A-AU Descripción general
A microcontroller (MCU) is a single-chip computer that integrates a processor core, program memory, data memory, and peripherals such as timers, UARTs, and ADCs. The ATmega645A belongs to the AVR ATmega family of 8-bit microcontrollers, which sit within the broader hierarchy of embedded processors used in industrial, consumer, and automotive-adjacent electronics. AVR cores execute most instructions in a single clock cycle, delivering roughly 1 MIPS per MHz.
Key features include an advanced RISC architecture with approximately 130 powerful instructions, most executing in a single cycle; 54 general-purpose I/O lines in the 64-pin TQFP; a 10-bit ADC with up to 8 single-ended or 7 differential channels; an integrated LCD controller supporting up to 4 COM x 25 SEG for segment displays; and an 8-channel, 2-wire (TWI/I2C) plus SPI and UART serial interface set.
Technical depth comes from the Harvard-architecture AVR core with 32 general-purpose working registers directly connected to the ALU, allowing two independent registers to be accessed in one instruction. The 64 KB Flash supports read-while-write operation, enabling self-programming and firmware updates in the field, while in-system programming via SPI allows production programming without removing the device from the PCB.
Typical applications include industrial control panels and instruments with segment-LCD displays, battery-powered meters and data loggers, building automation nodes, and consumer appliances requiring a low-power 8-bit core with generous Flash headroom. The LCD controller eliminates an external LCD driver in display-based designs.
Design consideration: the ATmega645A achieves its 16 MHz maximum over the 4.5 V to 5.5 V supply range; use the 1.8 V/3 V -rated V variant for low-voltage designs and derate clock speed at lower VCC per the datasheet frequency-voltage curve.
This page synthesizes drop-in same-family alternatives, application guidance, and structured comparison data not consolidated in the manufacturer datasheet.
Alternativas directas para ATMEGA645A-AU — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con ATMEGA645A-AU (mismo factor de forma y huella) — difiere en Flash Memory, Package, RoHS Status, General Purpose I/O, Supply Voltage Range.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
ATMEGA645-16AI
✅ Sustitución directa ⚠️ Especificaciones sin verificar✓ En stock
$6.45 / unidad
Ver hoja de datos →ATMEGA649A-AU
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
ATMEGA645P-20AU
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
ATMEGA645V-8AU
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
ATMEGA325A-AU
✅ Sustitución directa ⚠️ Especificaciones sin verificar✓ En stock
$3.12 / unidad
Ver hoja de datos →ATMEGA645A-AU Valores máximos y características eléctricas
| Core Architecture | 8-bit AVR RISC |
| Max CPU Frequency | 16 MHz |
| Flash Memory | 64 KB (32K x 16) In-System Programmable |
| EEPROM | 2 KB |
| SRAM | 4 KB |
| General Purpose I/O | 54 GPIO |
| Encapsulado | 64-TQFP (14x14 mm) |
| Tipo de montaje | Surface Mount |
| Tensión de alimentación | 4.5 V to 5.5 V (16 MHz operation) |
| ADC | 10-bit, up to 8 channels |
| LCD Controller | Yes, up to 4 COM x 25 SEG |
| Communication Interfaces | USART, SPI, TWI (I2C) |
| Timers | 2 x 8-bit, 1 x 16-bit (plus watchdog) |
| Número de pines | 64 |
| Estado RoHS | Compliant |
Guía de configuración de pines de ATMEGA645A-AU 64-tqfp (14x14 mm)
Configuración de pines para ATMEGA645A-AU (encapsulado 64-tqfp (14x14 mm)). Este CI digital incluye GPIO, interfaces de comunicación (UART, SPI, I2C) y pines de alimentación. Consulte la hoja de datos del fabricante para conocer las funciones alternativas de los pines y las opciones de configuración. Esencial para el diseño de sistemas embebidos y el diseño de PCB.
No hay datos detallados de patillaje disponibles para ATMEGA645A-AU.
Consulte la hoja de datos para ver la configuración completa de patillas.
Aplicaciones típicas
ATMEGA645A-AU es adecuado para 6 aplicacións: Utility and Panel Meters with Segment LCD, Industrial Control Panels, Building Automation Sensor Nodes, Battery-Powered Data Loggers, Consumer Appliance Control, Test and Measurement Instruments.
Utility and Panel Meters with Segment LCD
The ATMEGA645A-AU is purpose-built for metering applications because its integrated LCD controller drives up to 4 COM x 25 SEG lines directly, eliminating an external LCD driver IC and its associated BOM cost and routing complexity. Combined with the 10-bit ADC (8 channels) for voltage, current, or sensor measurement and 4 KB SRAM for accumulation buffers, a single chip implements the entire signal chain of an energy meter or panel indicator. The 64 KB Flash accommodates scaling tables, multi-tariff logic, and field-updatable firmware via read-while-write self-programming. Placed on a 5 V rail at 16 MHz, the part delivers roughly 16 MIPS, sufficient for real-time metering math; at idle the CPU can halt and leave only the LCD and RTC active, extending battery life in split-phase meters.
Recomendado
Industrial Control Panels
In industrial control and automation panels, the ATMEGA645A-AU provides 54 GPIO lines plus USART, SPI, and TWI (I2C) interfaces, allowing one MCU to coordinate relays, keypads, status displays, and serial links to PLCs or HMIs. The 5 V-tolerant AVR I/O structure drives optocouplers and relay coils (via drivers) directly at 16 MHz with deterministic single-cycle instruction timing, simplifying timing-critical sequencing logic. The 64 KB ISP Flash stores parameter tables and communication stacks while read-while-write support permits field firmware updates over the existing UART without a programming header visit. Onboard EEPROM retains calibration and configuration data across power cycles, and the industrial drop-in variant ATMEGA645-16AI extends the operating temperature envelope for cabinet-mounted hardware.
Recomendado
Building Automation Sensor Nodes
For building automation nodes such as thermostats, occupancy displays, and environmental sensors, the ATMEGA645A-AU combines an LCD driver, 10-bit ADC, and TWI (I2C) master in a single TQFP-64 package. The TWI bus connects digital temperature, humidity, or light sensors, while the ADC handles analog inputs like potentiometers or NTC thermistors. A segment LCD driven from the internal controller shows setpoints and status without a driver IC, and the 54 GPIO handles relays, dampers, and keypad scanning. The 64 KB Flash runs MODBUS or proprietary protocol stacks with room to spare. Power management is handled by sleep modes; in wall-powered nodes the 5 V, 16 MHz configuration maximizes responsiveness for fast loop control.
Recomendado
Battery-Powered Data Loggers
The ATMEGA645A-AU supports data-logger designs that log periodically and display results on a segment LCD. Its 64 KB Flash stores logging tables and a bootloader for field firmware updates, while 2 KB EEPROM holds calibration constants that survive battery replacement. The 10-bit ADC samples sensor channels (temperature, pressure bridges, voltage dividers), and the SRAM-based buffer batches writes to external EEPROM or Flash over SPI. Although the -AU variant targets 5 V systems at up to 16 MHz, designers can run it below maximum clock at reduced voltage within datasheet limits, trading throughput for current draw; sleep modes gate the CPU between samples. For strict battery designs, the picoPower ATMEGA645P-20AU drop-in offers lower deep-sleep currents on the identical footprint.
Recomendado
Consumer Appliance Control
Consumer appliances - cookers, coffee machines, HVAC wall units, washing machine controllers - routinely use ATmega parts because the ATMEGA645A-AU integrates everything a display-based appliance UI needs: a segment LCD driver, capacitive or matrix keypad scanning on GPIO, ADC for NTC temperature sensing and mains zero-cross detection, and timers for triac phase control. The 64 KB Flash leaves generous headroom for localized menus and diagnostic routines, and in-factory ISP programming via SPI speeds production. The 5 V, 16 MHz operating point provides ample real-time margin for safety interlocks, while the mature AVR toolchain and long Microchip lifecycle status keep certification and re-manufacturing straightforward across multi-year appliance production runs.
Recomendado
Test and Measurement Instruments
Bench and handheld test instruments benefit from the ATMEGA645A-AU's combination of 10-bit ADC, LCD drive, and generous memory. The MCU sequences analog front ends via GPIO and TWI, samples DC/slow signals on the internal ADC, and presents readings and menu systems on a segment LCD with 25 SEG capacity. The 64 KB Flash supports multi-page menu firmware, unit-conversion tables, and calibration routines stored in EEPROM. Because AVR GPIO toggles are cycle-deterministic, bit-banged protocols for custom DACs or display modules meet tight timing without hardware overhead. Typical companion design uses an external precision reference and an op-amp front end; the MCU's ADC channels are multiplexed across 8 inputs, enabling multi-channel handheld meters in one 64-TQFP chip.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para ATMEGA645A-AU — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | ATMEGA645-16AI | ATMEGA649A-AU | ATMEGA645P-20AU | ATMEGA645V-8AU | ATMEGA325A-AU |
|---|---|---|---|---|---|---|
| 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 | 64-TQFP (14x14 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 64 KB | 64 KB | 64 KB | 64 KB | 64 KB | 32 KB |
| Max CPU Frequency | 16 MHz | 16 MHz | 16 MHz | 20 MHz | 8 MHz | 16 MHz |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 1.8 V to 5.5 V | 4.5 V to 5.5 V |
| SRAM | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB | 2 KB |
| LCD Controller | 4 COM x 25 SEG | 4 COM x 25 SEG | 4 COM x 40 SEG | 4 COM x 25 SEG | 4 COM x 25 SEG | 4 COM x 25 SEG |
| Power Technology | Standard AVR | Standard AVR | Standard AVR | picoPower | Standard AVR (wide V) | Standard AVR |
Diferenciadores clave
- Higher GPIO count when LCD not fully populated (frente a ATMEGA649A-AU)
- Lower cost for equal memory at 16 MHz (frente a ATMEGA645P-20AU)
- Double the Flash of the footprint-compatible budget part (frente a ATMEGA325A-AU)
Notas de diseño
The ATMEGA645A-AU requires 4.5 V to 5.5 V for guaranteed 16 MHz operation; running the clock above the datasheet frequency-versus-VCC limit causes core timing failure. Decouple VCC with 100 nF ceramics at every VCC pin plus a 10 uF bulk capacitor near the regulator. AVR cores draw supply current spikes on clock edges, so keep the VCC/GND loop short. For mixed 3 V/5 V systems, note the -AU variant I/O is 5 V referenced - use level shifters for 3 V peripherals or select the ATMEGA645V-8AU wide-voltage drop-in instead.
For the 64-TQFP (14x14 mm), place the 100 nF decoupling capacitors within 2 mm of each VCC pin and connect them to a solid ground plane with short vias. Route the LCD SEG/COM lines as short, parallel groups; LCD bias resistors (or internal bias configuration) should sit close to the pins to minimize display ghosting caused by line capacitance mismatch. Keep the SPI ISP header traces under 10 cm and avoid routing them under the crystal area. Provide a testpoint on RESET for in-system programming access.
Do not exceed the maximum frequency for your VCC - this is the most common migration error when swapping between ATmega645A (16 MHz @ 5 V) and the V variant (8 MHz max). Second, the JTAG interface present on some megaAVR parts is not available on this LCD family variant; do not assume JTAG-based debugging. Third, when using the LCD controller, pins shared with PF ADC functions become unavailable for analog input - plan pin budgeting before layout. Finally, verify the RESET pin is not left floating; use a 10 kOhm pull-up to VCC for reliable ISP.
Información de cumplimiento
RoHS compliant and lead-free per DigiKey/Microchip listings for the AU (lead-free TQFP) suffix. REACH, halogen-free, and conflict-minerals declarations should be confirmed via the Microchip product page compliance documents.
