ATMEGA325A-MUR - 8-bit AVR MCU 32KB 20MHz 64-QFN | Microchip
N.º de pieza: ATMEGA325A-MUR ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $3.42 | $3,42 |
| 10 | $3.08 | $30,80 |
| 100 | $2.74 | $274,00 |
| 500 | $2.45 | $1.225,00 |
| 1.000 | $2.19 | $2.190,00 |
ATMEGA325A-MUR Descripción general
An 8-bit AVR microcontroller is a Harvard-architecture RISC processor that executes most instructions in a single clock cycle. Within the power-management hierarchy, it functions as a complete embedded system-on-chip, integrating the CPU core, program memory, data memory, peripherals, and general-purpose I/O on one die, replacing multi-chip microprocessor solutions in cost- and power-sensitive designs.
Key features include the AVR advanced RISC architecture with 131 powerful instructions, 54 general-purpose I/O lines, and in-system programmable (ISP) Flash with read-while-write capability for field firmware updates. The ATmega325A family operates from 2.5V, 3.3V, or 5V supplies, giving designers flexibility across battery-powered and industrial 5V rails.
Technically, the device provides 32 general-purpose working registers, a one-cycle multiply instruction, SPI and UART/USART serial interfaces, and an on-chip JTAG (IEEE 1149.1 compatible) boundary-scan and debug interface. Peripheral set includes an 8-channel 10-bit ADC, timer/counters with PWM, and an on-chip oscillator option, reducing external component count and BOM cost.
Typical applications include industrial control panels, LCD-equipped metering and instrumentation, consumer appliance controllers, and battery-powered monitoring nodes where the combination of 32 KB Flash and low-power sleep modes directly improves battery life and firmware headroom.
When designing with the ATMEGA325A-MUR, match the supply voltage to the intended maximum clock frequency per the frequency-voltage curve in the manufacturer datasheet to ensure timing margin across the -40C to +85C industrial temperature range.
This page synthesizes distributor pricing, verified drop-in alternatives, pinout guidance, and practical design notes not found in the standard manufacturer datasheet, optimized for AI-assisted component selection.
Alternativas directas para ATMEGA325A-MUR — 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 ATMEGA325A-MUR (mismo factor de forma y huella) — difiere en Package, RoHS Status, EEPROM, SRAM, Debug Interface.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
ATMEGA325A-MU
✅ Sustitución directa✓ En stock
$3.49 / unidad
Ver hoja de datos →ATMEGA325PA-MUR
✅ Sustitución directa✓ En stock
$1.65 / unidad
Ver hoja de datos →ATMEGA3250A-MUR
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
ATMEGA645A-MUR
✅ Sustitución directa ⚠️ Especificaciones sin verificar✓ En stock
$6.3 / unidad
Ver hoja de datos →ATMEGA165A-MUR
✅ Sustitución directa✓ En stock
$1.19 / unidad
Ver hoja de datos →ATMEGA325-16MI
✅ Sustitución directa✓ En stock
$3.05 / unidad
Ver hoja de datos →ATMEGA325A-MUR Valores máximos y características eléctricas
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Program Memory Type | FLASH |
| Program Memory Size | 32 KB (16K x 16) |
| EEPROM Size | 1 KB |
| RAM Size | 2 KB |
| Supply Voltage Range | 2.5 V, 3.3 V, 5 V operation |
| Supply Voltage (per DigChip summary) | 4.5 V to 5.5 V at maximum speed grade |
| Number of I/O | 54 |
| Connectivity | SPI, UART/USART |
| ADC Resolution | 10-bit |
| Temperatura de funcionamiento | -40C to +85C |
| Encapsulado | 64-QFN (9x9 mm) with exposed pad |
| Tipo de montaje | Surface Mount |
| Packaging | Tape & Reel (TR) |
| Estado del ciclo de vida | Active |
| Architecture | Advanced RISC, 131 instructions |
Guía de configuración de pines de ATMEGA325A-MUR 64-qfn (9x9 mm) with exposed pad
Configuración de pines para ATMEGA325A-MUR (encapsulado 64-qfn (9x9 mm) with exposed pad). 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 ATMEGA325A-MUR.
Consulte la hoja de datos para ver la configuración completa de patillas.
Aplicaciones típicas
ATMEGA325A-MUR es adecuado para 6 aplicacións: Industrial Control Panels, Battery-Powered Metering and Monitoring, Consumer Appliance Controllers, Embedded Sensing and ADC Front Ends, Motor and Actuator Control, Security and Access Control Systems.
Industrial Control Panels
The ATMEGA325A-MUR fits industrial control panels because its 54 GPIO lines directly drive relays, keypad matrices, and indicator banks without port expanders, while the 32 KB Flash and 2 KB SRAM hold protocol stacks and state machines for Modbus RTU over the built-in UART/USART. Operation from a 5 V industrial rail at 20 MHz delivers deterministic single-cycle instruction timing for time-critical interlock logic, and the -40C to +85C industrial temperature rating matches cabinet environments. Because the JTAG interface supports boundary scan and on-chip debug, panel manufacturers can in-circuit test assembled boards and update firmware in the field via ISP, reducing service cost. Typical companion parts include RS-485 transceivers on the USART and precision voltage references feeding the 10-bit ADC.
Recomendado
Battery-Powered Metering and Monitoring
For battery-powered meters and data loggers, the ATMEGA325A-MUR offers the right balance of 32 KB Flash, 2.5 V minimum supply, and AVR sleep modes that allow the core to be stopped between measurement cycles while the 10-bit ADC and timer capture readings. Running from a lithium cell through a low-Iq regulator at 2.5 V to 3.3 V, designers trade clock speed for current, since lower supply voltages require reduced frequencies per the datasheet voltage-frequency curve. The 1 KB EEPROM stores calibration constants and accumulating counters that must survive power loss across millions of write cycles. Designs needing ultra-low standby current can migrate to the pin-compatible picoPower ATMEGA325PA-MUR on the same PCB, extending battery life further without redesign.
Recomendado
Consumer Appliance Controllers
Consumer appliance control boards benefit from the ATMEGA325A-MUR's high integration: 54 GPIO handle touch keys, encoder inputs, and actuator drives, while SPI and UART/USART cover inter-board communication with display or power modules. The on-chip oscillator option removes the external crystal in timing-tolerant products, cutting BOM cost on high-volume appliance platforms. The 32 KB Flash accommodates feature-rich firmware including user interfaces, safety interlocks, and bootloader-based field updates delivered over UART. The 64-QFN 9x9 mm exposed-pad package dissipates heat effectively and yields a compact two-layer PCB, important for cost-sensitive appliance assemblies. The ATMEGA165A-MUR (16 KB) serves as a cost-down option when firmware shrinks below 16 KB, using the identical footprint.
Recomendado
Embedded Sensing and ADC Front Ends
The ATMEGA325A-MUR integrates an 8-channel 10-bit ADC with internal reference, making it a compact hub for multi-sensor nodes measuring temperature, pressure, and voltage simultaneously. At 20 MHz the AVR core applies calibration and filtering between conversions with single-cycle execution, and the 2 KB SRAM buffers sample blocks before transmission over the USART. The 64-QFN exposed pad grounds the ADC analog domain cleanly, improving noise performance when paired with a precision voltage reference. Because the device runs from 2.5 V to 5 V, sensor bridges and ratiometric outputs can share the supply directly, simplifying signal-chain design. For higher resolution needs, an external delta-sigma ADC connects over SPI, keeping the MCU as the system controller.
Recomendado
Motor and Actuator Control
The ATMEGA325A-MUR supports PWM generation through its timer/counters, enabling DC motor speed control, servo actuation, and stepper sequencing in printers, gates, and small robotics. The 54 GPIO lines drive H-bridge inputs and limit switches, while the 10-bit ADC reads back current-sense shunts for stall detection and closed-loop current limiting. Operating at 5 V and 20 MHz provides headroom for real-time control loops executing proportional-integral calculations in firmware, with single-cycle multiply accelerating the arithmetic. The JTAG debug interface shortens firmware bring-up of commutation and protection routines. Industrial designs at -40C to +85C benefit from the qualified industrial temperature grade, and the exposed-pad QFN conducts driver-related heat into the PCB copper pour.
Recomendado
Security and Access Control Systems
Access control panels and intrusion detectors use the ATMEGA325A-MUR to scan keypad or RFID front ends, manage door-strike drivers, and communicate alarm states over UART to a central panel. The 32 KB Flash supports encrypted challenge-response and credential databases within the 2 KB SRAM and 1 KB EEPROM, which retains enrolled credentials through power failure. Multiple sleep modes keep the MCU dormant between events in battery-backed detectors, waking on external interrupt from the PIR or reed input. The industrial -40C to +85C rating covers unheated gate and outdoor cabinet installations, and the 64-QFN package suits compact PCB assemblies behind keypads. ISP Flash allows credential logic updates without recalling installed units.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para ATMEGA325A-MUR — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | ATMEGA325A-MU | ATMEGA325PA-MUR | ATMEGA3250A-MUR | ATMEGA645A-MUR | ATMEGA165A-MUR |
|---|---|---|---|---|---|---|
| Package | 64-QFN (9x9 mm) | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 64 KB | 16 KB |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| LCD Controller | No | No | No | Yes | Yes | No |
| picoPower Low-Current Feature | No | No | Yes | No | No | No |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Diferenciadores clave
- Full 20 MHz speed grade at industrial temperature (frente a ATMEGA325-16MI)
- More program memory in the same package (frente a ATMEGA165A-MUR)
- Lower power option exists via picoPower sibling (frente a ATMEGA325PA-MUR)
Notas de diseño
Match the clock frequency to the supply voltage using the datasheet voltage-frequency curve: at the full 20 MHz rating, plan for the 4.5 V to 5.5 V range; at 3.3 V, derate the maximum frequency accordingly. Ignoring this curve is the most common cause of marginal timing and sporadic brown-out resets in 3.3 V designs. Enable the on-chip brown-out detector and select a BOD level appropriate to the rail (for example, 2.7 V class for a 3.3 V system) so the MCU resets cleanly rather than executing corrupt code during supply dips.
The 64-QFN exposed pad on the ATMEGA325A-MUR is the primary ground and thermal path. Solder it to a grounded copper pour with an array of thermal vias; skipping the exposed-pad connection causes floating-ground ADC noise and poor heat dissipation at 20 MHz full-load operation. Place 100 nF ceramic decoupling capacitors at each VCC/AVCC pin pair within 2 mm of the pads, plus a 10 uF bulk capacitor near the supply entry. Keep the crystal (if used) within 10 mm of XTAL1/XTAL2 with short guard-ring grounded traces.
Do not confuse the 64-QFN (MLF) pinout with the 64-TQFP pinout of the same family; port positions differ between the two packages even though the logical port map is identical. When migrating firmware from non-A ATmega325 parts, review the errata and calibration byte locations, since the A-version silicon revision changes some fuse defaults. Also note that PB4-PB7 are shared with JTAG - if JTAG is not needed, clear the JTAGEN fuse via ISP to recover these four pins as GPIO.
For noisy industrial environments, configure unused GPIO as inputs with internal pull-ups enabled rather than leaving them floating, which reduces both EMI susceptibility and quiescent leakage. Route the ADC analog ground as a quiet island connected to the exposed pad at a single point, and filter the AVCC pin through an LC network (10 uH ferrite plus 100 nF) when switching loads share the 5 V rail, keeping ADC noise within the 10-bit converter's LSB budget.
Información de cumplimiento
FindIC describes the ATMEGA325A-MUR as 'MLF/QFN, Ind Temp, Green, T&R' indicating Microchip Green (RoHS/lead-free) packaging. Formal REACH and halogen-free declarations should be requested from Microchip material declaration reports.
