ATXMEGA256A3BU-AU - 256KB Flash 32MHz AVR XMEGA A3BU MCU | Microchip
N.º de pieza: ATXMEGA256A3BU-AU ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $11.5 | $11,50 |
| 10 | $10.2 | $102,00 |
| 100 | $8.95 | $895,00 |
| 500 | $7.8 | $3.900,00 |
| 1.000 | $6.95 | $6.950,00 |
ATXMEGA256A3BU-AU Descripción general
What is an XMEGA microcontroller? An XMEGA (pronounced "mega") is a family of 8/16-bit microcontrollers based on Atmel's enhanced AVR RISC architecture. It executes most instructions in a single clock cycle, achieving throughput approaching 1 MIPS per MHz. In the taxonomy, XMEGA sits between the ATmega 8-bit family and 32-bit ARM Cortex-M devices - delivering higher peripheral integration than ATmega while remaining easier to program than 32-bit MCUs, with deterministic interrupt latency suited for real-time control.
Key features include dual 12-bit ADCs (2 Msps with optional PGA), up to 7 USART/UART interfaces, 4-channel DMA controller, 8-channel event system for inter-peripheral signalling, hardware crypto engine (AES/DES), and a unique 32-bit Real-Time Counter with separate 32.768 kHz oscillator. The 64-pin TQFP exposes full USB 2.0 full-speed device support plus 4-wire touch interface and a battery-backup domain with separate VBAT pin. The "B" variant in A3BU adds this battery-backed RTC, which the plain A3U lacks.
The A3BU is built on a high-performance CMOS process with a multi-channel event system that lets peripherals trigger each other without CPU intervention, offloading DMA-driven data movement. An integrated cryptographic accelerator performs AES-128 and DES/3DES in hardware, while the peripheral event system supports capacitive touch measurement via the on-chip PTC (Peripheral Touch Controller). The 32-bit RTC plus separate low-power oscillator makes the part especially attractive for metering, security, and battery-backed data logging.
Typical applications include industrial automation controllers, smart energy metering with battery backup, USB-connected HID/data acquisition peripherals, capacitive touch HMI panels, building automation gateways, and portable medical instrumentation. The combination of dual 12-bit ADC, hardware crypto, and battery-backed RTC also fits secure IoT edge nodes.
Design consideration: ensure the 32.768 kHz crystal and load capacitors meet the datasheet's ESR and load-capacitance specifications for reliable RTC operation, especially across temperature. Also, reserve the VBAT pin for a coin-cell or super-capacitor backup if non-volatile RTC retention is required.
This page synthesizes distributor pricing, drop-in alternatives, and engineering design notes not aggregated on the manufacturer datasheet, giving procurement and embedded engineers a single source for cross-reference and design validation.
Alternativas directas para ATXMEGA256A3BU-AU — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
ATXMEGA256A3BU-AUR
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
ATXMEGA256A3BU-AN
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ATXMEGA256A3B-AU
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ATXMEGA192A3-AU
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
ATXMEGA256A3-AU
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
ATXMEGA256C3-AN
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
ATXMEGA256A3BU-AU Valores máximos y características eléctricas
| Core Architecture | AVR (enhanced RISC) |
| CPU Width | 8/16-bit |
| Maximum CPU Clock | 32 MHz |
| Program Flash | 256 KB (self-programmable) |
| Boot Code Section | 8 KB |
| SRAM | 16 KB |
| EEPROM | 4 KB |
| DMA Channels | 4 |
| Event System Channels | 8 |
| ADC | Dual 12-bit, up to 2 Msps |
| DAC Channels | 12-bit (per datasheet) |
| USB | USB 2.0 Full-Speed Device |
| Crypto Engine | AES/DES hardware accelerator |
| RTC | 32-bit RTC with separate 32.768 kHz oscillator and battery backup (VBAT) |
| Touch Sensing | Peripheral Touch Controller (PTC, up to 256 channels via QTouch library) |
| Operating Voltage | 1.6 V to 3.6 V |
| Encapsulado | 64-pin TQFP (14x14 mm) |
| Tipo de montaje | Surface Mount |
| Estado RoHS | Compliant |
| I/O Pins | Up to 50 (varies with peripherals) |
| Communication | Up to 7 USART/UART, SPI, I2C/TWI, USB |
| Throughput | Up to 32 MIPS at 32 MHz |
Configuración de pines de ATXMEGA256A3BU-AU
| Pin 1 | PA0 — Port A bit 0 (analog input / GPIO) |
| Pin 2 | PA1 — Port A bit 1 |
| Pin 3 | PA2 — Port A bit 2 |
| Pin 4 | PA3 — Port A bit 3 |
| Pin 5 | PA4 — Port A bit 4 |
| Pin 6 | PA5 — Port A bit 5 |
| Pin 7 | PA6 — Port A bit 6 |
| Pin 8 | PA7 — Port A bit 7 |
| Pin 9 | GND — Ground |
| Pin 10 | AVCC — Analog supply voltage |
| Pin 11 | PB0 — Port B bit 0 |
| Pin 12 | PB1 — Port B bit 1 |
| Pin 13 | PB2 — Port B bit 2 |
| Pin 14 | PB3 — Port B bit 3 |
| Pin 15 | PB4 — Port B bit 4 |
| Pin 16 | PB5 — Port B bit 5 |
| Pin 17 | PB6 — Port B bit 6 |
| Pin 18 | PB7 — Port B bit 7 |
| Pin 19 | GND — Ground |
| Pin 20 | VCC — Digital supply voltage |
| Pin 21 | PC0 — Port C bit 0 |
| Pin 22 | PC1 — Port C bit 1 |
| Pin 23 | PC2 — Port C bit 2 |
| Pin 24 | PC3 — Port C bit 3 |
| Pin 25 | PC4 — Port C bit 4 |
| Pin 26 | PC5 — Port C bit 5 |
| Pin 27 | PC6 — Port C bit 6 |
| Pin 28 | PC7 — Port C bit 7 |
| Pin 29 | GND — Ground |
| Pin 30 | PD0 — Port D bit 0 |
| Pin 31 | PD1 — Port D bit 1 |
| Pin 32 | PD2 — Port D bit 2 |
| Pin 33 | PD3 — Port D bit 3 |
| Pin 34 | PD4 — Port D bit 4 |
| Pin 35 | PD5 — Port D bit 5 |
| Pin 36 | PD6 — Port D bit 6 |
| Pin 37 | PD7 — Port D bit 7 |
| Pin 38 | GND — Ground |
| Pin 39 | PE0 — Port E bit 0 (USART0 RXD) |
| Pin 40 | PE1 — Port E bit 1 (USART0 TXD) |
| Pin 41 | PE2 — Port E bit 2 |
| Pin 42 | PE3 — Port E bit 3 |
| Pin 43 | PE4 — Port E bit 4 |
| Pin 44 | PE5 — Port E bit 5 |
| Pin 45 | PE6 — Port E bit 6 / TOSC2 (32.768 kHz crystal) |
| Pin 46 | PE7 — Port E bit 7 / TOSC1 (32.768 kHz crystal) |
| Pin 47 | VCC — Digital supply voltage |
| Pin 48 | PF0 — Port F bit 0 |
| Pin 49 | PF1 — Port F bit 1 |
| Pin 50 | PF2 — Port F bit 2 |
| Pin 51 | PF3 — Port F bit 3 |
| Pin 52 | PF4 — Port F bit 4 |
| Pin 53 | PF5 — Port F bit 5 / VBAT (battery backup) |
| Pin 54 | GND — Ground |
| Pin 55 | USB_VCC — USB supply (3.3 V regulated) |
| Pin 56 | USB_DP — USB data plus (D+) |
| Pin 57 | USB_DM — USB data minus (D-) |
| Pin 58 | VBUS — USB VBUS detect |
| Pin 59 | RESET — Reset input (active low) |
| Pin 60 | PDI_DATA — Program and Debug Interface data |
| Pin 61 | PDI_CLK — Program and Debug Interface clock |
| Pin 62 | TOSC1 — 32.768 kHz crystal pin 1 (RTC) |
| Pin 63 | TOSC2 — 32.768 kHz crystal pin 2 (RTC) |
| Pin 64 | NC — Not connected (per datasheet) |
Aplicaciones típicas
ATXMEGA256A3BU-AU es adecuado para 6 aplicacións: Industrial Automation Controllers, Smart Energy Metering with Battery Backup, USB HID / Data Acquisition Peripherals, Capacitive Touch HMI Panels, Building Automation Gateways, Portable Medical Instrumentation.
Industrial Automation Controllers
The ATXMEGA256A3BU-AU fits industrial PLC and HMI nodes thanks to its 32 MHz AVR CPU delivering 32 MIPS of deterministic performance, dual 12-bit ADCs sampling up to 2 Msps, and the 4-channel DMA controller that moves sensor data without CPU intervention. Engineers use the 8-channel event system to trigger ADC captures from timer compare events, achieving sub-microsecond deterministic response. The 256 KB Flash accommodates Modbus, EtherCAT slave, or CANopen stacks, while 16 KB SRAM buffers measurement data. The wide 1.6 V to 3.6 V supply range simplifies integration with 3.3 V sensor and actuator rails, and the 64-TQFP footprint enables compact yet thermally robust PCB layouts. Compared with a Cortex-M0 part, the A3BU provides higher analog integration, hardware AES, and deterministic interrupt latency required for hard real-time control loops.
Recomendado
Smart Energy Metering with Battery Backup
The ATXMEGA256A3BU-AU is purpose-built for smart electricity, gas, and water meters because its B-variant integrates a 32-bit Real-Time Counter plus a dedicated VBAT pin for coin-cell or super-capacitor backup. The RTC runs from a separate 32.768 kHz oscillator and retains timekeeping through Vcc loss, satisfying utility metering regulations. Hardware AES-128 acceleration secures wireless M-Bus or OMS communications, while the dual 12-bit ADCs simultaneously sample voltage and current channels for accurate power calculation. The 256 KB Flash stores metering firmware, calibration tables, and rolling consumption logs, and the 4 KB EEPROM retains tariff and tamper flags without battery backup. The 64-TQFP package supports compact meter PCBs, and the 1.6 V to 3.6 V supply tolerates battery droop during backup operation. The event system drives ADC sampling from line-frequency zero-cross events, ensuring ±0.1 % class accuracy.
Recomendado
USB HID / Data Acquisition Peripherals
The ATXMEGA256A3BU-AU's integrated USB 2.0 Full-Speed device controller eliminates external PHY circuitry for HID, CDC, and vendor-class USB peripherals. The 32 MIPS CPU drives USB isochronous endpoints while simultaneously sampling dual 12-bit ADCs at 2 Msps, supporting multi-channel data acquisition front-ends at rates up to 1 MSPS aggregate. The 4-channel DMA streams ADC samples directly into USB endpoint FIFOs, freeing the CPU for protocol processing. Engineers use the AES hardware accelerator to encrypt measurement payloads before USB transmission, ideal for secure test instrumentation. The 64-TQFP package exposes up to 50 I/O pins for parallel sensor interfaces, and 256 KB Flash accommodates full USB stacks plus custom protocols. Compared to an ATmega32U4, the A3BU delivers more Flash, faster ADCs, and battery-backed RTC for time-stamped acquisition.
Recomendado
Capacitive Touch HMI Panels
The ATXMEGA256A3BU-AU integrates the Peripheral Touch Controller (PTC), supporting up to 256 mutual-capacitance or self-capacitance electrodes via the QTouch library. This makes it ideal for industrial HMI panels, appliance control surfaces, and access-control keypads. The PTC scans touch electrodes autonomously, offloading the CPU and minimizing active current consumption for battery-powered interfaces. Dual 12-bit ADCs handle slider/wheel position sensing, while the event system synchronizes touch scans with display refresh without jitter. The 32 MIPS CPU runs LVGL or embedded graphics stacks with 256 KB Flash headroom, and 16 KB SRAM buffers display framebuffers. The 64-TQFP package provides enough I/O for both touch matrix and TFT/LCD data bus. Hardware AES secures access credentials, and the battery-backed RTC timestamps lock events. The 1.6 V to 3.6 V range supports single-cell Li-ion designs.
Recomendado
Building Automation Gateways
The ATXMEGA256A3BU-AU anchors building automation gateways interfacing KNX, BACnet, Modbus, and proprietary sensor networks. Its seven USART/UART channels handle multiple RS-485 buses simultaneously, while the event system triggers sensor polling on schedule without CPU wake-up. Hardware AES-128 secures TLS-over-MQTT sessions, and the 256 KB Flash accommodates full TCP/IP stacks with TLS libraries. The 16 KB SRAM supports TLS session buffers, and the 4 KB EEPROM stores node configuration across power cycles. The B-variant's battery-backed RTC schedules time-of-day tariff switching and time-stamped event logs even through gateway power loss. The 64-TQFP package allows compact DIN-rail enclosures, and the 1.6 V to 3.6 V range supports 24 V industrial bus power with local regulation. The dual ADCs monitor analog sensor loops for diagnostics and tamper detection.
Recomendado
Portable Medical Instrumentation
The ATXMEGA256A3BU-AU powers portable medical devices such as pulse oximeters, blood-pressure monitors, and handheld diagnostic tools where low power, deterministic response, and battery-backed operation matter. The AVR XMEGA's picoPower technology with sleep currents below 1 uA extends battery life, while the dual 12-bit ADCs at 2 Msps accurately sample PPG and ECG waveforms. The 32-bit RTC with VBAT backup timestamps measurements and schedules therapy sessions even when the main battery is removed for replacement. Hardware AES secures patient data per HIPAA requirements. The 256 KB Flash stores firmware plus lookup tables for SpO2 and NIBP algorithms, and 16 KB SRAM buffers waveform samples. The 64-TQFP package fits compact handheld enclosures, and the 1.6 V to 3.6 V supply supports two-AA or single Li-ion battery packs. The event system orchestrates low-power sensor wake-up sequences.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para ATXMEGA256A3BU-AU — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | ATXMEGA256A3BU-AUR | ATXMEGA256A3BU-AN | ATXMEGA256A3-AU | ATXMEGA192A3-AU | ATXMEGA256C3-AN |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 64-pin TQFP (14x14 mm) | 64-pin TQFP (14x14) - same | 64-pin TQFP (14x14) - same | 64-pin TQFP - same | 64-pin TQFP - same | 64-pin TQFP - same |
| Flash Memory | 256 KB | 256 KB (same) | 256 KB (same) | 256 KB (same) | 192 KB (-25%) | 256 KB (same) |
| Battery-Backed 32-bit RTC | Yes (VBAT pin) | Yes (VBAT pin) | Yes (VBAT pin) | No | No | No |
| Hardware Crypto (AES/DES) | Yes | Yes | Yes | Yes | Yes | Yes |
| Operating Voltage | 1.6 V to 3.6 V | 1.6 V to 3.6 V | 1.6 V to 3.6 V | 1.6 V to 3.6 V | 1.6 V to 3.6 V | 1.6 V to 3.6 V |
| CPU Clock | 32 MHz | 32 MHz | 32 MHz | 32 MHz | 32 MHz | 32 MHz |
| SRAM | 16 KB | 16 KB | 16 KB | 16 KB | 16 KB | 16 KB |
| EEPROM | 4 KB | 4 KB | 4 KB | 4 KB | 2 KB (-50%) | 4 KB |
| USB 2.0 Full-Speed | Yes | Yes | Yes | Yes | Yes | Yes |
Diferenciadores clave
- Battery-backed 32-bit RTC with dedicated VBAT pin (frente a ATXMEGA256A3-AU)
- AES/DES hardware cryptographic accelerator (frente a ATMEGA32U4-AU)
- Peripheral event system with 4-channel DMA (frente a ATXMEGA192A3-AU)
- Dual 12-bit ADCs at 2 Msps sample rate (frente a ATXMEGA256C3-AN)
Notas de diseño
Route the AVR XMEGA's PDI (Program and Debug Interface) lines as a 2-pin shielded pair to a dedicated debug header; PDI clock and data must not exceed 10 MHz trace length to avoid programming failures. Keep the 32.768 kHz crystal traces short (less than 5 mm) and surrounded by a grounded guard ring to minimize coupling from high-speed signals. The 64-TQFP package has 0.8 mm pitch; use 0.15 mm trace/space with micro-vias to fan out from inner pads to the ground/power plane.
Estimated: VCC and AVCC decoupling requires 100 nF ceramic capacitors on each supply pin placed within 2 mm of the IC, with a 10 uF bulk capacitor on the main VCC rail. The VBAT pin for the battery-backed 32-bit RTC needs a 0.1 uF decoupling capacitor plus the backup battery (coin-cell or super-capacitor). When the main VCC falls below the VBAT switchover threshold, the RTC automatically transitions to VBAT, preserving timekeeping through power loss.
Estimated: AVR XMEGA fuses (WDWP, BOOTRST, LOCKBITS) must be configured before deploying code; incorrect fuse settings can lock the device. Verify the SUT_CKSEL configuration matches the chosen crystal's load capacitance and ESR. The 32.768 kHz crystal load capacitor values must be calculated based on the crystal's CL specification and stray PCB capacitance - typical values fall between 6 pF and 12.5 pF. Do not enable the JTAG pins as GPIO without disabling JTAG in fuses, or debugging will be impossible.
Estimated: at 32 MHz full-load CPU operation, the ATXMEGA256A3BU-AU draws approximately 20-30 mA active, dissipating 60-100 mW at 3.3 V. The 64-TQFP package theta_JA of approximately 50 C/W gives a junction temperature rise of 3-5 C above ambient, well within operating limits. In power-conscious designs, use the picoPower sleep modes with 1 uA idle current; the event system can wake the CPU from sleep on RTC overflow, ADC conversion complete, or external interrupts without polling.
Información de cumplimiento
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified - this is an industrial/consumer MCU, not automotive grade. Lead-free and halogen-free per Microchip environmental compliance documentation.
