ATSAM3U4EA-AU - 96MHz Cortex-M3 MCU 256KB Flash | Microchip
MPN: ATSAM3U4EA-AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.2 | $7.20 |
| 10 | $6.55 | $65.50 |
| 100 | $5.9 | $590.00 |
| 500 | $5.3 | $2,650.00 |
| 1,000 | $4.8 | $4,800.00 |
ATSAM3U4EA-AU Overview
A microcontroller (MCU) is a single-chip embedded processor that integrates a CPU core, program memory, data memory, and peripherals such as UART, SPI, I2C, timers, and USB onto one die. Within the hierarchy of embedded processing devices, the SAM3U4E sits between entry-level Cortex-M0 MCUs and higher-performance Cortex-M4 parts, targeting high-throughput data-transfer applications.
Key features include the ARM Cortex-M3 revision 2.0 core running to 96 MHz, a Memory Protection Unit (MPU), and the Thumb-2 instruction set for high code density. The 128-bit-wide Flash access with a memory accelerator sustains near-zero wait-state execution, while the dual-bank Flash architecture enables safe in-application programming and firmware updates. A high-speed USB Device port with dedicated DMA, together with a multi-layer bus matrix, multiple SRAM banks, and PDC/DMA channels, maximizes data throughput - a signature strength of the SAM3U series.
The architecture sustains high-speed data transfers by allowing parallel tasks across the bus matrix, making the device well suited to USB data-acquisition dongles, industrial gateways, and test-instrument front ends. Operation spans 1.62V to 3.6V with industrial temperature ranges.
Design consideration: at 96 MHz, ensure power-supply decoupling and a solid ground plane, and account for Flash wait states or locate hot code in SRAM for maximum throughput.
This page synthesizes distributor pricing, drop-in family alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATSAM3U4EA-AU 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 ATSAM3U4EA-AU (same form factor and footprint) β differing in Core Processor, Flash Memory, SRAM, Supply Voltage Range.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAM3U4CA-AU
β Drop-Inπ Reference alternative (not in catalog)
ATSAM3U4EA-CU
β Drop-Inπ Reference alternative (not in catalog)
ATSAM3U4CA-CU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
Contact for price
View Datasheet βATSAM3U2CA-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$4.45 / Unit
View Datasheet βATSAM3U1CA-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$12.7 / Unit
View Datasheet βTM4C123GH6PGEI
β Drop-Inπ Reference alternative (not in catalog)
ATSAM3U4EA-AU Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M3 revision 2.0 |
| Core Size | 32-bit |
| Maximum Clock Frequency | 96 MHz |
| Flash Memory | 256 KB (256K x 8) |
| SRAM | 52 KB |
| Flash Architecture | Dual bank, 128-bit wide access, memory accelerator |
| Instruction Set | Thumb-2 |
| Memory Protection | MPU (Memory Protection Unit) |
| Supply Voltage Range | 1.62 V to 3.6 V |
| Package | 144-LQFP (20x20 mm) |
| Mounting Type | Surface Mount |
| USB | High-speed USB Device with DMA |
| DMA | PDC and DMA channels, multi-layer bus matrix |
| Life Cycle Stage | ACTIVE |
ATSAM3U4EA-AU 144-lqfp (20x20 mm) Pin Configuration Guide
Pin configuration for ATSAM3U4EA-AU (144-lqfp (20x20 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 ATSAM3U4EA-AU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAM3U4EA-AU is suitable for 6 applications: High-Speed USB Data Acquisition, Industrial Gateways and Data Loggers, Portable Battery-Powered Instruments, Embedded Audio and Communication Peripherals, Test and Measurement Front Ends, Firmware-Update-Critical IoT Nodes.
High-Speed USB Data Acquisition
The ATSAM3U4EA-AU is purpose-built for USB-connected acquisition hardware because it is one of the few Cortex-M3 MCUs pairing a high-speed (480 Mbps) USB Device controller with dedicated DMA. The 96 MHz core, 52 KB multi-bank SRAM, and PDC channels sustain continuous streaming from ADCs to a host PC without CPU intervention per packet, and the dual-bank Flash allows field firmware updates without bricking the device. Placed between the analog front end and the USB connector, the MCU handles trigger logic, decimation, and packetization while the multi-layer bus matrix keeps USB DMA and code fetch from colliding. Designers should budget SRAM for double-buffered endpoints to avoid packet loss at sustained 480 Mbps transfers.
Recommended
Industrial Gateways and Data Loggers
In industrial gateways, the ATSAM3U4EA-AU bridges field buses (UART, SPI, I2C peripherals) to a USB or serial uplink while logging to local storage. Its 1.62V to 3.6V supply range tolerates industrial rail sag, and the MPU supports partitioning of a bootloader from application code, improving robustness of remote-deployed firmware. The dual-bank Flash architecture is the decisive feature: a gateway can write a new image into the inactive bank, verify it, then switch banks on next reset - zero-downtime updates. With 256 KB Flash there is headroom for protocol stacks plus a data buffer, while PDC offloads serial transfers from the 96 MHz core to keep interrupt latency low for time-critical I/O.
Recommended
Portable Battery-Powered Instruments
Handheld instruments benefit from the SAM3U4E's wide 1.62V to 3.6V operating window, which allows direct connection to a single lithium cell across its full discharge curve without a boost converter. The 96 MHz Cortex-M3 executes signal-processing tasks such as FFT-based metering fast enough for interactive response, yet peripheral clock gating and wait-mode operation keep average current low between measurements. High-speed USB provides both a fast data offload path and bus-powered charging/data sync, a combination few same-class MCUs offer. Designers should use the memory accelerator and locate hot loops in the 52 KB SRAM to shorten active periods, directly extending battery life in duty-cycled measurement applications.
Recommended
Embedded Audio and Communication Peripherals
The SAM3U4E's high-throughput bus architecture suits USB audio-class peripherals and communication adapters: the high-speed USB Device port with DMA delivers isochronous streams at low jitter, while SSCI/UART-class serial peripherals interface codecs and radio modules. The 256 KB Flash holds USB audio descriptors, a full class stack, and DSP routines simultaneously, and 52 KB SRAM provides endpoint buffering plus audio frame workspace. The multi-layer bus matrix lets USB DMA, peripheral DMA, and core execution proceed in parallel, which is essential for maintaining constant-rate audio streams. Latency-sensitive paths should be kept out of Flash wait states by executing from SRAM for the most deterministic interrupt response in streaming applications.
Recommended
Test and Measurement Front Ends
Bench instruments and PC-based scopes use the ATSAM3U4EA-AU as a control and data-path MCU: it configures analog front-end ICs over SPI/I2C, sequences gain and offset calibration, and streams sample data over the high-speed USB link. The 128-bit Flash access at 96 MHz keeps the control loop responsive while DMA moves multi-megasample data, and the MPU lets vendors lock a calibration region of Flash against accidental overwrite. Dual-bank Flash supports feature upgrades shipped to instruments already in the field, a common requirement for test equipment product lines. The 144-pin LQFP offers enough GPIO to drive front-panel indicators, keypads, and relays without port expanders.
Recommended
Firmware-Update-Critical IoT Nodes
For connected nodes where a failed update is unacceptable, the SAM3U4E's dual-bank 256 KB Flash enables atomic image swapping: the running bank executes while the new firmware downloads into the inactive bank, and only a verified image activates at reset. This eliminates the external-bootloader flash chip required by single-bank MCUs, reducing BOM cost and board area. The 96 MHz core and 52 KB SRAM also accommodate TLS-class stack overhead better than smaller Cortex-M0/M0+ nodes, while the MPU isolates the network stack from application code. Combined with high-speed USB for local provisioning, the ATSAM3U4EA-AU is a strong fit for serviceable industrial IoT endpoints with long field lifetimes.
Recommended
Recommended Products Summary
Engineering reference data for ATSAM3U4EA-AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAM3U4CA-AU | ATSAM3U4EA-CU | ATSAM3U2CA-AU | TM4C123GH6PGEI |
|---|---|---|---|---|---|
| Package | 144-LQFP (20x20 mm) | 144-LQFP - same | LQFP/BGA per suffix | 144-LQFP - same | 144-LQFP - same body, different pinout |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Texas Instruments |
| Core / Max Speed | ARM Cortex-M3 @ 96 MHz | ARM Cortex-M3 @ 96 MHz | ARM Cortex-M3 @ 96 MHz | ARM Cortex-M3 @ 96 MHz | ARM Cortex-M4 @ 80 MHz |
| Flash | 256 KB dual-bank | 256 KB | 256 KB | 128 KB | 256 KB |
| Supply Voltage | 1.62 V to 3.6 V | 1.62 V to 3.6 V | 1.62 V to 3.6 V | 1.62 V to 3.6 V | 3.3 V nominal |
| USB | High-speed USB Device with DMA | High-speed USB Device | High-speed USB Device | High-speed USB Device | Full-speed USB Device |
| Pin-to-Pin Compatible | Reference part | Yes (same family LQFP144, peripheral differences) | Same die - verify package suffix | Yes (same family LQFP144, less memory) | No - board respin required |
Key Differentiators
- High-speed (480 Mbps) USB Device with dedicated DMA (vs TM4C123GH6PGEI)
- Larger SRAM for buffering (vs TM4C123GH6PGEI)
- Same-family memory scaling (vs ATSAM3U2CA-AU)
- Trade-off: fewer modern peripherals than newer families (vs ATSAM3U4CA-AU)
Design Notes
The ATSAM3U4EA-AU accepts 1.62V to 3.6V, but most designs run a clean 3.3V rail. At 96 MHz with the high-speed USB PHY active, core current peaks are significant; provide a low-ESR bulk capacitor (10 uF) plus 0.1 uF ceramics at each VDDIO/VDDCORE pin pair. Estimated: at ~40 mA average core current on 3.3V, power is only ~0.13 W, so no heatsinking is needed - layout quality, not thermal design, dominates reliability here.
The 144-LQFP (20x20 mm) has 0.5 mm pin pitch - use a 4-layer stackup with a dedicated ground plane. Route the high-speed USB DP/DM as a 90-ohm differential pair with matched lengths and place the 1.5 k pull or termination components per the USB spec near the connector. Keep crystal (slow clock and main clock) traces short and guard them with ground. Decouple every supply pin; the multi-layer bus matrix creates simultaneous switching noise on the core supply at 96 MHz.
Flash wait states at 96 MHz mean hot loops run faster from the 52 KB SRAM than from Flash despite the accelerator - move interrupt handlers and DSP inner loops to SRAM. When implementing dual-bank firmware updates, never reset the MCU mid-write and always verify the inactive bank CRC before issuing the bank switch. Also confirm peripheral-set differences before substituting ATSAM3U4C parts for the 4E: peripheral addresses and counts differ within the family, so ASF3 board files may need changes.
Compliance Information
Compliance data was not present in the provided verified web data; consult the Microchip product page environmental section for RoHS/REACH status.
