ATSAM3U2EA-AU - 96MHz Cortex-M3 MCU 128KB Flash | Microchip
MPN: ATSAM3U2EA-AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.12 | $9.12 |
| 10 | $8.67 | $86.70 |
| 100 | $8.12 | $812.00 |
| 500 | $7.66 | $3,830.00 |
| 1,000 | $7.22 | $7,220.00 |
ATSAM3U2EA-AU Overview
A microcontroller (MCU) is a single integrated circuit that combines a processor core, program memory, data memory, and a rich set of peripherals into one chip, forming the complete control engine of an embedded system. Within the power-management hierarchy of electronics, the MCU sits above discrete logic and below application processors, and the SAM3U family belongs to Microchip (formerly Atmel) AT91 SMART ARM-based flash MCU portfolio, which targets high-throughput USB-connected embedded designs.
Key features of the ATSAM3U2EA-AU include the ARM Cortex-M3 revision 2.0 core with Thumb-2 instruction set and a Memory Protection Unit (MPU), 128-bit-wide flash access with a memory accelerator and dual-bank architecture for concurrent read-while-write operation, and a supply range of 1.62V to 3.6V. The device integrates an internal 1.80V voltage regulator with a start-up time to Normal mode of less than 400 microseconds, simplifying power-tree design.
Technically, the SAM3U family is distinguished by a high-speed USB Device port and an EBI (External Bus Interface), with peripherals clocked independently of the core so system designers can trade performance against power consumption. The 144-LQFP (20x20 mm) gull-wing package provides abundant GPIO for parallel displays, external memories, and industrial I/O, and the industrial temperature grade supports demanding environments.
Typical applications include USB audio and mass-storage devices, industrial human-machine interfaces, data loggers, and instrumentation that benefits from the 96 MHz core bandwidth and fast flash access. The ATSAM3U2EA-AU fits designs that need substantial I/O count and USB connectivity without an operating system running from external memory.
When designing with this device, decouple the internal 1.80V regulator per the Voltage Regulator section of the datasheet electrical characteristics, and verify flash wait-state settings at 96 MHz operation. Price data is as of 2026-09-19 (reference unit price about $9.12 from distributor listings).
This page synthesizes distributor pricing, drop-in alternatives, comparison tables, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATSAM3U2EA-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 ATSAM3U2EA-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:
ATSAM3U2EA-CU
β Drop-Inπ Reference alternative (not in catalog)
ATSAM3U4EA-AU
β Drop-Inβ In Stock
$4.8 / Unit
View Datasheet βATSAM3U4CA-AU
β Drop-Inπ Reference alternative (not in catalog)
ATSAM3U1EA-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAM3U2CA-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$4.45 / Unit
View Datasheet βATSAM3U2EA-AU Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M3 (revision 2.0) |
| Core Size | 32-bit |
| Maximum Clock Speed | 96 MHz |
| Instruction Set | Thumb-2 |
| Memory Protection | MPU (Memory Protection Unit) |
| Flash Memory | 128 KB (128K x 8) |
| SRAM | 36 KB |
| Flash Access | 128-bit wide with memory accelerator, dual bank |
| Supply Voltage Range | 1.62V to 3.6V |
| Internal Regulator | 1.80V default output, start-up < 400 us to Normal mode |
| Series | SAM3U (AT91 SMART ARM-based) |
| Package | 144-LQFP (20x20 mm) |
| Mounting Type | Surface Mount |
| Number of Pins | 144 |
| Terminal Form | Gull Wing |
| Temperature Grade | Industrial |
| Life Cycle Stage | Active |
ATSAM3U2EA-AU Pin Configuration
| Pin 1 | PA0 β Parallel I/O controller A, pin 0 (peripheral function multiplexed per datasheet) |
| Pin 2 | PA1 β Parallel I/O controller A, pin 1 |
| Pin 3 | PA2 β Parallel I/O controller A, pin 2 |
| Pin 4 | PA3 β Parallel I/O controller A, pin 3 |
| Pin 5 | PA4 β Parallel I/O controller A, pin 4 |
| Pin 6 | PA5 β Parallel I/O controller A, pin 5 |
| Pin 7 | PA6 β Parallel I/O controller A, pin 6 |
| Pin 8 | PA7 β Parallel I/O controller A, pin 7 |
| Pin 9 | PA8 β Parallel I/O controller A, pin 8 |
| Pin 10 | PA9 β Parallel I/O controller A, pin 9 |
| Pin 21 | VDDCORE β Core power supply (from internal 1.80V regulator), decouple per datasheet Voltage Regulator section |
| Pin 22 | VDDIO β I/O power supply (1.62V to 3.6V) |
| Pin 23 | GND β Ground |
| Pin 71 | VDDPLL β PLL power supply |
| Pin 72 | GND β Ground |
| Pin 102 | VDDIN β Regulator input supply (1.62V to 3.6V) |
| Pin 103 | VDDOUT β Regulator output (default 1.80V), external capacitor required per datasheet |
| Pin 104 | GND β Ground |
| Pin 131 | NRST β Bidirectional reset pin with internal pull-up |
| Pin 132 | TEST β Test mode pin (tie to GND in normal operation) |
| Pin 133 | TCK β JTAG test clock |
| Pin 134 | TDI β JTAG test data input |
| Pin 135 | TDO β JTAG test data output |
| Pin 136 | TMS β JTAG test mode select |
| Pin 137 | XIN β Main oscillator input |
| Pin 138 | XOUT β Main oscillator output |
| Pin 139 | VDDOSC β Oscillator power supply |
| Pin 140 | GND β Ground |
Typical Applications
ATSAM3U2EA-AU is suitable for 6 applications: USB Mass Storage and Peripheral Devices, Industrial Human-Machine Interfaces (HMI), Data Loggers and Instrumentation, USB Audio Class Devices, Embedded Networking and Protocol Gateways, Consumer and Portable Embedded Systems.
USB Mass Storage and Peripheral Devices
The ATSAM3U2EA-AU fits USB device applications because the SAM3U family integrates a high-speed USB Device peripheral and the 96 MHz Cortex-M3 core with 128-bit-wide flash access sustains the throughput required for USB 2.0 bulk transfers. In a mass-storage design, the MCU services the USB stack while streaming data to and from storage media; the memory accelerator keeps fetches ahead of the core so interrupt latency stays low during long transfers. The 144-LQFP package provides ample GPIO for status LEDs, media-detection inputs, and auxiliary serial links. Because the internal 1.80V regulator starts in under 400 microseconds, USB enumeration timing budgets are easy to meet after bus attach. Use the part where a self-contained, firmware-only USB device endpoint is needed without an external processor or operating system.
Recommended
Industrial Human-Machine Interfaces (HMI)
The ATSAM3U2EA-AU is a strong fit for industrial HMI panels because 96 MHz of Cortex-M3 processing refreshes graphical segments and services touch inputs while the 144-pin LQFP supplies the large GPIO count needed for parallel displays, keypads, and relay outputs. The 128-bit flash interface with memory accelerator keeps code execution deterministic, which matters for scan-cycle consistency in operator panels. The 1.62V to 3.6V supply range tolerates industrial rail variation, and the industrial temperature grade suits factory-floor enclosures. The Memory Protection Unit helps partition display, communication, and control code for robustness. In a typical design, the MCU drives a segmented or small TFT display over FSMC/EBI-style parallel bus while UART or USB links report to a PLC, making one chip sufficient for the whole interface node.
Recommended
Data Loggers and Instrumentation
For data loggers, the ATSAM3U2EA-AU offers a balanced combination: 36 KB of SRAM buffers sensor samples between write cycles, the dual-bank flash architecture allows firmware updates and parameter storage in the field, and the 96 MHz core executes FFT and filtering on collected data. The MPU assists in isolating the acquisition kernel from the logging stack, improving reliability in long-term deployments. The internal 1.80V regulator simplifies battery- or rail-powered designs, and its sub-400 us start-up supports duty-cycled logging that wakes, samples, stores, and sleeps. The gull-wing 144-LQFP reflows reliably on standard industrial assembly lines. Multiple USART/UART-style serial channels accept inputs from flow meters, ADC front-ends, and RTC modules simultaneously without external glue logic, keeping logger BOM count low.
Recommended
USB Audio Class Devices
The ATSAM3U2EA-AU suits USB audio endpoints because the SAM3U high-speed USB Device peripheral and 96 MHz Cortex-M3 bandwidth handle isochronous audio streaming plus sample-rate processing without dropped frames. The 128-bit flash accelerator ensures the interrupt service routines for audio buffers execute with bounded latency, which directly governs audible artifacts. The 144-pin LQFP exposes enough GPIO to attach I2S-style serial audio codecs, volume encoders, and status indicators on one board. The 1.62V to 3.6V supply window accommodates USB-bus-powered or self-powered configurations; the internal 1.80V regulator removes one external LDO from the power tree. Firmware typically implements the USB Audio Class descriptor set plus control endpoint handling, all comfortably within the 128 KB flash budget for a single-role audio device.
Recommended
Embedded Networking and Protocol Gateways
The ATSAM3U2EA-AU performs well as a protocol gateway because multiple serial peripherals on the 144-pin device terminate several links concurrently - for example a USB upstream port bridged to industrial RS-485-style or CAN-style downstream buses - while the 96 MHz core keeps framing, checksum, and translation overhead hidden from wire latency. The Memory Protection Unit partitions the protocol stacks so a fault in one link does not corrupt the other, a key reliability feature for unattended gateways. The dual-bank flash permits firmware update with rollback, essential in fielded network equipment. The industrial temperature grade and 1.62V to 3.6V tolerance match DIN-rail and panel power conditions. With 144 pins, designers also expose diagnostics LEDs, DIP configuration switches, and a maintenance UART on the same controller.
Recommended
Consumer and Portable Embedded Systems
In consumer and portable designs the ATSAM3U2EA-AU offers a single-chip solution where USB connectivity, moderate compute, and rich I/O converge - examples include docking stations, accessories, test gadgets, and smart appliances. The 96 MHz core executes application logic and USB stacks together, the 128 KB flash holds feature-complete firmware, and the 144-LQFP provides GPIO for buttons, encoders, and display segments without port expanders. Power behavior is helped by the integrated 1.80V regulator and clock-domain flexibility of the SAM3U peripheral bus, allowing unused peripherals to be clock-gated. The industrial temperature grade also covers automotive-cabin-adjacent and outdoor consumer environments. For cost-sensitive models, the same PCB can accept lower-flash family siblings (such as ATSAM3U1EA) to create a derivative product line.
Recommended
Recommended Products Summary
Engineering reference data for ATSAM3U2EA-AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAM3U2EA-CU | ATSAM3U4EA-AU | ATSAM3U4CA-AU | ATSAM3U1EA-AU |
|---|---|---|---|---|---|
| Package | 144-LQFP (20x20 mm) | 144-LQFP (20x20 mm) - same | 144-LQFP (20x20 mm) - same | 144-LQFP (20x20 mm) - same | 144-LQFP (20x20 mm) - same |
| Brand | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) |
| Core / Speed | ARM Cortex-M3, 96 MHz | ARM Cortex-M3, 96 MHz | ARM Cortex-M3, 96 MHz | ARM Cortex-M3, 96 MHz | ARM Cortex-M3, 96 MHz |
| Flash Memory | 128 KB | 128 KB | 256 KB | 256 KB | 64 KB |
| Supply Voltage | 1.62V to 3.6V | 1.62V to 3.6V | 1.62V to 3.6V | 1.62V to 3.6V | 1.62V to 3.6V |
| Memory Accelerator / Dual Bank Flash | Yes (128-bit wide) | Yes (128-bit wide) | Yes (128-bit wide) | Yes (128-bit wide) | Yes (128-bit wide) |
Key Differentiators
- Cost-optimized flash size within pin-compatible family (vs ATSAM3U4EA-AU)
- High-speed USB device focus of the SAM3U family (vs ATSAM3N4BA-MU)
- Fast integrated regulator start-up (vs Generic external-LDO designs)
Design Notes
The ATSAM3U2EA-AU integrates an internal voltage regulator with a default 1.80V output (VDDOUT) and a start-up time to Normal mode of less than 400 microseconds. Per the datasheet's Voltage Regulator section, the VDDOUT pin requires an adequate output capacitor and VDDIN (1.62V to 3.6V) requires proper input decoupling for regulator stability. Do not drive VDDOUT from an external 1.8V rail unless the datasheet's external-supply configuration is followed, and size the VDDIN rail for core plus I/O transient currents during 96 MHz operation.
The 144-LQFP (20x20 mm) gull-wing package places power and ground pins distributed around the die; connect every VDDIO, GND, VDDCORE, VDDPLL, and VDDOSC pin individually - never daisy-chain a rail across multiple pins with a single trace. Place 100 nF ceramic decoupling capacitors within 2 mm of each supply pin group and use a solid ground plane. The NRST pin includes an internal pull-up but benefits from an external 100 kOhm pull-up plus 100 nF filter capacitor for noise immunity in industrial environments.
Two common pitfalls: (1) Flash wait states - at 96 MHz the flash accelerator settings must match the datasheet electrical characteristics table; running with incorrect wait states after changing clock configuration from an ROM bootloader can corrupt execution. (2) Second-sourcing assumptions - although SAM3U siblings (ATSAM3U4EA-AU, ATSAM3U4CA-AU) are pin-compatible upgrades, no cross-brand 144-LQFP Cortex-M3 is pin-for-pin identical, so qualification of a different vendor requires PCB respin. Also verify JTAG/DBGU pin muxing early, as these debug pins share GPIO on PA-bank pins.
For USB device operation, route the USB DP/DM pair as a 90-ohm differential pair with matched lengths and keep it away from the main crystal (XIN/XOUT) circuit. The main oscillator traces should be short and guarded by ground to prevent coupling into the PLL (which has its own VDDPLL pin and decoupling). When using the parallel EBI-style bus at high GPIO toggle rates, add series termination (22-33 ohm) on long lines to control ringing driven by the fast I/O edges of the 96 MHz-class output buffers.
Compliance Information
Compliance data not explicitly stated in the provided web data. The industrial temperature grade and gull-wing lead form are confirmed by distributor data; confirm RoHS/REACH status on the official Microchip product page before export.
