ATSAM3U1CA-AU - 96MHz Cortex-M3, 64KB Flash MCU | Microchip
MPN: ATSAM3U1CA-AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.7 | $12.70 |
| 10 | $12.7 | $127.00 |
| 100 | $12.7 | $1,270.00 |
| 500 | $12.7 | $6,350.00 |
| 1,000 | $12.7 | $12,700.00 |
ATSAM3U1CA-AU Overview
A microcontroller (MCU) is a single-chip computer that integrates a processor core, program memory, data memory, and peripheral controllers on one die. Within the embedded-systems hierarchy, the SAM3U family sits in the ARM Cortex-M class of 32-bit microcontrollers, which are widely used where deterministic real-time behavior, low power, and rich serial connectivity are required, sitting above 8-bit MCUs and below application processors.
Key differentiating features include the ARM Cortex-M3 revision 2.0 core executing the Thumb-2 instruction set, a Memory Protection Unit (MPU) for robust task isolation, and embedded flash organized 128-bit wide to sustain zero-wait-state execution at full core speed. The integrated high-speed USB transceiver is the headline feature, enabling fast up/downloading of data with robust EMI tolerance and plug-and-play high-speed serial connectivity without an external PHY.
Architecturally, the SAM3U is built around a multi-layer bus matrix with multiple SRAM banks, supported by a Peripheral DMA Controller (PDC) and DMA channels. This parallel data-path design sustains high-speed USB throughput while the CPU services other peripherals, minimizing bus contention during bulk data transfers. Operation spans a 1.62V to 3.6V supply range.
Typical applications include USB data-logging instruments, industrial gateways and field tools, and consumer devices requiring fast USB mass-storage or firmware update paths, where the 96 MHz core and 64 KB flash cover the code and throughput budget of mid-complexity embedded designs.
When designing with this part, budget flash carefully: 64 KB is generous for bare-metal firmware but tight for USB stacks with file systems, so consider the pin-compatible 128 KB (ATSAM3U2CA-AU) or 256 KB (ATSAM3U4CA-AU) siblings for growth headroom.
This page synthesizes distributor pricing, drop-in family alternatives, and practical design notes not found in the manufacturer datasheet, with pricing referenced as of 2026-09-19.
Drop-in alternatives for ATSAM3U1CA-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 ATSAM3U1CA-AU (same form factor and footprint) β differing in Package, USB, Core Processor, DMA, Flash Memory.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAM3U2CA-AU
β Drop-Inβ In Stock
$4.45 / Unit
View Datasheet βATSAM3U4CA-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAM3U1CC-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAM3U1CA-AU Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M3 revision 2.0 |
| Core Size | 32-bit |
| Maximum Clock Frequency | 96 MHz |
| Instruction Set | Thumb-2 |
| Memory Protection | MPU (Memory Protection Unit) |
| Program Memory Size | 64 KB (64K x 8) Flash |
| Flash Organization | 128-bit wide |
| SRAM Size | 20 KB |
| Supply Voltage Range | 1.62 V to 3.6 V |
| USB | High-speed USB device with integrated transceiver |
| DMA | PDC and DMA, multi-layer bus matrix, multiple SRAM banks |
| Package | 100-LQFP (14x14 mm) |
| Mounting Type | Surface Mount |
| Series | SAM3U |
ATSAM3U1CA-AU 100-lqfp (14x14 mm) Pin Configuration Guide
Pin configuration for ATSAM3U1CA-AU (100-lqfp (14x14 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 ATSAM3U1CA-AU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAM3U1CA-AU is suitable for 6 applications: USB Data Loggers and Instruments, Industrial Gateways and Field Tools, USB Mass-Storage Consumer Devices, Embedded Firmware Update and Programming Tools, Battery-Powered Portable Measurement, Medical Data Acquisition Modules.
USB Data Loggers and Instruments
The ATSAM3U1CA-AU fits USB data-logging instruments because its integrated high-speed USB device transceiver sustains fast bulk transfers of logged data to a host PC without an external PHY, reducing BOM cost and board area. The 96 MHz Cortex-M3 with the multi-layer bus matrix, multiple SRAM banks, and PDC/DMA channels can write sensor streams to external memory and stream them over USB concurrently with minimal CPU stalls. The 20 KB SRAM buffers burst data between the 1.62V-3.6V analog front-end domain and the USB stack. Unlike full-speed-only MCUs, 480 Mbps HS USB shortens dump times for multi-gigabyte logs, while the Memory Protection Unit helps isolate the USB stack from acquisition firmware for robustness in field instruments.
Recommended
Industrial Gateways and Field Tools
Industrial gateways and handheld field tools benefit from the ATSAM3U1CA-AU's combination of a 96 MHz Cortex-M3, Thumb-2 code density, and plug-and-play high-speed serial connectivity. In these products the MCU typically bridges Modbus/CAN-class industrial interfaces to a USB service port used for configuration, firmware updates, and data extraction; the integrated HS USB transceiver with robust EMI tolerance is well suited to electrically noisy factory environments. The 1.62V to 3.6V supply range tolerates industrial rail variation and battery-backed operation, and the MPU supports layered firmware architectures separating safety-critical acquisition code from communication stacks. The 100-pin LQFP (14x14 mm) provides enough GPIO for display, keypad, and multiple UART/SPI peripherals in a reflow-friendly, reworkable package.
Recommended
USB Mass-Storage Consumer Devices
Consumer devices presenting themselves as USB mass-storage drives - card readers, media dongles, portable recorders - map directly onto the ATSAM3U1CA-AU's strengths. The 128-bit-wide embedded flash executes the USB and file-system stack from the same die, and the high-speed USB device port achieves fast up/downloading of data as highlighted in the Atmel SAM3U datasheet. PDC/DMA offloads SD-card-class storage transfers from the CPU, so the 96 MHz core can maintain sustained USB throughput without dropping to full-speed rates. The 64 KB flash accommodates a lean mass-storage stack; designs adding a file system GUI should step up to the pin-compatible ATSAM3U2CA-AU. The single 1.62V-3.6V supply simplifies battery-powered form factors such as recorders and readers.
Recommended
Embedded Firmware Update and Programming Tools
Programmers, debug probes, and in-circuit firmware-update tools exploit the ATSAM3U1CA-AU's high-speed USB link on the host side and multiple UART/SPI interfaces on the target side. Fast up/downloading of data over the integrated HS USB transceiver cuts programming time for large target images, while the PDC/DMA keeps streaming between USB and target interfaces independent of core load. The 96 MHz Cortex-M3 provides headroom for CRC verification, encryption, and protocol translation inline. Thumb-2 code density and the MPU allow a compact, robust host firmware in 64 KB flash; the pin-compatible 128 KB and 256 KB siblings (ATSAM3U2CA-AU, ATSAM3U4CA-AU) let one PCB design serve entry-level and professional tool tiers with different flash budgets.
Recommended
Battery-Powered Portable Measurement
Portable measurement devices - multimeters, environmental loggers, handheld analyzers - operate well within the ATSAM3U1CA-AU's 1.62V to 3.6V single-supply envelope, allowing direct use of two-cell alkaline or single-cell Li-ion supplies with a simple regulator. The 96 MHz Cortex-M3 executes DSP-style filtering and calibration math quickly, then sleeps between conversions; the 20 KB SRAM holds waveform capture buffers. Results upload over the integrated high-speed USB port for report generation, avoiding slow full-speed bottlenecks when exporting long acquisition sessions. The Memory Protection Unit separates safety-related measurement firmware from the USB stack, and the 100-pin LQFP exposes sufficient GPIO for keypads, displays, and multiple sensor interfaces in a 14x14 mm, hand-reworkable surface-mount footprint.
Recommended
Medical Data Acquisition Modules
Desktop medical data-acquisition modules - ECG front-ends, patient-data terminals, lab instrument interfaces - use the ATSAM3U1CA-AU to move digitized physiological data to a PC over high-speed USB with low latency. The multi-layer bus matrix and PDC/DMA keep ADC streaming continuous while the 96 MHz Cortex-M3 applies filtering and scaling; the MPU supports partitioning between measurement code and the USB communication stack, aiding structured software validation. Robust EMI tolerance of the integrated USB transceiver suits electrically demanding clinical environments, and the 1.62V to 3.6V range pairs with low-noise 3.3V analog rails. The 14x14 mm 100-LQFP package offers ample peripheral-multiplexed GPIO for front-end control, and pin-compatible flash-upgrade siblings protect the design across product revisions.
Recommended
Recommended Products Summary
Engineering reference data for ATSAM3U1CA-AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAM3U2CA-AU | ATSAM3U4CA-AU | ATSAM3U1CC-AU |
|---|---|---|---|---|
| Package | 100-LQFP (14x14) | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same | 100-pin family package - verify footprint |
| Brand | Microchip Technology (Atmel) | Microchip Technology | Microchip Technology | Microchip Technology |
| Core / Frequency | Cortex-M3 rev 2.0, 96 MHz | Cortex-M3, 96 MHz | Cortex-M3, 96 MHz | Cortex-M3, 96 MHz |
| Flash | 64 KB (128-bit wide) | 128 KB | 256 KB | 64 KB |
| SRAM | 20 KB | 20 KB | 24 KB class - verify datasheet | 20 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 |
| USB | High-speed USB, integrated transceiver | High-speed USB, integrated transceiver | High-speed USB, integrated transceiver | High-speed USB, integrated transceiver |
| Drop-in Compatibility | Reference part | Pin-to-pin drop-in | Pin-to-pin drop-in | Family variant - verify package pinout |
Key Differentiators
- Integrated high-speed USB transceiver (vs ATSAM3S8BA-MUR)
- Entry cost point of the SAM3U HS-USB family (vs ATSAM3U2CA-AU)
- Balanced 64 KB flash / 20 KB SRAM for lean USB firmware (vs ATSAM3U4CA-AU)
Design Notes
Design the 3.3V rail for the worst-case sum of core, GPIO, and USB transceiver current; the SAM3U accepts 1.62V-3.6V but high-speed USB signaling is specified at the nominal 3.3V domain, so regulate battery inputs down rather than running the part near 3.6V with USB active. Place a 0.1uF ceramic decoupling capacitor at each VDD/VDDIO pin pair plus bulk 10uF near the regulator. The USB DP/DM pair needs the datasheet-specified termination; because the transceiver is integrated, do not add external series PHY components.
For the 100-LQFP (14x14 mm) with 0.5 mm pitch, keep USB DP/DM as a tightly length-matched differential pair routed away from switching regulators and crystal traces. Place the 0.1uF decoupling capacitors within 2 mm of their supply pins and use short, wide return paths to the ground plane. On a two-layer board, dedicate a continuous ground pour; for high-speed USB compliance testing, a four-layer stack with an unbroken ground plane under the USB pair significantly improves eye-diagram margin.
64 KB flash fills quickly once a USB device stack plus mass-storage or CDC class is included - compile early with your chosen stack and, if the image approaches 56 KB, plan the pin-compatible ATSAM3U2CA-AU (128 KB) as the alternate population. Also confirm SRAM allocation: USB endpoint buffers plus application buffers must fit in the 20 KB SRAM, including DMA descriptors. Finally, verify your peripheral pin choices against the SAM3U peripheral multiplexing tables before layout; shared-pin conflicts are the most common SAM3U schematic rework cause.
Compliance Information
Compliance status for ATSAM3U1CA-AU was not stated in the retrieved distributor data; verify RoHS/REACH status on the official Microchip product page before procurement.