ATSAM3S4BA-MU - Cortex-M3 64MHz MCU 256KB Flash | Microchip
MPN: ATSAM3S4BA-MU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.04 | $7.04 |
| 10 | $6.55 | $65.50 |
| 100 | $6.02 | $602.00 |
| 500 | $5.58 | $2,790.00 |
| 1,000 | $5.12 | $5,120.00 |
ATSAM3S4BA-MU Overview
A flash microcontroller is a single-chip computing device that integrates a processor core, program memory, data memory, and peripherals such as UART, SPI, I2C, ADC, and timers onto one silicon die. Microcontrollers sit at the device level of the embedded-system hierarchy, below SoCs and application processors, and the SAM3S series belongs to the broader ARM Cortex-M MCU family alongside SAM3N, SAM4S, and SAMD product lines from Microchip.
Key features include the ARM Cortex-M3 revision 2.0 core with Memory Protection Unit (MPU) and Thumb-2 instruction set, 128-bit wide Flash access with a memory accelerator for near-zero-wait-state execution, and pin-to-pin compatibility with the AT91SAM7S series in 48- and 64-pin versions, which simplifies migration for designs needing more performance. Operating supply is 1.62V to 3.6V with core operation at 1.08V to 1.32V, and the part is rated for industrial temperature ranges.
Technically, the SAM3S integrates a multilayer bus matrix, 12-channel DMA controller (PDC), USB 2.0 full-speed device port, and a rich peripheral set including USART, SPI, TWI, PWM, and a 12-bit ADC, allowing deterministic real-time control with low interrupt latency.
Typical applications include industrial control and automation, battery-powered portable instruments, and human-machine interface nodes, where the combination of 64 MHz performance, DMA offload, and 1.62V low-voltage operation fits power-conscious designs.
A key design consideration is that peripheral-to-pin mapping on the 64-QFN requires careful pin multiplexing review; confirm ADC channel assignments and USB D+/D- routing before locking the PCB footprint.
This page synthesizes distributor pricing, drop-in alternatives, design notes, and parametric comparisons not found in the manufacturer datasheet.
Drop-in alternatives for ATSAM3S4BA-MU 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 ATSAM3S4BA-MU (same form factor and footprint) β differing in Package, Supply Voltage, Flash Memory, Series, Packaging.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAM3SD8BA-MU
β Drop-Inβ In Stock
$4.95 / Unit
View Datasheet βATSAM3S8BA-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$5.72 / Unit
View Datasheet βATSAM3S2BA-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAM3N4BA-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$3.48 / Unit
View Datasheet βAT91SAM7S256D-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAM3S4BA-MU Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M3 revision 2.0 |
| Core Size | 32-bit |
| Maximum Clock Frequency | 64 MHz |
| Flash Memory | 256 KB (256K x 8) |
| SRAM | 48 KB |
| Supply Voltage (VDDIO) | 1.62 V to 3.6 V |
| Core Supply Voltage | 1.08 V to 1.32 V |
| Number of I/O | 47 |
| Peripherals | DMA (PDC), PWM, WDT, USB 2.0 full-speed device |
| Connectivity | USART, SPI, TWI (I2C), USB |
| ADC Resolution | 12-bit |
| Package | 64-QFN (9x9 mm) with exposed pad |
| Mounting Type | Surface Mount |
| Instruction Set | Thumb-2 |
| Memory Protection Unit | Yes (MPU) |
| Life Cycle Stage | Active |
| Packaging | Tray |
ATSAM3S4BA-MU 64-qfn (9x9 mm) with exposed pad Pin Configuration Guide
Pin configuration for ATSAM3S4BA-MU (64-qfn (9x9 mm) with exposed pad 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 ATSAM3S4BA-MU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAM3S4BA-MU is suitable for 6 applications: Industrial Control and Automation, Battery-Powered Portable Instruments, USB Peripherals and Data Acquisition, Human-Machine Interface Panels, Building Automation and Smart Sensors, Legacy AT91SAM7S Migration and Refresh.
Industrial Control and Automation
The ATSAM3S4BA-MU fits industrial control nodes that require deterministic real-time response and multiple communication interfaces. Its 64 MHz ARM Cortex-M3 core with MPU provides interrupt latency low enough for closed-loop control, while the multichannel DMA controller offloads UART, SPI, and ADC transfers so the CPU remains free for the control loop. The 12-bit ADC samples process variables such as temperature and pressure, and PWM outputs drive actuators or motor drivers directly. Operating from a 1.62V to 3.6V rail, it integrates easily into 3.3V industrial logic designs. Field firmware updates are handled by the embedded SAM-BA boot loader over UART, avoiding physical reprogramming during maintenance. Its 64-QFN exposed-pad package provides a large ground plane for noise immunity in electrically harsh factory environments.
Recommended
Battery-Powered Portable Instruments
Portable instruments benefit from the ATSAM3S4BA-MU's combination of 64 MHz processing and a 1.62V minimum supply, which allows direct operation from a single lithium cell through a simple regulator. The device's multiple low-power modes, combined with peripheral DMA that moves ADC samples into SRAM while the core sleeps, reduce average current consumption in duty-cycled measurement applications such as handheld meters and data loggers. The 48KB SRAM buffers extended acquisition sessions, and the 256KB Flash stores application code plus logged calibration data. The 12-bit ADC with multiple channels supports multi-sensor front ends without an external converter. USB full-speed device capability enables quick data offload to a PC without additional bridge chips, simplifying the bill of materials in cost-sensitive portable designs.
Recommended
USB Peripherals and Data Acquisition
The ATSAM3S4BA-MU integrates a USB 2.0 full-speed device controller, making it a natural fit for USB-connected peripherals such as sensor dongles, custom HID devices, and acquisition pods. The DMA controller streams sample data from the 12-bit ADC or external SPI sensors directly to the USB endpoint buffers, sustaining full-speed throughput with minimal CPU loading. The 64 MHz Cortex-M3 core handles USB enumeration, protocol handling, and signal conditioning concurrently. Its 256KB Flash accommodates complete USB class stacks (CDC, HID, MSC) alongside application logic, and the SAM-BA ROM boot loader doubles as a field firmware-update channel over the same USB port, letting end customers upgrade devices without special tools or disassembly.
Recommended
Human-Machine Interface Panels
HMI panels and operator terminals use the ATSAM3S4BA-MU's 47 GPIO lines, PWM channels, and rich communication set to drive keypads, indicators, and display interfaces. The 64 MHz Cortex-M3 scans large key matrices debounced in hardware-timed routines, generates PWM backlight dimming, and talks to display controllers or touch chips over SPI or TWI. USART links connect to host PLCs or remote controllers for command exchange. The 48KB SRAM supports frame or menu buffers, while the MPU allows safe separation of stack and application regions for robust long-running kiosk-style operation. Pin-to-pin compatibility within the SAM3S family lets designers scale Flash memory up to 512KB (ATSAM3S8BA-MU) as menu and localization content grows, without changing the PCB.
Recommended
Building Automation and Smart Sensors
Smart sensors and building automation nodes leverage the ATSAM3S4BA-MU's multiple TWI (I2C), SPI, and USART interfaces to aggregate data from environmental sensors and report over wired links. The 12-bit ADC digitizes analog sensor outputs directly, and the DMA controller schedules background sampling without CPU intervention, keeping latency predictable in networking stacks. Operation from 1.62V suits energy-harvesting or battery-backed nodes, and the Cortex-M3 core delivers enough headroom to run lightweight protocol stacks alongside the measurement application. The 64-QFN exposed-pad package offers good thermal behavior for sealed enclosures with limited airflow. Firmware update over UART via the embedded SAM-BA monitor enables fleet-wide maintenance of deployed sensor networks without physical access to the PCB.
Recommended
Legacy AT91SAM7S Migration and Refresh
Designs originally built on the AT91SAM7S series can migrate to the ATSAM3S4BA-MU with no PCB footprint change, because the datasheet explicitly states the SAM3S series is pin-to-pin compatible with the AT91SAM7S series in 48- and 64-pin versions. The migration immediately doubles maximum clock frequency (55 MHz to 64 MHz), moves from the ARM7TDMI to the Cortex-M3 with Thumb-2 efficiency, and adds a DMA controller, faster ADC, and full-speed USB. The 128-bit wide Flash interface with memory accelerator keeps execution near zero wait states, so code ported from SAM7S often runs faster without hand optimization. This makes the SAM3S4 the lowest-risk refresh path for aging SAM7S-based industrial products facing component obsolescence.
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Recommended Products Summary
Engineering reference data for ATSAM3S4BA-MU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAM3SD8BA-MU | ATSAM3S8BA-MU | ATSAM3S2BA-MU | ATSAM3N4BA-MU |
|---|---|---|---|---|---|
| Package | 64-QFN (9x9) EP | 64-QFN (9x9) EP - same | 64-QFN (9x9) EP - same | 64-QFN (9x9) EP - same | 64-QFN - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Core / Max Frequency | Cortex-M3, 64 MHz | Cortex-M3, 64 MHz | Cortex-M3, 64 MHz | Cortex-M3, 64 MHz | Cortex-M3, 64 MHz |
| Flash Memory | 256 KB | 256 KB | 512 KB | 128 KB | 256 KB |
| USB Full-Speed Device | Yes | Yes | Yes | Yes | No |
| Lifecycle Status | Active | Active | Active | Active | Active |
Key Differentiators
- Balanced memory configuration for cost-optimized designs (vs ATSAM3S8BA-MU)
- Full peripheral set including USB full-speed device (vs ATSAM3N4BA-MU)
- Modern Cortex-M3 with DMA and Thumb-2 (vs AT91SAM7S256D-MU)
Design Notes
The exposed pad on the bottom of the 64-QFN is the primary ground connection for the die. Solder it to a grounded PCB pad with an array of thermal vias (typically 3x3 or larger) connecting to the internal ground plane. Skipping the exposed-pad solder connection is a common cause of intermittent behavior and poor EMC performance on SAM3S designs. Follow Microchip's SAM3S hardware design application guidance for land pattern dimensions and stencil apertures to ensure void-free pad coverage during reflow.
The SAM3S4 uses separate VDDIO (1.62V-3.6V), VDDCORE (1.08V-1.32V, typically regulated internally via VDDPLL/VDDCORE pins per the datasheet power architecture), and analog supplies. Decouple each supply pin with 100nF ceramics placed within 2 mm of the pin, plus bulk 10uF capacitance per rail. Power the analog supply (VDDANA) from a clean source or an RC/LC filter from VDDIO to preserve 12-bit ADC accuracy; switching-regulator ripple on VDDANA shows up directly as ADC noise.
Pins on the SAM3S are heavily multiplexed: verify the peripheral function assignment table in the datasheet pinout section before routing, especially for TWI/SPI/USART overlaps on the 64-QFN where only 47 of 64 pins are I/O. Also note the Flash accelerator means most code executes at 0 wait states at 64 MHz, but performance-critical routines should still be checked with the Flash wait-state settings configured correctly in the EEFC register after reset.
Compliance Information
Compliance status not explicitly stated in provided data; Mouser listing references 'MRL A' and 'Ind Temp' designation, and the Microchip datasheet indicates industrial temperature rating. Verify RoHS/REACH status on the official Microchip product page before procurement.
