ATSAM3S4BA-AUR - 64MHz Cortex-M3 MCU 256KB Flash | Microchip
MPN: ATSAM3S4BA-AUR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.42 | $5.42 |
| 10 | $4.87 | $48.70 |
| 100 | $4.32 | $432.00 |
| 500 | $3.85 | $1,925.00 |
| 1,000 | $3.44 | $3,440.00 |
ATSAM3S4BA-AUR Overview
A microcontroller unit (MCU) is a single integrated circuit that combines a processor core, memory, and peripherals into one chip, forming the heart of embedded systems. Within the product hierarchy, the SAM3S sits under ARM Cortex-M3 based flash microcontrollers -> 32-bit MCUs -> embedded processors. The ATSAM3S4BA is a member of Microchip's (formerly Atmel) SAM3S series, a cost-optimized Cortex-M3 family targeting industrial and consumer embedded designs.
Key features include the 64 MHz ARM Cortex-M3 RISC core, 256KB of on-chip Flash, 49KB of SRAM, and a rich peripheral set covering HSMCI (high-speed multi-media card interface), I2C, I2S, IrDA, SPI, SSC (synchronous serial controller), TWI, UART, USART, and USB device connectivity. A DMA controller offloads the CPU by moving data directly to memory, improving real-time throughput.
Technically, the device operates from a single 1.62V to 3.6V supply (typical 1.8V/3.3V rails), and Microchip documents that it is pin-to-pin compatible with the SAM3N4B and SAM7S64, allowing footprint reuse and BOM migration across the family. The 10x10 mm 64-LQFP with 0.5 mm pitch is hand-solderable and suitable for two-layer and four-layer industrial boards.
Typical applications include industrial control nodes, consumer appliances, battery-powered portable instruments, and USB-connected sensor interfaces, where the Cortex-M3 performance, USB device port, and DMA-driven peripherals fit well.
When designing with this MCU, budget Flash and SRAM conservatively: 256KB Flash and 49KB SRAM are ample for bare-metal or RTOS-based control firmware, but leave headroom for OTA-style field updates.
This page synthesizes distributor pricing, drop-in family alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATSAM3S4BA-AUR — 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-AUR (same form factor and footprint) — differing in RoHS Status, Core Processor, Package, Flash Memory, Packaging.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATSAM3S4AA-AUR
✅ Drop-In✓ In Stock
$5.42 / Unit
View Datasheet →ATSAM3SD8BA-AU
✅ Drop-In✓ In Stock
$8.05 / Unit
View Datasheet →ATSAM3N4BA-MU
✅ Drop-In✓ In Stock
$3.48 / Unit
View Datasheet →ATSAM3S4BA-AUR Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M3 (32-bit RISC) |
| Core Size | 32-bit |
| Maximum Clock Frequency | 64 MHz |
| Program Memory Size | 256KB (256K x 8) Flash |
| RAM Size | 49KB SRAM |
| Supply Voltage Range | 1.62 V to 3.6 V |
| Supply Voltage (Typical) | 1.8 V / 3.3 V |
| Connectivity | HSMCI, I2C, I2S, IrDA, SPI, SSC, TWI, UART, USART, USB |
| DMA | Yes (peripheral DMA controller) |
| Package | 64-LQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| Pin Count | 64 |
| Series | SAM3S (SAM3S4B) |
| Pin Compatibility | Pin-to-pin compatible with SAM3N4B and SAM7S64 |
| RoHS Status | Compliant (RoHS/Green per distributor listings) |
ATSAM3S4BA-AUR 64-lqfp (10x10 mm) Pin Configuration Guide
Pin configuration for ATSAM3S4BA-AUR (64-lqfp (10x10 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 ATSAM3S4BA-AUR.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAM3S4BA-AUR is suitable for 6 applications: Industrial Control Nodes, USB-Connected Sensor Interfaces, Portable and Battery-Powered Instruments, Consumer Appliance Control, Data Logging and Metering, IoT Edge Nodes and Gateways.
Industrial Control Nodes
The ATSAM3S4BA-AUR fits factory automation nodes, motor-control auxiliaries, and PLC I/O modules because its 64 MHz ARM Cortex-M3 core executes deterministic control loops while the DMA controller moves ADC and serial data to the 49KB SRAM without CPU stalls. Connectivity spans UART, USART, SPI, TWI (I2C), SSC, and IrDA, covering the standard industrial field-bus PHY layer interfaces. The 1.62V to 3.6V supply range tolerates noisy 3.3V rails, and the 256KB Flash stores ladder-logic interpreters plus communication stacks with headroom for field updates. Distributor listings classify this MCU as industrial temperature, matching DIN-rail and cabinet environments.
Recommended
USB-Connected Sensor Interfaces
With its integrated USB device port, the ATSAM3S4BA-AUR is well suited to benchtop instruments, data loggers, and USB sensor pods that stream measurements to a PC. The 64 MHz Cortex-M3 sustains USB enumeration and bulk-transfer firmware while the peripheral DMA feeds the endpoint buffers from SPI- or USART-attached front-end devices. The 256KB Flash holds the USB stack plus application logic, and the 49KB SRAM buffers acquisition bursts between host polls. Because the same footprint accepts the ATSAM3S4AA (no USB), a single PCB layout can serve both USB and non-USB product SKUs, cutting inventory complexity.
Recommended
Portable and Battery-Powered Instruments
Handheld meters and portable test devices benefit from the ATSAM3S4BA-AUR's 1.62V to 3.6V operating range, which maps directly onto single-cell Li-ion discharge curves through an LDO. The 64 MHz Cortex-M3 delivers compute bursts for filtering and calibration math, then the firmware can gate clocks to extend battery life between measurements. The HSMCI interface attaches SD-card storage for logged data, while the 256KB Flash keeps the full application on-chip with room for bootloaders supporting field firmware upgrades. The 10x10 mm 64-LQFP balances routing ease against board area in ergonomic handheld enclosures.
Recommended
Consumer Appliance Control
White-goods and small-appliance controllers use the ATSAM3S4BA-AUR to run touch-sense or rotary-encoder user interfaces, motor-assist PWM, and UART links to display modules. The Cortex-M3's 64 MHz performance comfortably handles a lightweight RTOS alongside the control tasks, and the SSC plus I2S peripherals support audio feedback and annunciator tones. RoHS-compliant green packaging meets consumer environmental requirements, and distributor volume pricing around $3.44 at 1000 units (as of 2026-09-19) supports cost-sensitive BOMs. The pin compatibility with SAM3N4B lets one hardware platform scale across feature tiers by swapping the MCU.
Recommended
Data Logging and Metering
Energy meters and environmental loggers leverage the ATSAM3S4BA-AUR's combination of HSMCI for SD-card storage, USART/UART for modem or RS-485 transceiver attachment, and TWI (I2C) for RTC and sensor access. The DMA engine transfers measurement data into the 49KB SRAM so the 64 MHz core can spend cycles on CRC, scaling, and tariff calculations rather than byte shuffling. The 256KB Flash retains calibration tables, logging firmware, and a bootloader for remotely updated firmware. The wide 1.62V to 3.6V input range simplifies power design from mains-derived or battery-backed rails in metering enclosures.
Recommended
IoT Edge Nodes and Gateways
As an edge node controller, the ATSAM3S4BA-AUR aggregates SPI- or UART-connected radio modules (sub-GHz, BLE, or LoRa) and sensors over TWI, buffering traffic in SRAM with DMA support. The 64 MHz Cortex-M3 runs protocol parsing, JSON/encryption preprocessing, and local control rules before offloading to the radio. Its 256KB Flash accommodates a TCP/IP or mesh stack plus OTA bootloader, and the 1.62V to 3.6V supply range fits both mains-adapter and battery designs. Distributor aggregation on Octopart across 7 sources eases long-term sourcing for multi-year IoT deployments requiring lifecycle continuity.
Recommended
Recommended Products Summary
Engineering reference data for ATSAM3S4BA-AUR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAM3S4AA-AUR | ATSAM3SD8BA-AU | ATSAM3N4BA-MU |
|---|---|---|---|---|
| Package | 64-LQFP (10x10 mm) | 64-LQFP (10x10 mm) - same | 64-LQFP (10x10 mm) - same | 64-QFN - pin-compatible family, different package body |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| 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 (SAM3N family) |
| USB Device Port | Yes | No | Yes | No |
Key Differentiators
- Integrated USB device port in a low-cost Cortex-M3 family (vs ATSAM3S4AA-AUR)
- Lower memory cost point than the 512KB sibling (vs ATSAM3SD8BA-AU)
- Documented pin-to-pin family migration path (vs ATSAM3N4BA-MU)
Design Notes
Estimated: The SAM3S series core draws low tens of milliamps at 64 MHz (typical Cortex-M3 class consumption); budget the 3.3V rail for roughly 50-80 mA peak including I/O, then add peripheral loads. Use a 10 uF bulk capacitor plus 0.1 uF ceramics at each VDDIO/VDDCORE pin pair, placed within 2 mm of the pins. The 1.62V minimum means a discharging Li-ion cell (down to 2.5-3.0 V) still regulates through a low-dropout LDO; verify the LDO dropout at your worst-case load current.
Route the USB D+/D- differential pair at 90 ohm differential impedance with matched lengths when using the USB device port, and keep the pair away from switching-regulator nodes. The 0.5 mm pitch 64-LQFP tolerates 0.1 mmtrace/0.1 mm space routing on a standard 4-layer board; a 2-layer board is feasible but plan return paths under high-speed traces. Provide a solid ground plane and stitch the exposed grounding around the crystal and analog pins.
Do not assume firmware portability between SAM3S and SAM3N despite pin compatibility: peripheral register maps and available peripherals differ, and the SAM3N lacks USB. Order the -AUR (tape and reel) suffix for automated assembly; -AU tray stock cannot be reeled at most contract manufacturers. Verify MSL handling requirements from the Microchip packing label before floor-life decisions, as baked-floor-life rules apply to 0.5 mm-pitch LQFP during reflow.
Compliance Information
Mouser listing describes the part as LQFP GREEN IND TEMP MRL A, indicating RoHS/green industrial-temperature packaging. Formal REACH and conflict-minerals declarations should be requested from Microchip.