ATSAM3S1BA-MU - 64MHz Cortex-M3 MCU, 64KB Flash | Microchip
MPN: ATSAM3S1BA-MU β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.06 | $5.06 |
| 10 | $4.55 | $45.50 |
| 100 | $3.79 | $379.00 |
| 500 | $2.51 | $1,255.00 |
| 1,000 | $1.53 | $1,530.00 |
ATSAM3S1BA-MU Overview
A microcontroller unit (MCU) is a single-chip computer that integrates a processor core, memory, and peripherals into one package. Within the power-management hierarchy of embedded systems, the MCU sits at the top: it orchestrates sensors, interfaces, and actuators. The SAM3S family is a member of Atmel's AT91SAM ARM-based flash MCU lineup and is pin-to-pin compatible with the earlier SAM7S series, enabling straightforward migration of legacy ARM7 designs.
Key features of the ATSAM3S1BA-MU include the high-performance ARM Cortex-M3 RISC core at 64 MHz, 64 KB (64K x 8) of on-chip flash, rich connectivity peripherals including I2C (TWI), SPI, USART/UART, SSC (synchronous serial controller), USB 2.0 full-speed device port, and MMC/SD card controller. The supply voltage range of 1.62V to 3.6V supports battery-powered designs directly from single-cell lithium or dual-cell alkaline rails.
Technically, the Cortex-M3 core provides a 3-stage pipeline, Harvard architecture, and a nested vectored interrupt controller (NVIC) with low, deterministic interrupt latency. The device integrates a power management controller (PMC) with multiple clock sources and sleep/back-up modes, supporting low-power applications. Flash and SRAM are on a fast bus matrix, allowing simultaneous peripheral and CPU access.
Typical applications include industrial control and automation nodes, consumer appliances with USB or SD-card interfaces, battery-powered metering, and touch-sensing human interface devices leveraging SAM3S peripheral support.
When designing, remember the flash memory of 64 KB is the smallest in the SAM3S family, so verify code size headroom or plan the pin-compatible upgrade path to 128 KB or 256 KB family members before committing the PCB layout.
This page synthesizes distributor pricing, drop-in alternatives, pin-compatibility guidance, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for ATSAM3S1BA-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 ATSAM3S1BA-MU (same form factor and footprint) β differing in SRAM, Core Processor, Package, Connectivity, Flash Memory.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAM3S2BA-MU
β Drop-Inπ Reference alternative (not in catalog)
ATSAM3S4BA-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$5.12 / Unit
View Datasheet βATSAM3S1BA-AUR
β Drop-Inπ Reference alternative (not in catalog)
ATSAM3S1BA-MU Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M3 |
| Core Size | 32-Bit |
| Maximum Clock Speed | 64 MHz |
| Flash Program Memory | 64 KB (64K x 8) |
| SRAM | 16 KB (16K x 8) |
| Supply Voltage Range | 1.62 V to 3.6 V |
| Package | 64-QFN (9x9 mm) |
| Mounting Type | Surface Mount |
| Connectivity | I2C, MMC, SPI, SSC, UART/USART, USB |
| Series | SAM3S |
| Program Memory Type | FLASH |
ATSAM3S1BA-MU 64-qfn (9x9 mm) Pin Configuration Guide
Pin configuration for ATSAM3S1BA-MU (64-qfn (9x9 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 ATSAM3S1BA-MU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAM3S1BA-MU is suitable for 6 applications: Industrial Control and Automation Nodes, USB Consumer Devices, Battery-Powered Metering, Touch-Sensing Human Interface Devices, Data Acquisition and Logger Systems, Legacy SAM7S Design Migration.
Industrial Control and Automation Nodes
The ATSAM3S1BA-MU fits industrial control nodes that need deterministic interrupt handling and robust serial connectivity. Its ARM Cortex-M3 core at 64 MHz with a nested vectored interrupt controller provides low, deterministic latency for real-time control loops, while the 1.62V to 3.6V supply range tolerates industrial rail fluctuations. The USART, SPI, and I2C (TWI) peripherals drive PLC expansion modules, motor-control front ends, and sensor concentrators over RS-485 or isolated links. The 64 KB flash accommodates ladder-logic interpreters or Modus-RTU stacks of modest size; teams needing headroom can drop in the pin-compatible 128 KB or 256 KB ATSAM3S2BA-MU or ATSAM3S4BA-MU without PCB changes. Power management controller sleep modes cut standby current between polling cycles in distributed I/O installations.
Recommended
USB Consumer Devices
Consumer products such as card readers, HID game controllers, and USB audio accessories benefit from the ATSAM3S1BA-MU integrated USB 2.0 full-speed device controller. Per Microchip USA product data, connectivity spans USB, USART, SSC, SPI, I2C, and MMC, allowing one chip to bridge a USB host to an SD card or audio codec without external protocol ICs. The 9x9 mm 64-QFN package keeps consumer PCB footprints compact, and the 3.3V-typical operation aligns with USB VBUS-derived rails through a simple LDO. The 64 KB flash is sufficient for HID and mass-storage class stacks; designs needing richer firmware can adopt the pin-compatible ATSAM3S4BA-MU. Deterministic Cortex-M3 interrupt behavior supports isochronous and interrupt endpoint timing requirements reliably in production firmware.
Recommended
Battery-Powered Metering
Utility metering and data-logger designs exploit the ATSAM3S1BA-MU wide 1.62V to 3.6V operating range, which permits direct connection to single-cell lithium or three-cell alkaline stacks with minimal regulation loss. The Cortex-M3 core at 64 MHz completes measurement and communication bursts quickly, then the power management controller places the chip in sleep or wait modes to stretch battery life between sampling intervals. The 16 KB SRAM retains measurement buffers, and the MMC/SD controller writes logged data to removable cards. The SSC peripheral interfaces precision ADC front ends over synchronous serial links. Because the part is pin-compatible across the SAM3S memory range, meter platforms can scale firmware (for example, adding encryption with the 256 KB ATSAM3S4BA-MU) on an unchanged PCB.
Recommended
Touch-Sensing Human Interface Devices
Human-interface panels such as appliance keypads and thermostats use the ATSAM3S1BA-MU GPIO matrix with charge-transfer touch sensing implemented in firmware, a common SAM3S design pattern. The 64 MHz Cortex-M3 core executes capacitive-sensing acquisition and filtering with margin to spare, while USART or USB reports touches to a host controller. The industrial-grade supply range of 1.62V to 3.6V allows operation directly from appliance electronics rails. The 64-QFN 9x9 mm package provides enough GPIO count for key matrices, LEDs, and buzzer outputs on a single chip, reducing bill-of-material cost. For panels requiring a certified touch library with more memory, designers can migrate to pin-compatible SAM3S family members with larger flash without touching the PCB layout.
Recommended
Data Acquisition and Logger Systems
Portable data-acquisition instruments leverage the ATSAM3S1BA-MU combination of SSC synchronous serial controller, multiple USARTs, and the SD-card-class MMC interface. Front-end ADCs stream samples over SSC or SPI into the 16 KB SRAM ring buffer, while the MMC controller spools data to removable media between acquisitions. The 64 MHz Cortex-M3 pipeline sustains kilohertz-rate streaming with time-stamping, and the wide supply range supports battery field operation. The 64 KB flash holds acquisition firmware, FAT file-system code, and a USB bulk-transfer bridge for host offload. Because 64 KB is the family minimum, instrument makers should compile early and budget headroom, or plan the pin-compatible 128 KB ATSAM3S2BA-MU as the stocking part to derisk firmware growth across product variants.
Recommended
Legacy SAM7S Design Migration
Products originally built on Atmel ARM7TDMI SAM7S microcontrollers can migrate to the ATSAM3S1BA-MU on the same PCB footprint, since the SAM3S series is explicitly pin-to-pin compatible with the SAM7S series per the Atmel datasheet. This addresses obsolete-part sourcing of SAM7S silicon while delivering a performance uplift: the Cortex-M3 core at 64 MHz provides significantly higher DMIPS than the ARM7 at comparable clock rates, with a modern NVIC interrupt architecture. Firmware requires recompilation for the Thumb-2 instruction set and adaptation to the updated peripheral register map, but board layout, connectors, and power design carry over. This migration path suits long-lifecycle appliances, test fixtures, and industrial subassemblies that must remain manufacturable for years.
Recommended
Recommended Products Summary
Engineering reference data for ATSAM3S1BA-MU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAM3S2BA-MU | ATSAM3S4BA-MU | ATSAM3S1BA-AUR |
|---|---|---|---|---|
| Package | 64-QFN (9x9 mm) | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same |
| Brand | Atmel (Microchip Technology) | Atmel (Microchip Technology) | Atmel (Microchip Technology) | Atmel (Microchip Technology) |
| Core / Speed | ARM Cortex-M3, 64 MHz | ARM Cortex-M3, 64 MHz | ARM Cortex-M3, 64 MHz | ARM Cortex-M3, 64 MHz |
| Flash Memory | 64 KB | 128 KB | 256 KB | 64 KB |
| SRAM | 16 KB | 16 KB | 16 KB | 16 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 |
| Packaging | Tray (MU suffix) | Tray | Tray | Tape & Reel |
Key Differentiators
- Lowest-cost member of the 64-QFN SAM3S family (vs ATSAM3S2BA-MU)
- Full backward footprint compatibility with SAM7S (vs AT91SAM7S64)
- Tape-and-reel variant available for automated assembly (vs ATSAM3S1BA-AUR)
Design Notes
Design the supply for the full 1.62V to 3.6V window. The SAM3S integrates an internal regulator that produces the 1.8V core supply (VDDCORE) from VDDIO, so all core decoupling specified in the datasheet power-supply section is mandatory; do not short VDDCORE to VDDIO. Estimated: at 3.3V VDDIO and typical 64 MHz active current in the tens of mA range, a 100 mA-rated LDO such as the MCP1700 provides comfortable margin for USB-transceiver surges and external peripheral loads on the same rail.
The 9x9 mm 64-QFN exposes a central thermal pad that must be soldered to a grounded copper pour with an array of thermal vias, both for heat dissipation and for the ground return of the internal regulator. Place 100 nF ceramic decoupling capacitors within 2 mm of each VDDIO pin pair plus bulk 4.7 uF to 10 uF at the supply entry. Follow the SAM3S datasheet layout example; QFN center-pad voiding is the most common assembly defect on this family.
Verify flash headroom before committing to the 64 KB part: with USB, FAT file-system, and application layers, 64 KB fills quickly. Because the part is obsolete, stock position matters more than unit price - confirm lot date codes from aftermarket suppliers such as Rochester Electronics, and qualify the pin-compatible ATSAM3S2BA-MU (128 KB) as the documented fallback so a second PCB spin is never required. Firmware written for SAM7S must be ported to the Cortex-M3 register map despite the shared footprint.
Compliance Information
Compliance status not stated in the provided web data; verify against the Microchip product page or the original Atmel datasheet environmental appendix before production use.
