ATSAM3N4BA-MU - 48MHz Cortex-M3 MCU, 256KB Flash | Microchip
MPN: ATSAM3N4BA-MU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.62 | $5.62 |
| 10 | $5.06 | $50.60 |
| 100 | $4.42 | $442.00 |
| 500 | $3.94 | $1,970.00 |
| 1,000 | $3.48 | $3,480.00 |
ATSAM3N4BA-MU Overview
A microcontroller unit (MCU) is a single integrated circuit that combines a processor core, memory, and programmable peripherals into one chip, forming the lowest tier of the embedded processing hierarchy that spans MCUs, microprocessors (MPUs), and systems-on-chip (SoCs). Within that hierarchy, the SAM3N series belongs to Microchip (formerly Atmel) ARM-based Flash MCU portfolio, positioned as the cost-reduced migration path from the SAM3S series for high-volume, cost-sensitive applications.
Key features include the ARM Cortex-M3 revision 2.0 core with Thumb-2 instruction set, a 24-bit SysTick timer, and a Nested Vector Interrupt Controller (NVIC). The embedded Flash uses a 128-bit wide access bus with a memory accelerator, sustaining near-zero-wait-state execution at the full 48 MHz clock rate. An internal oscillator eliminates the need for an external crystal in clock-tolerant designs, reducing bill-of-materials cost. Supply operation spans 1.8V to 3.3V, and the device is qualified for industrial temperatures from -40C to +85C.
Architecturally, the SAM3N is pin-to-pin compatible with the SAM3S series (48-, 64-, and 100-pin versions) and with legacy SAM7S products (48- and 64-pin versions), which means designers can migrate between the two families - trading peripheral count for lower BOM cost - without PCB rework. The MU suffix denotes the lead-free, RoHS-compliant QFN package in tray packaging.
Typical applications include industrial automation nodes, consumer electronics, and medical device peripherals - domains the manufacturer explicitly targets with this part. Its 47 I/O lines and peripheral set (USART, SPI, TWI, ADC) suit sensor aggregation, motor control interfaces, and human-machine interface boards.
A key design consideration: since the device runs from a single 1.8V to 3.3V rail, decouple each supply pin with 100 nF ceramics placed close to the exposed pad, and connect the QFN backside pad to a ground pour for thermal and signal-integrity performance.
This page synthesizes distributor pricing context, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATSAM3N4BA-MU β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAM3S4BA-MU
β Drop-Inπ Reference alternative (not in catalog)
ATSAM3N4AA-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAM3N2BA-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAM3N1BA-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAM3N4BA-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAM3N4BA-MU Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M3 revision 2.0 |
| Core Size | 32-bit |
| Maximum Clock Frequency | 48 MHz |
| Flash Memory Size | 256KB (256K x 8) |
| RAM Size | 24K x 8 |
| Number of I/O | 47 |
| Supply Voltage | 1.8 V to 3.3 V |
| Oscillator Type | Internal |
| Instruction Set | Thumb-2 |
| SysTick Timer | 24-bit |
| Interrupt Controller | NVIC (Nested Vector Interrupt Controller) |
| Package / Case | 64-QFN (9x9 mm) with exposed pad |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C |
| Packaging | Tray |
| Pin Compatibility | Pin-to-pin compatible with SAM3S (48/64/100-pin) and SAM7S (48/64-pin) |
| RoHS Status | Compliant (lead-free MU suffix) |
ATSAM3N4BA-MU 64-qfn (9x9 mm) with exposed pad Pin Configuration Guide
Pin configuration for ATSAM3N4BA-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 ATSAM3N4BA-MU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAM3N4BA-MU is suitable for 6 applications: Industrial Automation Nodes, Cost-Sensitive Consumer Electronics, Medical Device Peripherals, Legacy SAM7S Design Migration, Sensor Aggregation and Data Loggers, Human-Machine Interface Boards.
Industrial Automation Nodes
The ATSAM3N4BA-MU fits industrial automation nodes such as sensor concentrators, valve controllers, and remote I/O modules because its industrial -40C to +85C rating and 47 GPIO lines cover the environmental and connectivity demands of factory-floor equipment. The 48 MHz Cortex-M3 core with 128-bit Flash accelerator executes control loops and Modbus-style communication stacks deterministically, while the 24KB SRAM buffers sensor data and protocol frames. In this role the MCU typically interfaces with RS-485 transceivers via its USART and reads analog sensors through its ADC. Because the part operates from a wide 1.8V to 3.3V supply, it can share a rail with 3.3V logic and analog front ends, simplifying power-tree design in DIN-rail and cabinet-mounted hardware. Its pin compatibility with the SAM3S series also lets vendors offer a low-cost and a feature-rich SKU on one PCB, amortizing layout and certification costs across product tiers.
Recommended
Cost-Sensitive Consumer Electronics
Consumer products such as small appliances, chargers, toys, and smart-home accessories value unit cost above all, and the SAM3N series was created explicitly as the aggressive-price-point, reduced-BOM option in Microchip's ARM portfolio. The ATSAM3N4BA-MU contributes to that goal in two ways: its internal oscillator removes the external crystal from the bill of materials in clock-tolerant designs, and the 64-QFN (9x9 mm) package minimizes board area in compact enclosures. The 256KB Flash provides generous room for feature-rich firmware, OLED or segment-LCD driving, capacitive-touch handling, and Bluetooth/Wi-Fi module management over USART or SPI. Because the part runs at 1.8V to 3.3V, it pairs directly with single-cell lithium systems through an LDO. Products in this segment also benefit from the pin-to-pin SAM3S compatibility, allowing a performance upgrade path without a respin if a derivative product needs richer peripherals later in the product roadmap.
Recommended
Medical Device Peripherals
Benchtop and portable medical peripherals - patient-data hubs, glucose-meter docks, handheld diagnostic readers - benefit from the ATSAM3N4BA-MU's combination of 32-bit processing headroom and industrial-grade reliability. The 48 MHz Cortex-M3 core handles data aggregation from analog front ends over SPI or TWI, checksum-protected record storage in the 256KB Flash, and USB- or UART-based communication with a host. Its -40C to +85C operating envelope exceeds the requirements of clinical environments, providing margin for autoclave-adjacent and logistics stress. The device's low-supply operation (down to 1.8V) supports battery-powered portable units where cell voltage sags toward end of life, extending usable runtime. Designers should note that medical certifications apply to the end product, not the MCU; however, the long-lifecycle SAM3N family and Microchip's documented migration path from SAM7S help satisfy regulatory expectations for component availability over a decade-long product service life.
Recommended
Legacy SAM7S Design Migration
Many installed products still use Atmel SAM7S (ARM7TDMI) microcontrollers, and the ATSAM3N4BA-MU is documented as pin-to-pin compatible with SAM7S devices in the 48- and 64-pin versions. This makes it the natural modernization vehicle: the existing PCB, connectors, and mechanical design remain untouched while the core moves from ARM7 to the more efficient Cortex-M3 with Thumb-2 code density, improving performance-per-mA and reducing code size. The migration is a firmware port rather than a recompile - peripheral register maps differ - but Microchip provides migration documentation across the SAM7/SAM3 families. The 256KB Flash of the SAM3N4BA comfortably exceeds the 64KB to 256KB typical of legacy SAM7S parts, giving headroom for added features such as encrypted bootloaders, richer UIs, or expanded protocol stacks. Sites maintaining long-life industrial or medical products should evaluate this drop-in footprint path before any board respin.
Recommended
Sensor Aggregation and Data Loggers
Battery-powered data loggers and wireless sensor nodes exploit the ATSAM3N4BA-MU's 47 I/O lines and mixed peripheral set to poll multiple sensor types simultaneously - I2C environmental sensors on TWI, SPI flash for local buffering, and analog channels through the on-chip ADC. The 128-bit-wide Flash with memory accelerator means wake-up code and ISRs execute quickly from stop modes, shortening the active duty cycle that dominates logger battery life. Its 24KB SRAM holds time-stamped sample buffers between radio or SD-card bursts. Supplying the MCU from 1.8V in single-cell designs, or 3.3V where sensors require it, is supported across the full -40C to +85C range for outdoor deployments. Because the internal oscillator drives the clock tree, designs can omit the crystal and its associated startup energy, further reducing average current - a measurable benefit at multi-month battery lifetimes typical of environmental monitoring products.
Recommended
Human-Machine Interface Boards
HMI boards for white goods, industrial panels, and building controls use the ATSAM3N4BA-MU to drive segment LCDs or small TFT modules over SPI, scan keypads across the 47 GPIO lines, manage backlight PWM, and talk to a main controller or cloud gateway over USART. The 48 MHz Cortex-M3 core has ample throughput for touch-debounce logic, display refresh, and menu state machines while maintaining responsive interrupt latency via the NVIC. Its industrial temperature rating suits enclosures mounted in garages, panels, and outdoor walls. The 256KB Flash stores multi-language string tables, glyph bitmaps, and OTA-updatable firmware with a dual-image scheme, a common requirement in connected appliances. Designers should decouple each supply pin with 100 nF ceramics and solder the QFN exposed pad to a ground pour, since display drivers on the same rail inject switching noise that good local bypassing keeps out of the ADC and analog comparator readings.
Recommended
Recommended Products Summary
Engineering reference data for ATSAM3N4BA-MU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAM3S4BA-MU | ATSAM3N4AA-MU | ATSAM3N2BA-MU | ATSAM3N1BA-MU |
|---|---|---|---|---|---|
| Package | 64-QFN (9x9) with exposed pad | 64-QFN (9x9) - same footprint | 64-QFN (9x9) - same footprint | 64-QFN (9x9) - same footprint | 64-QFN (9x9) - same footprint |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Core | ARM Cortex-M3 rev 2.0, 48 MHz | ARM Cortex-M3, 48 MHz | ARM Cortex-M3, 48 MHz | ARM Cortex-M3, 48 MHz | ARM Cortex-M3, 48 MHz |
| Flash Memory | 256KB | 256KB | 256KB | 128KB | 64KB |
| SRAM | 24KB | 24KB | 24KB | 24KB | 16KB |
| Pin Compatibility | SAM3S (48/64/100-pin), SAM7S (48/64-pin) | Pin-to-pin compatible with SAM3N | Same SAM3N family pinout | Same SAM3N family pinout | Same SAM3N family pinout |
| Series Positioning | SAM3N - cost-reduced BOM path | SAM3S - fuller peripheral integration | SAM3N - same tier | SAM3N - lower memory tier | SAM3N - lowest memory/cost tier |
| Operating Temperature | -40C to +85C (industrial) | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Key Differentiators
- Lowest BOM cost within the pin-compatible family (vs ATSAM3S4BA-MU)
- Full 256KB Flash at the family memory top (vs ATSAM3N2BA-MU)
- Direct legacy ARM7 modernization path (vs ATSAM3N4AA-MU)
- Trade-off: reduced peripheral set (vs ATSAM3S4BA-MU)
Design Notes
The 64-QFN (9x9 mm) package has an exposed die-attach pad on the bottom side that must be soldered to a grounded copper pour. Define the PCB land pattern with an array of thermal vias (0.3 mm drill, filled or tented) connecting the pad to internal ground planes. This grounding serves double duty: it removes heat from the die and provides a low-inductance return path that improves signal integrity on fast I/O edges. Follow the Microchip QFN land-pattern application guidance for solder-mask-defined versus non-solder-mask-defined pads to ensure reliable reflow wetting of the center pad.
Place one 100 nF ceramic capacitor at each VDD/VDDIO pin pair, as physically close to the pins as routing allows, plus one bulk capacitor of 4.7 uF to 10 uF near the device. The device operates from 1.8 V to 3.3 V; at the low end of this range, consult the datasheet electrical characteristics for any derating of maximum frequency and analog performance before committing to a 1.8 V rail. The internal oscillator eliminates the external crystal and its load capacitors in clock-tolerant applications, removing both BOM cost and an oscillator start-up failure mode.
When migrating from SAM7S or SAM3S parts onto the same footprint, do not assume firmware compatibility: the Cortex-M3 core and peripheral register maps differ from the ARM7TDMI SAM7S, so the code must be ported even though the PCB is unchanged. Verify that every peripheral used by the application exists in the SAM3N peripheral set, since the series trades some peripherals for lower cost relative to SAM3S. Finally, confirm the datasheet pinout for the 64-pin option pin-by-pin before releasing the footprint - pins can differ between the QFN (MU) and TQFP (AU) package variants.
Compliance Information
The MU package suffix denotes Microchip/Atmel matte-tin lead-free RoHS-compliant packaging. REACH, halogen-free, and conflict-minerals declarations were not stated in the verified web data.
