ATMEGA3250A-MN - 8-bit AVR MCU 32KB Flash 64QFN | Microchip
MPN: ATMEGA3250A-MN β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
ATMEGA3250A-MN Overview
An 8-bit AVR microcontroller is a single-chip computer built around the AVR enhanced RISC architecture, executing most instructions in a single clock cycle. Within the power-management hierarchy, an MCU such as the ATmega3250A sits at the top of the embedded control stack: it combines a processor core, program memory, data memory, and peripherals (timers, USART, SPI, JTAG) on one die, replacing multi-chip processor-plus-memory solutions in cost- and power-sensitive systems.
Key features include the 32 KB in-system-programmable Flash with read-while-write support for field firmware updates, 1 KB of non-volatile EEPROM for parameter storage, and up to 69 GPIO lines that suit large keypads, displays, and multi-board control. The device integrates a JTAG interface for on-chip debugging and boundary-scan, plus SPI and USART serial connectivity. A brown-out detector and internal RC oscillator options reduce external component count.
Technically, the AVR core uses a Harvard architecture with 32 general-purpose working registers directly connected to the ALU, allowing one-cycle execution of most instructions and delivering up to 20 MIPS throughput at 20 MHz. Boot-section Flash supports self-programming for in-application upgrades.
Typical applications include industrial control panels, building automation nodes, LCD-based instrumentation, and consumer appliance controllers where rich I/O and code densities near 32 KB are required.
Design consideration: verify the supply-voltage and clock configuration against the manufacturer datasheet before layout, since the MN (QFN) package thermal pad must be soldered to a ground plane for reliable operation.
This page synthesizes distributor availability, drop-in family alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA3250A-MN 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:
ATMEGA3250P-MN
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA3250PA-MN
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA6450A-MN
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA6450P-MN
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA3250A-MN Maximum Ratings & Electrical Characteristics
| Core Processor | AVR 8-bit RISC |
| Core Size | 8-bit |
| Flash Memory | 32 KB ISP Flash (read-while-write) |
| EEPROM | 1 KB |
| SRAM | 2 KB |
| General Purpose I/O | 54/69 lines |
| Working Registers | 32 general purpose |
| Connectivity | SPI, UART/USART |
| Debug Interface | JTAG (boundary-scan) |
| Peripherals | Brown-out detect/reset, POR, WDT |
| Operating Temperature | up to 105 C (per distributor listing) |
| Package | 64-QFN (MN) |
| Mounting Type | Surface Mount |
| Programmability | In-System Programmable (ISP), self-programming boot section |
| Green Package | Yes (green/RoHS variant per AiPCBA listing) |
ATMEGA3250A-MN yes (green/rohs variant per aipcba listing) Pin Configuration Guide
Pin configuration for ATMEGA3250A-MN (yes (green/rohs variant per aipcba listing) 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 ATMEGA3250A-MN.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA3250A-MN is suitable for 6 applications: Industrial Control Panels, Building Automation Nodes, LCD Instrumentation and Metering, Consumer Appliance Controllers, Access Control and Security Systems, Prototyping and Legacy Design Maintenance.
Industrial Control Panels
The ATMEGA3250A-MN fits industrial control panels because its 69 general-purpose I/O lines drive button matrices, relay banks, and status LEDs directly without port expanders, while 32 KB ISP Flash with read-while-write allows field firmware updates over a USART bootloader. The JTAG boundary-scan capability supports production test of densely populated boards, and the 1 KB EEPROM retains calibration constants across power cycles. Typical deployment places the MCU between a 24 V I/O isolation front end and a local 5 V rail, with SPI linking to ADCs or RTCs. The green 105 C-rated QFN variant tolerates enclosed-panel temperatures, and brown-out detection ensures deterministic reset during supply dips.
Recommended
Building Automation Nodes
In building automation, the ATMEGA3250A-MN serves as a zone controller where its large GPIO count handles occupancy sensors, damper actuators, and keypad input on one chip. The USART supports RS-485 transceiver attachment for multi-drop networks, and SPI connects external EEPROM or real-time clocks. Because the 32 KB Flash self-programs from a boot section, installers can update firmware remotely in the field without a programmer on site. The picoPower ATMEGA3250P-MN sibling can be substituted where battery-backed sensors require microamp sleep currents, using the same PCB footprint. Brown-out reset plus watchdog timer guarantees recovery from power glitches common in large buildings.
Recommended
LCD Instrumentation and Metering
The ATmega3250 family is designed around LCD control, and the ATMEGA3250A-MN suits panel meters and handheld instruments needing many segment drive lines plus ADC-based measurement. Its 2 KB SRAM buffers display frames and averaging windows, while the 32 general-purpose registers let the AVR core sustain single-cycle arithmetic for filtering. The 64-QFN package's exposed pad provides a solid ground reference that reduces measurement noise coupling into analog front ends. Combined with a precision voltage reference over SPI, the device implements energy or process meters where the 1 KB EEPROM stores accumulated registers safely. JTAG debugging shortens firmware bring-up for display-heavy code.
Recommended
Consumer Appliance Controllers
For washing machines, cookers, and HVAC appliances, the ATMEGA3250A-MN offers a cost-effective single-chip solution combining user-interface scanning (up to 69 I/O), actuator control via timers, and serial links to inverter or sensor boards. The 32 KB Flash accommodates multi-language UI code and state machines, and read-while-write Flash permits saving the last cycle state to the boot area or EEPROM after a power interruption. The green 64-QFN package supports lead-free reflow in high-volume assembly. Its 8-bit AVR core at 20 MIPS-class throughput is sufficient for motor sequencing and temperature regulation loops without a more expensive 32-bit MCU.
Recommended
Access Control and Security Systems
Door controllers and small security panels benefit from the ATMEGA3250A-MN's keypad-scanning I/O count, USART for Wiegand or RS-485 interfaces, and 1 KB EEPROM for storing credential tables through power outages. The lock-bit Flash protection keeps access logic and keys from being read out of the chip, an important IP and security feature. JTAG boundary-scan eases ICT coverage on boards with dense connectors, though production units typically disable JTAGEN via fuses to free shared pins. The 105 C-capable green package variant suits enclosures mounted near door strikes or in ceilings where ambient temperature rise is common.
Recommended
Prototyping and Legacy Design Maintenance
Because the ATmega325/3250 family remains in Microchip's active catalog and shares toolchains (AVR GCC, MPLAB X, AVR Studio lineage) with other AVRs, the ATMEGA3250A-MN is a practical platform for maintaining legacy AVR designs and university/embedded training boards. The 64-QFN footprint can be adapted with QFN-to-DIP adapter boards for bench development, and JTAG on-chip debugging gives full visibility during prototyping. Designers refreshing older ATmega3250-16AU TQFP boards can keep firmware nearly unchanged while choosing the QFN MN package for new layouts, since the die and register map are common across the family datasheet.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA3250A-MN β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA3250P-MN | ATMEGA3250PA-MN | ATMEGA6450A-MN | ATMEGA6450P-MN |
|---|---|---|---|---|---|
| Package | 64-QFN (MN) | 64-QFN (MN) - same | 64-QFN (MN) - same | 64-QFN (MN) - same | 64-QFN (MN) - same |
| Brand | Microchip Technology (Atmel) | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 64 KB | 64 KB |
| Power Technology | Standard AVR (ATmega3250A) | picoPower | picoPower | Standard | picoPower |
| GPIO Lines | 54/69 | 54/69 | 54/69 | 54/69 | 54/69 |
| JTAG / Debug | Yes (JTAG + boundary-scan) | Yes | Yes | Yes | Yes |
Key Differentiators
- Balanced 32 KB Flash / 2 KB SRAM configuration (vs ATMEGA6450A-MN)
- Standard AVR power profile (vs ATMEGA3250P-MN)
- 69 GPIO with JTAG boundary-scan (vs ATMEGA3250PA-MN)
Design Notes
The 64-QFN (MN) package has an exposed center pad that must be soldered to ground. Use a segmented stencil aperture on the center pad (about 50-70% paste coverage) to prevent the part floating or bridging during reflow, and place a 5x5 (or finer) via array under the pad tied to the ground plane. This gives both heat spreading and a low-inductance ground return for the AVR core and I/O rings, which improves EMC and signal integrity on the SPI and USART lines.
Decouple each VCC/AVCC pin pair with 100 nF ceramic capacitors placed within a few millimeters of the pins, plus one bulk 4.7-10 uF capacitor near the supply entry. Connect AVCC to VCC through a low-pass filter (for example 10 ohm in series with 100 nF) when the ADC is used, to keep analog measurements free of digital switching noise. Verify the exact supply-voltage operating range against the family datasheet before layout freeze, as this page's web data did not capture it.
JTAG pins are shared with Port C GPIO. If JTAG is not needed in production, clear the JTAGEN fuse to release the pins, otherwise the corresponding I/O will not function. When substituting ATMEGA3250A-MN with picoPower P-variants or 64 KB 6450 variants, re-check fuse defaults and clock configuration since register/fuse maps can differ slightly across family revisions. Always confirm package marking and temperature grade when mixing stock from multiple distributors.
Compliance Information
AiPCBA distributor listing describes the part as a Green package (20MHz QFN 105C, Green), indicating RoHS/lead-free construction. Formal REACH and conflict-minerals declarations should be confirmed via Microchip's official environmental documentation.
