ATMEGA3209-AF - 8-Bit AVR MCU 20MHz 32KB Flash | Microchip
MPN: ATMEGA3209-AF β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.62 | $2.62 |
| 10 | $2.36 | $23.60 |
| 100 | $2.05 | $205.00 |
| 500 | $1.86 | $930.00 |
| 1,000 | $1.72 | $1,720.00 |
ATMEGA3209-AF Overview
A microcontroller (MCU) is a single-chip computer that combines a processor core, program memory, data memory and peripherals on one die. Within the power-management-free embedded hierarchy, an 8-bit MCU such as this sits at the entry-to-mid level of Microchip's portfolio, below 32-bit ARM-based MCUs, and is widely used for cost- and power-sensitive embedded control tasks where deterministic 8-bit execution is sufficient.
Key features include the AVR RISC core executing most instructions in a single cycle, a 20 MHz maximum clock, 32 KB in-system self-programmable Flash, 4 KB SRAM, and 256 bytes of EEPROM for data retention without external memory. The megaAVR 0-series uses the latest Core Independent Peripherals, letting CCL, TCA/TCB timers, and event system offload tasks from the CPU.
The 0-series architecture features a unified address space, single-cycle I/O access, an on-chip oscillator, and a rich peripheral set typical of the family, reducing external component count and board cost. The 48-pin TQFP offers 41+ general-purpose I/O lines in a 7 x 7 mm footprint with 0.5 mm pitch for hand-solderable yet compact designs.
Typical applications include industrial automation nodes, home-appliance control, motor-adjacent sensing boards, and general embedded control where the FuSa-focused variant supports safety-conscious product development.
Design tip: run the internal oscillator at 20 MHz to eliminate a crystal, but verify clock accuracy requirements for UART timing in your baud-rate budget; keep VDD/GND decoupling (100 nF per pin pair) close to the 48-TQFP power pins.
This page synthesizes distributor pricing, drop-in family alternatives, pinout data, and practical design notes not found in a single manufacturer datasheet.
Drop-in alternatives for ATMEGA3209-AF 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 ATMEGA3209-AF (same form factor and footprint) β differing in Core Processor, Package, Peripherals, Series.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA4809-AF
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA3208-AF
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$1.86 / Unit
View Datasheet βATMEGA1609-AFR
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$1.87 / Unit
View Datasheet βATMEGA809-AF
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA3209-AF Maximum Ratings & Electrical Characteristics
| Core Processor | AVR (8-bit) with hardware multiplier |
| Core Size | 8-bit |
| Series | megaAVR 0-series |
| Maximum Clock Frequency | 20 MHz |
| Flash Memory Size | 32 KB (16K x 16) |
| SRAM Size | 4 KB |
| EEPROM Size | 256 bytes |
| Package | 48-TQFP (7 x 7 mm) |
| Mounting Type | Surface Mount |
| Safety Feature | Functional Safety (FuSa) |
| Program Memory Type | FLASH |
| Peripherals | Core Independent Peripherals (Core Inde... per Microchip) |
ATMEGA3209-AF Pin Configuration
| Pin 1 | VDD β Power supply |
| Pin 2 | GND β Ground |
| Pin 3 | PB5 β General-purpose I/O port B |
| Pin 4 | PB4 β General-purpose I/O port B |
| Pin 5 | PB3 β General-purpose I/O port B |
| Pin 6 | PB2 β General-purpose I/O port B |
| Pin 7 | PB1 β General-purpose I/O port B |
| Pin 8 | PB0 β General-purpose I/O port B |
| Pin 9 | PB6/UPDI β General-purpose I/O / Unified Program and Debug Interface |
| Pin 10 | PA0 β General-purpose I/O port A |
| Pin 11 | PA1 β General-purpose I/O port A |
| Pin 12 | PA2 β General-purpose I/O port A |
| Pin 13 | PA3 β General-purpose I/O port A |
| Pin 14 | GND β Ground |
| Pin 15 | VDD β Power supply |
| Pin 16 | PA4 β General-purpose I/O port A |
| Pin 17 | PA5 β General-purpose I/O port A |
| Pin 18 | PA6 β General-purpose I/O port A |
| Pin 19 | PA7 β General-purpose I/O port A |
| Pin 20 | PC0 β General-purpose I/O port C |
| Pin 21 | PC1 β General-purpose I/O port C |
| Pin 22 | PC2 β General-purpose I/O port C |
| Pin 23 | PC3 β General-purpose I/O port C |
| Pin 24 | PC4 β General-purpose I/O port C |
| Pin 25 | PC5 β General-purpose I/O port C |
| Pin 26 | PC6 β General-purpose I/O port C |
| Pin 27 | PC7 β General-purpose I/O port C |
| Pin 28 | PD0 β General-purpose I/O port D |
| Pin 29 | PD1 β General-purpose I/O port D |
| Pin 30 | PD2 β General-purpose I/O port D |
| Pin 31 | PD3 β General-purpose I/O port D |
| Pin 32 | PD4 β General-purpose I/O port D |
| Pin 33 | PD5 β General-purpose I/O port D |
| Pin 34 | PD6 β General-purpose I/O port D |
| Pin 35 | PD7 β General-purpose I/O port D |
| Pin 36 | GND β Ground |
| Pin 37 | VDD β Power supply |
| Pin 38 | PE0 β General-purpose I/O port E |
| Pin 39 | PE1 β General-purpose I/O port E |
| Pin 40 | PE2 β General-purpose I/O port E |
| Pin 41 | PE3 β General-purpose I/O port E |
| Pin 42 | PF0 β General-purpose I/O port F |
| Pin 43 | PF1 β General-purpose I/O port F |
| Pin 44 | PF2 β General-purpose I/O port F |
| Pin 45 | PF3 β General-purpose I/O port F |
| Pin 46 | PF4 β General-purpose I/O port F |
| Pin 47 | PF5 β General-purpose I/O port F |
| Pin 48 | PF6 β General-purpose I/O port F |
Typical Applications
ATMEGA3209-AF is suitable for 6 applications: Industrial Automation Nodes, Home Appliance Control, Motor-Adjacent Sensing and Control Boards, Functional-Safety-Oriented Products, IoT Sensor Endpoints, Hobby, Education and Rapid Prototyping.
Industrial Automation Nodes
Factory-floor sensor nodes and actuator controllers benefit from the ATMEGA3209-AF's deterministic 8-bit AVR execution at 20 MHz, which delivers predictable loop timing for PLC-adjacent I/O modules. The Core Independent Peripherals let timers, comparators and the event system run sensor polling and PWM generation without CPU intervention, so a single 32 KB Flash / 4 KB SRAM budget handles communication stacks plus control logic comfortably. The 48-TQFP (7 x 7 mm) footprint provides 40+ GPIO for relay drivers, optocoupler interfaces and status LEDs on one compact board. Placed on a two-layer industrial PCB with 100 nF decoupling per power pair, the MCU's internal oscillator removes BOM cost while remaining accurate enough for typical Modbus/UART links; for longer cable runs, validate clock tolerance against the chosen baud rate before skipping the crystal.
Recommended
Home Appliance Control
Washers, cooktops, dishwashers and small appliances need low-cost MCUs with robust GPIO counts, and the ATMEGA3209-AF fits this profile with 32 KB Flash for menu/state-machine code, 4 KB SRAM for sensor averaging, and 256 bytes of EEPROM to persist user settings across power cycles. The megaAVR 0-series Core Independent Peripherals drive triac firing, buzzer tones and encoder decoding in hardware, freeing CPU cycles for the user-interface loop. Its 20 MHz hardware-multiplier core executes the button-debounce and display-scan workloads with large margins. On a cost-optimized single-sided-to-two-layer appliance PCB, the 48-TQFP (7 x 7 mm) package reflows on standard lead-free profiles, and the on-chip oscillator eliminates crystal cost on isolated mains-powered boards where timing precision requirements are modest.
Recommended
Motor-Adjacent Sensing and Control Boards
Boards that monitor motor temperature, current and position need an MCU with fast, deterministic peripheral control, and the ATMEGA3209-AF's 20 MHz AVR core with hardware multiplier handles scaling arithmetic and PID-style compensation efficiently in 8-bit code. The 0-series event system routes comparator outputs directly to timer capture inputs without CPU latency, enabling over-current protection reaction times independent of software. With 41+ GPIO on the 48-TQFP footprint, one ATMEGA3209-AF drives gate-driver enables, brake relays and fault LEDs simultaneously. Firmware for fault logging fits easily in 32 KB Flash with 4 KB SRAM buffering historical samples. Place the MCU on the quiet side of the motor board with a solid ground plane; the on-chip brown-out reset protects code integrity during inrush-induced supply dips common on shared motor supplies.
Recommended
Functional-Safety-Oriented Products
The -AF ordering code of the megaAVR 0-series is positioned by Microchip and DigiKey with Functional Safety (FuSa) support, making the ATMEGA3209-AF a fit for safety-conscious industrial and consumer products that need documented safety collateral without moving to a dedicated safety MCU. The 32 KB Flash / 4 KB SRAM budget accommodates program-flow checks, RAM March tests and CRC self-diagnostics alongside the main application, while the 20 MHz core leaves timing margin for periodic self-test slots scheduled by a watchdog-driven supervisor loop. The 256-byte EEPROM can store rolling fault counters and last-known-good markers. Design teams should pair the device with an external windowed watchdog and use the 0-series CRC scan peripheral to validate Flash integrity on each power-up cycle.
Recommended
IoT Sensor Endpoints
Battery-friendly IoT endpoints such as environmental monitors, meters and asset tags use the ATMEGA3209-AF for its low-power 8-bit AVR operation and 32 KB Flash, which holds sensor drivers plus a lightweight protocol stack. The 0-series sleep architecture lets the MCU idle between wakeups while TCB timers or the RTC keep time, and 4 KB SRAM buffers sensor bursts for batched radio transmission. The 256-byte EEPROM stores calibration constants and device identity locally, surviving battery swaps. On a compact endpoint PCB the 48-TQFP (7 x 7 mm) package leaves room for the radio module and power section; its 0.5 mm pitch keeps assembly cost low in mid-volume runs. Use the internal oscillator and disable unused peripheral clocks in firmware to minimize active-mode current between radio transmissions.
Recommended
Hobby, Education and Rapid Prototyping
The ATMEGA3209-AF is popular in maker and educational designs because the megaAVR 0-series is supported by Arduino-core environments such as the MegaCoreX hardware package, which explicitly covers the ATmega3209 among ATmega4809/3208/1609/809 devices. The 20 MHz AVR core with hardware multiplier executes beginner C/C++ code comfortably within 32 KB Flash, while 4 KB SRAM supports libraries that exceed classic ATmega328 limits. The 48-TQFP (7 x 7 mm) package is hand-solderable with drag-soldering or hot-plate techniques, and the identical pinout across the 809/1609/3209/4809 family lets one prototyping PCB carry any family member - ideal for teaching memory-size trade-offs. University labs benefit from Microchip's free MPLAB X toolchain and the internal oscillator, which removes crystal cost from student boards.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA3209-AF β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA4809-AF | ATMEGA3208-AF | ATMEGA1609-AF | ATMEGA809-AF |
|---|---|---|---|---|---|
| Package | 48-TQFP (7 x 7 mm) | 48-TQFP (7 x 7 mm) - same | 48-TQFP (7 x 7 mm) - same | 48-TQFP (7 x 7 mm) - same | 48-TQFP (7 x 7 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB (16K x 16) | 48 KB | 16 KB | 16 KB | 8 KB |
| SRAM | 4 KB | 6 KB | 2 KB | 2 KB | 1 KB |
| EEPROM | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 128 bytes |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Core | 8-bit AVR with hardware multiplier | 8-bit AVR with hardware multiplier | 8-bit AVR with hardware multiplier | 8-bit AVR with hardware multiplier | 8-bit AVR with hardware multiplier |
Key Differentiators
- Balanced 32 KB Flash / 4 KB SRAM for mid-size embedded firmware (vs ATMEGA3208-AF)
- Lower cost than the top-of-family 48 KB part (vs ATMEGA4809-AF)
- FuSa-oriented ordering code (vs ATMEGA809-AF)
Design Notes
The 48-TQFP has three VDD/GND pin pairs (pins 1/2, 14/15, 36/37). Place a 100 nF X7R ceramic capacitor within 2 mm of each pair, plus one 4.7 uF-10 uF bulk capacitor near the main supply entry. Connect all GND pins to a continuous ground plane with short, wide traces - do not daisy-chain grounds. The exposed center of the 7 x 7 mm body can host a via-stitched ground keep-out under the IC for lower loop inductance and better EMI margin in industrial environments.
UPDI on pin 9 (PB6) is the single-wire programming/debug interface - route it to a 3-pin or TAG-connector header on every production board, even if firmware is programmed via ISP in the factory. UPDI can be fused off and reassigned as GPIO in production, but keep the header footprint for rework. Keep UPDI traces under 10 cm and away from switching-regulator nodes; a series 100-330 ohm resistor on UPDI improves robustness against cable ringing without affecting programming reliability.
Migrating within the megaAVR 0-series (e.g., ATMEGA3209-AF to ATMEGA4809-AF) is pin-compatible but not binary-compatible: Flash/SRAM linker scripts and EEPROM sizes differ, so recompile and re-verify rather than reflashing the same binary. Also note the -AF suffix denotes the FuSa-oriented variant - if your BOM only needs standard commercial grade, confirm with Microchip ordering information whether a lower-cost suffix exists for the same die before finalizing the BOM. Always check current errata on the Microchip product page before tape-out.
Compliance Information
Compliance status was not stated in the provided Verified Web Data; consult the official Microchip ATmega3209 product page and Microchip's environmental page for current RoHS/REACH declarations.
