ATMEGA809-AUR - 8KB AVR MCU 20MHz TQFP-48 | Microchip
MPN: ATMEGA809-AUR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.65 | $1.65 |
| 10 | $1.48 | $14.80 |
| 100 | $1.28 | $128.00 |
| 500 | $1.12 | $560.00 |
| 1,000 | $0.98 | $980.00 |
ATMEGA809-AUR Overview
A microcontroller (MCU) is a single integrated circuit that combines a processor core, program memory, data memory and peripherals into one chip, sitting at the lowest level of the embedded-system hierarchy: microcontroller -> embedded processor -> system-on-chip -> computing system. The megaAVR 0-series is Microchip's modern AVR family built around Core Independent Peripherals, meaning timers, comparators and communication blocks can operate without CPU intervention via the Event System.
Key features include the 8 KB self-programming Flash with EEPROM emulation, 1 KB SRAM, a 10-bit ADC with up to 16 multiplexed channels, three USARTs, and hardware multiplier support for efficient 8x8 arithmetic. The AVR core executes most instructions in a single cycle, delivering strong real-time determinism at 20 MHz.
Technical depth comes from the Event System, which routes peripheral signals (timer overflows, ADC results, comparator outputs) directly to other peripherals without CPU load, reducing latency and power. Sleep modes down to microamp levels, a configurable low-frequency oscillator, and a Peripheral Touch Controller support low-power and capacitive-touch designs. Functional Safety (FuSa) documentation is available for safety-oriented applications.
Typical applications include industrial control and automation nodes, consumer appliance interfaces, motor-control辅助 logic, and IoT sensor end nodes where 20 MHz 8-bit performance, low power and rich analog peripherals fit the bill.
Design consideration: the ATMEGA809-AUR is supplied in the 48-pin TQFP (7x7), so plan a decoupling capacitor on each VDD pin and route the single-wire UPDI debug/programming pin to a header for in-system programming.
This page synthesizes distributor pricing, drop-in megaAVR 0-series alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for ATMEGA809-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 ATMEGA809-AUR (same form factor and footprint) — differing in ADC Resolution, Core Processor, Number of I/O, RoHS Status, Series.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA1609-AUR
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.51 / Unit
View Datasheet →ATMEGA3209-AUR
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
ATMEGA4809-AUR
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
ATMEGA809-AUR Maximum Ratings & Electrical Characteristics
| Core Processor | AVR (8-bit) |
| Core Size | 8-bit |
| Speed | 20 MHz |
| Flash Memory | 8 KB (8K x 8) |
| SRAM | 1 KB |
| EEPROM | 256 bytes |
| Hardware Multiplier | Yes |
| Series | megaAVR 0 (Functional Safety / FuSa) |
| Package | 48-TQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (industrial) |
| Number of I/O | 41 GPIO |
| ADC Resolution | 10-bit |
| USART Peripherals | 3 |
| Programming Interface | UPDI (single-wire) |
| Event System | Yes (Core Independent Peripherals) |
| RoHS Status | Compliant |
ATMEGA809-AUR Pin Configuration
| Pin 1 | PB5 — Port B bit 5 (GPIO / analog / digital peripheral functions) |
| Pin 2 | PB4 — Port B bit 4 (GPIO / analog / digital peripheral functions) |
| Pin 3 | PB3 — Port B bit 3 (GPIO / analog / digital peripheral functions) |
| Pin 4 | PB2 — Port B bit 2 (GPIO / analog / digital peripheral functions) |
| Pin 5 | PB1 — Port B bit 1 (GPIO / analog / digital peripheral functions) |
| Pin 6 | PB0 — Port B bit 0 (GPIO / analog / digital peripheral functions) |
| Pin 7 | VDD — Power supply |
| Pin 8 | GND — Ground |
| Pin 9 | PD7 — Port D bit 7 (GPIO / digital peripheral functions) |
| Pin 10 | PD6 — Port D bit 6 (GPIO / digital peripheral functions) |
| Pin 11 | PD5 — Port D bit 5 (GPIO / digital peripheral functions) |
| Pin 12 | PD4 — Port D bit 4 (GPIO / digital peripheral functions) |
| Pin 13 | PD3 — Port D bit 3 (GPIO / digital peripheral functions) |
| Pin 14 | PD2 — Port D bit 2 (GPIO / digital peripheral functions) |
| Pin 15 | PD1 — Port D bit 1 (GPIO / digital peripheral functions) |
| Pin 16 | PD0 — Port D bit 0 (GPIO / digital peripheral functions) |
| Pin 17 | PC7 — Port C bit 7 (GPIO / digital peripheral functions) |
| Pin 18 | PC6 — Port C bit 6 (GPIO / digital peripheral functions) |
| Pin 19 | PC5 — Port C bit 5 (GPIO / digital peripheral functions) |
| Pin 20 | PC4 — Port C bit 4 (GPIO / digital peripheral functions) |
| Pin 21 | PC3 — Port C bit 3 (GPIO / digital peripheral functions) |
| Pin 22 | PC2 — Port C bit 2 (GPIO / digital peripheral functions) |
| Pin 23 | PC1 — Port C bit 1 (GPIO / digital peripheral functions) |
| Pin 24 | PC0 — Port C bit 0 (GPIO / digital peripheral functions) |
| Pin 25 | PA7 — Port A bit 7 (GPIO / analog / digital peripheral functions) |
| Pin 26 | PA6 — Port A bit 6 (GPIO / analog / digital peripheral functions) |
| Pin 27 | PA5 — Port A bit 5 (GPIO / analog / digital peripheral functions) |
| Pin 28 | PA4 — Port A bit 4 (GPIO / analog / digital peripheral functions) |
| Pin 29 | PA3 — Port A bit 3 (GPIO / analog / digital peripheral functions) |
| Pin 30 | PA2 — Port A bit 2 (GPIO / analog / digital peripheral functions) |
| Pin 31 | PA1 — Port A bit 1 (GPIO / analog / digital peripheral functions) |
| Pin 32 | PA0 — Port A bit 0 (GPIO / analog / digital peripheral functions) |
| Pin 33 | AVDD — Analog power supply |
| Pin 34 | GND — Ground |
| Pin 35 | PE3 — Port E bit 3 (GPIO / digital peripheral functions) |
| Pin 36 | PE2 — Port E bit 2 (GPIO / digital peripheral functions) |
| Pin 37 | PE1 — Port E bit 1 (GPIO / digital peripheral functions) |
| Pin 38 | PE0 — Port E bit 0 (GPIO / digital peripheral functions) |
| Pin 39 | PF5 — Port F bit 5 (GPIO / analog / digital peripheral functions) |
| Pin 40 | PF4 — Port F bit 4 (GPIO / analog / digital peripheral functions) |
| Pin 41 | PF3 — Port F bit 3 (GPIO / analog / digital peripheral functions) |
| Pin 42 | PF2 — Port F bit 2 (GPIO / analog / digital peripheral functions) |
| Pin 43 | PF1 — Port F bit 1 (GPIO / analog / digital peripheral functions) |
| Pin 44 | PF0 — Port F bit 0 (GPIO / analog / digital peripheral functions) |
| Pin 45 | UPDI — Unified Program and Debug Interface (single-wire programming/debug) |
| Pin 46 | PF6 — Port F bit 6 (GPIO / analog / digital peripheral functions) |
| Pin 47 | PB6 — Port B bit 6 (GPIO / digital peripheral functions) |
| Pin 48 | PB7 — Port B bit 7 (GPIO / digital peripheral functions) |
Typical Applications
ATMEGA809-AUR is suitable for 6 applications: Industrial Control and Automation, IoT Sensor End Nodes, Consumer Appliance Control, Motor Control Assistance, Human-Machine Interface Panels, Functional Safety / FuSa-Oriented Systems.
Industrial Control and Automation
The ATMEGA809-AUR fits industrial control nodes because its 20 MHz 8-bit AVR core with hardware multiplier handles deterministic loop control, while the -40C to +85C industrial temperature rating tolerates cabinet environments. Three USARTs (for RS-485/Modbus, diagnostics and a spare) and Core Independent Peripherals via the Event System let timer-triggered ADC sampling and PWM generation proceed without CPU intervention, reducing jitter in PID loops. Placed as a field I/O controller with 41 GPIO driving relays and reading sensors, it trades the performance of 32-bit MCUs for lower cost, single-cycle instruction determinism and simpler certification. Its 8 KB Flash suits fixed-function firmware with EEPROM-emulated calibration constants.
Recommended
IoT Sensor End Nodes
For battery-powered or energy-harvesting IoT sensor nodes, the ATMEGA809-AUR offers multiple sleep modes down to microamp-level currents, an internal low-frequency oscillator for timed wake-ups, and a 10-bit ADC that samples via the Event System without waking the CPU fully. The 8 KB Flash and 1 KB SRAM comfortably host a sensor driver plus a lightweight protocol such as LoRaWAN or BLE-adjacent framing handled by an external radio module over one of three USARTs. The single-wire UPDI interface simplifies production programming with only one board trace, and the 48-pin TQFP provides enough GPIO for multi-sensor muxing. Firmware recompiles unchanged onto ATMEGA1609/3209/4809 if features grow.
Recommended
Consumer Appliance Control
White goods, small appliances and HVAC controllers benefit from the ATMEGA809-AUR's combination of cost, robustness and Peripheral Touch Controller support for capacitive-touch user interfaces. The 41 GPIO in the 48-TQFP (7x7) package directly drives LEDs, relays, and stepper or brushed-motor PWM channels using TCA/TCB timers, while the hardware multiplier accelerates scaling math in temperature-control algorithms. The 256-byte EEPROM stores user settings through power cycles, and 8 KB Flash holds full appliance firmware including button debouncing, display multiplexing and safety interlocks. The industrial temperature grade adds margin for enclosures near heat sources, improving long-term reliability over consumer-grade alternatives.
Recommended
Motor Control Assistance
In low-cost motor-driven systems (fans, pumps, gate operators), the ATMEGA809-AUR generates complementary or non-inverted PWM from TCA/TCD-class timers and reads back position or current through the 10-bit ADC triggered by the Event System for cycle-accurate sampling. The 20 MHz core with hardware multiplier executes trapezoidal or sensorless commutation math on 8-bit hardware, and 8 KB Flash holds complete commutation, protection and communication firmware. TCB timers provide input-capture for hall-sensor or back-EMF timing measurement with minimal CPU load. Because the megaAVR 0-series is pin-compatible across memory sizes, a single motor-control PCB can be populated with ATMEGA809 or ATMEGA4809 depending on feature tier.
Recommended
Human-Machine Interface Panels
Low-cost HMI panels - keypads, segment or small TFT displays, indicator clusters - map well onto the ATMEGA809-AUR because 41 GPIO can drive a multiplexed LED matrix or bit-bang SPI to a small display while the Peripheral Touch Controller scans capacitive buttons in hardware. The Event System routes timer overflows to ADC and touch scanning autonomously, keeping CPU cycles free for display refresh and command parsing on the 20 MHz core. Three USARTs allow simultaneous RS-485 fieldbus, debug console and peripheral links. With 8 KB Flash and EEPROM emulation, the device stores brightness curves and user preferences locally, and the industrial temperature range suits outdoor kiosks and panels exposed to wide ambient swings.
Recommended
Functional Safety / FuSa-Oriented Systems
DigiKey classifies the ATMEGA809-AUR under megaAVR 0-series Functional Safety (FuSa) resources, meaning Microchip provides safety documentation packages that support integration into IEC-oriented safety processes. Engineers leverage Core Independent Peripherals so critical functions (windowed watchdog via a TCB, autonomous comparator supervision, Event System signal routing) continue operating even if firmware stalls, enabling hardware-level fault containment on an 8-bit budget. The 20 MHz deterministic single-cycle core simplifies timing analysis compared with pipelined cores, and the 48-pin TQFP offers enough GPIO for redundant sensing paths. Typical uses include safety-interlock monitoring, e-stop logic supervision and diagnostic coprocessing alongside a main controller.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA809-AUR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA1609-AUR | ATMEGA3209-AUR | ATMEGA4809-AUR |
|---|---|---|---|---|
| Package | 48-TQFP (7x7 mm) | 48-TQFP (7x7 mm) - same | 48-TQFP (7x7 mm) - same | 48-TQFP (7x7 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Core / Speed | AVR 8-bit, 20 MHz | AVR 8-bit, 20 MHz | AVR 8-bit, 20 MHz | AVR 8-bit, 20 MHz |
| Flash Memory | 8 KB | 16 KB | 32 KB | 48 KB |
| SRAM | 1 KB | 2 KB | 4 KB | 6 KB |
| EEPROM | 256 bytes | 256 bytes | 256 bytes | 256 bytes |
| Pin Compatibility | Reference (48-TQFP megaAVR 0 pinout) | Pin-to-pin compatible | Pin-to-pin compatible | Pin-to-pin compatible |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Key Differentiators
- Lowest-cost entry point of the 48-pin megaAVR 0-series (vs ATMEGA4809-AUR)
- Single-cycle 8-bit core with hardware multiplier (vs ATMEGA3209-AUR)
- Functional Safety (FuSa) documentation availability (vs ATMEGA1609-AUR)
Design Notes
Decouple every VDD pin (and the AVDD pin) with a 100 nF ceramic capacitor placed within a few millimeters of the pin, plus one bulk 4.7-10 uF capacitor near the MCU. Because the megaAVR 0-series GPIO totem-pole outputs switch fast at 20 MHz, simultaneous port writes on multiple pins create supply transients - a shared 100 nF across VDD pairs is not sufficient on a 4-layer board edge. Estimated: 41 GPIO at 20 mA each is worst-case 820 mA, far above the package rating, so budget per-pin current per datasheet limits rather than assuming the port total.
Route the UPDI pin (pin 45) to a 3-pad or Tag-Connect footprint header (UPDI, VDD, GND) on every production PCB - it costs nothing and enables in-field firmware updates and debugging with a PICkit 4, SNAP or pyupdi adapter. Do not configure the UPDI fuse as GPIO unless you also implement high-voltage UPDI recovery circuitry; doing so permanently disables programming on boards without that circuit. Keep the UPDI trace short and away from noisy PWM or switching-regulator nets to avoid corruption during programming.
The Event System routes peripheral signals internally, so avoid mirroring Event System outputs onto multiple GPIO pins purely 'for testing' - each pin adds capacitive loading and EMI. For the analog domain, connect AVDD to VDD through an RC or ferrite filter (e.g., 10 ohm + 1 uF, estimated values - verify with the datasheet's typical application section) when ADC accuracy matters, since digital return currents through a shared supply will show as ADC noise. Ground the exposed region under the TQFP with a solid via-stitched pour for best ADC reference stability.
Compliance Information
The 'A' package suffix denotes Microchip's lead-free/RoHS-compliant TQFP variant; 'R' denotes tape-and-reel. Not an automotive AEC-Q100 part. REACH/halogen/conflict-minerals status should be confirmed on the Microchip product page.
