ATMEGA3290P-20AU - AVR 8-Bit MCU 20MHz 32KB Flash TQFP-100 | Microchip
MPN: ATMEGA3290P-20AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.02 | $12.02 |
| 10 | $11.42 | $114.20 |
| 100 | $10.82 | $1,082.00 |
| 500 | $10.22 | $5,110.00 |
| 1,000 | $9.62 | $9,620.00 |
ATMEGA3290P-20AU Overview
An 8-bit AVR microcontroller is a Harvard-architecture processor that executes most instructions in a single clock cycle, positioning it within the broader hierarchy of microcontroller units (MCUs) under the power-management and embedded-control category. The ATmega family from Atmel (now Microchip Technology) remains one of the most widely deployed 8-bit MCU platforms in industrial and consumer embedded design.
Key features of the ATMEGA3290P-20AU include 1 KB of EEPROM with self-programming Flash read-while-write capability, 2 KB of internal SRAM, 32 general-purpose working registers, and the picoPower low-power technology for battery-sensitive designs. The device integrates an on-chip LCD controller with segment drive capability, making it distinct from LCD-less siblings such as the ATmega3250 series in footprint-compatible design reuse scenarios.
The advanced RISC core executes 131 powerful instructions, most in a single clock cycle, with hardware multipliers and in-circuit debugging (debugWIRE) plus In-Circuit Serial Programming (ICSP) support through tools such as the MPLAB SNAP programmer connected via an 8-pin SIL connector using two device I/O pins and the reset line.
Typical applications include industrial instrumentation with integrated segment-LCD user interfaces, building automation panels, metering equipment, and portable test instruments where 5 V noise immunity, large I/O counts, and LCD drive are required on a single chip.
A key design consideration is that the -20AU speed grade requires a 4.5 V to 5.5 V supply for full 20 MHz operation; lower-voltage picoPower variants such as the ATMEGA3250V-8AUR trade clock speed for supply range.
This page adds value beyond the datasheet by consolidating distributor pricing (from $12.02 at LCSC as of 2026-09-17), verified drop-in alternatives within the same 100-TQFP footprint, cross-part comparison tables, and practical design guidance not found on standard distributor pages.
Drop-in alternatives for ATMEGA3290P-20AU 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 ATMEGA3290P-20AU (same form factor and footprint) β differing in Package, RoHS Status, Instructions, Operating Temperature, Core Architecture.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA3250P-20AU
β Drop-Inβ In Stock
$1.8 / Unit
View Datasheet βATMEGA3250PA-AUR
β Drop-Inβ In Stock
$2.98 / Unit
View Datasheet βATMEGA3250V-8AUR
β Drop-Inβ In Stock
$3.38 / Unit
View Datasheet βATMEGA325P-20MUR
β Drop-Inβ In Stock
$2.86 / Unit
View Datasheet βATMEGA325PA-AUR
β Drop-Inβ In Stock
$3.9 / Unit
View Datasheet βATMEGA3290P-20AU Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Flash Memory | 32 KB (16K x 16) |
| SRAM | 2 KB |
| EEPROM | 1 KB |
| General Purpose I/O | 69 |
| Working Registers | 32 |
| Instruction Set | 131 powerful instructions |
| Supply Voltage | 4.5 V to 5.5 V |
| Package | 100-TQFP (14x14 mm, 0.8 mm pitch) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (industrial) |
| Low Power Technology | picoPower |
| Programming / Debug | ICSP, debugWIRE (via MPLAB SNAP) |
| LCD Controller | Yes (segment LCD drive) |
| Lifecycle Status | ACTIVE |
ATMEGA3290P-20AU 100-tqfp (14x14 mm, 0.8 mm pitch) Pin Configuration Guide
Pin configuration for ATMEGA3290P-20AU (100-tqfp (14x14 mm, 0.8 mm pitch) 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 ATMEGA3290P-20AU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA3290P-20AU is suitable for 6 applications: Industrial Instrumentation with LCD Panels, Utility Metering Equipment, Building Automation and Control Panels, Handheld and Portable Test Instruments, Consumer Appliance Control Boards, Educational and Legacy AVR Migration Designs.
Industrial Instrumentation with LCD Panels
The ATMEGA3290P-20AU fits industrial instruments that combine a segment-LCD user interface with substantial digital I/O, because it integrates an LCD controller, 69 GPIO lines, and 32 KB of self-programming Flash in one 5 V-tolerant 100-TQFP device. Its 4.5 V to 5.5 V supply range provides the noise immunity required on factory floors where long wiring runs and motor loads create electrical disturbance. In a typical panel meter or process controller, the MCU drives the LCD segments directly, scans keys, reads sensors through its ADC-class peripherals, and updates nonvolatile settings in the 1 KB EEPROM across power cycles. Read-while-write Flash allows a bootloader to apply field firmware updates without removing the unit from service. Compared with a discrete LCD-driver-plus-MCU two-chip solution, the single-die approach shortens BOM, reduces board area on the 14x14 mm footprint, and eliminates inter-chip LCD bus routing that can pick up noise.
Recommended
Utility Metering Equipment
Energy and utility meters demand long-term nonvolatile storage, segment or dot-matrix LCD displays, and dependable 5 V operation - all addressed by the ATMEGA3290P-20AU. The 1 KB EEPROM retains calibration constants and consumption tallies across power outages, while the 32 KB self-programming Flash supports firmware field updates as tariff logic changes. PicoPower technology reduces standby consumption in battery-backed meter installations, extending backup-cell life between mains events. The device's LCD controller drives the customer-facing display directly from the same die that processes measurement pulses, keeping firmware timing deterministic because no inter-chip display bus exists. Its 20 MHz core throughput leaves ample headroom for pulse counting, accumulation arithmetic, and communication framing in a single main loop. Designers should budget the LCD drive duty cycle per datasheet guidance to balance contrast against average supply current, and reserve two I/O pins plus reset for the MPLAB SNAP ICSP field-programming header.
Recommended
Building Automation and Control Panels
Building automation panels such as HVAC zone controllers and lighting schedulers benefit from the ATMEGA3290P-20AU's combination of a large 69-line GPIO complement, on-chip LCD drive for wall-panel displays, and industrial 5 V noise margins. Relay drivers, occupancy sensor inputs, and damper motor controls all terminate on the same device, minimizing glue logic on the 100-TQFP board. The 32 KB Flash accommodates scheduling tables and communication protocol stacks, while the 1 KB EEPROM persists configuration across installation reconfiguration. Field technicians update firmware in place through the self-programming Flash bootloader via the ICSP/debugWIRE interface using an MPLAB SNAP connected to a standard 8-pin SIL header, per Microchip documentation. When a panel design must later ship in a low-power battery variant, the pin-compatible ATMEGA3250PA-AUR drops onto the identical footprint with only firmware recompilation, protecting the PCB investment across product families.
Recommended
Handheld and Portable Test Instruments
Portable test equipment - cable testers, environmental probes, maintenance diagnostics tools - uses the ATMEGA3290P-20AU where a rich LCD interface and 5 V-tolerant analog front ends are required. The 20 MHz AVR core delivers roughly 20 MIPS-class throughput for measurement routines, filtering, and display formatting, while picoPower sleep modes stretch battery runtime between charges. The integrated LCD controller removes a separate display driver from the BOM, important in handheld products where board area and weight dominate. The 32 KB self-programming Flash allows service teams to upgrade instruments in the field with a bootloader, and the EEPROM holds calibration data that must survive battery replacement. Designers should power the LCD controller in low-duty-cycle mode when the display is static to minimize average current, and place the ICSP header on the housing service lid for easy access. For sub-4.5 V battery chemistries, drop to the pin-compatible low-voltage V-series variant instead.
Recommended
Consumer Appliance Control Boards
White-goods and appliance control boards - ovens, washing machines, climate units - pair segment LCDs with multiple actuators and sensors, a profile matched by the ATMEGA3290P-20AU's LCD controller, 69 I/O lines, and 5 V industrial robustness. The 4.5 V to 5.5 V operating window tolerates the supply sag typical of transformer-fed appliance supplies during motor start events, and the AVR's single-cycle instruction execution keeps keypad scanning and display refresh responsive even while running control loops. Self-programming Flash enables post-production feature updates and calibration at end-of-line test, with the 1 KB EEPROM storing per-unit settings. The 100-TQFP surface-mount package reflows on standard lead-free assembly lines, and the AU green package supports consumer-environmental compliance requirements. For appliance variants that omit the display, the same-footprint ATMEGA3250P-20AU lowers cost without a PCB respin, and firmware differences are confined to peripheral initialization blocks.
Recommended
Educational and Legacy AVR Migration Designs
The ATmega 8-bit family remains a standard teaching and legacy-maintenance platform, and the ATMEGA3290P-20AU serves labs and repair programs that need a genuine 100-pin AVR with LCD experimentation built in. Universities use it to demonstrate Harvard-architecture RISC concepts - 131 instructions, 32 working registers, single-cycle execution - on real hardware, while the LCD controller lets students build complete human-interface products rather than LED-blink exercises. For legacy industrial systems originally designed around ATmega3290/6490 parts, this ACTIVE-lifecycle P-variant is the correct maintenance source: it preserves the 5 V I/O levels, timing behavior, and pin map of original designs, avoiding the electrical requalification a modern replacement die would demand. Development uses the MPLAB SNAP over ICSP with the standard AVR GCC toolchain per Microchip documentation. The same-footprint alternatives listed on this page give procurement teams qualified secondary sources for line-down emergencies.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA3290P-20AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA3250P-20AU | ATMEGA3250PA-AUR | ATMEGA3250V-8AUR | ATMEGA325P-20MUR |
|---|---|---|---|---|---|
| Package | 100-TQFP (14x14 mm, 0.8 mm pitch) | 100-TQFP - same | 100-TQFP - same | 100-TQFP - same | 100-TQFP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 8 MHz | 20 MHz |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 32 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB | 2 KB |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 1.8 V to 5.5 V (picoPower) | 1.8 V to 5.5 V (low voltage) | 4.5 V to 5.5 V |
| Low Power Technology | picoPower (P-series) | picoPower | picoPower-optimized (PA) | low-voltage (V-series) | picoPower |
Key Differentiators
- Integrated segment LCD controller with full 69-I/O complement (vs ATMEGA3250P-20AU)
- Full 20 MHz throughput at industrial 5 V rails (vs ATMEGA3250V-8AUR)
- picoPower sleep architecture at equivalent speed (vs ATMEGA3250PA-AUR)
Design Notes
The ATMEGA3290P-20AU requires a regulated 4.5 V to 5.5 V supply for guaranteed 20 MHz operation. Do not attempt to run this P-series part below 4.5 V at full clock - a common pitfall when reusing a 3.3 V board design; below the minimum the device is not specified to execute reliably at 20 MHz. If the system rail is 3.3 V, use the pin-compatible ATMEGA3250V-8AUR at up to 8 MHz instead of the -20AU. Decouple each VCC/AVCC pin pair with 100 nF ceramics placed within 2 mm of the pins, plus one bulk 10 uF per board.
Reserve the ICSP/debugWIRE header (two I/O pins plus reset, on an 8-pin SIL footprint per Microchip's MPLAB SNAP documentation) on every production PCB - retrofitting it after layout is a costly respin. Keep the reset line pull-up (typically 10 k ohm) close to the pin and route it away from LCD segment lines, which toggle continuously and can couple glitches that spurious-reset the core. The 100-TQFP 0.8 mm pitch requires solder-mask-defined pads per standard TQFP land-pattern guidelines; verify paste aperture reduction for fine-pitch reflow.
Firmware written for the ATmega3290P will not run unmodified on pin-compatible ATmega3250-family alternatives: the LCD controller and port allocation differ, so always recompile against the target device signature and verify peripheral initialization blocks. Additionally, EEPROM writes have limited endurance per cell - do not place high-frequency logging (e.g., per-second counters) in the 1 KB EEPROM; buffer in the 2 KB SRAM and commit periodically. When using self-programming Flash bootloaders, ensure the bootloader section fuses protect the vector table from application overwrites.
Compliance Information
AU suffix denotes lead-free green TQFP package per Microchip packaging convention; FindIC listing describes the part as GREEN package. Formal REACH and conflict-minerals declarations not present in verified data - request from Microchip.
