ATMEGA3290PA-AU - 8-Bit AVR MCU, 32KB Flash, 20MHz | Microchip
MPN: ATMEGA3290PA-AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.9 | $6.90 |
| 10 | $6.21 | $62.10 |
| 100 | $5.52 | $552.00 |
| 500 | $4.97 | $2,485.00 |
| 1,000 | $4.48 | $4,480.00 |
ATMEGA3290PA-AU Overview
An 8-bit AVR microcontroller is a Harvard-architecture processor that executes most of its instructions in a single clock cycle. Within the power-management IC hierarchy, the ATmega family serves as the main system controller, sitting above simple logic devices and below 32-bit application processors, and is widely used for embedded control with human-machine interfaces.
Key differentiating features include the picoPower technology that reduces power consumption in active, idle, and standby modes, 131 powerful instructions with mostly single-cycle execution, 32 general-purpose working registers, and an AVR-enhanced RISC architecture. The device operates from a 1.8 V to 5.5 V supply, supporting both battery-powered and 5 V industrial designs.
Technically, the ATMEGA3290PA combines self-programming Flash with read-while-write capability, a JTAG interface for boundary-scan, on-chip debugging, and programming, a complete LCD controller driving segment and common lines with internal contrast control, plus standard AVR peripherals including timers, USART, SPI, and an ADC. The picoPower variant (PA suffix) improves on the earlier 3290P with lower quiescent and power-down currents.
Typical applications include utility metering with LCD displays, battery-powered handheld instruments, industrial control panels, and building-automation front ends where a segment LCD and low average power are mandatory.
A key design consideration is that the LCD controller requires careful selection of the LCD drive mode and frame frequency to balance contrast against power consumption; at 1.8 V operation the maximum clock frequency must also be derated per the datasheet speed-versus-voltage curve.
This page synthesizes distributor availability, drop-in family alternatives, and practical design notes beyond what the manufacturer datasheet provides.
Drop-in alternatives for ATMEGA3290PA-AU 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 ATMEGA3290PA-AU (same form factor and footprint) β differing in Package, Supply Voltage Range, Operating Temperature, RAM Size, Connectivity.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA3290A-AU
β Drop-Inβ In Stock
$3.85 / Unit
View Datasheet βATMEGA3290P-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA3250PA-AUR
β Drop-Inβ In Stock
$2.98 / Unit
View Datasheet βATMEGA3250P-20AU
β Drop-Inβ In Stock
$1.8 / Unit
View Datasheet βATMEGA6490P-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA6490A-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA3290PA-AU Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR 8-bit RISC |
| Core Size | 8-Bit |
| Max Clock Frequency | 20 MHz |
| Flash Memory | 32 KB (16K x 16) |
| SRAM | 2 KB |
| EEPROM | 1 KB |
| Number of I/O Lines | 69 |
| General Purpose Working Registers | 32 |
| Instruction Set | 131 Powerful Instructions, Most Single-Cycle |
| Supply Voltage Range | 1.8 V to 5.5 V |
| LCD Controller | On-chip segment LCD with internal contrast control |
| Debug/Programming Interface | JTAG (boundary-scan, on-chip debug, programming) |
| Flash Programming | In-System Programmable (ISP), read-while-write |
| Low Power Technology | picoPower |
| Package | 100-TQFP (14 x 14 mm) |
| Mounting Type | Surface Mount |
| Temperature Range | Industrial |
| RoHS / Green Status | Green (RoHS compliant per distributor listing) |
ATMEGA3290PA-AU 100-tqfp (14 x 14 mm) Pin Configuration Guide
Pin configuration for ATMEGA3290PA-AU (100-tqfp (14 x 14 mm) 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 ATMEGA3290PA-AU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA3290PA-AU is suitable for 6 applications: Utility Metering with LCD Display, Handheld Battery-Powered Instruments, Industrial Control Panels and HMI, Building Automation Front Ends, Security and Access Control Panels, Automotive and Marine Instrument Clusters.
Utility Metering with LCD Display
Electricity, water, and gas meters are the classic home of the ATMEGA3290PA-AU. The device pairs picoPower technology with an integrated segment LCD controller and internal contrast control, so a single chip drives the consumer-facing display while accumulating pulses and managing the metering engine. Operating from 1.8 V to 5.5 V allows direct battery or mains-derived supply, and 32 KB of self-programming ISP Flash holds calibration tables and communication firmware with room for field updates via read-while-write. The 69 general-purpose I/O lines interface optical sensors, reed switches, and RF or PLC communication modules. With sleep currents in the microamp class, the PA variant meets multi-year battery-life targets that the older 3290A could not, and the JTAG interface supports boundary-scan testing of the dense TQFP-100 assembly during production.
Recommended
Handheld Battery-Powered Instruments
Portable measurement and test instruments benefit directly from the ATMEGA3290PA-AU's combination of a 1.8 V minimum supply, picoPower sleep modes, and an on-chip LCD driver that keeps a readable readout alive at microamp average current. The 20 MHz AVR core executes 131 mostly single-cycle instructions, giving enough throughput for ADC post-processing, button debounce, and display refresh in a simple superloop or low-power event-driven architecture. The 2 KB SRAM buffers logged readings, while the 1 KB EEPROM stores calibration constants across battery replacement. The integrated LCD contrast control eliminates an external contrast potentiometer, and the JTAG interface supports on-chip debugging during firmware development. Because the device is pin-compatible with the ATMEGA6490 64 KB family, firmware can later grow into the same footprint without a PCB respin.
Recommended
Industrial Control Panels and HMI
Industrial control panels need robust 5 V-compatible logic, plentiful I/O, and a status display - all native strengths of the ATMEGA3290PA-AU. Its 69 general-purpose I/O lines drive relays, read switch banks, and interface RS-485 transceivers through the USART, while the integrated LCD controller renders setpoints and alarm text on a segment LCD. The industrial temperature rating and AVR's high immunity profile suit electrically noisy factory environments, and operation to 5.5 V provides generous noise margin against 24 V-system transients coupling into logic rails. The 20 MHz maximum clock, with 131 single-cycle instructions, handles PID loops and Modbus RTU polling comfortably. JTAG boundary-scan enables full netlist verification of the dense 100-TQFP solder joints, and ISP Flash allows field firmware upgrades without removing the device from the panel.
Recommended
Building Automation Front Ends
Thermostats, room controllers, and occupancy panels in building automation demand low standby power, a display, and network connectivity - a match for the ATMEGA3290PA-AU. PicoPower sleep modes keep the panel dormant between keystrokes at microamp-level current, while the segment LCD controller with internal contrast control presents setpoint and schedule information without a dedicated driver IC. The 1.8 V to 5.5 V range supports both battery and bus-powered variants of the same PCB, simplifying product SKUs. The 32 KB ISP Flash accommodates protocol stacks for BACnet MS/TP or proprietary RS-485 links via the USART, with 1 KB EEPROM retaining configuration during power loss. Three flexible timers generate PWM for damper or valve actuation, and SPI connects external flash for trend logging, making a complete room-controller front end on one chip.
Recommended
Security and Access Control Panels
Keypad and proximity-card access panels use the ATMEGA3290PA-AU to combine user-interface display, credential reading, and lock control in one low-cost device. The 69 I/O lines matrix-scan a keypad, drive LEDs, and control door relays, while the LCD controller displays entry prompts and system status. The 20 MHz core handles Wiegand or clock-and-data credential decoding in software with precise timing, and the 1 KB EEPROM stores user credentials and event counters that survive outages. ISP self-programming with read-while-write lets the panel log events to Flash while remaining responsive. The industrial temperature rating suits outdoor gate controllers, and picoPower sleep current keeps the backup battery viable through extended mains outages. JTAG on-chip debugging shortens firmware bring-up for the security-critical state machine.
Recommended
Automotive and Marine Instrument Clusters
Aftermarket and marine instrument clusters value the ATMEGA3290PA-AU's rugged AVR core, 5 V operation, and integrated LCD drive for gauges and warning indicators. The 69 I/O lines read speed, tachometer, and fluid-level sensor inputs through timers and the ADC, while the LCD controller renders odometer and status segments with internal contrast control that compensates for temperature-induced LCD drift. The 1.8 V to 5.5 V supply range tolerates load-dump-protected rails, and the industrial temperature rating covers under-dash environments. Note that for applications requiring AEC-Q100 qualification, this commercial-grade part should be evaluated against the qualified alternates in Microchip's automotive AVR portfolio before use. The 32 KB ISP Flash supports OTA-style firmware updates over the vehicle's diagnostic link via the USART with read-while-write programming.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA3290PA-AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA3290A-AU | ATMEGA3290P-AU | ATMEGA3250PA-AUR | ATMEGA6490P-AU |
|---|---|---|---|---|---|
| Package | 100-TQFP (14x14) | 100-TQFP (14x14) - same | 100-TQFP (14x14) - same | 100-TQFP (14x14) - same | 100-TQFP (14x14) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 64 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB | 4 KB |
| EEPROM | 1 KB | 1 KB | 1 KB | 1 KB | 2 KB |
| Max Clock Frequency | 20 MHz | 16 MHz | 20 MHz | 20 MHz | 20 MHz |
| picoPower Low-Power Technology | Yes | No | No | Yes | No |
| Supply Voltage | 1.8 V to 5.5 V | 2.7 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| On-chip LCD Controller | Yes | Yes | Yes | Yes | Yes |
Key Differentiators
- picoPower ultra-low sleep current (vs ATMEGA3290A-AU)
- Lower minimum supply voltage (vs ATMEGA3290A-AU)
- Maximum I/O in the LCD-AVR family (vs ATMEGA3250PA-AUR)
- Smaller Flash keeps cost down (vs ATMEGA6490P-AU)
Design Notes
The ATMEGA3290PA-AU operates from 1.8 V to 5.5 V, but the 20 MHz maximum clock is only valid at the upper end of the range - apply the datasheet speed-versus-voltage derating curve before choosing a 20 MHz crystal at 3.3 V or below. For battery designs, exploit the picoPower sleep modes and disable the LCD controller or reduce its frame frequency during deep sleep; LCD drive current scales directly with frame rate and the number of active segments, so a clock-driven contrast strategy saves measurable average current.
With 100 pins at 0.5 mm pitch on a 14 x 14 mm body, fan-out requires at least two signal layers plus dedicated power and ground planes. Place 100 nF ceramic decoupling capacitors on every VCC pin pair, as close to the pins as possible, plus a bulk 10 uF capacitor near the supply entry. The LCD segment lines carry AC drive waveforms; route them away from the analog ADC inputs and high-impedance sense nodes to prevent charge injection artifacts in measurement firmware.
The JTAG interface shares pins with general-purpose I/O and is enabled by default from the factory, which surprises designers who lose four port pins. If JTAG debugging is not needed in production, disable it via the JTAGEN fuse to reclaim the pins - but program this before final assembly access is lost. Also note the LCD controller has a dedicated voltage generator/contrast scheme; do not connect LCD bias networks to a noisy digital rail, or ghost segments and reduced contrast will result.
Estimated: even at full 20 MHz operation, an AVR 8-bit core draws only tens of milliamps; at 5 V this implies roughly 0.1-0.3 W of internal dissipation including I/O and LCD drive. The 100-TQFP thermal resistance on a standard four-layer PCB keeps the junction rise well below 20 C over ambient at these levels, so no heatsink is required. Verify against the datasheet power consumption tables for your exact clock, voltage, and LCD configuration.
Compliance Information
Distributor and Microchip listings identify the ATMEGA3290PA-AU as a Green (RoHS-compliant, lead-free) part. REACH, halogen-free, and conflict-minerals declarations were not present in the retrieved data - consult Microchip environmental documentation.
