ATMEGA3250PA-AUR - 8-bit AVR MCU 32KB Flash 20MHz | Microchip
MPN: ATMEGA3250PA-AUR β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.62 | $4.62 |
| 10 | $4.16 | $41.60 |
| 100 | $3.71 | $371.00 |
| 500 | $3.34 | $1,670.00 |
| 1,000 | $2.98 | $2,980.00 |
ATMEGA3250PA-AUR Overview
An 8-bit AVR microcontroller is a Harvard-architecture RISC device that executes most of its 131 instructions in a single clock cycle, making it a member of the broader microcontroller hierarchy: MCU -> embedded processor -> semiconductor IC. MCUs integrate CPU, memory, timers, and peripherals on one die, eliminating external glue logic in cost-sensitive embedded systems.
Key features include the advanced RISC AVR core delivering up to 20 MIPS throughput at 20MHz, read-while-write Flash for safe in-application self-programming, 32 general purpose working registers directly connected to the ALU, and picoPower technology for ultra-low sleep-mode consumption. On-chip peripherals include JTAG for boundary scan and on-chip debugging, 10-bit ADC channels, multiple 8-bit and 16-bit timers with PWM, USARTs, SPI, and two-wire interface (I2C-compatible).
The PA suffix denotes the picoPower-optimized die with low-voltage operation down to 1.8V and industry-leading active and sleep current, while the -AUR ordering code specifies industrial temperature range (-40C to +85C), lead-free RoHS/Green packaging on tape and reel for automated assembly.
Typical applications include industrial control panels with many switch and relay I/O points, building automation and HVAC controllers, battery-powered metering, and consumer appliance front-end boards where 69 I/O lines in a single 14x14 mm footprint reduce BOM cost.
Design consideration: the AVR core is a 5V-tolerant-friendly design but speed derates with VCC; at 1.8V the maximum safe clock is approximately 4MHz, so set the CKDIV8 fuse or scale the system clock when running from batteries or 3.3V rails.
This page adds value beyond the manufacturer datasheet by consolidating drop-in family alternatives, application pairings, design notes, and distributor pricing context in one AI-citable reference.
Drop-in alternatives for ATMEGA3250PA-AUR 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 ATMEGA3250PA-AUR (same form factor and footprint) β differing in Package, Instructions, RoHS Status, Packaging, Connectivity.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA3250PA-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$4.43 / Unit
View Datasheet βATMEGA3250P-20AU
β Drop-Inβ In Stock
$1.8 / Unit
View Datasheet βATMEGA3250-16AU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$5.74 / Unit
View Datasheet βATMEGA3290PA-AUR
β Drop-Inβ In Stock
$2.95 / Unit
View Datasheet βATMEGA6450P-20AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA3250PA-AUR 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 |
| Number of I/O | 69 |
| General Purpose Working Registers | 32 |
| Instructions | 131 (mostly single-cycle) |
| Supply Voltage Range | 1.8 V to 5.5 V |
| Operating Temperature | -40C to +85C |
| Package | 100-TQFP (14x14 mm) |
| Mounting Type | Surface Mount |
| Debug / Programming | JTAG, ICSP (In-Circuit Serial Programming) |
| Low Power Technology | picoPower |
| Connectivity | USART, SPI, I2C (Two-Wire Interface) |
| Packaging | Tape & Reel (TR) |
| RoHS Status | Compliant (Green) |
ATMEGA3250PA-AUR 100-tqfp (14x14 mm) Pin Configuration Guide
Pin configuration for ATMEGA3250PA-AUR (100-tqfp (14x14 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 ATMEGA3250PA-AUR.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA3250PA-AUR is suitable for 6 applications: Industrial Control Panels, Building Automation and HVAC Controllers, Battery-Powered Metering Devices, Consumer Appliance Front-End Boards, Security and Access Control Systems, Test and Measurement Fixtures.
Industrial Control Panels
Industrial control panels routinely scan dozens of buttons, limit switches, and relay outputs, and the ATMEGA3250PA-AUR's 69 GPIO lines in one 14x14 mm 100-TQFP package cover this count without port expanders. The 20MHz AVR core executes the 131-instruction RISC set mostly in single cycles, keeping scanning and state-machine loops deterministic. Multiple 16-bit timers generate PWM for actuator control while USART/SPI links handle Modbus-style communication. The industrial -40C to +85C rating and 5.5V supply ceiling suit 24V systems via simple level conditioning, and ICSP allows firmware updates without desoldering.
Recommended
Building Automation and HVAC Controllers
HVAC zone controllers need analog sensing, serial networking, and battery-backup resilience. The ATMEGA3250PA-AUR's on-chip 10-bit ADC reads temperature and humidity sensors directly, while the two-wire (I2C) and SPI interfaces connect RTCs and EEPROM. PicoPower technology reduces standby draw so a backup battery holds configuration through outages; the 1.8V floor even allows 2-cell coin-cell designs for wall thermostats. Its 69 I/O lines drive dampers, valves, and LEDs without expansion chips, and 32KB Flash with read-while-write support stores learned schedules in Flash while running from the same bank.
Recommended
Battery-Powered Metering Devices
Utility submeters and portable data loggers demand multi-year battery life. The picoPower ATMEGA3250PA-AUR operates down to 1.8V, allowing direct use of two alkaline cells without a boost converter, and its sleep modes cut average current to microamp levels between wake events. The 20MHz ceiling provides full-speed burst processing for metrology math, then the device sleeps. With 1KB EEPROM for calibration constants and 2KB SRAM for buffering, the ATMEGA3250PA-AUR handles tariff logging, and its USART streams data over RS-485 using minimal external circuitry.
Recommended
Consumer Appliance Front-End Boards
Washers, ovens, and range hoods use keypad-and-display front-end boards where BOM cost dominates. The ATMEGA3250PA-AUR integrates everything needed in one 100-TQFP die: 69 I/O for matrix keypads, LED segments, and relays; timers for buzzer tones and PWM dimming; and an ADC for NTC temperature sensing. Replacing an MCU plus I/O expander plus peripheral logic with this single ATmega device cuts component count and assembly cost. Green/RoHS packaging meets global appliance regulations, and in-application self-programming supports field firmware updates via the service port.
Recommended
Security and Access Control Systems
Door controllers, alarm panels, and keypads benefit from the ATMEGA3250PA-AUR's combination of many I/O lines and robust serial links. Zone inputs occupy up to 69 GPIO points, the ADC supervises tamper and battery-health voltages, and the USART interfaces with RS-485 or Wiegand-adjacent readers through level shifting. JTAG enables boundary-scan testing of assembled boards during production and on-chip debugging during development with an MPLAB Snap. The industrial temperature range ensures relay-bay environments near -40C or +85C remain within specification without derating the 20MHz clock at 5V supply.
Recommended
Test and Measurement Fixtures
Bench fixtures and ATE subsystems use the ATMEGA3250PA-AUR as a flexible sequencer: its 69 GPIO drive DUT test points, 16-bit timers produce precise stimulus pulses, and the ADC captures slow analog responses. ICSP plus JTAG allow fixture firmware to be re-flashed per product variant without hardware change, cutting fixture cost across product families. The fully static core permits clocking down or pausing without state loss, useful for single-step debugging of handshake logic. Development uses the same MPLAB Snap 8-pin SIL interface described by Microchip for in-circuit debugging and ICSP programming.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA3250PA-AUR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA3250PA-AU | ATMEGA3250P-20AU | ATMEGA3250-16AU | ATMEGA3290PA-AUR | ATMEGA6450P-20AU |
|---|---|---|---|---|---|---|
| Package | 100-TQFP (14x14 mm) | 100-TQFP (14x14 mm) - same | 100-TQFP (14x14 mm) - same | 100-TQFP (14x14 mm) - same | 100-TQFP (14x14 mm) - same | 100-TQFP (14x14 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 16 MHz | 20 MHz | 20 MHz |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 32 KB | 64 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB | 2 KB | 4 KB |
| picoPower Low-Power Die | Yes (PA) | Yes | No | No | Yes | No |
| On-chip LCD Controller | No | No | No | No | Yes | Yes |
| Packaging | Tape & Reel (AUR) | Tray | Tray | Tray | Tape & Reel | Tray |
Key Differentiators
- picoPower low-power die at full 20MHz (vs ATMEGA3250P-20AU)
- 20MHz clock headroom (vs ATMEGA3250-16AU)
- General-purpose I/O focus over LCD integration (vs ATMEGA3290PA-AUR)
Design Notes
Respect the AVR frequency-versus-voltage curve: the 20MHz maximum applies only near 5V supply, while a 1.8V rail supports roughly 4MHz. For battery designs, set the CKDIV8 fuse at startup and ramp the system clock via the CLKPR register once the rail is stable, or simply spec a 4-8MHz crystal for 3.3V operation. Estimated: a firmware loop averaging 1mA active for 5% duty and 5uA sleep otherwise yields about 105uA mean draw - verify against the picoPower datasheet sleep tables for your exact sleep mode.
Place a 100nF ceramic decoupling capacitor at each VCC/AVCC pin pair and a 10uF bulk capacitor near the 100-TQFP. Tie unused I/O pins either to defined logic levels or configure them as inputs with internal pull-ups to prevent floating-input oscillation, which measurably raises current. Keep the analog ground return for AVCC/AREF separate through a single-point connection to reduce ADC noise. Expose the ICSP/JTAG header footprint in every layout, even production boards, for rework and field firmware updates.
Fuses are the most common AVR bring-up failure: setting RSTDISBL or an invalid clock-source fuse can brick the part in-circuit, requiring a 12V-capable HV programmer. Enable JTAGEN only if you need boundary scan, since JTAG pins are shared with port I/O. Also note that read-while-write self-programming erases a full Flash page at a time; store calibration data in the 1KB EEPROM rather than in the last Flash page to avoid accidental erasure during bootloader updates.
Compliance Information
DigiKey and Mouser list the part as RoHS compliant / Green with lead-free finish. REACH, halogen-free, and conflict-minerals declarations must be obtained from Microchip compliance certificates.