ATMEGA328PB-AUR - 8-Bit AVR MCU 32KB Flash 20MHz TQFP-32 | Microchip
MPN: ATMEGA328PB-AUR β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.25 | $2.25 |
| 10 | $1.98 | $19.80 |
| 100 | $1.68 | $168.00 |
| 500 | $1.55 | $775.00 |
| 1,000 | $1.42 | $1,420.00 |
| 3,000 | $1.31 | $3,930.00 |
ATMEGA328PB-AUR Overview
A microcontroller unit (MCU) is a single-chip computer integrating a processor core, program memory, data memory, and peripherals. The ATmega328PB belongs to the AVR ATmega family, part of the broader 8-bit microcontroller hierarchy within embedded processing semiconductors. Executing powerful instructions in a single clock cycle, the picoPower AVR architecture achieves throughput close to 1 MIPS per MHz, letting designers trade clock speed against power.
Key features include 27 general-purpose I/O lines, 32 general-purpose working registers, two flexible 8-bit timer/counters, two 16-bit timer/counters (up from one on the ATmega328P), a 10-bit ADC, and dual SPI and dual TWI (I2C) interfaces - the PB adds a second SPI and second I2C bus versus the classic 328P. Functional Safety (FuSa) support is listed by DigiKey for this part.
The enhanced AVR core uses single-cycle RISC execution with Harvard architecture, separating instruction and data buses. Software is fully backward compatible with the ATmega328P, and code and fuses port over without modification, while the richer peripheral set enables designs that previously required external expansion.
Typical applications include Arduino-compatible boards, industrial control and sensor nodes, consumer appliances, and battery-powered portable devices where picoPower sleep modes extend battery life.
Design consideration: the added Port E / second-bus pins make the PB not an officially guaranteed pin-for-pin drop-in in every legacy footprint - verify pins shared with the 328P per Microchip migration guidance before layout reuse.
This page synthesizes distributor pricing (as of 2026-09-17), drop-in alternatives, pinout, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA328PB-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 ATMEGA328PB-AUR (same form factor and footprint) β differing in Package, SRAM, Operating Temperature, General Purpose I/O, Core Processor.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA328PB-AU
β Drop-Inβ In Stock
$1.12 / Unit
View Datasheet βATMEGA328P-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$1.85 / Unit
View Datasheet βATMEGA328P-AUR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA328PB-AUR Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Maximum Clock Frequency | 20 MHz |
| Flash Program Memory | 32 KB (16K x 16) |
| SRAM | 4 KB |
| EEPROM | 2 KB |
| General Purpose I/O | 27 I/O lines |
| Working Registers | 32 x 8-bit |
| Throughput | Up to 1 MIPS per MHz (single-cycle instructions) |
| Timers | 2 x 8-bit and 2 x 16-bit timer/counters |
| Communication Interfaces | 2 x SPI, 2 x TWI (I2C), USART |
| ADC | 10-bit ADC |
| Package | 32-TQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (AUR suffix) |
| Temperature Grade | Industrial (per Mouser listing) |
| Special Features | picoPower technology, Functional Safety (FuSa) |
ATMEGA328PB-AUR Pin Configuration
| Pin 1 | PD3 β Port D bit 3 (PCINT19/OC2B/INT1) |
| Pin 2 | PD4 β Port D bit 4 (PCINT20/XCK/T0) |
| Pin 3 | GND β Ground |
| Pin 4 | VCC β Digital supply voltage |
| Pin 5 | GND β Ground |
| Pin 6 | VCC β Digital supply voltage |
| Pin 7 | PB6 β Port B bit 6 (PCINT6/XTAL1/TOSC1) |
| Pin 8 | PB7 β Port B bit 7 (PCINT7/XTAL2/TOSC2) |
| Pin 9 | PD5 β Port D bit 5 (PCINT21/OC0B/T1) |
| Pin 10 | PD6 β Port D bit 6 (PCINT22/OC0A/AIN0) |
| Pin 11 | PD7 β Port D bit 7 (PCINT23/AIN1) |
| Pin 12 | PB0 β Port B bit 0 (PCINT0/CLKO/ICP1) |
| Pin 13 | PB1 β Port B bit 1 (PCINT1/OC1A) |
| Pin 14 | PB2 β Port B bit 2 (PCINT2/SS/OC1B) |
| Pin 15 | PB3 β Port B bit 3 (PCINT3/MOSI/OC2A) |
| Pin 16 | PB4 β Port B bit 4 (PCINT4/MISO) |
| Pin 17 | PB5 β Port B bit 5 (PCINT5/SCK) |
| Pin 18 | AVCC β ADC supply voltage |
| Pin 19 | ADC6 β Analog input channel 6 |
| Pin 20 | AREF β Analog reference voltage |
| Pin 21 | GND β Ground |
| Pin 22 | ADC7 β Analog input channel 7 |
| Pin 23 | PC0 β Port C bit 0 (ADC8/PCINT8) |
| Pin 24 | PC1 β Port C bit 1 (ADC9/PCINT9) |
| Pin 25 | PC2 β Port C bit 2 (ADC10/PCINT10) |
| Pin 26 | PC3 β Port C bit 3 (ADC11/PCINT11) |
| Pin 27 | PC4 β Port C bit 4 (ADC12/PCINT12/SDA) |
| Pin 28 | PC5 β Port C bit 5 (ADC13/PCINT13/SCL) |
| Pin 29 | PC6 β Port C bit 6 (PCINT14/RESET, active low) |
| Pin 30 | PD0 β Port D bit 0 (PCINT16/RXD) |
| Pin 31 | PD1 β Port D bit 1 (PCINT17/TXD) |
| Pin 32 | PD2 β Port D bit 2 (PCINT18/INT0) |
Typical Applications
ATMEGA328PB-AUR is suitable for 6 applications: Arduino-Compatible Development Boards, Industrial Sensor Nodes, Consumer Appliances, Battery-Powered Portable Devices, Motor Control and PWM Systems, IoT Edge Devices and Gateways.
Arduino-Compatible Development Boards
The ATmega328PB is the direct descendant of the ATmega328P used on the Arduino Uno, so it runs the same bootloader mechanism, fuses, and code ecosystem while adding a second SPI and second TWI bus. On an Arduino-compatible board the MCU runs at 16 MHz from a crystal on XTAL1/XTAL2, boots via the in-system programmable 32KB Flash, and exposes 27 GPIO through headers. Designers get shield compatibility with less BOM cost than the 328P, since distributor data shows the PB priced below the 328P-AU at equal quantities. Firmware development uses the Arduino IDE with community board packages or Microchip Studio for full register-level control.
Recommended
Industrial Sensor Nodes
In industrial monitoring nodes the ATMEGA328PB-AUR combines its 10-bit ADC, 27 GPIO, and dual I2C/TWI buses to read multiple sensors and drive local actuators from one low-cost MCU. The picoPower architecture enables duty-cycled operation - sleeping between conversions and waking on interrupt - which reduces average current in battery or energy-harvesting nodes. The industrial temperature grade matches cabinet and factory-floor environments, and the 32KB Flash accommodates protocol stacks (Modbus over UART, for example) with headroom for OTA-style in-system reprogramming. Dual SPI also lets one MCU manage an ADC front end and an isolated transceiver simultaneously.
Recommended
Consumer Appliances
Home appliances - coffee machines, fans, small pumps, thermostat controls - use the ATMEGA328PB-AUR as the main control MCU because it integrates timers, ADC for potentiometer or NTC sensing, and enough GPIO for keys, relays, and indicators in a single 7x7 mm TQFP. The two 8-bit and two 16-bit timer/counters provide PWM channels for motor speed control and buzzer generation without software bit-banging. Production economics favor the part: tape-and-reel delivery supports automated placement, and Microchip's active lifecycle status secures long-term supply. Code and fuses inherited from the vast ATmega328P knowledge base shorten development cycles significantly.
Recommended
Battery-Powered Portable Devices
For handheld meters, remotes, and wearable accessories, the ATMEGA328PB-AUR's picoPower features - multiple sleep modes, interrupt-on-pin-change, and the ability to run near 1 MIPS per MHz at reduced clocks - let designers average current into the microamp range between wakeups. The 10-bit ADC samples battery voltage and user inputs, while dual TWI buses connect a sensor and a display controller simultaneously. The 32-TQFP package balances pin count with a compact 7x7 mm footprint for slim enclosures. Firmware stored in 32KB Flash with 4KB SRAM handles sensor fusion and UI code with margin, and in-system programming supports manufacturing programming on the final assembly line.
Recommended
Motor Control and PWM Systems
The ATmega328PB's complement of timers - two 8-bit (including overflow-compare PWM on OC0A/OC0B) and two 16-bit with input capture and complementary outputs such as OC1A/OC1B - generates multiple synchronized PWM channels for DC motor drives, servo control, and LED dimming. Single-cycle RISC execution at up to 20 MHz closes control loops in software with deterministic timing, while the ADC reads back current or position feedback. The 27 GPIO lines drive H-bridge ICs or MOSFET gate drivers directly. Compared with the ATmega328P, the added second 16-bit timer means one MCU can control two independent motors with hardware PWM instead of sharing timers.
Recommended
IoT Edge Devices and Gateways
At the IoT edge the ATMEGA328PB-AUR acts as a sensor-aggregation MCU feeding a radio module over one of its two SPI or two I2C buses, keeping the wireless link electrically and logically isolated from local sensing. The dual-interface advantage is unique to the PB variant in this footprint: one bus serves a temperature/humidity sensor chain while the second drives a display or secure element. The 32KB Flash stores mesh protocol code, and EEPROM retains calibration and network credentials through power cycles. picoPower sleep modes suit battery or coin-cell deployments, waking on radio interrupts or periodic timers. Industrial temperature grading supports outdoor enclosures.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA328PB-AUR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA328PB-AU | ATMEGA328P-AU | ATMEGA328P-AUR |
|---|---|---|---|---|
| Package | 32-TQFP (7x7 mm) | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB (16K x 16) | 32 KB | 32 KB | 32 KB |
| Maximum Clock | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| GPIO Count | 27 | 27 | 23 | 23 |
| SPI Interfaces | 2 | 2 | 1 | 1 |
| TWI (I2C) Interfaces | 2 | 2 | 1 | 1 |
| 16-bit Timers | 2 | 2 | 1 | 1 |
| Packaging | Tape & Reel | Tray | Tray | Tape & Reel |
Key Differentiators
- Dual SPI and dual TWI interfaces in the classic AVR footprint (vs ATMEGA328P-AU)
- Lower cost than its predecessor (vs ATMEGA328P-AU)
- Two 16-bit timers instead of one (vs ATMEGA328P-AUR)
Design Notes
The 32-TQFP (7x7 mm) has 0.8 mm pin pitch, which is hand-solderable and reflow-friendly. Place a 100 nF ceramic decoupling capacitor within 2 mm of each VCC pin (4 and 6) and a 100 nF capacitor on AVCC (pin 18) with a 10 uH ferrite or low-value resistor isolating AVCC from digital VCC for clean ADC operation. Tie GND pins 3, 5, and 21 to a solid ground pour. Keep the AREF pin (20) decoupled with 100 nF and route analog traces away from the XTAL lines.
Migration from ATmega328P: the PB routes its added peripherals to pins whose multiplexing differs from the 328P. Microchip's migration application note states the PB is not officially a guaranteed drop-in; community reports (Reddit r/microcontrollers) confirm that if the affected pins are left disconnected, the swap is functionally complete and code/fuses are compatible. Before respinning a 328P PCB with the PB, cross-check every pin's alternate function against the ATmega328PB datasheet (document 40001906) and confirm the device signature bytes are handled by your programmer.
Current consumption depends strongly on clock source and voltage. Running at reduced clock via the prescaler or internal RC oscillator exploits the picoPower architecture's roughly linear MIPS-per-MHz scaling, letting sleep-heavy firmware cut average current dramatically. Use the brown-out detector and set fuse levels appropriate to your supply; disable unused peripheral clocks in the power-reduction registers (PRR) as recommended in the datasheet's power management section for maximum battery life.
When using the full 20 MHz external crystal, keep XTAL1/XTAL2 traces (pins 7/8) under 10 mm with ground guard, and load the crystal per its datasheet CL specification. For SPI lines driving long cables, add series 22-33 ohm resistors to control ringing; the second SPI bus shares port pins that default to other functions, so initialize DDRB direction registers before enabling the peripheral to avoid bus contention during startup.
Compliance Information
Verified web data does not state RoHS/REACH/lead-free status for this MPN. Modern Microchip active products are typically RoHS compliant, but per data authenticity rules the status is left unknown - confirm on the Microchip product page.