ATMEGA328PB-MNR - 20MHz 8-Bit AVR MCU | Microchip Technology
MPN: ATMEGA328PB-MNR ✓ ActiveATMEGA328PB-MNR Overview
A microcontroller is a programmable semiconductor that integrates a CPU core, memory, and peripherals into one compact device. The ATmega328PB belongs to the hierarchy of 8-bit MCU -> AVR microcontroller -> RISC embedded controller -> semiconductor. It executes instructions in a single clock cycle, providing throughput close to 1 MIPS per MHz, making it suitable for compact control systems that must combine responsive processing with low power consumption.
Key features include 32 KB of Flash memory organized as 16K × 16, 4 KB of internal SRAM, 2 KB of EEPROM, 27 general-purpose I/O pins, and 32 general-purpose working registers. The ATmega328PB also provides I2C, SPI, and UART interfaces. Its picoPower implementation supports low-power operation, while the 20 MHz maximum clock rate provides useful processing headroom for control, communication, and peripheral coordination tasks.
The AVR enhanced-RISC architecture uses a Harvard-style organization with separate program-memory and data-memory spaces. Flash supports read-while-write operation, allowing the MCU to continue operating from one Flash page while another page is programmed. The two flexible timer/counters support timing and waveform-generation tasks, while the serial peripherals enable connection to sensors, displays, transceivers, and service interfaces without requiring multiple external controller packages.
Typical applications include Arduino-compatible embedded modules, compact industrial controllers, battery-powered condition-monitoring equipment, serial data concentrators, hobby robotics, and small sensor nodes. The 32-VFQFN package also helps reduce board area, although its fine pitch and exposed-pad construction require careful PCB layout and assembly planning.
Designers should follow the manufacturer datasheet for the complete 32-pin assignment, exposed-pad connection, decoupling requirements, and programming interface. The exposed thermal pad must be connected to the supply and ground planes as specified, while high-current supply and return paths should be arranged to minimize switching-loop area and maintain stable operation.
This product record combines verified manufacturer and distributor information with practical application guidance, interface selection, pricing context, and same-package replacement analysis. It is intended to help engineers identify whether the ATMEGA328PB-MNR fits a compact 8-bit embedded-control design without overlooking package, memory, peripheral, or programming constraints.
Drop-in alternatives for ATMEGA328PB-MNR — 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-MNR (same form factor and footprint) — differing in Package, Operating Temperature, SRAM, EEPROM, Communication Interfaces.
ATMEGA328PB-MN
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA328PB-MBTVAO
✅ Drop-InContact for price
View Datasheet →ATMEGA328P-MNR
✅ Drop-InContact for price
View Datasheet →ATMEGA328P-MUR
✅ Drop-InContact for price
View Datasheet →ATMEGA328PB-MNR Maximum Ratings & Electrical Characteristics
| Processor Architecture | AVR enhanced RISC |
| CPU Width | 8-bit |
| Maximum Clock Frequency | 20 MHz |
| Program Memory Type | Flash |
| Program Memory Size | 32 KB (16K × 16) |
| Maximum ISP Flash Memory | 64 KB |
| EEPROM Memory | 2 KB |
| SRAM | 4 KB |
| General-Purpose I/O Lines | 27 |
| General-Purpose Working Registers | 32 |
| Flexible Timer/Counters | 2 |
| Serial Interfaces | I2C, SPI, UART |
| Process Technology | Low-power CMOS |
| Low-Power Technology | picoPower |
| Package | 32-VFQFN, 5 mm × 5 mm |
| Mounting Type | Surface mount |
| Operating Temperature | -40°C to +105°C |
| Temperature Grade | Industrial |
| RoHS Packaging | Pb-free packaging complies with RoHS |
ATMEGA328PB-MNR 32-vfqfn, 5 mm × 5 mm Pin Configuration Guide
Pin configuration for ATMEGA328PB-MNR (32-vfqfn, 5 mm × 5 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 ATMEGA328PB-MNR.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA328PB-MNR is suitable for 6 applications: Arduino-Compatible Embedded Modules, Industrial Sensor and Condition Monitoring, Battery-Powered Remote Sensor Nodes, Serial Data Concentrators, Hobby Robotics and Small Motor Systems, Programmable Logic and Interface Control.
Arduino-Compatible Embedded Modules
ATMEGA328PB-MNR fits compact Arduino-compatible controller modules because it provides a 20 MHz AVR core, 32 KB of Flash, 2 KB of EEPROM, 4 KB of SRAM, and 27 general-purpose I/O lines. I2C and SPI support common sensor and display connections, while UART provides a programming and serial-command path. Designers should compare the PB pin table against the legacy ATmega328P layout before reusing an existing shield, and should preserve the exposed-pad supply and ground connection. Compared with the earlier ATmega328P, the PB revision provides 27 rather than up to 22 I/O lines, creating additional peripheral-routing options when the PCB is designed specifically for it.
Recommended
Industrial Sensor and Condition Monitoring
The ATMEGA328PB-MNR is suitable for industrial condition-monitoring controllers that combine local sensing, periodic sampling, and status reporting. Its two flexible timer/counters can support timing or output-waveform functions, while I2C and SPI provide interfaces to sensors and data-capture devices. The industrial-grade temperature range is -40°C to +105°C, and 4 KB of SRAM plus 2 KB of EEPROM provide resources for buffering and persistent configuration. A practical implementation should use picoPower-compatible sleep modes between samples, validate the external sensor's accuracy requirements, and include watchdog recovery so a firmware fault does not interrupt long-term monitoring.
Recommended
Battery-Powered Remote Sensor Nodes
ATMEGA328PB-MNR can serve as the low-power controller in a compact remote sensor node because it combines picoPower technology with a 4 KB SRAM, 2 KB of EEPROM, and 27 I/O lines. The 20 MHz clock supports responsive local processing while low-power operating modes can reduce consumption between sensor measurements. Two timer/counters, I2C, SPI, and UART make it possible to coordinate a sensor, local indicator, and communications link without a separate host MCU. Runtime is primarily determined by the selected sleep mode, sensor duty cycle, and radio activity; the implementation should measure the complete sleep current rather than relying only on processor current.
Recommended
Serial Data Concentrators
ATMEGA328PB-MNR works well in a small serial concentrator that receives commands through UART and distributes control or monitoring functions across I2C and SPI peripherals. The 32 KB Flash memory supports application firmware and protocol tables, while 4 KB of SRAM handles transient packet buffering and the two timer/counters support periodic polling. The MCU can also provide a bootloader through its serial programming interface. For a production design, use robust connector protection, separate logic levels where required, and verify that the serial transceiver's supply and signal limits match the ATMEGA328PB-MNR operating conditions before release.
Recommended
Hobby Robotics and Small Motor Systems
The ATMEGA328PB-MNR is appropriate for compact robotics controllers that need deterministic digital I/O, timers, and multiple communication buses. Its 20 MHz AVR core provides ample responsiveness for coordinating sensors, actuators, and operator commands, while 27 I/O lines offer more routing flexibility than the earlier ATmega328P's up to 22 lines. PWM-capable timer outputs can control compatible actuator signals, but motor systems require suitable drivers because the microcontroller pins cannot directly source motor current. Keep high-current switching paths away from sensitive timing traces and use a separate regulator or driver where transient loads could disturb the MCU supply rail.
Recommended
Programmable Logic and Interface Control
ATMEGA328PB-MNR can implement compact programmable logic or interface-control functions where a small deterministic firmware task is preferable to a larger MCU. The two flexible timer/counters, 27 I/O lines, and support for I2C, SPI, and UART allow the device to coordinate sensors, displays, and communications without external programmable logic. Flash provides read-while-write operation, helping firmware remain available while nonvolatile parameters are updated. The 32-VFQFN package reduces board area, but its fine pitch and exposed pad require careful assembly process control, continuous ground-plane connection, and verification of the manufacturer's recommended reflow profile.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA328PB-MNR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA328PB-MN | ATMEGA328PB-MBTVAO | ATMEGA328P-MNR | ATMEGA328P-MUR |
|---|---|---|---|---|---|
| Package | 32-VFQFN, 5 mm × 5 mm | 32-VFQFN, 5 mm × 5 mm | 32-VFQFN, 5 mm × 5 mm | 32-VFQFN, 5 mm × 5 mm | 32-VFQFN, 5 mm × 5 mm |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Processor Architecture | AVR enhanced RISC, 8-bit | AVR enhanced RISC, 8-bit | AVR enhanced RISC, 8-bit | AVR enhanced RISC, 8-bit | AVR enhanced RISC, 8-bit |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Flash Memory | 32 KB (16K × 16) | 32 KB | 32 KB | 32 KB | 32 KB |
| EEPROM Memory | 2 KB | 2 KB | 2 KB | 1 KB | 1 KB |
| SRAM | 4 KB | 4 KB | 4 KB | 2 KB | 2 KB |
| General-Purpose I/O Lines | 27 | 27 | 27 | Up to 22 | Up to 22 |
| Timer/Counters | 2 | 2 | 2 | 2 | 2 |
Key Differentiators
- Expanded general-purpose I/O availability within the established AVR family (vs ATMEGA328P-MNR)
- Larger SRAM and EEPROM resources for embedded-control workloads (vs ATMEGA328P-MNR)
- Same 32-VFQFN device available in reel and tray logistics (vs ATMEGA328PB-MN)
- Compact 20 MHz AVR processing in a 5 mm × 5 mm package (vs ATMEGA165PV-8MNR)
Design Notes
Implement the 32-VFQFN footprint from the Microchip package drawing and connect the exposed thermal pad to the appropriate ground or supply structure specified by the manufacturer. Place the MCU close to its decoupling network, route the exposed-pad vias with the land pattern's thermal-via guidance, and avoid placing high-current switching nodes beneath the package. Fine-pitch assembly also requires checking the PCB's minimum feature capability and solder-mask behavior before production release.
Provide local bulk and high-frequency decoupling according to Microchip datasheet 40001906C, and keep the supply return path continuous beneath the MCU and exposed pad. Since the verified excerpts do not provide numeric voltage limits, do not infer a voltage range from generic ATmega328P material. Validate the exact supply window, I/O levels, and peripheral operating conditions from the PB datasheet. If external sensors, radios, or motors share the rail, isolate their switching-current paths to prevent controller resets.
Do not assume that every 32-VFQFN ATmega328P board can use ATMEGA328PB without modification. The PB revision provides 27 general-purpose I/O lines, while the earlier family provides up to 22, and selected PB-specific pins differ in function. Review the exact signal on every changed footprint location, disconnect inaccessible PB-only pins as applicable, and recompile with the correct device definition and fuse settings. The bootloader and application should also be tested on the production PCB revision.
Keep I2C, SPI, UART, and timer traces short where possible, especially when the MCU drives sensors, displays, or fast serial devices. Provide pull-ups or series termination according to the connected peripheral and trace topology rather than applying a universal value. For asynchronous serial communication, verify signal levels and grounding with the transceiver in the complete system. Clock, programming, and debug routes should be kept away from motor-drive nodes and high-current switching loops.
Although the ATMEGA328PB-MNR uses a 5 mm × 5 mm VQFN, normal 8-bit control workloads generally place more emphasis on exposed-pad continuity and local supply stability than on an external heatsink. Estimate PCB copper temperature rise from the actual regulator dissipation and ambient conditions during sustained maximum-clock operation. Do not combine the package area with a generic theta-JA value to predict junction temperature; use the manufacturer's board-dependent thermal guidance and validate the assembled design in its final enclosure.
Compliance Information
The verified ordering data explicitly states that Pb-free packaging complies with the European RoHS Directive. No verified REACH, halogen-free, conflict-minerals, or automotive AEC-Q100 statement was provided.
