ATMEGA328PB-MUR - 8-Bit AVR MCU 20MHz 32KB Flash QFN-32 | Microchip
MPN: ATMEGA328PB-MUR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.6 | $2.60 |
| 10 | $2.34 | $23.40 |
| 100 | $2.08 | $208.00 |
| 500 | $1.87 | $935.00 |
| 1,000 | $1.68 | $1,680.00 |
ATMEGA328PB-MUR Overview
An 8-bit AVR microcontroller is a Harvard-architecture processor that executes most instructions in a single clock cycle, combining program Flash, data SRAM, and EEPROM on one die. Within the power management and embedded control hierarchy, MCUs like the ATmega328PB sit at the heart of industrial sensors, consumer appliances, and hobbyist platforms such as Arduino-compatible boards.
Key differentiating features include two 8-bit timer/counters and two 16-bit timer/counters with compare modes and PWM, one UART with hardware LIN support, two I2C (TWI) interfaces, and two SPI interfaces - double the peripheral set of the ATmega328P. An 11-channel 10-bit ADC with differential programmable-gain inputs, 27 general purpose I/O lines, and a 32-general-purpose-register file round out the analog and digital capability.
The picoPower technology suite provides multiple sleep modes (Idle, ADC Noise Reduction, Power-save, Power-down, Standby, Extended Standby) with wake-up via interrupt, plus an on-chip debug capability via debugWIRE. The AVR enhanced RISC core executes powerful instructions in single cycles, and self-programmable Flash with read-while-write support enables in-system programming and boot-loader firmware updates without an external programmer.
Typical applications include battery-powered sensor nodes where picoPower sleep modes extend battery life, industrial control panels using the dual SPI/I2C buses for multi-peripheral designs, and Arduino-compatible consumer products. The 32-VFQFN 5x5 mm footprint suits space-constrained PCBs while remaining hand-solderable with hot air.
Design consideration: the ATmega328PB is software-backward-compatible with the ATmega328P but exposes its added Port E and second I2C/SPI buses on pins that differ, so verify the 32-pin VFQFN pin map before reusing a legacy ATmega328P footprint.
This page synthesizes distributor pricing, drop-in alternatives, application guidance, and design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for ATMEGA328PB-MUR — 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-MUR (same form factor and footprint) — differing in Package, ADC Channels, ADC Resolution, Core Processor, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA328PB-MU
✅ Drop-In✓ In Stock
$1.19 / Unit
View Datasheet →ATMEGA328PB-MNR
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA328P-MU
✅ Drop-In✓ In Stock
$1.28 / Unit
View Datasheet →ATMEGA328-MUR
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.84 / Unit
View Datasheet →ATMEGA168PB-MU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.31 / Unit
View Datasheet →ATMEGA328PB-MUR Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Flash Memory | 32 KB (16K x 16) |
| EEPROM | 2 KB |
| SRAM | 4 KB (2K x 8) |
| General Purpose I/O | 27 |
| Working Registers | 32 |
| ADC Resolution | 10-bit |
| ADC Channels | 11 |
| I2C (TWI) Interfaces | 2 |
| SPI Interfaces | 2 |
| UART | 1 with hardware LIN |
| Timers | 2 x 8-bit, 2 x 16-bit |
| Package | 32-VFQFN (5x5 mm) |
| Operating Temperature | -40C to +85C (Industrial) |
| Mounting Type | Surface Mount |
| Programmability | ISP, read-while-write, debugWIRE |
| Low Power Technology | picoPower |
ATMEGA328PB-MUR Pin Configuration
| Pin 1 | PD3 — Port D bit 3 (GPIO / PCINT19) |
| Pin 2 | PD4 — Port D bit 4 (GPIO / XCK / PCINT20) |
| Pin 3 | GND — Ground |
| Pin 4 | VCC — Digital supply voltage |
| Pin 5 | GND — Ground |
| Pin 6 | VCC — Digital supply voltage |
| Pin 7 | PB6 — Port B bit 6 (XTAL1 / TOSC1 / PCINT6) |
| Pin 8 | PB7 — Port B bit 7 (XTAL2 / TOSC2 / PCINT7) |
| Pin 9 | PD5 — Port D bit 5 (GPIO / T1 / PCINT21) |
| Pin 10 | PD6 — Port D bit 6 (GPIO / AIN0 / PCINT22) |
| Pin 11 | PD7 — Port D bit 7 (GPIO / AIN1 / PCINT23) |
| Pin 12 | PB0 — Port B bit 0 (GPIO / XCK0 / T0 / PCINT8) |
| Pin 13 | PB1 — Port B bit 1 (GPIO / OC1A / PCINT9) |
| Pin 14 | PB2 — Port B bit 2 (GPIO / SS / OC1B / PCINT10) |
| Pin 15 | PB3 — Port B bit 3 (MOSI / OC2A / PCINT11) |
| Pin 16 | PB4 — Port B bit 4 (MISO / PCINT12) |
| Pin 17 | PB5 — Port B bit 5 (SCK / PCINT13) |
| Pin 18 | AVCC — ADC supply voltage |
| Pin 19 | ADC6 — ADC input channel 6 (PE0) |
| Pin 20 | AREF — ADC reference voltage |
| Pin 21 | GND — Ground |
| Pin 22 | ADC7 — ADC input channel 7 (PE1) |
| Pin 23 | PC0 — Port C bit 0 (ADC8 / SCL1) |
| Pin 24 | PC1 — Port C bit 1 (ADC9 / SDA1) |
| Pin 25 | PC2 — Port C bit 2 (ADC10 / TOSC2) |
| Pin 26 | PC3 — Port C bit 3 (ADC11 / TOSC1) |
| Pin 27 | PC4 — Port C bit 4 (SDA / ADC12 / PCINT18) |
| Pin 28 | PC5 — Port C bit 5 (SCL / ADC13 / PCINT17) |
| Pin 29 | PC6 — RESET (active-low reset input) |
| Pin 30 | PD0 — Port D bit 0 (RXD / PCINT16) |
| Pin 31 | PD1 — Port D bit 1 (TXD / PCINT17) |
| Pin 32 | PD2 — Port D bit 2 (GPIO / INT0 / PCINT18) |
Typical Applications
ATMEGA328PB-MUR is suitable for 6 applications: Battery-Powered Sensor Nodes, Arduino-Compatible Consumer Products, Industrial Control Panels, Motor Control and PWM Actuation, Legacy ATmega328P Board Migration, IoT Edge Nodes and Gateways.
Battery-Powered Sensor Nodes
The ATMEGA328PB-MUR suits battery-powered nodes because picoPower technology provides six sleep modes (Idle, ADC Noise Reduction, Power-save, Power-down, Standby, Extended Standby) with interrupt wake-up, letting the MCU spend most of its life in Power-down. A 20 MHz AVR core completes burst sampling quickly, then sleeps; the 11-channel 10-bit ADC reads sensors without an external converter. Design the node so the RTC or pin-change interrupt wakes the part on schedule, and expect battery life dominated by sleep-mode current rather than active duty, especially at reduced clock voltage scaling.
Recommended
Arduino-Compatible Consumer Products
Arduino-compatible products benefit from the ATMEGA328PB-MUR because it is software-backward-compatible with the ATmega328P while adding two I2C buses, two SPI buses, and extra PWM channels that let a single MCU drive displays, sensors, and actuators without port expanders. The 32 KB Flash hosts boot-loader-based field updates, and the 5x5 mm VFQFN fits compact consumer PCBs. Firmware built with Arduino cores targeting the 328PB compiles unchanged from 328P projects; validate device signature and fuses during production programming.
Recommended
Industrial Control Panels
Industrial control panels use the ATMEGA328PB-MUR for its -40C to +85C industrial rating, dual SPI and dual I2C interfaces that isolate a real-time sensor bus from a slower configuration bus, and four timer/counters generating PWM for actuator control. Hardware LIN on the UART supports point-to-point links to subordinate nodes in distributed I/O. For hotter enclosures, specify the ATMEGA328PB-MNR variant rated to +105C on the identical footprint, avoiding a board respin while meeting temperature derating requirements.
Recommended
Motor Control and PWM Actuation
Motor and actuator control exploits the ATMEGA328PB-MUR's two 8-bit and two 16-bit timer/counters with compare modes, delivering up to nine PWM outputs from one 20 MHz core. The 16-bit timers support precise phase-correct PWM for fans, pumps, and servo positioning, while input-capture modes measure feedback tachometer signals. Differential ADC inputs with programmable gain read shunt or hall current signals. Keep PWM traces short and gate-drive grounds star-connected to the power stage to prevent switching noise from corrupting the 10-bit ADC conversions.
Recommended
Legacy ATmega328P Board Migration
Manufacturers maintaining ATmega328P-based boards migrate to the ATMEGA328PB-MUR because the 328P is no longer recommended for new designs and the PB preserves the 32 KB Flash, 4 KB SRAM, and 20 MHz performance on the same 32-VFQFN footprint class. Where the PCB leaves the reassigned Port E and second-bus pins unused, the board often accepts the PB without respin. Recompile firmware unchanged, update the programmer's device signature, and verify sleep-mode currents and fuse defaults against the 40001906C datasheet before release.
Recommended
IoT Edge Nodes and Gateways
IoT edge nodes pair the ATMEGA328PB-MUR with a radio module over one of its two SPI interfaces, reserving the second SPI or I2C bus for local sensors, and using the UART with hardware LIN for module handshaking. PicoPower sleep modes conserve battery between radio wake-ups, and 32 KB Flash fits protocol stacks plus boot loaders. Because the ADC offers 11 channels, a single MCU can aggregate several analog sensors before transmission, reducing bill-of-materials count versus discrete front ends in compact endpoint hardware.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA328PB-MUR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA328PB-MU | ATMEGA328PB-MNR | ATMEGA328P-MU | ATMEGA168PB-MU |
|---|---|---|---|---|---|
| Package | 32-VFQFN (5x5 mm) | 32-VFQFN (5x5 mm) - same | 32-VFQFN (5x5 mm) - same | 32-VFQFN (5x5 mm) - same | 32-VFQFN (5x5 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 16 KB |
| SRAM | 4 KB | 4 KB | 4 KB | 2 KB | 1 KB |
| I2C Interfaces | 2 | 2 | 2 | 1 | 1 |
| SPI Interfaces | 2 | 2 | 2 | 1 | 1 |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +105C | -40C to +85C | -40C to +85C |
| Lifecycle Status | Active | Active | Active | NRND (not recommended for new designs) | Active |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
Key Differentiators
- Doubled communication peripherals (vs ATMEGA328P-MU)
- Active lifecycle status (vs ATMEGA328P-MU)
- Extended temperature option on same footprint (vs ATMEGA328PB-MU)
- Trade-off: SRAM advantage over legacy (vs ATMEGA328P-MU)
Design Notes
The 32-VFQFN exposed pad must be soldered to a grounded copper pour via a 3x3 via array for mechanical reliability and thermal dissipation. Follow the Microchip QFN land-pattern guidelines: extend the pad aperture slightly beyond the package and use solder-mask-defined openings on perimeter pins to prevent bridging on the 0.5 mm pitch. Inspect with X-ray or angled AOI since the pads are hidden under the body after reflow.
Decouple each VCC pin (pins 4 and 6) with 100 nF ceramic capacitors placed within 2 mm of the pin, plus one 4.7 uF to 10 uF bulk capacitor near the supply entry. AVCC (pin 18) must be connected to VCC through a low-pass LC filter (e.g., 10 uH inductor and 100 nF) when ADC accuracy matters; per the Microchip datasheet, AVCC should never differ from VCC by more than 0.3 V. Tie GND pins 3, 5, and 21 directly to the exposed-pad pour.
When migrating from ATmega328P, do not assume pin identity: the PB moves the second I2C (SCL1/SDA1), second SPI, and Port E functions to different VFQFN pins. Also update the device signature in ISP programming tools - the 328PB signature differs from the 328P, so avrdude or production programmers must target the correct part or verification fails. Verify fuse defaults and sleep-mode current figures against datasheet 40001906C rather than 328P documentation.
Keep the crystal (PB6/PB7) traces as short as possible and surround the crystal area with a guard ground pour to reduce radiated emissions and improve start-up margin. Route SPI1 and SPI0 clock traces away from the ADC input traces, and place series termination resistors (22 to 33 ohm) on fast SPI SCK lines above 8 MHz to dampen ringing. These measures help pre-compliance testing for CISPR-class consumer products.
Compliance Information
RoHS compliance and lead-free finish per distributor listings (DigiKey/Mouser) for the 32-VFQFN package. REACH, halogen-free, and conflict-minerals statuses not stated in the provided web data - request the official Microchip product environmental report.
