ATMEGA324PB-MUR - 8-bit AVR MCU 20MHz 32KB | Microchip
MPN: ATMEGA324PB-MUR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.42 | $3.42 |
| 10 | $3.08 | $30.80 |
| 100 | $2.74 | $274.00 |
| 500 | $2.46 | $1,230.00 |
| 1,000 | $2.21 | $2,210.00 |
ATMEGA324PB-MUR Overview
An ATmega microcontroller is a member of the AVR family of 8-bit RISC microcontrollers - a product hierarchy spanning microcontroller unit (MCU), embedded processor, and integrated circuit. MCUs of this class integrate CPU, program memory, data memory, peripherals (UART, SPI, I2C, timers, ADC), and I/O on a single die, making them the backbone of embedded control systems in industrial, consumer, and touch-sensing applications.
Key features of the ATMEGA324PB include five USARTs, two SPI and two I2C (TWI) interfaces for expanded connectivity, a 10-bit ADC, and a Peripheral Touch Controller (PTC) that supports 32 buttons in self-capacitance mode or up to 256 buttons in mutual-capacitance mode. The ATmega324PB also provides seven additional GPIOs on PORTE, giving engineers more I/O than the earlier ATmega324PA generation.
Architecturally, the device executes most AVR instructions in a single clock cycle through an efficient RISC pipeline, delivering roughly 1 MIPS per MHz. Operating from 1.7 V to 5.5 V (industrial temperature range per the Mouser listing of GREEN, industrial temp, 5 V reference), it supports multiple sleep modes for aggressive power reduction in battery-operated designs.
Typical applications include capacitive touch HMI panels (leveraging the QTouch PTC supported by Microchip QTouch Composer), industrial control and automation nodes, and embedded systems with rich serial connectivity such as multi-channel communications bridges.
A key design consideration: program the device through its SPI interface or bootloader, and reserve the PORTE pins (PE0, PE1, PE4 multiplexed with XTAL2, XTAL1, AREF) carefully when using an external crystal.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA324PB-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 ATMEGA324PB-MUR (same form factor and footprint) — differing in Package, Flash Memory, RoHS Status, Connectivity, Functional Safety.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA324PA-MU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.05 / Unit
View Datasheet →ATMEGA324A-MUR
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA324P-20MQ
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$4.15 / Unit
View Datasheet →ATMEGA644PV-10MU
✅ Drop-In✓ In Stock
$4.88 / Unit
View Datasheet →ATMEGA32A-MU
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA324PB-MUR Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Flash Memory Size | 32 KB (16K x 16) |
| SRAM | 2 KB |
| EEPROM | 1 KB |
| Connectivity | I2C, SPI, UART/USART |
| Number of USARTs | 5 |
| Peripheral Touch Controller | 32 self-cap buttons / 256 mutual-cap buttons |
| Package | 44-VQFN (7x7 mm) with exposed pad |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (T&R) |
| Functional Safety | FuSa qualified series |
| Series | AVR ATmega, Functional Safety (FuSa) |
| RoHS Status | Green (RoHS compliant per Mouser GREEN listing) |
ATMEGA324PB-MUR 44-vqfn (7x7 mm) with exposed pad Pin Configuration Guide
Pin configuration for ATMEGA324PB-MUR (44-vqfn (7x7 mm) with exposed pad 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 ATMEGA324PB-MUR.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA324PB-MUR is suitable for 6 applications: Capacitive Touch HMI Panels, Industrial Control and Automation Nodes, Multi-Channel Serial Communication Bridges, Battery-Powered Portable Devices, Consumer Appliance Control Boards, Sensor Data Acquisition Systems.
Capacitive Touch HMI Panels
The ATMEGA324PB-MUR is purpose-built for touch interfaces through its hardware Peripheral Touch Controller (PTC), which acquires capacitive sensor signals and supports 32 buttons in self-capacitance mode or up to 256 buttons in mutual-capacitance mode according to Microchip's product page. Because PTC scanning is performed in hardware, the 20 MHz AVR core remains free for application logic, display updates, and communications - a decisive advantage over software-only touch implementations on the ATMEGA324PA-MU. Microchip's QTouch Composer tool (QTouch Library project builder and QTouch Analyzer) accelerates design, tuning, and validation of touch channels. Placed in a 44-VQFN 7x7 mm footprint with exposed pad for grounding, the device drives multiple sensor lines while its five USARTs and dual I2C interfaces report touch events to host controllers or displays.
Recommended
Industrial Control and Automation Nodes
In factory automation, the ATMEGA324PB-MUR serves as a control node combining sensor acquisition and actuator drive. Its membership in the AVR ATmega Functional Safety (FuSa) series, noted on DigiKey's listing, supports functional-safety-oriented industrial design workflows, while the Mouser listing confirms industrial temperature grading. The five USARTs allow simultaneous connection of sensors, RS-485 modems, and diagnostic ports; dual SPI and dual I2C (TWI) buses interface ADCs, EEPROMs, and real-time clocks without bus contention. The 20 MHz core delivers approximately 20 MIPS of AVR RISC throughput, sufficient for PID loops and protocol stacking, and the 10-bit ADC handles analog sensor inputs. The 44-VQFN exposed-pad package dissipates heat efficiently in sealed industrial enclosures, and the 1 KB EEPROM retains calibration data across power cycles without external memory.
Recommended
Multi-Channel Serial Communication Bridges
With five USARTs, two SPI, and two I2C interfaces, the ATMEGA324PB-MUR is one of the most serially connected ATmega devices in its class, making it a natural protocol bridge or gateway. A typical design links multiple asynchronous channels - for example three device UARTs, one debug console, and one RS-485 fieldbus port - simultaneously at up to 20 MHz-derived baud rates, something the ATMEGA324PA-MU (two USARTs) cannot do without external UART expansion. The 2 KB SRAM supports modest buffering of multiple concurrent streams, and the 32 KB FLASH hosts protocol stacks for Modbus, custom telemetry, or command parsing. The 44-VQFN (7x7 mm) footprint keeps the bridge compact on dense industrial PCBs while the exposed pad provides low-impedance ground for signal integrity across mixed-voltage domains.
Recommended
Battery-Powered Portable Devices
The ATMEGA324PB-MUR suits battery-operated equipment through the AVR architecture's multiple sleep modes combined with a rich peripheral set that stays usable across low-voltage rails. The PB generation's additional PORTE GPIOs (seven extra pins multiplexed with XTAL1, XTAL2, and AREF) let designers control more peripherals - power switches, LED indicators, and sensor enables - without adding an I/O expander, reducing board cost and standby quiescent draw. The Peripheral Touch Controller enables touch buttons on sealed enclosures where mechanical switches compromise ingress protection, and hardware scanning wakes the core only on detection, extending battery life. Designers should size sleep-mode currents and crystal startup time carefully per the datasheet, balancing 20 MHz peak performance against average power budget in intermittent-operation products such as meters and handheld instruments.
Recommended
Consumer Appliance Control Boards
Appliance controllers - washing machines, cooktops, and HVAC interfaces - benefit from the ATMEGA324PB-MUR's combination of touch sensing, serial connectivity, and cost-efficient 8-bit processing. The QTouch PTC implements capacitive button and slider interfaces on glass or plastic panels, supporting up to 256 mutual-capacitance nodes for premium user interfaces, while the five USARTs and dual I2C buses talk to display drivers, motor-drive controllers, and cloud-connectivity modules. The Mouser listing confirms the GREEN (halogen-free/RoHS-oriented) industrial-temp build in tape and reel, aligning with consumer-product compliance requirements. The 44-VQFN 7x7 mm exposed-pad package reflows on standard lead-free SMT lines, and the 20 MHz AVR core with 32 KB FLASH covers wash-cycle state machines, PWM heater/motor control, and safety interlock logic in one chip.
Recommended
Sensor Data Acquisition Systems
The ATMEGA324PB-MUR fits multi-sensor acquisition nodes where its 10-bit ADC, dual I2C buses, and dual SPI interfaces gather data from diverse sensor types simultaneously - analog channels on the ADC, digital temperature/pressure sensors on one I2C bus, and high-rate SPI sensors such as accelerometers on the other. Five USARTs stream acquired data to local loggers, radio modules, or PLC links in parallel. The 1 KB EEPROM stores calibration coefficients per unit, and the 20 MHz RISC core executes averaging, filtering, and threshold logic with deterministic single-cycle instruction timing beneficial for sampling discipline. According to Microchip documentation, PE0/PE1/PE4 multiplex with XTAL2, XTAL1, and AREF; in ADC-critical designs, running on the internal RC oscillator frees those pins, reserving external-crystal accuracy only where the timebase demands it.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA324PB-MUR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA324PA-MU | ATMEGA324A-MUR | ATMEGA32A-MU | ATMEGA644PV-10MU |
|---|---|---|---|---|---|
| Package | 44-VQFN (7x7 mm) EP | 44-VQFN (7x7 mm) - same | 44-VQFN - same | 44-QFN - same footprint | 44-QFN - same footprint |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 16 MHz | 10 MHz |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 64 KB |
| USART Count | 5 | 2 | 1 | 1 | 2 |
| Peripheral Touch Controller (PTC) | Yes (32 self-cap / 256 mutual-cap) | No | No | No | No |
| I2C / SPI Interfaces | 2 / 2 | 1 / 1 | 1 / 1 | 1 / 1 | 1 / 1 |
| Functional Safety Series | Yes (FuSa) | No | No | No | No |
| Lifecycle Status | Active | Active | Active | Active | Active |
Key Differentiators
- Five hardware USARTs versus two (vs ATMEGA324PA-MU)
- Hardware QTouch Peripheral Touch Controller (vs ATMEGA324A-MUR)
- Functional Safety (FuSa) series qualification (vs ATMEGA32A-MU)
Design Notes
Reserve PORTE multiplexed pins deliberately: per Microchip online documentation, PE0, PE1, and PE4 are assigned to pin 7, pin 8, and pin 29 and are multiplexed with XTAL2, XTAL1, and AREF. If you use an external crystal, PE0 and PE1 are consumed; if you rely on the external ADC reference, PE4 is unavailable as GPIO. Firmware written for the ATMEGA324PA will run on the PB die, but features that assume only two USARTs must be audited before migrating the reverse direction - code that programs UART2-4 register addresses will fault or no-op on older variants.
The 44-VQFN (7x7 mm) exposed-pad package requires the exposed pad to be soldered to a grounded copper pour for both mechanical reliability and thermal/noise performance. Use an array of thermal vias (typical 4x4 pattern) under the pad to tie it to internal ground planes. Decouple VCC and AVCC with 100 nF ceramic capacitors placed within 2 mm of the respective pins, and add 10 uF bulk capacitance near the supply entry. During reflow, follow Microchip's MSL rating and VQFN reflow profile to avoid wetting failures on the concealed pad.
For PTC touch designs, route sensor traces as short as possible, away from switching traces and crystal lines, and keep ground floods between adjacent channels to reduce crosstalk. Microchip's QTouch Composer provides channel tuning and sensitivity analysis - calibrate each channel on the production PCB, not a reference board, because overlay thickness and trace capacitance shift thresholds. For crystal operation, keep XTAL1/XTAL2 traces under 10 mm and guard them with ground to maintain startup margin at 20 MHz, especially across the industrial temperature range.
Compliance Information
Mouser listing identifies the ATMEGA324PB-MUR as a GREEN industrial-temp part, indicating RoHS-aligned green packaging; formal REACH/halogen-free declarations were not present in the provided data.