ATMEGA324PB-MU - 8-bit AVR MCU 20MHz 32KB Flash 44-VQFN | Microchip
MPN: ATMEGA324PB-MU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.88 | $1.88 |
| 25 | $1.72 | $43.00 |
| 100 | $1.56 | $156.00 |
| 500 | $1.45 | $725.00 |
| 1,000 | $1.35 | $1,350.00 |
ATMEGA324PB-MU Overview
A microcontroller (MCU) is a single-chip computer that integrates a processor core, memory, and programmable peripherals into one integrated circuit, forming the lowest layer of the embedded-system hierarchy that spans from discrete transistors up to application processors. The ATmega family belongs to Microchip's (formerly Atmel) 8-bit AVR product line, widely used across industrial, consumer, and automotive-adjacent designs.
Key features of the ATMEGA324PB include the QTouch Peripheral Touch Controller (PTC), which supports 32 buttons in self-capacitance mode or up to 256 buttons in mutual-capacitance mode, dramatically simplifying capacitive touch designs. Compared with the earlier ATmega324PA, the PB variant adds seven extra GPIOs on PORTE and additional timers, connectivity peripherals, and serial interfaces for the same footprint.
Technically, the device uses the AVR enhanced RISC architecture with 32 general-purpose working registers, executing most instructions in a single clock cycle for high code efficiency. The picoPower technology provides multiple sleep modes for ultra-low standby consumption, while brown-out detection and an on-chip debugger via debugWIRE/ISP support robust, in-system development. I2C (TWI), SPI, and UART/USART interfaces cover typical communication needs.
Typical applications include capacitive touch HMI panels (human-machine interfaces), industrial sensors and control nodes, and consumer appliance controls, where the PTC offloads touch acquisition from the CPU and the 20 MHz core handles real-time tasks. Functional Safety (FuSa) documentation support also assists safety-oriented designs.
When designing with the ATMEGA324PB-MU, note that PE0, PE1, and PE4 are multiplexed with XTAL2, XTAL1, and AREF respectively, so using these pins as GPIO requires external-clock or RC-oscillator configurations. Ensure 5 V supply operation for the full 20 MHz speed rating.
This page synthesizes verified distributor pricing, drop-in alternative cross-references, and practical design notes not found in the manufacturer datasheet, providing engineers a single citable reference for selection and sourcing decisions as of 2026-09-17.
Drop-in alternatives for ATMEGA324PB-MU — 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-MU (same form factor and footprint) — differing in Package, Flash Memory, Connectivity, Packaging, Operating Temperature.
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-MU
✅ Drop-In✓ In Stock
$3.9 / Unit
View Datasheet →ATMEGA324P-20MU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$3.8 / Unit
View Datasheet →ATMEGA324PV-10MU
✅ Drop-In✓ In Stock
$5.98 / Unit
View Datasheet →ATMEGA324PB-MU Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Flash Memory | 32 KB (16K x 16) ISP, read-while-write |
| EEPROM | 1 KB |
| SRAM | 2 KB |
| Number of I/O | 39 |
| Timers/Counters | 5 flexible timer/counters |
| Connectivity | I2C, SPI, UART/USART |
| Touch Controller | QTouch PTC - 32 buttons self-cap, up to 256 buttons mutual-cap |
| Peripherals | Brown-out Detect/Reset, picoPower low-power modes |
| Operating Voltage | 5 V |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | 44-VQFN (7x7 mm) |
| Mounting Type | Surface Mount |
| Oscillator Type | Internal (XTAL1/XTAL2 pins on PE1/PE0) |
| Features | Functional Safety (FuSa) supported |
ATMEGA324PB-MU 44-vqfn (7x7 mm) Pin Configuration Guide
Pin configuration for ATMEGA324PB-MU (44-vqfn (7x7 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 ATMEGA324PB-MU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA324PB-MU is suitable for 6 applications: Capacitive Touch HMI Panels, Industrial Sensors and Control Nodes, Home Appliance Controls, Embedded IoT Sensor Endpoints, Motor Control and PWM Systems, Safety-Oriented Embedded Systems.
Capacitive Touch HMI Panels
The ATMEGA324PB-MU fits capacitive touch human-machine interface designs because its integrated QTouch Peripheral Touch Controller acquires sensor signals in dedicated hardware, supporting 32 buttons in self-capacitance mode and up to 256 buttons in mutual-capacitance mode. This hardware acquisition offloads the 20 MHz AVR core, freeing CPU cycles for application logic and communication. In a typical design, the PTC scans electrode arrays connected to the 39 GPIOs while the QTouch Composer tool (QTouch Library project builder and QTouch Analyzer) generates tuning parameters, reducing development risk. Because touch scanning happens in the peripheral, response latency stays low even with many keys active, a quantified benefit over software-only touch implementations on standard MCUs.
Recommended
Industrial Sensors and Control Nodes
The ATMEGA324PB-MU suits industrial sensing and control nodes due to its -40C to +85C industrial temperature rating, 5 V noise-tolerant operation, brown-out detection/reset, and I2C, SPI, and UART/USART connectivity for field buses and sensor links. The five flexible timer/counters handle PWM motor control, encoder counting, and precise event timing, while 32 KB flash with read-while-write allows field firmware updates without stalling execution. The 39 GPIO lines interface relays, optocouplers, and multiple sensor channels in one 7x7 mm VQFN footprint, shrinking PCB area versus larger packages. Microchip's Functional Safety (FuSa) documentation for the AVR ATmega family additionally assists designs targeting safety-related industrial functions.
Recommended
Home Appliance Controls
The ATMEGA324PB-MU is well matched to appliance control boards that combine touch buttons, displays, motors, and communication. The QTouch PTC replaces discrete touch ICs, detecting up to 32 self-capacitance keys directly, while the 20 MHz AVR core drives segment/LCD-style indicators through GPIOs and manages fan or pump motors via timer PWM outputs. PicoPower sleep modes keep standby consumption low for always-plugged appliances, an important regulatory consideration, and the 1 KB EEPROM stores user settings and cycle counters across power cycles. Industrial temperature rating and brown-out protection maintain reliability in kitchens with wide ambient swings and noisy motor-driven supply lines, reducing warranty returns in volume consumer production.
Recommended
Embedded IoT Sensor Endpoints
For battery- and mains-powered IoT endpoints, the ATMEGA324PB-MU offers picoPower technology with multiple sleep modes that minimize average current between sensor readings, while the 20 MHz core processes and packages measurements quickly to shorten active-duty windows. UART/USART and I2C interfaces connect to radio modules and digital sensors, and 2 KB SRAM plus 32 KB flash accommodate protocol stacks such as lightweight messaging formats. The 44-VQFN 7x7 mm package keeps endpoint PCBs compact. Designers should note PE0/PE1/PE4 multiplexing with XTAL2/XTAL1/AREF when budgeting GPIO for sensor banks. Five timers support duty-cycled sampling schedules and wake-up timing without CPU supervision, extending battery life measurably versus polled designs.
Recommended
Motor Control and PWM Systems
The ATMEGA324PB-MU supports small motor control applications through its five flexible timer/counters, which generate multiple independent PWM channels for brushed DC, stepper, and small BLDC drive stages at 20 MHz resolution. The 39 GPIOs provide gate or driver-interface lines plus limit-switch and encoder inputs, and the brown-out detector prevents corrupt PWM states during supply dips. Industrial temperature rating tolerates drive-enclosure heat, and the 5 V logic integrates directly with common gate-driver families. Because PWM generation is peripheral-driven, interrupt latency does not distort duty cycles, a measurable benefit for closed-loop speed control. UART connectivity enables command interfaces to supervisory controllers or fieldbus bridges in machinery retrofits.
Recommended
Safety-Oriented Embedded Systems
The ATMEGA324PB-MU is positioned for functional-safety-oriented designs: DigiKey classifies it under AVR ATmega Functional Safety (FuSa) microcontrollers, and Microchip provides supporting safety documentation for the family. Key hardware building blocks for such systems include the brown-out detect/reset circuit, the on-chip ISP/debug infrastructure for verified field updates, and read-while-write flash enabling safe self-programming with integrity checks. The 20 MHz single-cycle RISC core gives deterministic instruction timing that simplifies worst-case execution-time analysis compared with pipelined competitors. Designers typically pair the MCU with external supervision and use the QTouch PTC for safety-rated touch inputs, relying on Microchip's QTouch Analyzer to validate sensor behavior across environmental conditions.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA324PB-MU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA324PA-MU | ATMEGA324A-MU | ATMEGA324P-20MU | ATMEGA324PV-10MU |
|---|---|---|---|---|---|
| Package | 44-VQFN (7x7 mm) | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 10 MHz |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 32 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB | 2 KB |
| GPIO Count | 39 | 32 | 32 | 32 | 32 |
| Timers/Counters | 5 | 4 | 4 | 4 | 4 |
| Touch Controller (QTouch PTC) | Yes (32 self-cap / 256 mutual-cap buttons) | Limited PTC support | No | No | No |
Key Differentiators
- Highest GPIO count in the ATmega324 44-VQFN family (vs ATMEGA324PA-MU)
- Fifth timer/counter for complex PWM and timing (vs ATMEGA324A-MU)
- Full QTouch PTC with 256-button mutual-capacitance support (vs ATMEGA324P-20MU)
Design Notes
The 44-VQFN 7x7 mm package has a peripheral lead pitch that requires careful stencil design for reflow soldering. Use a standard 0.5 mm pitch QFN footprint with thermal vias under the center pad tied to a ground plane for heat spreading and a solid ground return. Keep decoupling capacitors (100 nF ceramic per supply pin) within 2 mm of the VCC/AVCC pins. The 7x7 mm body is hand-solderable with hot air but inspect with X-ray or angled optical to confirm lead wetting.
PORTE adds seven GPIOs compared with the ATMEGA324PA, but PE0, PE1, and PE4 are multiplexed with XTAL2, XTAL1, and AREF respectively (PE0 on pin 7, PE1 on pin 8, PE4 on pin 29 per Microchip documentation). If your firmware assumes 39 GPIOs and uses PE0/PE1 as outputs, you must configure an external clock or RC oscillator first. Firmware written for the ATMEGA324PA that touches PB-only registers will not run unchanged on older variants during cost-down redesigns.
The device is specified at 5 V for the full 20 MHz speed rating; always verify the AVCC pin is connected to a clean supply when using the ADC or the QTouch PTC, since touch sensitivity degrades with noisy analog rails. Add a 100 nF capacitor close to AVCC and route the analog ground separately back to the center pad. Brown-out detection should be enabled in fuses for industrial supplies to prevent EEPROM corruption during brown-outs.
Compliance Information
Mouser listing describes the part as GREEN, suggesting lead-free/RoHS-aligned packaging, but explicit RoHS/REACH certificates were not present in the provided verified data; consult Microchip's product page for compliance documents.