ATMEGA324PB-MN - 8-bit AVR MCU 20MHz 32KB Flash | Microchip
MPN: ATMEGA324PB-MN ✓ 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 | $2.19 | $2,190.00 |
ATMEGA324PB-MN Overview
An 8-bit AVR microcontroller is a single-chip processor that executes an AVR enhanced RISC instruction set, combining flash program memory, SRAM, EEPROM, timers, and peripherals on one die. Microcontrollers sit at the heart of embedded systems, above discrete logic and below application processors in the computing hierarchy, and the ATmega series is one of the most widely deployed 8-bit MCU families in industrial and consumer designs.
Key features of the ATmega324PB include 32KB of read-while-write ISP flash, 1KB EEPROM, 2KB SRAM, 39 general purpose I/O lines, and five flexible timer/counters. Compared with the earlier ATmega324PA, the PB variant adds two additional USARTs, an extra SPI and TWI (I2C) interface, and a Peripheral Touch Controller (PTC) supporting 32 buttons in self-capacitance mode or up to 256 buttons in mutual-capacitance mode.
The AVR core executes most instructions in a single clock cycle, achieving up to 20 MIPS at 20MHz. The picoPower technology provides multiple sleep modes for very low average power consumption, while seven additional GPIOs on PORTE (PE0-PE6) extend package pin utility; PE0, PE1, and PE4 are multiplexed with XTAL2, XTAL1, and AREF respectively.
Typical applications include capacitive touch interfaces (human-machine interfaces, appliance controls), industrial sensor nodes and factory automation, and consumer products requiring multiple serial channels, with QTouch Composer tool support from Microchip.
Design consideration: the -MN suffix denotes extended temperature operation in the VQFN package; verify thermal pad soldering on the exposed pad for reliable ground and heat dissipation in enclosed products.
This page synthesizes distributor pricing, drop-in alternatives, pinout guidance, and practical design notes not found in the manufacturer datasheet, with prices as of 2026-09-17.
Drop-in alternatives for ATMEGA324PB-MN — 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-MN (same form factor and footprint) — differing in Package, Flash Memory, Connectivity, Functional Safety, Number of I/O.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA324PB-MU
✅ Drop-In✓ In Stock
$1.35 / Unit
View Datasheet →ATMEGA324PB-MNR
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA324PB-MUR
✅ Drop-In✓ In Stock
$2.21 / Unit
View Datasheet →ATMEGA324PA-MCHR
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.55 / Unit
View Datasheet →ATMEGA324PA-MCH
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.45 / Unit
View Datasheet →ATMEGA324PB-MN Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Flash Memory | 32 KB (16K x 16) |
| EEPROM | 1 KB |
| SRAM | 2 KB |
| GPIO Count | 39 |
| Timer/Counters | 5 |
| Supply Voltage Range | 1.8 V to 5.5 V |
| Package | 44-VQFN (7x7 mm) Exposed Pad |
| Mounting Type | Surface Mount |
| USART Peripherals | Multiple USARTs (PB variant adds 2 vs PA) |
| Touch Controller | QTouch PTC, 32 self-cap / 256 mutual-cap buttons |
| Connectivity | SPI, I2C (TWI), USART |
| Functional Safety | FuSa capable |
| Technology | picoPower low-power technology |
ATMEGA324PB-MN 44-vqfn (7x7 mm) exposed pad Pin Configuration Guide
Pin configuration for ATMEGA324PB-MN (44-vqfn (7x7 mm) 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-MN.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA324PB-MN is suitable for 6 applications: Capacitive Touch HMI Panels, Industrial Sensor Nodes, Multi-Port Serial Gateways, Consumer Appliance Controls, Battery-Powered Portable Devices, Functional Safety Subsystems.
Capacitive Touch HMI Panels
The ATMEGA324PB-MN is arguably the strongest 8-bit AVR choice for touch user interfaces because its built-in QTouch Peripheral Touch Controller (PTC) acquires capacitive sensor signals in hardware, supporting 32 buttons in self-capacitance mode and up to 256 buttons in mutual-capacitance mode. The multiple USART and TWI interfaces let the same chip drive displays or backhaul data while scanning keys. Development is accelerated with Microchip QTouch Composer, whose QTouch Library project builder and QTouch Analyzer simplify tuning sensitivity and drift compensation. Place sensors with proper ground guarding and scan in intervals between sleep modes to keep average current low, leveraging the picoPower technology for battery-powered touch panels in appliances and building controls.
Recommended
Industrial Sensor Nodes
For industrial sensing and factory automation nodes, the ATMEGA324PB-MN pairs a 20MHz AVR core with 32KB flash and 1.8V-5.5V operation, so a single design tolerates 3.3V logic environments and noisy 5V industrial rails alike. Five timer/counters handle PWM actuator drive and input capture from flow or encoder sensors, while the multiple USART, SPI, and TWI interfaces connect RS-485 transceivers, ADCs, and EEPROM simultaneously. The extended temperature -MN grade suits enclosures that see wide ambient swings. With picoPower sleep modes, a periodically waking sensor node can run for years on a small supply, and the 39 GPIOs plus seven PORTE extras provide headroom for status LEDs, relays, and configuration DIP inputs.
Recommended
Multi-Port Serial Gateways
The ATmega324PB's headline upgrade over the ATmega324PA is serial connectivity: two additional USARTs plus an extra SPI and TWI interface make the ATMEGA324PB-MN a compact protocol converter for translating between UART, I2C, and SPI devices. A typical gateway uses one USART toward an RS-485 field bus, another toward a host or modem, and the TWI/SPI buses for local sensors and configuration memory, all serviced by the 20MHz single-cycle AVR core. The 2KB SRAM accommodates buffering several frames per port, and 1KB EEPROM stores node addresses and calibration constants through power cycles. The VQFN-44's exposed pad gives a solid ground reference that helps serial signal integrity in electrically noisy cabinets.
Recommended
Consumer Appliance Controls
Appliance control boards benefit from the ATMEGA324PB-MN's combination of QTouch PTC touch keys, five timers for triac and buzzer control, and 1.8V-5.5V operation across mains-derived supplies. The 32KB flash is ample for washing-machine or oven state machines with local language strings stored in flash, while the 1KB EEPROM retains user settings such as cycle preferences. picoPower sleep modes meet standby-energy targets because the MCU can dwell in deep sleep and wake on PTC touches or timer overflow. The extended temperature grade -MN covers the warm interiors of appliances near motors and heating elements. QTouch Composer tuning tools shorten the certification-relevant EMI and sensitivity verification cycle.
Recommended
Battery-Powered Portable Devices
Handheld and portable instruments exploit the ATmega324PB's picoPower architecture, which provides multiple sleep modes so the 20MHz core runs only when needed. Operating down to 1.8V, the ATMEGA324PB-MN runs directly from two alkaline cells or a single Li-cell via a simple LDO, extending battery life versus fixed-5V designs. The 39 GPIOs drive segmented LCD logic, keypads, and status indicators, and the multiple USARTs talk to Bluetooth or LoRa modules without bit-banging. Designers should schedule ADC sampling and radio bursts between PTC scans and place the VQFN's exposed pad on a solid ground pour for analog accuracy on the battery rail.
Recommended
Functional Safety Subsystems
The ATmega324PB family is positioned by Microchip as Functional Safety (FuSa) capable, which suits watchdog-backed supervision logic, safety interlock controllers, and monitoring subsystems inside larger machines. The five timer/counters enable windowed watchdog and heartbeat schemes, while the internal voltage and temperature sensors support plausibility checks in firmware. Multiple independent serial channels let one MCU both drive actuators and report diagnostic telemetry over separate USARTs, aiding channel-level fault detection. Designers should follow Microchip's safety documentation for the family and reserve flash headroom (32KB total) for diagnostic code plus CRC checks of program and EEPROM contents executed at startup and periodically at runtime.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA324PB-MN — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA324PB-MU | ATMEGA324PB-MNR | ATMEGA324PB-MUR | ATMEGA324PA-MCHR | ATMEGA324PA-MCH |
|---|---|---|---|---|---|---|
| Package | 44-VQFN (7x7 mm) Exposed Pad | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same | 44-VQFN/MLF (7x7 mm) - same footprint | 44-VQFN/MLF (7x7 mm) - same footprint |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB (16K x 16) | 32 KB | 32 KB | 32 KB | 32 KB | 32 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB | 2 KB | 2 KB |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Serial Interfaces | Multiple USART + SPI + TWI (PB superset) | Same as -MN (PB die) | Same as -MN (PB die) | Same as -MN (PB die) | Fewer: 2 USART, 1 SPI, 1 TWI (PA die) | Fewer: 2 USART, 1 SPI, 1 TWI (PA die) |
| QTouch PTC | Yes (32 self-cap / 256 mutual-cap buttons) | Yes | Yes | Yes | No | No |
| Supply Voltage | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
Key Differentiators
- Four serial interfaces in one 44-pin chip (vs ATMEGA324PA-MCHR)
- Integrated QTouch PTC hardware touch sensing (vs ATMEGA324PA-MCHR)
- Extended temperature grade for harsh enclosures (vs ATMEGA324PB-MU)
Design Notes
The 44-VQFN 7x7 mm package has an exposed thermal pad on the underside that is the primary ground connection for the die. The PCB land pattern must include a matching center pad connected to the ground plane through an array of 4-9 vias. Skipping the exposed-pad connection is a common pitfall that causes intermittent resets and degraded analog performance, especially when the analog comparator (ACO on PC5) or ADC channels are used in the application.
Decouple VCC and AVCC with 100 nF ceramic capacitors placed within 3-5 mm of the respective pins, plus a bulk 4.7-10 uF capacitor near the supply entry. AVCC must be connected to VCC even if the ADC is unused, per standard AVR design practice. When operating below 2.7V, consult the datasheet speed-versus-voltage curve before configuring the 20MHz clock, since the maximum safe frequency scales with supply voltage.
PORTE pins PE0, PE1, and PE4 are multiplexed with XTAL2, XTAL1, and AREF respectively. Enabling an external crystal silently removes PE0/PE1 as GPIOs, so firmware and schematics must agree on crystal versus GPIO usage before layout. Similarly, when using the QTouch PTC, allocate Y-lines and sense lines early because they share ports with the 39 general purpose I/O; the PTC supports 32 self-capacitance or 256 mutual-capacitance buttons depending on the chosen scanning topology.
Estimated: at 5V, 20MHz, and roughly 20 mA active current, the ATmega324PB dissipates about 0.1 W, which is trivial for the VQFN-44's thermal capability; no heatsink is needed. Thermal attention is only warranted when the part sources or sinks large GPIO currents (up to 40 mA per pin, 200 mA total per device class limits) - sum pin currents and keep total package dissipation well under the datasheet absolute maximum to protect the extended-temperature rating.
Compliance Information
Mouser lists the part as GREEN (halogen-free/lead-free per Microchip green designation). Formal REACH and conflict-minerals status not stated in provided data.