ATMEGA324PA-CU - 8-bit AVR MCU 32KB Flash 20MHz VFBGA-49 | Microchip
MPN: ATMEGA324PA-CU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.75 | $3.75 |
| 10 | $3.38 | $33.80 |
| 100 | $3.02 | $302.00 |
| 500 | $2.72 | $1,360.00 |
| 1,000 | $2.45 | $2,450.00 |
ATMEGA324PA-CU Overview
A microcontroller unit (MCU) is a single-chip computer that integrates a processor core, program memory, data memory, and peripherals into one package. Within the power-management hierarchy of embedded systems, the 8-bit AVR family from Microchip (originally Atmel) sits in the cost- and power-sensitive segment between tiny 6-pin MCUs and 32-bit ARM cores, and the ATmega324 series is its mid-density 44/49-pin workhorse for general-purpose embedded control.
Key features of the ATMEGA324PA-CU include 32 general-purpose I/O lines, 32 general-purpose working registers directly connected to the ALU, 131 mostly single-cycle instructions yielding throughput close to 1 MIPS per MHz, and the picoPower low-power technology for sleep currents suited to battery designs. Memory resources are generous for the class: 32 KB of self-programmable ISP Flash with read-while-write capability, 1 KB of EEPROM for non-volatile calibration data, and 2 KB of internal SRAM.
The AVR enhanced RISC architecture executes powerful instructions in a single clock cycle, achieving throughputs up to ten times faster than conventional CISC microcontrollers at the same clock rate. The device supplies three flexible timer/counters with compare modes and PWM, two USARTs for serial communication, a byte-oriented Two-Wire Interface (TWI/I2C), and an 8-channel 10-bit ADC, allowing one chip to service sensing, actuation, and communication simultaneously. Operating supply spans 2.5 V, 3.3 V, and 5 V rails, easing reuse across 5 V industrial and 3.3 V portable designs.
Typical applications include industrial automation nodes, portable battery-powered instruments exploiting picoPower sleep modes, consumer appliance control boards, and sensor hubs using the ADC plus TWI. The 5x5 mm VFBGA-49 ball grid array makes the part attractive for compact, two-sided PCB layouts.
Design consideration: at 20 MHz and 5 V the device is near its speed/voltage corner; verify the speed-versus-voltage curve in the manufacturer datasheet and provide 100 nF decoupling on every VCC/AVCC ball pair.
This page synthesizes distributor cross-reference data, drop-in replacement guidance, and design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA324PA-CU β 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 ATMEGA324PA-CU (same form factor and footprint) β differing in Package, SRAM, Flash Memory, Instruction Set, Timers/Counters.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA324PA-CUR
β Drop-Inβ In Stock
$2.58 / Unit
View Datasheet βATMEGA324PA-CU Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR enhanced RISC |
| Flash Memory | 32 KB (16K x 16) ISP Flash |
| EEPROM | 1 KB |
| SRAM | 2 KB |
| Maximum Clock Frequency | 20 MHz |
| Supply Voltage | 2.5 V / 3.3 V / 5 V |
| I/O Lines | 32 |
| General Purpose Working Registers | 32 |
| Instruction Set | 131 instructions, most single-cycle |
| Timers/Counters | 3 with compare modes and PWM |
| USART | 2 |
| Serial Interface | TWI (I2C-compatible), byte-oriented |
| ADC | 8-channel, 10-bit |
| Low-Power Technology | picoPower |
| Package | 49-VFBGA (5x5 mm) |
| Mounting Type | Surface Mount |
| Programming | In-System Programmable (ISP), read-while-write |
| Lifecycle Stage | ACTIVE |
ATMEGA324PA-CU 49-vfbga (5x5 mm) Pin Configuration Guide
Pin configuration for ATMEGA324PA-CU (49-vfbga (5x5 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 ATMEGA324PA-CU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA324PA-CU is suitable for 6 applications: Industrial Automation Control Nodes, Portable Battery-Powered Instruments, Consumer Appliance Control Boards, Sensor Hubs and Data Acquisition, Embedded Networking Subsystems, Motor Control and Actuation.
Industrial Automation Control Nodes
The ATMEGA324PA-CU fits industrial automation nodes because it combines 32 KB of ISP Flash, two USARTs, and a TWI bus in a single 5x5 mm VFBGA package, enough resources to run Modbus-style serial links, a TWI sensor chain, and PWM actuator control concurrently. The AVR core delivers close to 1 MIPS per MHz, so at 20 MHz roughly 20 MIPS are available for control loops. The 8-channel 10-bit ADC accepts multiple analog sensor inputs without external multiplexers, and 1 KB EEPROM retains calibration data across power cycles. Operation at 5 V matches legacy industrial logic levels, improving noise margins on long board traces. Designers should allocate the two USARTs to RS-485 and a service port respectively and keep ISR latency within the timer period.
Recommended
Portable Battery-Powered Instruments
Battery-powered instruments benefit directly from the picoPower technology that defines the ATMEGA324PA: the PA revision of the ATmega324P was engineered specifically for reduced active and sleep current, so handheld meters, loggers, and testers can sleep for long intervals between measurements. The 2.5 V supply capability allows direct operation from two NiMH cells or a low-voltage LDO rail, while the 8-channel 10-bit ADC digitizes sensor outputs on-chip, removing external converter components and their quiescent budgets. The 49-ball VFBGA (5x5 mm) conserves board area in handheld enclosures, and the on-chip EEPROM stores calibration constants without external NVM. Design practice: use the deepest sleep mode compatible with the required wake latency and clock the ADC only during measurement windows.
Recommended
Consumer Appliance Control Boards
Home appliance control boards traditionally use mid-density AVR MCUs, and the ATMEGA324PA-CU matches this profile: 32 KB Flash holds UI, motor-timing, and communication firmware; three timer/counters with PWM drive triac or motor control signals; and two USARTs interface between a user-panel controller and a main communication link. The 5 V rating and wide family availability simplify 5 V appliance designs, while the 32 GPIO lines cover a button matrix, display drive, and relay outputs without port expanders. The VFBGA package reduces controller footprint on crowded mainboards, though manufacturers should confirm BGA rework procedures for serviceability. The 1 KB EEPROM retains user settings such as cycle preferences through power interruptions, improving perceived product quality.
Recommended
Sensor Hubs and Data Acquisition
As a compact sensor hub, the ATMEGA324PA-CU aggregates digital sensors on its TWI (I2C-compatible) interface and analog channels on the 8-channel 10-bit ADC, then forwards processed data over either USART - for example to an RS-485 transceiver or a wireless module. The single-cycle AVR core executes filtering and scaling math efficiently, and the 2 KB SRAM buffers sample blocks without external memory in many monitoring applications. Running from a 3.3 V rail keeps ADC full-scale compatible with common MEMS sensor outputs, while 20 MHz operation provides timing headroom for scheduled sampling. Place 100 nF decoupling at every supply ball and keep analog sensor traces away from USART lines to preserve 10-bit ADC accuracy.
Recommended
Embedded Networking Subsystems
With two independent USARTs and a hardware TWI, the ATMEGA324PA-CU can service a network link and a local device bus simultaneously, making it suitable as a protocol converter or subsystem controller inside larger equipment. Firmware can implement UART protocols such as Modbus RTU at standard baud rates using the 20 MHz clock, while the TWI manages EEPROMs, RTCs, or display controllers. The 32 KB Flash accommodates dual-protocol stacks plus a bootloader, and read-while-write Flash permits field firmware updates without halting serial communication. The 5x5 mm VFBGA keeps the controller compact next to the physical-layer components. Designers should verify ESD protection on externally wired USART lines, since AVR I/O tolerances assume board-level protection.
Recommended
Motor Control and Actuation
The three timer/counters with compare modes and PWM outputs let the ATMEGA324PA-CU generate multi-channel PWM for DC motor, servo, or LED-dimmer actuation, while the ADC reads current-sense or position-feedback signals in the same device. At 20 MHz the PWM resolution at typical motor frequencies (for example 16 kHz) remains high enough for smooth speed control, and single-cycle ALU operation keeps PID loop latency predictable. The 32 GPIO lines support limit switches, an H-bridge direction interface, and a fault-flag handshake. Operating at 5 V gives robust gate-drive levels for logic-level MOSFET drivers. Isolate ADC sense routing from PWM switching nodes on the PCB and use the input-capture timer for encoder feedback timing.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA324PA-CU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA324PA-CUR | ATMEGA324PA-AUR | ATMEGA324PA-MU |
|---|---|---|---|---|
| Package | 49-VFBGA (5x5 mm) | 49-VFBGA (5x5 mm) - same | TQFP-44 (different footprint) | VQFN-44 (different footprint) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB |
| EEPROM | 1 KB | 1 KB | 1 KB | 1 KB |
| Maximum Clock | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage | 2.5 V / 3.3 V / 5 V | 2.5 V / 3.3 V / 5 V | 2.5 V / 3.3 V / 5 V | 2.5 V / 3.3 V / 5 V |
| Pin Count | 49 balls | 49 balls | 44 pins | 44 pins |
Key Differentiators
- Only ATmega324PA ordering code in compact VFBGA-49 (vs ATMEGA324PA-AUR)
- picoPower low-power revision (vs ATMEGA324A-AU)
- Severe scarcity of true VFBGA-49 drop-ins (vs ATMEGA324PA-MU)
Design Notes
The 49-VFBGA (5x5 mm) ball array requires BGA-capable PCB fabrication with fine-pitch pads and typically 4-layer stack-up to route the 32 GPIO and power balls. Provide via-in-pad or dog-bone escape routing on 0.5 mm-class ball pitch, and place 100 nF ceramic decoupling capacitors within 2 mm of each VCC/AVCC ball pair with solid ground planes on layer 2. Confirm your assembler supports BGA placement and X-ray inspection before committing to the -CU package; otherwise the TQFP-44 ATMEGA324PA-AU uses the identical die.
The ATMEGA324PA-CU supports 2.5 V, 3.3 V, and 5 V supplies, but the maximum clock is voltage-dependent in the AVR family: full 20 MHz operation requires the highest voltage range. Verify the speed-versus-VCC curve in the manufacturer datasheet before running 20 MHz at reduced supply; if your design must run at 3.3 V, derate the clock accordingly or accept reduced MIPS. Connect AVCC to the clean analog supply even if only digital peripherals are used, and never leave AVCC floating - this is a documented requirement of ATmega devices.
Program the ATMEGA324PA-CU via ICSP using two I/O pins plus reset with tools such as MPLAB SNAP. A frequent field failure is enabling the JTAG/ debugger pins or the reset-disable fuse, which locks out subsequent in-system reprogramming - leave RESET functional unless field programming is definitely not required. Also note the RESET pin polarity and the EEPROM write timing during brownout: enable the on-chip brown-out detector so EEPROM corruption does not occur at low supply, and allocate the boot section in Flash if you intend to use a self-programming bootloader.
Compliance Information
Compliance certificates were not present in the provided web data. Verify RoHS/REACH/lead-free status on the official Microchip product page or via the Microchip environmental documentation before release.
