ATMEGA325P-20MUR - 8-bit AVR MCU 32KB 20MHz 64-QFN | Microchip
MPN: ATMEGA325P-20MUR β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.0749 | $4.07 |
| 10 | $3.87 | $38.70 |
| 100 | $3.46 | $346.00 |
| 500 | $3.12 | $1,560.00 |
| 1,000 | $2.86 | $2,860.00 |
ATMEGA325P-20MUR Overview
An 8-bit AVR microcontroller is a Harvard-architecture RISC processor that fetches instructions and data over separate buses, allowing most of its 131 instructions to execute in a single clock cycle. Within the power-management hierarchy, the ATmega family sits as a standalone general-purpose MCU, spanning Flash densities from 16 KB to 256 KB and serving as the computing core for embedded control systems that previously required multiple discrete logic ICs.
Key features include picoPower technology for extremely low sleep-mode consumption, a wide 1.8V to 5.5V operating range that supports both battery and 5V industrial rails, and 20 MIPS peak throughput at 20 MHz for demanding real-time loops. The P-suffix picoPower grade distinguishes this die from the earlier ATmega325 with lower active and idle current. On-chip JTAG enables boundary-scan, programming, and in-circuit debugging without additional sockets.
Architecturally, the device pairs the AVR RISC core with 32 KB of self-programmable Flash organized as 16K x 16, allowing firmware updates in the field through a boot loader section. Peripheral integration includes two 8-bit timers, two 16-bit timers, a USART, SPI, two-wire interface (I2C), analog comparator, and the 8-channel 10-bit ADC with internal bandgap reference.
Typical applications include industrial sensor nodes and automation controls leveraging the 1.8V to 5.5V tolerance, battery-powered metering instruments exploiting picoPower sleep modes, and consumer appliances using the ADC plus USART for human-machine interfaces. The 64-pin QFN footprint also suits compact automotive-style HMI panels when paired with the LCD-equipped family siblings.
Design consideration: derive the supply rail carefully because the 20 MHz speed grade requires 4.5V to 5.5V operation; at 2.7V the maximum rated clock drops to 10 MHz, so check your frequency-versus-voltage curve before finalizing the crystal selection.
This page synthesizes distributor pricing, drop-in same-package alternatives, and design guidance not consolidated in the manufacturer datasheet.
Drop-in alternatives for ATMEGA325P-20MUR 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 ATMEGA325P-20MUR (same form factor and footprint) β differing in Package, EEPROM, RoHS Status, Instruction Set, SRAM.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA325P-20MUR
β Drop-Inβ In Stock
$2.86 / Unit
View Datasheet βATMEGA325-20MUR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA329P-20MUR
β Drop-Inβ In Stock
$5.4 / Unit
View Datasheet βATMEGA3250P-20MUR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA3290P-20MUR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA325P-20MUR 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 |
| Operating Voltage | 1.8 V to 5.5 V |
| Peripherals | picoPower, Brown-out Detect/Reset, POR, PWM, WDT |
| Number of I/O | 54 |
| ADC Resolution | 10-bit |
| Number of ADC Channels | 8 |
| Communication Interfaces | USART, SPI, TWI (I2C) |
| Debug Interface | JTAG (on-chip debug, boundary scan) |
| Package | 64-QFN (9x9 mm) Exposed Pad / 64-VFQFN |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (Industrial) |
| Program Memory Type | In-System Programmable FLASH |
ATMEGA325P-20MUR 64-qfn (9x9 mm) exposed pad / 64-vfqfn Pin Configuration Guide
Pin configuration for ATMEGA325P-20MUR (64-qfn (9x9 mm) exposed pad / 64-vfqfn 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 ATMEGA325P-20MUR.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA325P-20MUR is suitable for 6 applications: Industrial Automation and Control, Battery-Powered Metering Instruments, Consumer Appliance Control Panels, Sensor Nodes and IoT Endpoints, Automotive-Style HMI and Display Modules, Test and Measurement Fixtures.
Industrial Automation and Control
The ATMEGA325P-20MUR fits industrial automation nodes that need substantial GPIO and a 5V-tolerant supply, since it provides 54 I/O lines and accepts a 1.8V to 5.5V rail that tolerates noisy 5V industrial supplies. With 20 MIPS of AVR RISC throughput at 20 MHz, it handles real-time PLC-style I/O scanning, relay sequencing, and Modbus-style UART protocols on the integrated USART. The 8-channel 10-bit ADC digitizes analog sensor loops directly, and JTAG enables field diagnostics. Compared with smaller 44-pin ATmega parts, the 64-QFN reduces external port expanders and shortens scan-cycle latency.
Recommended
Battery-Powered Metering Instruments
picoPower technology makes the ATMEGA325P-20MUR well suited to battery-powered energy, water, and gas meters where sleep current dominates battery life. Operating down to 1.8V, it can run directly from two alkaline cells or a lithium cell through an LDO, while the 10-bit 8-channel ADC samples shunt or divider-based measurement front ends. Wake-on-interrupt via the asynchronous timer keeps average current in the microamp range between measurement bursts. The 1 KB EEPROM retains calibration and tariff data across power cycles without external nonvolatile memory, and the 32 KB Flash hosts multiple communication stacks simultaneously.
Recommended
Consumer Appliance Control Panels
For appliance HMI boards, the ATMEGA325P-20MUR combines the GPIO density to drive keypads, LEDs, and relays with the ADC needed for temperature (NTC) and user-pot sensing on integrated channels. The 64-QFN (9x9 mm) exposed-pad package yields a compact single-chip controller, and the picoPower die meets standby-energy targets required by modern appliance efficiency schemes. The USART interfaces with display modules, while SPI drives external EEPROM or RFID readers. Cost-sensitive designs can migrate to the non-LCD ATmega324P footprint when I/O demand drops, keeping the same AVR toolchain and firmware base.
Recommended
Sensor Nodes and IoT Endpoints
The ATMEGA325P-20MUR serves wired IoT endpoints and sensor concentrators where the combination of SPI, TWI (I2C), and USART links sensors and radios without bit-banging overhead. Running at 1.8V conserves energy, and picoPower sleep modes cut average draw between polling intervals. The 8-channel ADC accepts multiple analog sensors simultaneously, while 54 GPIOs handle address selection and status signaling for dense sensor arrays. Firmware fits comfortably in 32 KB Flash with room for OTA-style boot loaders exploiting the self-programmable memory. JTAG simplifies bring-up of multi-drop sensor bus topologies during development.
Recommended
Automotive-Style HMI and Display Modules
Designers building instrument clusters and dashboard-style displays can base their controller choice on the ATmega LCD family that shares the ATMEGA325P-20MUR 64-QFN footprint: ATMEGA329P or ATMEGA3250P variants add segment LCD drivers (up to 4x25 or 4x40 segments) while preserving the same core, 32 KB Flash, and 20 MHz rating. This lets one PCB layout support both non-display (325P) and display (329P/3250P) builds. The wide 1.8V to 5.5V supply range handles load-dump-protected rails, and the JTAG interface supports boundary-scan production test on densely populated display boards.
Recommended
Test and Measurement Fixtures
The ATMEGA325P-20MUR is effective inside production test fixtures and portable instruments that need many digital stimulus/response lines plus analog measurement. Boundary-scan via JTAG lets the fixture itself be tested in-circuit, while 54 GPIOs drive relays, muxes, and pass/fail indicators. The 20 MHz AVR core executes test sequencing and UART reporting to a host PC, and the 10-bit ADC verifies analog thresholds without an external digitizer. The 9x9 mm QFN keeps fixture electronics compact, and the industrial -40C to +85C rating tolerates unconditioned factory-floor environments and seasonal temperature swings.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA325P-20MUR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA325-20MUR | ATMEGA329P-20MUR | ATMEGA3250P-20MUR | ATMEGA3290P-20MUR |
|---|---|---|---|---|---|
| Package | 64-QFN (9x9 mm) Exposed Pad | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) family MLF - same | 64-QFN (9x9 mm) family MLF - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB (16K x 16) | 32 KB (16K x 16) | 32 KB (16K x 16) | 32 KB (16K x 16) | 32 KB (16K x 16) |
| SRAM / EEPROM | 2 KB / 1 KB | 2 KB / 1 KB | 2 KB / 1 KB | 2 KB / 1 KB | 2 KB / 1 KB |
| Max Clock Speed | 20 MHz (20 MIPS) | 20 MHz (20 MIPS) | 20 MHz (20 MIPS) | 20 MHz (20 MIPS) | 20 MHz (20 MIPS) |
| picoPower Technology | Yes | No (standard die, higher current) | Yes | Yes | Yes |
| LCD Segment Driver | No | No | Yes (up to 4x25 segments) | Yes (up to 4x25 segments) | Yes (up to 4x40 segments) |
| JTAG Debug | Yes | Yes | Yes | Yes | Yes |
| Operating 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 |
Key Differentiators
- picoPower low-current die (vs ATMEGA325-20MUR)
- JTAG on-chip debug included (vs ATMEGA168PA-MU)
- Non-LCD die maximizes general-purpose I/O (vs ATMEGA329P-20MUR)
- 20 MHz top speed grade (vs ATMEGA325-16MI)
Design Notes
Derate the clock with supply voltage: the 20 MHz speed grade requires 4.5V to 5.5V, 16 MHz down to 4.0V, 8 MHz down to 2.7V, and roughly 10 MHz at 2.7V per the AVR frequency-vs-voltage safety curve. Estimated: running 20 MHz on a 3.3V rail violates the curve and can cause marginal flash timing; either add an LDO to hold a 5V rail or drop the crystal to 8-10 MHz for battery designs.
The 64-QFN (9x9 mm) exposed pad is the primary ground return. Connect the exposed pad to a solid ground plane with a via array (at least 5x5 per Microchip QFN layout guidelines) to reduce ground bounce across the 54-I/O port structure and to aid thermal dissipation during flash programming. Place 100 nF ceramic decoupling capacitors at all four VCC/GND pin pairs, plus 10 uF bulk capacitance near the regulator.
Keep the XTAL1/XTAL2 crystal traces under 10 mm and place guard ground around them; the full-swing crystal oscillator at 20 MHz is sensitive to stray capacitance. If JTAG is unused, disable it via the JTD fuse/bit to free PC2-PC7 as general-purpose I/O - leaving JTAG enabled also disables these pins as ADC or port pins, a frequent bring-up pitfall on ATmega325-family parts.
When substituting a non-P ATmega325 with this picoPower part, review sleep-mode register settings: picoPower die enforces additional clock-gating in deep sleep, so firmware that relied on idle-mode timer behavior of the older die may see different wake latency. Verify brown-out detector fuse settings, since BOD level options differ slightly across P and non-P family revisions.
Compliance Information
Current-production Microchip part in standard green/RoHS packaging. Formal REACH and halogen-free declarations should be pulled from Microchip's quality portal for this exact ordering code.
