ATMEGA325PA-MU Equivalent & Substitute Parts

Part Overview

The ATMEGA325PA-MU is an 8-bit AVR microcontroller from Microchip Technology's ATmega series, featuring 32KB FLASH program memory, 2KB RAM, and 1KB EEPROM. This Surface Mount device in 64-QFN packaging operates at 20MHz with integrated peripherals including SPI, UART/USART, and USI connectivity. The part maintains Active product status with full RoHS3 compliance and verified programmability through DiGi-Electronics. Substitute parts are identified when electrical specifications, memory configurations, and package formats remain functionally equivalent while meeting identical operational requirements.

Key Parameters

Parameter	Value
Core Processor	AVR
Core Size	8-Bit
Speed	20MHz
Program Memory Size	32KB (16K x 16)
Program Memory Type	FLASH
EEPROM Size	1K x 8
RAM Size	2K x 8
Number of I/O	54
Connectivity	SPI, UART/USART, USI
Peripherals	Brown-out Detect/Reset, POR, PWM, WDT
Data Converters	A/D 8x10b
Oscillator Type	Internal
Mounting Type	Surface Mount
Package / Case	64-VFQFN Exposed Pad
Operating Temperature	-40°C ~ 85°C (TA)
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	3 (168 Hours)

Substitute Part Grouping Explanation

Substitution eligibility for the ATMEGA325PA-MU is determined by strict equivalence across core electrical and mechanical parameters. The substitute part ATMEGA325A-MU qualifies based on the following criteria:

Matching Parameters:

Identical AVR core processor architecture
Identical 8-bit core size
Identical 20MHz operating speed
Identical 32KB FLASH program memory configuration
Identical 1KB EEPROM and 2KB RAM allocation
Identical 54 I/O pin count
Identical connectivity interfaces (SPI, UART/USART, USI)
Identical peripheral feature set
Identical 8x10-bit A/D converter specification
Identical 64-QFN (9x9) Surface Mount package format
Identical operating temperature range
Identical RoHS3 and REACH compliance status
Identical MSL rating

Allowable Variation:

Voltage supply range: ATMEGA325PA-MU operates 2.7V ~ 5.5V; ATMEGA325A-MU operates 1.8V ~ 5.5V. The substitute part extends the lower voltage boundary, maintaining full compatibility in applications using the original 2.7V ~ 5.5V range while enabling additional low-voltage applications.

Parameter Comparison

Parameter	ATMEGA325PA-MU	ATMEGA325A-MU	Compatibility
Manufacturer	Microchip Technology	Microchip Technology	Identical
Core Processor	AVR	AVR	Identical
Core Size	8-Bit	8-Bit	Identical
Speed	20MHz	20MHz	Identical
Program Memory Size	32KB (16K x 16)	32KB (16K x 16)	Identical
EEPROM Size	1K x 8	1K x 8	Identical
RAM Size	2K x 8	2K x 8	Identical
Number of I/O	54	54	Identical
Connectivity	SPI, UART/USART, USI	SPI, UART/USART, USI	Identical
Peripherals	Brown-out Detect/Reset, POR, PWM, WDT	Brown-out Detect/Reset, POR, PWM, WDT	Identical
Data Converters	A/D 8x10b	A/D 8x10b	Identical
Oscillator Type	Internal	Internal	Identical
Voltage - Supply (Vcc/Vdd)	2.7V ~ 5.5V	1.8V ~ 5.5V	Compatible (extended range)
Operating Temperature	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)	Identical
Mounting Type	Surface Mount	Surface Mount	Identical
Package / Case	64-VFQFN Exposed Pad	64-VFQFN Exposed Pad	Identical
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Identical
Moisture Sensitivity Level	3 (168 Hours)	3 (168 Hours)	Identical
Product Status	Active	Active	Identical

Engineering Selection Recommendations

Both ATMEGA325PA-MU and ATMEGA325A-MU maintain Active product status with full RoHS3 compliance and verified programmability. Selection between these parts is based on supply chain availability and voltage requirement specifications.

The ATMEGA325PA-MU is appropriate for applications requiring operation within the 2.7V ~ 5.5V supply range. The ATMEGA325A-MU is appropriate for applications requiring operation within the 1.8V ~ 5.5V supply range, including low-voltage battery-powered systems. Both parts are suitable for direct substitution in designs where the original voltage specification is met.

Current inventory status shows ATMEGA325A-MU at 1163 pieces and ATMEGA325PA-MU at 860 pieces, supporting component availability for production requirements.

Frequently Asked Questions (FAQ)

Q: Can ATMEGA325A-MU replace ATMEGA325PA-MU in existing designs?

A: Yes. The ATMEGA325A-MU is functionally equivalent across all core electrical specifications, memory configuration, I/O count, connectivity interfaces, and package format. The extended voltage range (1.8V ~ 5.5V versus 2.7V ~ 5.5V) provides additional operational flexibility without affecting designs operating within the original 2.7V ~ 5.5V specification.

Q: Are there differences in pin configuration between these parts?

A: No. Both parts use identical 64-QFN (9x9) Surface Mount packaging with 54 I/O pins in the same physical layout and electrical configuration.

Q: Do these parts require different programming or firmware?

A: No. Both parts use the identical AVR core processor and instruction set. Firmware compiled for ATMEGA325PA-MU executes without modification on ATMEGA325A-MU.

Q: What is the significance of the voltage range difference?

A: ATMEGA325A-MU extends operation to 1.8V minimum supply voltage, enabling use in low-voltage applications. ATMEGA325PA-MU operates from 2.7V minimum. Applications using supply voltages between 2.7V and 5.5V are compatible with both parts.

Q: Are compliance certifications identical?

A: Yes. Both parts maintain identical RoHS3 compliance, REACH status, and Moisture Sensitivity Level ratings.

Q: What is the base product number relationship?

A: Both ATMEGA325PA-MU and ATMEGA325A-MU share the base product number ATMEGA325, indicating they are variants within the same microcontroller family with equivalent core functionality.

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