ATMEGA644PA-MUR Equivalent & Substitute Parts

Part Overview

The ATMEGA644PA-MUR is an 8-bit AVR microcontroller from Microchip Technology's ATmega series, featuring 64KB of FLASH program memory, 4KB of RAM, and 2KB of EEPROM. This device operates at 20MHz with a supply voltage range of 1.8V to 5.5V and is housed in a 44-pin VQFN package. The part maintains Active product status and is RoHS3 compliant. Identifying equivalent substitute parts is necessary when the primary part number becomes unavailable or when alternative packaging formats better suit procurement or assembly requirements.

Key Parameters

Parameter	Value
Core Processor	AVR
Core Size	8-Bit
Speed	20MHz
Program Memory Size	64KB (32K x 16)
Program Memory Type	FLASH
RAM Size	4K x 8
EEPROM Size	2K x 8
Voltage Supply Range	1.8V ~ 5.5V
Number of I/O	32
Data Converters	A/D 8x10b
Connectivity	I2C, SPI, UART/USART
Peripherals	Brown-out Detect/Reset, POR, PWM, WDT
Operating Temperature	-40°C ~ 85°C
Package Type	44-VQFN (7x7)
Mounting Type	Surface Mount
RoHS Status	RoHS3 Compliant
MSL Rating	3 (168 Hours)

Substitute Part Grouping Explanation

The ATMEGA644PA-MUR qualifies for substitution with the ATMEGA644A-MUR based on strict parametric equivalence. Both parts share identical core specifications: 8-bit AVR processor architecture, 20MHz clock speed, 64KB FLASH memory, 4KB RAM, 2KB EEPROM, 32 I/O pins, and identical peripheral feature sets including I2C, SPI, UART/USART connectivity, brown-out detection, power-on reset, PWM, and watchdog timer functionality. Both operate across the same voltage supply range (1.8V to 5.5V) and temperature range (-40°C to 85°C). The devices are housed in the same 44-VQFN (7x7) package with exposed pad and maintain identical RoHS3 compliance and MSL ratings. The primary distinction lies in packaging format: ATMEGA644PA-MUR is supplied in Tape & Reel (TR) format, while ATMEGA644A-MUR is available in Cut Tape (CT) and Digi-Reel® format. This substitution is valid for applications where packaging format flexibility is acceptable.

Parameter Comparison

Parameter	ATMEGA644PA-MUR	ATMEGA644A-MUR	Match
Manufacturer	Microchip Technology	Microchip Technology	✓
Core Processor	AVR	AVR	✓
Core Size	8-Bit	8-Bit	✓
Speed	20MHz	20MHz	✓
Program Memory Size	64KB (32K x 16)	64KB (32K x 16)	✓
Program Memory Type	FLASH	FLASH	✓
RAM Size	4K x 8	4K x 8	✓
EEPROM Size	2K x 8	2K x 8	✓
Voltage Supply Range	1.8V ~ 5.5V	1.8V ~ 5.5V	✓
Number of I/O	32	32	✓
Data Converters	A/D 8x10b	A/D 8x10b	✓
Connectivity	I2C, SPI, UART/USART	I2C, SPI, UART/USART	✓
Peripherals	Brown-out Detect/Reset, POR, PWM, WDT	Brown-out Detect/Reset, POR, PWM, WDT	✓
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	✓
Package Type	44-VQFN (7x7)	44-VQFN (7x7)	✓
Mounting Type	Surface Mount	Surface Mount	✓
RoHS Status	RoHS3 Compliant	RoHS3 Compliant	✓
MSL Rating	3 (168 Hours)	3 (168 Hours)	✓
Product Status	Active	Active	✓
Packaging Format	Tape & Reel (TR)	Cut Tape (CT) & Digi-Reel®	Different

Engineering Selection Recommendations

Both the ATMEGA644PA-MUR and ATMEGA644A-MUR maintain Active product status with full RoHS3 compliance and identical regulatory certifications (REACH Unaffected, ECCN EAR99, HTSUS 8542.31.0001). Selection between these parts should be based on procurement and assembly requirements. The ATMEGA644PA-MUR in Tape & Reel format is suitable for high-volume automated assembly operations. The ATMEGA644A-MUR in Cut Tape and Digi-Reel® format provides flexibility for lower-volume production runs or mixed-component kitting scenarios. Both parts are functionally interchangeable at the circuit level with no design modifications required. Inventory availability and lead time considerations may influence part selection, as current stock levels differ between variants.

Frequently Asked Questions (FAQ)

Q: Are ATMEGA644PA-MUR and ATMEGA644A-MUR pin-compatible? A: Yes. Both devices use the 44-VQFN (7x7) package with identical pinout, electrical characteristics, and functional specifications. No PCB redesign is required for substitution.

Q: What is the difference between Tape & Reel and Cut Tape packaging? A: Tape & Reel (TR) packaging supplies components on continuous carrier tape wound on reels, optimized for high-speed automated pick-and-place assembly. Cut Tape (CT) and Digi-Reel® packaging provides components in smaller quantities on cut tape segments, suitable for lower-volume production or component kitting.

Q: Can I use ATMEGA644A-MUR as a direct replacement in existing designs? A: Yes. The ATMEGA644A-MUR is a direct functional equivalent with identical electrical performance, memory configuration, and peripheral features. No firmware or hardware modifications are necessary.

Q: Are there any compliance or certification differences? A: No. Both parts maintain identical RoHS3 compliance, REACH status, and regulatory classifications. MSL ratings and moisture sensitivity levels are equivalent.

Q: Which part should I select for new designs? A: Selection depends on production volume and assembly methodology. For high-volume automated assembly, ATMEGA644PA-MUR (Tape & Reel) is standard. For lower-volume or flexible procurement scenarios, ATMEGA644A-MUR (Cut Tape/Digi-Reel®) may be more practical.

Q: Do both parts have the same operating temperature range? A: Yes. Both devices operate across -40°C to 85°C and are suitable for industrial and commercial temperature environments.

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