ATXMEGA256A3B-AU Equivalent & Substitute Parts

Part Overview

The ATXMEGA256A3B-AU is an AVR XMEGA A3B microcontroller manufactured by Microchip Technology, featuring 8/16-bit processing at 32MHz with 256KB FLASH memory. This device is classified as obsolete, making identification of compatible substitute parts essential for ongoing design support and production continuity. The ATXMEGA256A3B-AU operates across a supply voltage range of 1.6V to 3.6V and integrates comprehensive peripheral support including I2C, IrDA, SPI, and UART/USART connectivity.

Key Parameters

Parameter	Value
Manufacturer Part Number	ATXMEGA256A3B-AU
Manufacturer	Microchip Technology
Core Processor	AVR
Core Size	8/16-Bit
Speed	32MHz
Program Memory Size	256KB (128K x 16)
Program Memory Type	FLASH
EEPROM Size	4K x 8
RAM Size	16K x 8
Voltage - Supply (Vcc/Vdd)	1.6V ~ 3.6V
Data Converters	A/D 16x12b; D/A 2x12b
Number of I/O	49
Connectivity	I2C, IrDA, SPI, UART/USART
Peripherals	Brown-out Detect/Reset, DMA, POR, PWM, WDT
Operating Temperature	-40°C ~ 85°C (TA)
Package / Case	64-TQFP (14x14)
Mounting Type	Surface Mount
Product Status	Obsolete
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	3 (168 Hours)

Substitute Part Grouping Explanation

Substitution of the ATXMEGA256A3B-AU is determined by strict alignment of the following electrical and mechanical parameters:

Core Electrical Parameters (Must Match):

Core Processor: AVR
Core Size: 8/16-Bit
Speed: 32MHz
Program Memory Size: 256KB (128K x 16)
Program Memory Type: FLASH
EEPROM Size: 4K x 8
RAM Size: 16K x 8
Voltage - Supply (Vcc/Vdd): 1.6V ~ 3.6V
Data Converters: A/D 16x12b; D/A 2x12b
Operating Temperature: -40°C ~ 85°C (TA)

Mechanical Parameters (Allowable Variation):

Package / Case: Different package types permitted (TQFP vs. QFN) provided pin count and functionality remain compatible
Mounting Type: Surface Mount (consistent across all candidates)

Connectivity & Peripherals (Allowable Enhancement):

Substitute parts may include additional connectivity options (such as USB) beyond the original specification
Peripheral feature sets must include all features present in the main part

The ATXMEGA256A3U-MH qualifies as a direct substitute based on matching all core electrical parameters while offering an alternative package form factor (64-QFN vs. 64-TQFP) and enhanced connectivity (addition of USB support).

Parameter Comparison

Parameter	ATXMEGA256A3B-AU	ATXMEGA256A3U-MH
Manufacturer	Microchip Technology	Microchip Technology
Core Processor	AVR	AVR
Core Size	8/16-Bit	8/16-Bit
Speed	32MHz	32MHz
Program Memory Size	256KB (128K x 16)	256KB (128K x 16)
Program Memory Type	FLASH	FLASH
EEPROM Size	4K x 8	4K x 8
RAM Size	16K x 8	16K x 8
Voltage - Supply (Vcc/Vdd)	1.6V ~ 3.6V	1.6V ~ 3.6V
Data Converters	A/D 16x12b; D/A 2x12b	A/D 16x12b; D/A 2x12b
Number of I/O	49	50
Connectivity	I2C, IrDA, SPI, UART/USART	I2C, IrDA, SPI, UART/USART, USB
Peripherals	Brown-out Detect/Reset, DMA, POR, PWM, WDT	Brown-out Detect/Reset, DMA, POR, PWM, WDT
Operating Temperature	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)
Package / Case	64-TQFP (14x14)	64-VFQFN Exposed Pad (9x9)
Mounting Type	Surface Mount	Surface Mount
Product Status	Obsolete	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	3 (168 Hours)	3 (168 Hours)

Engineering Selection Recommendations

The ATXMEGA256A3U-MH is a qualified substitute for the obsolete ATXMEGA256A3B-AU based on electrical equivalence across all core parameters. Both devices maintain identical processor architecture, memory configuration, supply voltage range, and data converter specifications.

The primary distinction is package form factor: the ATXMEGA256A3B-AU uses a 64-TQFP (14x14mm) package, while the ATXMEGA256A3U-MH employs a 64-VFQFN (9x9mm) package with exposed pad. This represents a reduction in board footprint and thermal profile. The ATXMEGA256A3U-MH provides one additional I/O pin (50 vs. 49) and includes USB connectivity as an enhancement.

Both parts maintain ROHS3 compliance and identical moisture sensitivity specifications. The ATXMEGA256A3U-MH carries active product status, ensuring ongoing availability and manufacturing support compared to the obsolete status of the original part.

Frequently Asked Questions (FAQ)

Q: Are the ATXMEGA256A3B-AU and ATXMEGA256A3U-MH pin-compatible?

A: Both devices feature 64-pin packages with identical electrical specifications. However, physical pin layout differs due to package geometry differences (TQFP vs. VFQFN). PCB redesign is required to accommodate the different package footprint.

Q: What is the primary advantage of the ATXMEGA256A3U-MH package?

A: The 64-VFQFN package reduces board area by approximately 60% compared to the 64-TQFP package. The exposed pad provides improved thermal dissipation characteristics.

Q: Does the ATXMEGA256A3U-MH provide additional functionality?

A: The ATXMEGA256A3U-MH includes USB connectivity in addition to the I2C, IrDA, SPI, and UART/USART interfaces present in the ATXMEGA256A3B-AU. All other electrical and peripheral specifications remain identical.

Q: Are both parts compliant with current regulatory standards?

A: Both the ATXMEGA256A3B-AU and ATXMEGA256A3U-MH are ROHS3 compliant and REACH unaffected. Moisture sensitivity level is identical at MSL 3 (168 Hours).

Q: What is the impact of the one additional I/O pin in the ATXMEGA256A3U-MH?

A: The ATXMEGA256A3U-MH provides 50 I/O pins versus 49 in the ATXMEGA256A3B-AU. This additional pin is available for application-specific use and does not affect compatibility with designs utilizing the original 49-pin configuration.

Q: Is the ATXMEGA256A3U-MH suitable for new designs?

A: The ATXMEGA256A3U-MH carries active product status, making it the appropriate choice for new designs. The ATXMEGA256A3B-AU is obsolete and should not be selected for new applications.

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