ATMEGA328-MMHR Equivalent & Substitute Parts

Part Overview

The ATMEGA328-MMHR is an 8-bit AVR microcontroller manufactured by Microchip Technology, designed for embedded applications requiring 32KB flash memory and integrated peripherals. This device is actively produced and widely used in industrial and consumer electronics. Identifying equivalent and substitute parts is essential for supply chain continuity, inventory optimization, and design flexibility across manufacturing batches and procurement channels.

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
Voltage Supply (Vcc/Vdd)	1.8V ~ 5.5V
Number of I/O	23
Data Converters	A/D 8x10b
Connectivity	I2C, SPI, UART/USART
Peripherals	Brown-out Detect/Reset, POR, PWM, WDT
Operating Temperature	-40°C ~ 85°C (TA)
Mounting Type	Surface Mount
Package / Case	28-VQFN (4x4) Exposed Pad
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	3 (168 Hours)

Substitute Part Grouping Explanation

Substitute parts for the ATMEGA328-MMHR are identified based on strict parametric equivalence across core functional and physical characteristics. The following parameters determine substitution eligibility:

Critical Matching Parameters:

Core Processor: AVR
Core Size: 8-Bit
Speed: 20MHz
Program Memory: 32KB FLASH (16K x 16)
EEPROM: 1K x 8
RAM: 2K x 8
Voltage Supply Range: 1.8V ~ 5.5V
I/O Count: 23
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: 28-VQFN (4x4) Exposed Pad
Compliance: ROHS3, REACH Unaffected

The ATMEGA328P-MMHR meets all parametric requirements for direct substitution. Differences in packaging format (Cut Tape & Digi-Reel® versus Tape & Reel) do not affect electrical or mechanical compatibility and reflect procurement and supply chain variations only.

Parameter Comparison

Parameter	ATMEGA328-MMHR	ATMEGA328P-MMHR
Manufacturer	Microchip Technology	Microchip Technology
Core Processor	AVR	AVR
Core Size	8-Bit	8-Bit
Speed	20MHz	20MHz
Program Memory Size	32KB (16K x 16)	32KB (16K x 16)
Program Memory Type	FLASH	FLASH
EEPROM Size	1K x 8	1K x 8
RAM Size	2K x 8	2K x 8
Voltage Supply (Vcc/Vdd)	1.8V ~ 5.5V	1.8V ~ 5.5V
Number of I/O	23	23
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 (TA)	-40°C ~ 85°C (TA)
Mounting Type	Surface Mount	Surface Mount
Package / Case	28-VQFN (4x4) Exposed Pad	28-VQFN (4x4) Exposed Pad
Product Status	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	3 (168 Hours)	3 (168 Hours)
REACH Status	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

Both the ATMEGA328-MMHR and ATMEGA328P-MMHR are active products from Microchip Technology with identical electrical specifications, memory configurations, and peripheral sets. Selection between these parts should be based on:

Product Status: Both devices maintain active production status, ensuring long-term availability and supply chain stability.

Compliance Certifications: Both parts are ROHS3 compliant and REACH unaffected, meeting regulatory requirements for industrial and consumer applications across global markets.

Packaging Format: The ATMEGA328-MMHR is supplied in Tape & Reel (TR) format, while the ATMEGA328P-MMHR is available in Cut Tape (CT) & Digi-Reel® format. Selection depends on procurement volume and assembly line requirements rather than technical performance.

Inventory Availability: Current stock levels differ between variants. The ATMEGA328P-MMHR maintains higher inventory (23,649 pcs) compared to the ATMEGA328-MMHR (5,282 pcs), which may influence procurement decisions for time-sensitive projects.

Frequently Asked Questions (FAQ)

Q: Can ATMEGA328P-MMHR replace ATMEGA328-MMHR in existing designs?

A: Yes. Both parts are electrically and mechanically identical across all specified parameters. Substitution requires no design modifications, PCB layout changes, or firmware adjustments.

Q: What is the difference between ATMEGA328-MMHR and ATMEGA328P-MMHR?

A: The primary difference is packaging format. ATMEGA328-MMHR uses Tape & Reel (TR) packaging, while ATMEGA328P-MMHR uses Cut Tape (CT) & Digi-Reel® packaging. Electrical specifications, memory configuration, and performance characteristics are identical.

Q: Are there any compatibility concerns with the 28-VQFN package?

A: No. Both parts use the identical 28-VQFN (4x4) Exposed Pad package. PCB footprints, soldering requirements, and thermal characteristics are fully compatible.

Q: Do these parts require different handling or storage procedures?

A: Both parts have identical Moisture Sensitivity Level (MSL) ratings of 3 (168 Hours). Storage, handling, and reflow procedures are the same.

Q: Which part should be selected for new designs?

A: Selection should be based on procurement availability and supply chain requirements. Both parts are equally suitable for new designs. The ATMEGA328P-MMHR offers higher current inventory availability.

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