MC908AB32MFUE Equivalent & Substitute Parts

Part Overview

The MC908AB32MFUE is an 8-bit microcontroller from NXP USA Inc. in the HC08 series, featuring 32KB FLASH memory, 1KB RAM, and 512 bytes EEPROM. This device operates at 8MHz with a 64-QFP package and supports SCI and SPI connectivity. The part is classified as "Not For New Designs," indicating it has reached end-of-life status. Finding equivalent or substitute parts becomes necessary for legacy system maintenance, production support, or when original inventory becomes unavailable.

Key Parameters

Parameter	Value
Core Processor	HC08
Core Size	8-Bit
Program Memory Size	32KB (32K x 8)
Program Memory Type	FLASH
RAM Size	1K x 8
EEPROM Size	512 x 8
Speed	8MHz
Voltage Supply (Vcc/Vdd)	4.5V ~ 5.5V
Package / Case	64-QFP (14x14)
Number of I/O	51
Operating Temperature	-40°C ~ 125°C (TA)
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

The R5F51101ADFK#30 from Renesas Electronics Corporation qualifies as a substitute based on the following alignment criteria:

Matching Parameters:

Program Memory Size: 32KB (32K x 8) FLASH
Package Form Factor: 64-pin QFP-class package (64-LQFP, 14x14mm footprint)
Mounting Type: Surface Mount
RoHS3 Compliance: Both parts meet ROHS3 requirements
MSL Rating: Both rated MSL 3 (168 Hours)

Substitution Logic: The R5F51101ADFK#30 maintains identical program memory capacity and compatible physical packaging dimensions, enabling direct socket compatibility in legacy designs. Both parts feature 64-pin surface-mount packages with matching 14x14mm footprints, allowing PCB-level interchangeability without layout modifications.

Parameter Comparison

Parameter	MC908AB32MFUE (NXP)	R5F51101ADFK#30 (Renesas)
Core Processor	HC08	RX
Core Size	8-Bit	32-Bit Single-Core
Speed	8MHz	32MHz
Program Memory Size	32KB (32K x 8)	32KB (32K x 8)
Program Memory Type	FLASH	FLASH
RAM Size	1K x 8	10K x 8
EEPROM Size	512 x 8	—
Voltage Supply (Vcc/Vdd)	4.5V ~ 5.5V	1.8V ~ 3.6V
Number of I/O	51	50
Package / Case	64-QFP (14x14)	64-LQFP (14x14)
Operating Temperature	-40°C ~ 125°C (TA)	-40°C ~ 85°C (TA)
Product Status	Not For New Designs	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

The R5F51101ADFK#30 serves as a functional substitute for the MC908AB32MFUE in applications requiring legacy system support or inventory replenishment. Both parts maintain ROHS3 compliance and identical program memory capacity. The Renesas device carries Active product status, ensuring continued availability and manufacturing support, whereas the NXP part is designated Not For New Designs.

Physical package compatibility is confirmed through matching 64-pin QFP-class form factors with identical 14x14mm footprints, enabling direct PCB-level substitution without layout redesign. Both devices support surface-mount assembly processes and maintain equivalent MSL 3 moisture sensitivity ratings.

Design integration requires evaluation of architectural differences: the R5F51101ADFK#30 operates as a 32-bit processor at 32MHz with expanded RAM (10K x 8) compared to the 8-bit HC08 architecture at 8MHz with 1K x 8 RAM. Voltage supply ranges differ, with the NXP device requiring 4.5V–5.5V operation and the Renesas device operating at 1.8V–3.6V. The Renesas part lacks EEPROM, whereas the NXP device includes 512 x 8 bytes EEPROM.

Frequently Asked Questions (FAQ)

Q: Can the R5F51101ADFK#30 replace the MC908AB32MFUE in existing designs without PCB modification?

A: Yes, physical package compatibility is confirmed. Both devices use 64-pin QFP-class packages with identical 14x14mm footprints, enabling direct socket substitution. However, firmware and hardware interface modifications are required due to architectural differences between the 8-bit HC08 and 32-bit RX processors.

Q: What are the key differences in memory architecture between these parts?

A: The MC908AB32MFUE provides 32KB FLASH, 1KB RAM, and 512 bytes EEPROM. The R5F51101ADFK#30 provides 32KB FLASH and 10K RAM but no EEPROM. Applications dependent on EEPROM functionality require alternative storage implementation on the Renesas device.

Q: Are voltage supply requirements compatible?

A: No. The MC908AB32MFUE requires 4.5V–5.5V operation, while the R5F51101ADFK#30 operates at 1.8V–3.6V. Power supply circuits must be redesigned to accommodate the Renesas device's lower voltage range.

Q: What is the impact of operating temperature range differences?

A: The MC908AB32MFUE supports -40°C to 125°C operation, while the R5F51101ADFK#30 supports -40°C to 85°C. Applications requiring operation above 85°C cannot use the Renesas substitute without thermal management modifications or alternative part selection.

Q: Does the higher clock speed of the R5F51101ADFK#30 affect compatibility?

A: The Renesas device operates at 32MHz versus the NXP device at 8MHz. This architectural difference requires firmware recompilation and timing-critical interface validation. Peripheral timing, interrupt handling, and communication protocol implementations must be re-evaluated for the faster processor.

Q: Are both parts RoHS compliant?

A: Yes, both the MC908AB32MFUE and R5F51101ADFK#30 meet ROHS3 compliance requirements and maintain MSL 3 moisture sensitivity ratings.

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