RM24C256DS-LSNI-B Equivalent & Substitute Parts

Part Overview

The RM24C256DS-LSNI-B is a 256Kbit CBRAM non-volatile memory IC manufactured by Renesas Electronics Corporation, designed for I2C interface applications at 1 MHz clock frequency in an 8-SOIC surface mount package. This component is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing system support and new design implementations. The CBRAM technology provides non-volatile storage with specified write cycle times suitable for embedded memory applications requiring I2C serial communication.

Key Parameters

Parameter	Value
Memory Size	256Kbit
Memory Type	Non-Volatile
Memory Format	CBRAM
Memory Interface	I2C
Clock Frequency	1 MHz
Voltage Supply Range	1.65V ~ 3.6V
Operating Temperature	-40°C ~ 85°C
Package Type	8-SOIC
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the RM24C256DS-LSNI-B is determined by the following critical parameters:

Memory Capacity: 256Kbit capacity requirement
Interface Protocol: I2C serial communication interface
Clock Frequency: 1 MHz operation
Supply Voltage Range: Compatibility with 1.65V ~ 3.6V operating range
Operating Temperature Range: -40°C ~ 85°C specification
Package Format: 8-SOIC surface mount package
Non-Volatile Storage: Persistent data retention requirement

The S-24C256CI-J8T1U4 qualifies as a substitute based on matching these core parameters. While the substitute employs EEPROM technology rather than CBRAM, both memory formats provide non-volatile storage with compatible electrical and mechanical specifications for this application category.

Parameter Comparison

Parameter	RM24C256DS-LSNI-B (Main)	S-24C256CI-J8T1U4 (Substitute)
Manufacturer	Renesas Electronics Corporation	ABLIC Inc.
Memory Size	256Kbit	256Kbit
Memory Type	Non-Volatile	Non-Volatile
Memory Format	CBRAM	EEPROM
Memory Organization	64 Bytes Page Size	32K x 8
Memory Interface	I2C	I2C
Clock Frequency	1 MHz	1 MHz
Write Cycle Time - Page	2.5ms	5ms
Access Time	Not specified	500 ns
Voltage Supply Range	1.65V ~ 3.6V	1.6V ~ 5.5V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount	Surface Mount
Product Status	Obsolete	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

The S-24C256CI-J8T1U4 is an active product from ABLIC Inc. and serves as the manufacturer-recommended substitute for the obsolete RM24C256DS-LSNI-B. Both components meet ROHS3 compliance and MSL Level 1 specifications, ensuring regulatory and environmental compatibility.

The substitute provides a wider supply voltage range (1.6V ~ 5.5V versus 1.65V ~ 3.6V), offering greater design flexibility for systems operating across extended voltage domains. The EEPROM technology in the substitute maintains full I2C protocol compatibility and identical clock frequency operation at 1 MHz.

Page write cycle time differs between the two devices: the main part specifies 2.5ms while the substitute requires 5ms. This parameter should be evaluated against system timing requirements. The substitute's specified 500 ns access time provides additional performance data for timing-critical applications.

Both components are housed in identical 8-SOIC packages with matching physical dimensions, enabling direct PCB-level substitution without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the S-24C256CI-J8T1U4 directly replace the RM24C256DS-LSNI-B on existing PCBs?

A: Yes. Both components use the 8-SOIC package with identical physical dimensions (0.154" width, 3.90mm). Pin-to-pin I2C interface compatibility and matching supply voltage overlap (1.65V ~ 3.6V) enable direct substitution without PCB redesign.

Q: What is the primary difference between CBRAM and EEPROM technologies in this application?

A: Both are non-volatile memory formats suitable for I2C serial communication. CBRAM (Conductive Bridging RAM) and EEPROM (Electrically Erasable Programmable Read-Only Memory) differ in internal cell architecture and write mechanisms. For this 256Kbit I2C interface application, both technologies provide equivalent functional performance.

Q: Does the wider voltage range of the substitute affect compatibility?

A: No. The substitute's 1.6V ~ 5.5V range encompasses the main part's 1.65V ~ 3.6V specification. Systems designed for the original part will operate within the substitute's supported voltage window.

Q: How does the page write cycle time difference impact system design?

A: The substitute requires 5ms per page write versus 2.5ms for the original part. Applications with strict write timing constraints should account for this 2.5ms increase. For most embedded applications, this difference is non-critical.

Q: Are both components RoHS compliant?

A: Yes. Both the RM24C256DS-LSNI-B and S-24C256CI-J8T1U4 are ROHS3 compliant with MSL Level 1 (unlimited moisture sensitivity level), meeting current environmental and regulatory standards.

Q: What is the inventory status for the substitute?

A: The S-24C256CI-J8T1U4 is an active product with 4355 pieces in stock, providing reliable supply availability compared to the obsolete main part.

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