Renesas Electronics 71256S70DB SRAM Equivalent & Substitute Parts

Part Overview

The Renesas Electronics 71256S70DB is a 256Kbit asynchronous parallel SRAM memory IC in 28-CDIP packaging with 70 ns access time. This component is classified as obsolete, making substitute parts necessary for new designs and ongoing system support. The part operates across an extended temperature range of -55°C to 125°C with a supply voltage range of 4.5V to 5.5V, typical for legacy industrial and military applications.

Substiute Parts

71256S70DB

Renesas Electronics CorporationIn Stock: 109071256S70DB Datasheet

Current PartRFQ

71256S100DB

Renesas Electronics CorporationIn Stock: 118071256S100DB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 71256S70DB is determined by strict equivalence in the following parameters:

• Memory capacity: 256Kbit
• Memory organization: 32K x 8 parallel format
• Package type: 28-CDIP form factor
• Supply voltage range: 4.5V ~ 5.5V
• Operating temperature range: -55°C ~ 125°C
• Mounting type: Through Hole

The primary substitute, Renesas Electronics 71256S100DB, maintains identical memory capacity, organization, packaging, voltage specifications, and temperature range. The key difference is access time and write cycle time, which increase from 70 ns to 100 ns. This timing difference is acceptable in applications where the slower access time does not violate system timing requirements.

Parameter Comparison

Engineering Selection Recommendations

The 71256S100DB is the designated substitute for the obsolete 71256S70DB. Both parts share identical memory specifications, packaging, and electrical characteristics. The 71256S100DB carries Active product status, ensuring continued availability and supply chain support compared to the Obsolete status of the original part.

Selection of the 71256S100DB requires verification that system timing constraints accommodate the 30 ns increase in access time and write cycle time (from 70 ns to 100 ns). Applications with timing-critical memory access paths must confirm that the slower device meets setup and hold time requirements.

Both parts maintain RoHS non-compliant status and are unaffected by REACH regulations. Compliance requirements for new designs should be evaluated independently.

Frequently Asked Questions (FAQ)

Q: Can the 71256S100DB directly replace the 71256S70DB in existing designs?

A: Direct pin-for-pin replacement is possible due to identical 28-CDIP packaging and pinout. However, functional compatibility depends on system timing requirements. The 100 ns access time of the substitute must not violate critical path timing in the application.

Q: What is the primary difference between these two parts?

A: The access time and write cycle time differ: the 71256S70DB operates at 70 ns while the 71256S100DB operates at 100 ns. All other electrical and mechanical specifications are identical.

Q: Are there any voltage or temperature compatibility concerns?

A: No. Both parts operate across the identical supply voltage range (4.5V ~ 5.5V) and temperature range (-55°C ~ 125°C), ensuring full compatibility in these parameters.

Q: Why is the 71256S70DB classified as obsolete?

A: The 71256S70DB has reached end-of-life status. The 71256S100DB remains in active production, making it the recommended path for new designs and system support.

Q: Are there any package or mounting differences?

A: No. Both parts use the 28-CDIP package with 0.600" (15.24mm) body width and through-hole mounting, ensuring identical PCB layout compatibility.

Q: What compliance certifications apply to these parts?

A: Both parts are RoHS non-compliant and REACH unaffected. Applications requiring RoHS compliance must source alternative memory solutions.