Renesas Electronics 71256L55DB SRAM Equivalent & Substitute Parts

Part Overview

The Renesas Electronics 71256L55DB is a 256Kbit asynchronous SRAM memory IC in 28-CDIP packaging with 55 ns access time. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support, maintenance, and new design implementations where this memory architecture remains applicable.

Substiute Parts

71256L55DB

Renesas Electronics CorporationIn Stock: 112571256L55DB Datasheet

Current PartRFQ

71256L45DB

Renesas Electronics CorporationIn Stock: 10718271256L45DB Datasheet

MFR RecommendedRFQ

71256L70DB

Renesas Electronics CorporationIn Stock: 225271256L70DB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 71256L55DB is determined by strict equivalence across the following critical parameters:

• Memory capacity: 256Kbit
• Memory organization: 32K x 8 parallel format
• Package type: 28-CDIP through-hole configuration
• Supply voltage range: 4.5V ~ 5.5V
• Operating temperature range: -55°C ~ 125°C
• RoHS3 compliance status
• Manufacturer: Renesas Electronics Corporation

The substitute parts listed below maintain identical memory architecture, pinout compatibility, and electrical specifications. Variations in access time and write cycle time do not affect functional substitution when the application timing requirements are met by the substitute part's performance characteristics.

Parameter Comparison

Engineering Selection Recommendations

All three parts—71256L55DB, 71256L45DB, and 71256L70DB—are functionally equivalent for applications requiring 256Kbit parallel SRAM in 28-CDIP packaging. Selection between these parts is determined by access time requirements:

The 71256L45DB offers the fastest access time at 45 ns and is suitable for applications with stringent timing constraints.

The 71256L55DB provides 55 ns access time and represents the baseline specification.

The 71256L70DB operates at 70 ns access time and is applicable where timing margins are less critical.

All parts maintain ROHS3 compliance and identical electrical specifications for supply voltage and operating temperature range. Through-hole mounting compatibility ensures direct board-level substitution without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the 71256L45DB replace the 71256L55DB in existing designs?

A: Yes. The 71256L45DB is a direct substitute with superior access time performance (45 ns versus 55 ns). It maintains identical memory capacity, organization, pinout, voltage specifications, and temperature range. No circuit modifications are required.

Q: Is the 71256L70DB compatible with the 71256L55DB?

A: Yes. The 71256L70DB is functionally compatible with identical memory specifications and packaging. However, its 70 ns access time is slower than the original 55 ns specification. Substitution is valid only when application timing requirements permit the slower access time.

Q: Are all three parts pin-compatible?

A: Yes. All three parts use the 28-CDIP package with identical pinout configuration, enabling direct through-hole board substitution without layout changes.

Q: What is the significance of the access time difference between these parts?

A: Access time defines the maximum delay from address input to valid data output. The 71256L45DB (45 ns) is faster, the 71256L55DB (55 ns) is intermediate, and the 71256L70DB (70 ns) is slower. Selection depends on the system's maximum allowable memory access time. Faster parts are backward compatible with designs requiring slower access times.

Q: Do all substitute parts meet the same compliance standards?

A: Yes. All three parts are ROHS3 compliant with identical moisture sensitivity level (MSL 1 - Unlimited) and REACH unaffected status.

Q: What packaging options are available for these parts?

A: All parts are supplied in 28-CDIP through-hole packaging. The 71256L45DB and 71256L70DB are available in tube packaging, while the 71256L55DB is supplied without specified packaging designation.