Renesas Electronics 71321LA55TF SRAM Equivalent & Substitute Parts

Part Overview

The Renesas Electronics 71321LA55TF is a 16Kbit dual-port asynchronous SRAM memory IC in 64-TQFP surface mount packaging. This component is classified as obsolete, which necessitates identification of functionally equivalent alternatives for ongoing system support and new design implementations. The part operates within a 4.5V to 5.5V supply voltage range with a 55 ns access time and write cycle time, suitable for parallel memory interface applications requiring volatile storage.

Key Parameters

Parameter	Value
Memory Type	Volatile SRAM
Memory Format	Dual Port, Asynchronous
Memory Size	16Kbit
Memory Organization	2K x 8
Memory Interface	Parallel
Access Time	55 ns
Write Cycle Time	55 ns
Voltage Supply Range	4.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C
Package Type	64-TQFP (10x10)
Mounting Type	Surface Mount
Moisture Sensitivity Level	MSL 3 (168 Hours)

Substitute Part Grouping Explanation

Substitution eligibility for the 71321LA55TF is determined by strict equivalence across the following critical parameters:

Memory capacity and organization (16Kbit, 2K x 8 configuration)
Dual-port asynchronous SRAM technology
Parallel memory interface architecture
64-TQFP (10x10) surface mount package
Supply voltage compatibility (4.5V ~ 5.5V)
Operating temperature range (0°C ~ 70°C)
Moisture sensitivity classification (MSL 3)

The 71321LA20TFG qualifies as a direct substitute based on identical memory specifications, package geometry, electrical operating parameters, and thermal characteristics. The primary distinction is improved access time and write cycle time performance (20 ns versus 55 ns), which represents a performance upgrade rather than a functional limitation.

Parameter Comparison

Parameter	71321LA55TF (Main Part)	71321LA20TFG (Substitute)
Manufacturer	Renesas Electronics Corporation	Renesas Electronics Corporation
Memory Type	Volatile SRAM	Volatile SRAM
Memory Format	Dual Port, Asynchronous	Dual Port, Asynchronous
Memory Size	16Kbit	16Kbit
Memory Organization	2K x 8	2K x 8
Memory Interface	Parallel	Parallel
Access Time	55 ns	20 ns
Write Cycle Time	55 ns	20 ns
Voltage Supply Range	4.5V ~ 5.5V	4.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C
Package Type	64-TQFP (10x10)	64-TQFP (10x10)
Mounting Type	Surface Mount	Surface Mount
Moisture Sensitivity Level	MSL 3 (168 Hours)	MSL 3 (168 Hours)
Product Status	Obsolete	Active
RoHS Compliance	Non-compliant	ROHS3 Compliant

Engineering Selection Recommendations

The 71321LA20TFG is the qualified substitute for the obsolete 71321LA55TF. Selection of the substitute part is supported by the following engineering criteria:

Functional equivalence across all memory specifications and electrical parameters
Active product status ensuring long-term availability and supply chain continuity
ROHS3 compliance status, addressing regulatory requirements for new designs and manufacturing processes
Identical package footprint and pinout, enabling direct PCB layout compatibility
Superior access time and write cycle time performance (20 ns), providing timing margin improvement over the original specification

The substitute part maintains backward compatibility with existing circuit designs while offering enhanced performance characteristics and improved regulatory compliance posture.

Frequently Asked Questions (FAQ)

Q: Can the 71321LA20TFG be used as a direct replacement for the 71321LA55TF in existing designs?

A: Yes. The 71321LA20TFG is functionally equivalent across all critical parameters including memory capacity, organization, interface type, supply voltage, operating temperature range, and package geometry. The improved access time represents a performance enhancement with no compatibility concerns.

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

A: The 71321LA55TF specifies 55 ns access time, while the 71321LA20TFG specifies 20 ns access time. This represents faster memory response in the substitute part. Designs originally specified for 55 ns operation will function correctly with the faster 20 ns part, as timing requirements are met or exceeded.

Q: Are there packaging differences between the main part and substitute?

A: No. Both parts use identical 64-TQFP (10x10) surface mount packaging with matching pinout and footprint geometry. PCB layout modifications are not required for substitution.

Q: What is the impact of RoHS compliance differences?

A: The main part (71321LA55TF) is RoHS non-compliant, while the substitute (71321LA20TFG) is ROHS3 compliant. For new designs and manufacturing environments subject to RoHS regulations, the substitute part is the appropriate selection. Existing designs using the obsolete part may require component substitution to maintain regulatory compliance during production transitions.

Q: How does the obsolete status of the main part affect component selection?

A: The obsolete classification of the 71321LA55TF indicates discontinued manufacturing and limited availability. The 71321LA20TFG maintains active product status, ensuring reliable supply chain access and long-term design support. Substitution is necessary for new production and design continuity.

Q: Are the moisture sensitivity levels identical?

A: Yes. Both parts are classified as MSL 3 (168 Hours), indicating identical moisture handling and storage requirements during manufacturing and assembly processes.

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