Renesas Electronics 7140LA55J SRAM Equivalent & Substitute Parts

Part Overview

The Renesas Electronics 7140LA55J is an 8Kbit dual-port asynchronous SRAM memory IC in a 52-PLCC package with 55 ns access time. This part is classified as obsolete, making substitute components necessary for new designs, maintenance, or production continuity. The 7140LA55J operates within the 4.5V to 5.5V supply range and is suitable for parallel memory interface applications requiring volatile storage.

Key Parameters

Parameter	Value
Memory Type	Volatile SRAM
Memory Format	Dual Port, Asynchronous
Memory Size	8Kbit
Memory Organization	1K 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	52-PLCC (J-Lead)
Mounting Type	Surface Mount
MSL Rating	3 (168 Hours)

Substitute Part Grouping Explanation

Substitution for the 7140LA55J is determined by strict equivalence across the following parameters:

Memory capacity and organization (8Kbit, 1K x 8 configuration)
Dual-port asynchronous SRAM technology
Parallel memory interface
52-PLCC package footprint and pinout compatibility
Supply voltage range (4.5V ~ 5.5V)
Operating temperature range (0°C ~ 70°C)
Surface mount mounting type

The primary substitute, Renesas Electronics 7140LA20JG, maintains full compatibility across all mechanical and electrical parameters while offering improved access time performance (20 ns versus 55 ns). This faster access time makes the 7140LA20JG a direct functional upgrade suitable for applications where the original part is no longer available.

Parameter Comparison

Parameter	7140LA55J (Main Part)	7140LA20JG (Substitute)
Manufacturer	Renesas Electronics Corporation	Renesas Electronics Corporation
Memory Type	Volatile SRAM	Volatile SRAM
Memory Format	Dual Port, Asynchronous	Dual Port, Asynchronous
Memory Size	8Kbit	8Kbit
Memory Organization	1K x 8	1K 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	52-PLCC (J-Lead)	52-PLCC (J-Lead)
Mounting Type	Surface Mount	Surface Mount
MSL Rating	3 (168 Hours)	3 (168 Hours)
Product Status	Obsolete	Last Time Buy
RoHS Compliance	Non-compliant	ROHS3 Compliant

Engineering Selection Recommendations

The 7140LA20JG is the qualified substitute for the 7140LA55J based on the following criteria:

Functional Equivalence: Both parts share identical memory capacity, organization, interface type, and package specifications. Pin-for-pin compatibility is maintained, enabling direct board-level replacement without layout modifications.

Performance Improvement: The 7140LA20JG provides superior access and write cycle times (20 ns versus 55 ns), making it suitable for applications with tighter timing requirements while remaining backward-compatible with designs originally specified for the 7140LA55J.

Compliance Status: The 7140LA20JG holds ROHS3 compliance, whereas the original part is non-compliant. For new production or designs subject to RoHS regulations, the 7140LA20JG is the appropriate selection.

Availability: The 7140LA55J is obsolete. The 7140LA20JG, classified as Last Time Buy, provides a defined procurement window for component sourcing before complete discontinuation.

Frequently Asked Questions (FAQ)

Q: Can the 7140LA20JG replace the 7140LA55J in existing designs?

A: Yes. The 7140LA20JG is pin-compatible and functionally equivalent. It operates within the same voltage and temperature ranges, uses the same 52-PLCC package, and maintains the same memory organization. No circuit modifications are required.

Q: What is the primary difference between these parts?

A: Access time and write cycle time differ. The 7140LA20JG operates at 20 ns, while the 7140LA55J operates at 55 ns. This represents a performance improvement with no functional trade-offs for the substitute part.

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

A: No. Both parts use the 52-PLCC (J-Lead) surface mount package with identical footprint dimensions (19.13 x 19.13 mm). Moisture sensitivity levels are also identical at MSL 3 (168 Hours).

Q: What is the significance of the RoHS compliance difference?

A: The 7140LA20JG is ROHS3 compliant, while the 7140LA55J is non-compliant. For applications or markets requiring RoHS compliance, the 7140LA20JG is the mandated selection.

Q: Why is the 7140LA55J listed as obsolete?

A: Obsolete status indicates the part is no longer manufactured and has been removed from active production. The 7140LA20JG, as a Last Time Buy component, represents the final procurement opportunity before complete discontinuation of this product line.

Q: Are supply voltage and operating temperature ranges identical?

A: Yes. Both parts operate across 4.5V to 5.5V supply voltage and 0°C to 70°C operating temperature ranges, ensuring thermal and electrical compatibility in equivalent applications.

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