U62256ADC07LLG1 Equivalent & Substitute Parts

Part Overview

The U62256ADC07LLG1 is a 256Kbit asynchronous SRAM memory IC in 28-DIP packaging manufactured by Alliance Memory, Inc. This part features parallel memory interface with 70 ns access time and operates across the 4.5V to 5.5V supply voltage range. The product is classified as obsolete, making identification of compatible substitute components essential for system redesign, legacy equipment maintenance, and production continuity.

Key Parameters

Parameter	Value
Memory Type	Volatile SRAM
Memory Size	256Kbit
Memory Organization	32K x 8
Memory Interface	Parallel
Access Time	70 ns
Write Cycle Time	70 ns
Voltage Supply Range	4.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C
Package Type	28-DIP (0.600", 15.24mm)
Mounting Type	Through Hole
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the U62256ADC07LLG1 is determined by the following critical parameters:

Memory Capacity & Organization: The substitute must maintain 256Kbit capacity with 32K x 8 organization to ensure address and data bus compatibility.

Package & Mounting: The 28-DIP through-hole package is mandatory for PCB footprint compatibility. Pin count and physical dimensions must remain identical.

Memory Interface: Parallel interface operation is required for direct signal compatibility with existing system designs.

Voltage Supply Range: The substitute must operate within or encompass the 4.5V ~ 5.5V range. Wider voltage ranges are acceptable if they include this specification.

Access Time & Performance: The substitute may have equal or faster access time. Faster access times (lower nanosecond values) are compatible with systems designed for 70 ns operation.

Compliance & Status: RoHS3 compliance and active product status are preferred for long-term availability and regulatory adherence.

Parameter Comparison

Parameter	U62256ADC07LLG1	AS6C62256-55PCN
Manufacturer	Alliance Memory, Inc.	Alliance Memory, Inc.
Memory Type	Volatile SRAM	Volatile SRAM
Memory Size	256Kbit	256Kbit
Memory Organization	32K x 8	32K x 8
Memory Interface	Parallel	Parallel
Access Time	70 ns	55 ns
Write Cycle Time	70 ns	55 ns
Voltage Supply Range	4.5V ~ 5.5V	2.7V ~ 5.5V
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C
Package Type	28-DIP (0.600", 15.24mm)	28-DIP (0.600", 15.24mm)
Mounting Type	Through Hole	Through Hole
RoHS Status	ROHS3 Compliant	ROHS3 Compliant
Product Status	Obsolete	Active

Engineering Selection Recommendations

The AS6C62256-55PCN is a direct functional substitute for the U62256ADC07LLG1. Both components share identical memory capacity, organization, package configuration, and operating temperature range. The substitute offers improved performance with 55 ns access time compared to the original 70 ns specification, providing faster memory operation without compromising compatibility.

The AS6C62256-55PCN features an extended voltage supply range of 2.7V to 5.5V, which encompasses the original 4.5V to 5.5V specification. This wider voltage tolerance provides additional design flexibility for systems with variable supply conditions.

Both parts maintain ROHS3 compliance and identical through-hole 28-DIP packaging. The substitute's active product status ensures ongoing availability and supply chain continuity, addressing the obsolescence of the original component.

Frequently Asked Questions (FAQ)

Q: Can the AS6C62256-55PCN directly replace the U62256ADC07LLG1 in existing designs?

A: Yes. Both components share identical memory capacity (256Kbit), organization (32K x 8), parallel interface, package type (28-DIP), and operating temperature range (0°C ~ 70°C). The substitute's faster 55 ns access time is compatible with systems designed for 70 ns operation.

Q: What is the significance of the faster access time in the substitute part?

A: The AS6C62256-55PCN operates at 55 ns compared to the original 70 ns. Faster access time means the memory responds more quickly to read requests. Systems designed for 70 ns operation will function correctly with faster memory without modification.

Q: Does the extended voltage range of the AS6C62256-55PCN affect compatibility?

A: No. The substitute's 2.7V ~ 5.5V range encompasses the original 4.5V ~ 5.5V specification. Systems operating within the original voltage range will function identically with the substitute.

Q: Are there any package or pinout differences between these parts?

A: No. Both components use identical 28-DIP through-hole packaging with 0.600" (15.24mm) body width. Pinout and PCB footprint compatibility is guaranteed.

Q: What is the inventory status of these parts?

A: The U62256ADC07LLG1 is obsolete with 953 units in stock. The AS6C62256-55PCN is an active product with 1313 units available, ensuring long-term supply availability.

Q: Are both parts RoHS compliant?

A: Yes. Both the U62256ADC07LLG1 and AS6C62256-55PCN are ROHS3 compliant, meeting environmental and regulatory requirements for electronic components.

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