AT27C1024-70JC EPROM Equivalent & Substitute Parts

Part Overview

The AT27C1024-70JC is a 1Mbit parallel EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 44-PLCC surface mount package. This OTP (One-Time Programmable) memory device operates at 70 ns access time with a 4.5V to 5.5V supply voltage range and supports operating temperatures from 0°C to 70°C.

The AT27C1024-70JC is classified as obsolete. Locating direct replacements becomes necessary for legacy system maintenance, repair operations, and component replenishment where original specifications must be maintained. The substitute part AT27C1024-70JU provides functional equivalence while offering improved product status and compliance certifications.

Key Parameters

Parameter	Value
Memory Size	1Mbit
Memory Organization	64K x 16
Memory Format	EPROM
Memory Interface	Parallel
Access Time	70 ns
Voltage Supply Range	4.5V ~ 5.5V
Package Type	44-PLCC (J-Lead)
Mounting Type	Surface Mount
Memory Type	Non-Volatile
Technology	EPROM - OTP

Substitute Part Grouping Explanation

The AT27C1024-70JU qualifies as a direct substitute for the AT27C1024-70JC based on the following critical parameters:

Memory Capacity & Organization: Both devices provide 1Mbit capacity with 64K x 16 organization
Access Time: Identical 70 ns specification
Memory Interface: Both use parallel interface architecture
Supply Voltage: Both operate within 4.5V to 5.5V range
Package & Pinout: Both use 44-PLCC (16.6x16.6) surface mount package with J-Lead configuration
Memory Technology: Both are EPROM OTP devices with non-volatile storage

The substitution is valid at the functional and electrical level. Differences exist in operating temperature range, product status, and compliance certifications, which are secondary to core memory functionality.

Parameter Comparison

Parameter	AT27C1024-70JC	AT27C1024-70JU
Manufacturer	Microchip Technology	Microchip Technology
Memory Size	1Mbit	1Mbit
Memory Organization	64K x 16	64K x 16
Memory Format	EPROM	EPROM
Memory Interface	Parallel	Parallel
Access Time	70 ns	70 ns
Voltage Supply	4.5V ~ 5.5V	4.5V ~ 5.5V
Package Type	44-PLCC (J-Lead)	44-PLCC (J-Lead)
Mounting Type	Surface Mount	Surface Mount
Operating Temperature	0°C ~ 70°C	-40°C ~ 85°C
Product Status	Obsolete	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant
Moisture Sensitivity Level	MSL 2 (1 Year)	MSL 3 (168 Hours)

Engineering Selection Recommendations

The AT27C1024-70JU is the recommended substitute for the AT27C1024-70JC based on the following factors:

Product Status: The AT27C1024-70JU maintains active product status with ongoing manufacturer support, whereas the AT27C1024-70JC is obsolete. Active status ensures continued availability and supply chain reliability.

Compliance Certifications: The AT27C1024-70JU is ROHS3 compliant, meeting current environmental and hazardous substance restrictions. The AT27C1024-70JC is non-compliant with RoHS requirements.

Operating Temperature Range: The AT27C1024-70JU supports an extended operating temperature range of -40°C to 85°C, compared to the AT27C1024-70JC range of 0°C to 70°C. This provides greater thermal flexibility for diverse application environments.

Programmability Verification: The AT27C1024-70JU is verified as programmable through DiGi-Electronics, whereas the AT27C1024-70JC programmability status is not verified.

Electrical & Functional Equivalence: Both devices are electrically and functionally identical across all critical memory parameters, ensuring direct substitution without circuit redesign.

Frequently Asked Questions (FAQ)

Q: Can the AT27C1024-70JU replace the AT27C1024-70JC in existing designs?

A: Yes. Both devices share identical memory capacity (1Mbit), organization (64K x 16), access time (70 ns), supply voltage (4.5V ~ 5.5V), and 44-PLCC package configuration. Direct substitution is valid at the functional level.

Q: What is the difference between the two part numbers?

A: The primary differences are product status (obsolete vs. active), operating temperature range (0°C ~ 70°C vs. -40°C ~ 85°C), RoHS compliance status, and moisture sensitivity level. The core memory functionality remains identical.

Q: Are there packaging differences between these parts?

A: Both use 44-PLCC (16.6x16.6) surface mount packages with J-Lead configuration. The AT27C1024-70JC is supplied in standard packaging, while the AT27C1024-70JU is supplied in tube packaging. Pinout and footprint are identical.

Q: Does the extended temperature range of the AT27C1024-70JU affect compatibility?

A: No. The extended range (-40°C ~ 85°C) is a superset of the original specification (0°C ~ 70°C). Applications operating within the original temperature window remain fully compatible.

Q: What does ROHS3 compliance mean for the AT27C1024-70JU?

A: ROHS3 compliance indicates the device meets Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, and other hazardous materials. This is required for many modern applications and supply chains.

Q: Is the AT27C1024-70JU programmable?

A: Yes. The AT27C1024-70JU is verified as programmable through DiGi-Electronics, confirming OTP programming capability.

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