AT27C512R-12PI Equivalent & Substitute Parts

Part Overview

The AT27C512R-12PI is a 512Kbit EPROM (Erasable Programmable Read-Only Memory) IC manufactured by Microchip Technology, housed in a 28-DIP package with 120 ns access time. This part is classified as obsolete, indicating it has been discontinued and is no longer in active production. Finding equivalent or substitute parts is necessary due to limited availability and the transition to newer memory technologies. Substitute parts must maintain identical electrical specifications and physical packaging to ensure direct compatibility in legacy systems.

Key Parameters

Parameter	Value
Memory Type	Non-Volatile EPROM
Memory Size	512Kbit
Memory Organization	64K x 8
Memory Interface	Parallel
Access Time	120 ns
Voltage Supply	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 85°C (TC)
Package Type	28-DIP (0.600", 15.24mm)
Mounting Type	Through Hole

Substitute Part Grouping Explanation

Substitution for the AT27C512R-12PI is determined by the following critical parameters:

Memory Capacity & Organization: Must be 512Kbit with 64K x 8 organization
Memory Technology: Must be EPROM - OTP (One-Time Programmable)
Parallel Interface: Must support parallel data access
Package Compatibility: Must use 28-DIP (0.600", 15.24mm) through-hole mounting
Voltage Specifications: Must operate within 4.5V ~ 5.5V supply range
Temperature Range: Must support -40°C ~ 85°C operating conditions
Access Time: Faster or equal access time is acceptable for direct substitution

The AT27C512R-70PU meets all substitution criteria. It shares identical memory capacity, organization, interface type, package, voltage, and temperature specifications. The 70 ns access time is faster than the original 120 ns specification, making it functionally compatible for all timing-critical applications.

Parameter Comparison

Parameter	AT27C512R-12PI (Main Part)	AT27C512R-70PU (Substitute)
Manufacturer	Microchip Technology	Microchip Technology
Memory Type	Non-Volatile EPROM	Non-Volatile EPROM
Memory Format	EPROM	EPROM
Technology	EPROM - OTP	EPROM - OTP
Memory Size	512Kbit	512Kbit
Memory Organization	64K x 8	64K x 8
Memory Interface	Parallel	Parallel
Access Time	120 ns	70 ns
Voltage - Supply	4.5V ~ 5.5V	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 85°C (TC)	-40°C ~ 85°C (TC)
Mounting Type	Through Hole	Through Hole
Package / Case	28-DIP (0.600", 15.24mm)	28-DIP (0.600", 15.24mm)
Supplier Device Package	28-PDIP	28-PDIP
Base Product Number	AT27C512	AT27C512
Product Status	Obsolete	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)
REACH Status	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

The AT27C512R-70PU is the direct substitute for the AT27C512R-12PI based on the following factors:

Product Status: The AT27C512R-12PI is obsolete, while the AT27C512R-70PU is active and in production. This ensures long-term availability and supply chain reliability for new designs or component replacement.

Compliance & Certifications: The AT27C512R-70PU achieves ROHS3 compliance, whereas the original part is RoHS non-compliant. Both parts maintain REACH Unaffected status. For applications requiring regulatory compliance with modern environmental standards, the substitute part is the appropriate choice.

Electrical & Physical Compatibility: All critical electrical parameters—memory capacity, organization, interface type, voltage supply, and operating temperature—are identical between the two parts. The 28-DIP through-hole package is identical, enabling direct socket replacement without PCB modifications.

Performance Enhancement: The AT27C512R-70PU provides faster access time (70 ns versus 120 ns), which improves system performance without introducing compatibility issues. Faster memory access is backward-compatible with designs specified for the original 120 ns part.

Frequently Asked Questions (FAQ)

Q: Can the AT27C512R-70PU be used as a direct replacement for the AT27C512R-12PI?

A: Yes. Both parts share identical memory capacity (512Kbit), organization (64K x 8), parallel interface, 28-DIP package, voltage supply (4.5V ~ 5.5V), and operating temperature range (-40°C ~ 85°C). The faster 70 ns access time of the substitute part is fully compatible with systems designed for the original 120 ns specification.

Q: What is the difference between the access time specifications?

A: The AT27C512R-12PI has 120 ns access time, while the AT27C512R-70PU has 70 ns access time. Access time defines the maximum delay from address input to valid data output. The faster specification of the substitute part does not create compatibility issues; it only improves performance.

Q: Are there any package or pinout differences?

A: No. Both parts use the 28-DIP (0.600", 15.24mm) package with identical pinout. The parts are physically and electrically interchangeable at the socket level.

Q: Why is the original part marked as obsolete?

A: The AT27C512R-12PI is classified as obsolete because Microchip Technology has discontinued production. The AT27C512R-70PU remains in active production and is the recommended alternative for new designs and component replacement.

Q: Does the substitute part meet modern compliance requirements?

A: The AT27C512R-70PU is ROHS3 compliant, making it suitable for applications requiring compliance with current environmental regulations. The original AT27C512R-12PI is RoHS non-compliant. Both parts maintain REACH Unaffected status.

Q: Are there any programming or functional differences?

A: No functional differences exist. Both parts are EPROM - OTP (One-Time Programmable) devices with identical memory organization and parallel interface. Programming procedures and data retention characteristics are equivalent.

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