AT27C040-90PI Equivalent & Substitute Parts

Part Overview

The AT27C040-90PI is a 4Mbit parallel EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 32-DIP package with 90 ns access time. This part is classified as obsolete, which necessitates identification of functionally equivalent alternatives for ongoing system support and component procurement. The AT27C040-90PI operates within the 4.5V to 5.5V supply voltage range and is suitable for applications requiring non-volatile memory storage in legacy embedded systems.

Key Parameters

Parameter	Value
Memory Type	Non-Volatile EPROM
Memory Size	4Mbit
Memory Organization	512K x 8
Memory Interface	Parallel
Access Time	90 ns
Voltage Supply Range	4.5V ~ 5.5V
Operating Temperature Range	-40°C ~ 85°C
Package Type	32-DIP (0.600", 15.24mm)
Mounting Type	Through Hole

Substitute Part Grouping Explanation

Substitution of the AT27C040-90PI is determined by strict equivalence across the following critical parameters:

Memory capacity: 4Mbit
Memory organization: 512K x 8 configuration
Access time: 90 ns
Supply voltage: 4.5V ~ 5.5V
Operating temperature range: -40°C ~ 85°C
Package: 32-DIP through-hole form factor
Memory interface: Parallel

The AT27C040-90PU meets all these criteria and is therefore a direct functional equivalent. The primary distinction between these parts is packaging format (tube vs. standard) and product status (active vs. obsolete).

Parameter Comparison

Parameter	AT27C040-90PI	AT27C040-90PU
Memory Type	Non-Volatile EPROM	Non-Volatile EPROM
Memory Size	4Mbit	4Mbit
Memory Organization	512K x 8	512K x 8
Memory Interface	Parallel	Parallel
Access Time	90 ns	90 ns
Voltage Supply	4.5V ~ 5.5V	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	32-DIP (0.600", 15.24mm)	32-DIP (0.600", 15.24mm)
Mounting Type	Through Hole	Through Hole
Product Status	Obsolete	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant

Engineering Selection Recommendations

The AT27C040-90PU is the direct substitute for the AT27C040-90PI. Both parts share identical electrical and mechanical specifications, ensuring pin-for-pin compatibility and functional interchangeability in circuit applications.

The AT27C040-90PU is preferred for new procurement due to its active product status and ROHS3 compliance. The AT27C040-90PI, being obsolete and RoHS non-compliant, should be replaced with the AT27C040-90PU in ongoing designs and system maintenance.

Frequently Asked Questions (FAQ)

Q: Can the AT27C040-90PU directly replace the AT27C040-90PI?

A: Yes. Both parts are electrically and mechanically identical. The AT27C040-90PU is a direct pin-for-pin substitute with no circuit modifications required.

Q: What is the difference between AT27C040-90PI and AT27C040-90PU?

A: The primary differences are packaging format (tube packaging for the -90PU variant) and product lifecycle status. The AT27C040-90PI is obsolete, while the AT27C040-90PU is active. The AT27C040-90PU also carries ROHS3 compliance certification.

Q: Are there any performance differences between these parts?

A: No. Both parts deliver identical performance specifications: 4Mbit capacity, 512K x 8 organization, 90 ns access time, and parallel interface operation.

Q: What supply voltage do these parts require?

A: Both the AT27C040-90PI and AT27C040-90PU operate within the 4.5V to 5.5V supply voltage range.

Q: What is the operating temperature range?

A: Both parts operate across the -40°C to 85°C temperature range.

Q: Is the 32-DIP package compatible with standard through-hole PCB layouts?

A: Yes. The 32-DIP package (0.600", 15.24mm) is a standard through-hole form factor compatible with conventional PCB designs and sockets.

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