AT28C17E-20SC Equivalent & Substitute Parts

Part Overview

The AT28C17E-20SC is a 16Kbit parallel EEPROM memory IC manufactured by Microchip Technology in a 28-SOIC surface mount package. This device features a 200 ns access time and operates across a 4.5V to 5.5V supply voltage range with an operating temperature range of 0°C to 70°C. The product is classified as obsolete, making identification of compatible substitute components essential for ongoing system support and new design implementations.

Key Parameters

Parameter	Value
Memory Size	16Kbit
Memory Organization	2K x 8
Memory Interface	Parallel
Access Time	200 ns
Write Cycle Time	200µs
Voltage Supply Range	4.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C
Package Type	28-SOIC
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the AT28C17E-20SC is determined by the following critical parameters:

Package Compatibility: Both the main part and substitute must use the 28-SOIC surface mount package to ensure mechanical and electrical compatibility with existing PCB layouts.

Electrical Interface: The parallel memory interface is mandatory. Both devices must support identical address and data bus configurations.

Supply Voltage: The substitute must operate within the 4.5V to 5.5V range to maintain compatibility with existing power distribution systems.

Memory Organization: While the substitute may have different total capacity, the 8-bit data width (x8 organization) must be preserved for bus compatibility.

Pin Configuration: The 28-SOIC package ensures identical pin count and spacing, allowing direct physical replacement.

The AT28HC64B-12SU qualifies as a substitute based on these parameters. It maintains the same package, parallel interface, supply voltage range, and 8-bit data organization while offering increased memory capacity (64Kbit vs. 16Kbit) and improved performance characteristics.

Parameter Comparison

Parameter	AT28C17E-20SC (Main)	AT28HC64B-12SU (Substitute)
Memory Size	16Kbit	64Kbit
Memory Organization	2K x 8	8K x 8
Memory Interface	Parallel	Parallel
Access Time	200 ns	120 ns
Write Cycle Time	200µs	10ms
Voltage Supply Range	4.5V ~ 5.5V	4.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C	-40°C ~ 85°C
Package Type	28-SOIC	28-SOIC
Mounting Type	Surface Mount	Surface Mount
Product Status	Obsolete	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant

Engineering Selection Recommendations

The AT28HC64B-12SU is an active product with verified programmability and ROHS3 compliance, addressing the obsolescence status of the AT28C17E-20SC. The substitute maintains identical package and electrical interface specifications, ensuring direct compatibility with existing circuit designs.

The AT28HC64B-12SU provides superior performance with a 120 ns access time compared to the 200 ns specification of the original part. The extended operating temperature range (-40°C to 85°C) accommodates broader environmental conditions. The increased memory capacity (64Kbit) provides additional storage without requiring circuit modifications, as the 8-bit parallel interface and pin configuration remain unchanged.

For applications requiring strict adherence to the original 16Kbit capacity specification, address decoding logic may be implemented to utilize only the lower 2K x 8 address space of the substitute device. This approach maintains functional equivalence while leveraging the active product status and improved compliance profile of the AT28HC64B-12SU.

Frequently Asked Questions (FAQ)

Q: Can the AT28HC64B-12SU be used as a direct replacement for the AT28C17E-20SC?

A: Yes. Both devices share the 28-SOIC package, parallel memory interface, identical pin configuration, and compatible supply voltage range (4.5V to 5.5V). The substitute can be installed without PCB modifications.

Q: What are the differences in memory capacity between these parts?

A: The AT28C17E-20SC provides 16Kbit (2K x 8) capacity, while the AT28HC64B-12SU provides 64Kbit (8K x 8) capacity. The additional address lines in the substitute accommodate the larger memory space. Existing firmware addressing the lower 2K x 8 space will function without modification.

Q: How do the access times compare?

A: The AT28HC64B-12SU offers faster access at 120 ns versus the 200 ns specification of the AT28C17E-20SC. This improvement is backward compatible and does not require circuit adjustments.

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

A: The AT28C17E-20SC is RoHS non-compliant, while the AT28HC64B-12SU is ROHS3 compliant. For new designs and applications subject to RoHS regulations, the substitute is the appropriate selection.

Q: Are there temperature range considerations for substitution?

A: The AT28HC64B-12SU operates from -40°C to 85°C, compared to the 0°C to 70°C range of the original part. Applications operating within the original temperature specification will function without issue. Applications requiring extended temperature operation benefit from the substitute's broader range.

Q: What is the write cycle time difference, and does it affect compatibility?

A: The AT28C17E-20SC specifies 200µs write cycle time, while the AT28HC64B-12SU specifies 10ms. Write cycle time affects programming speed but not functional compatibility. Existing firmware write routines will operate correctly with the longer cycle time of the substitute.

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