AT28HC256F-90TU-T Equivalent & Substitute Parts

Part Overview

The AT28HC256F-90TU-T is a 256Kbit parallel EEPROM memory IC manufactured by Microchip Technology, featuring 90 ns access time and 28-TSSOP surface mount packaging. This component is classified as obsolete, making substitute parts necessary for new designs and ongoing production requirements. The part operates across the industrial temperature range of -40°C to 85°C with 4.5V to 5.5V supply voltage specifications.

Substiute Parts

AT28HC256F-90TU-T

Microchip TechnologyIn Stock: 1035AT28HC256F-90TU-T Datasheet

Current PartRFQ

AT28HC256F-90SU-T

Microchip TechnologyIn Stock: 2506AT28HC256F-90SU-T Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT28HC256F-90TU-T is determined by strict equivalence across core electrical and memory specifications. The substitute part AT28HC256F-90SU-T maintains identical memory capacity (256Kbit), organization (32K x 8), access time (90 ns), write cycle time (3ms), supply voltage range (4.5V ~ 5.5V), and operating temperature range (-40°C ~ 85°C). Both parts share the same base product number (AT28HC256) and manufacturer (Microchip Technology), confirming functional equivalence.

The primary distinction between these parts is packaging format: the main part uses 28-TSSOP (0.465", 11.80mm width) while the substitute uses 28-SOIC (0.295", 7.50mm width). Both are surface mount packages with identical pin counts and electrical characteristics. Compliance parameters including RoHS3 status and MSL rating remain consistent across both parts.

Parameter Comparison

Engineering Selection Recommendations

The AT28HC256F-90SU-T serves as the direct functional equivalent to the AT28HC256F-90TU-T. Selection between these parts depends on PCB layout constraints and packaging requirements. The substitute part features a narrower 28-SOIC package (7.50mm width) compared to the main part's 28-TSSOP package (11.80mm width), enabling more compact board designs where space is limited.

Both parts maintain identical electrical performance and compliance certifications. The substitute part holds active product status with established supply availability (2400 pcs in stock), whereas the main part is obsolete. For new designs and production continuity, the AT28HC256F-90SU-T is the appropriate selection. PCB footprint redesign is required when transitioning from 28-TSSOP to 28-SOIC packaging, as pin pitch and body dimensions differ between these package types.

Frequently Asked Questions (FAQ)

Q: Are the AT28HC256F-90TU-T and AT28HC256F-90SU-T electrically identical?

A: Yes. Both parts share identical memory specifications (256Kbit, 32K x 8 organization), access time (90 ns), write cycle time (3ms), supply voltage (4.5V ~ 5.5V), and operating temperature range (-40°C ~ 85°C). Electrical performance is equivalent.

Q: What is the primary difference between these two parts?

A: The packaging format differs. The AT28HC256F-90TU-T uses 28-TSSOP (0.465", 11.80mm width) while the AT28HC256F-90SU-T uses 28-SOIC (0.295", 7.50mm width). Both are surface mount packages with 28 pins.

Q: Can I use the AT28HC256F-90SU-T as a direct replacement on existing PCBs designed for the AT28HC256F-90TU-T?

A: No. Different package types require different PCB footprints. The 28-SOIC and 28-TSSOP packages have different pin pitches and body dimensions, necessitating PCB layout redesign.

Q: Why is the main part listed as obsolete?

A: The AT28HC256F-90TU-T is classified as obsolete by the manufacturer. The AT28HC256F-90SU-T remains in active production status with current availability.

Q: Are both parts RoHS compliant?

A: Yes. Both the AT28HC256F-90TU-T and AT28HC256F-90SU-T are ROHS3 compliant with identical MSL ratings of 3 (168 hours).

Q: Which part should I specify for new designs?

A: The AT28HC256F-90SU-T is recommended for new designs due to its active product status, established supply chain, and compact 28-SOIC packaging. The main part's obsolete status makes it unsuitable for new applications.