LC4256B-5FT256AI Equivalent & Substitute Parts

Part Overview

The LC4256B-5FT256AI is a Complex Programmable Logic Device (CPLD) from Lattice Semiconductor Corporation's ispMACH® 4000B series. This device integrates 256 macrocells with 128 I/O pins in a 256-pin fine-pitch ball grid array package, delivering 5 nanosecond propagation delay performance. The part operates across an industrial temperature range of -40°C to 105°C with internal voltage supply specifications of 2.3V to 2.7V.

The LC4256B-5FT256AI is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support long-term product lifecycle management for applications currently utilizing this device.

Substiute Parts

LC4256B-5FT256AI

Lattice Semiconductor CorporationIn Stock: 1022LC4256B-5FT256AI Datasheet

Current PartRFQ

LC4256V-5FTN256AC

Lattice Semiconductor CorporationIn Stock: 1482LC4256V-5FTN256AC Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LC4256B-5FT256AI is determined by the following critical parameters:

• Macrocell Count: 256 macrocells (functional equivalence requirement)
• I/O Pin Count: 128 I/O pins (pinout compatibility requirement)
• Package Type: 256-FTBGA 17x17 (mechanical and thermal compatibility requirement)
• Propagation Delay: 5 ns maximum (timing performance requirement)
• Programmable Architecture: In System Programmable (functional requirement)
• Voltage Supply Range: Internal supply specifications (electrical compatibility requirement)
• Operating Temperature Range: Device thermal operating envelope (application suitability requirement)

The LC4256V-5FTN256AC from the ispMACH® 4000V series meets the functional, mechanical, and electrical requirements for substitution. Both devices share identical macrocell count, I/O configuration, package geometry, and propagation delay specifications. Differences in voltage supply range and operating temperature reflect the distinct design specifications of each series and must be evaluated against application requirements.

Parameter Comparison

Engineering Selection Recommendations

The LC4256V-5FTN256AC is the designated manufacturer-recommended substitute for the obsolete LC4256B-5FT256AI. Both devices maintain identical functional specifications across macrocell count, I/O configuration, package geometry, and timing performance.

The LC4256V-5FTN256AC offers the following advantages for new designs and replacement applications:

• Active Product Status: Currently manufactured and supported by Lattice Semiconductor Corporation, ensuring ongoing availability and technical support
• RoHS3 Compliance: Meets current environmental and regulatory requirements, whereas the LC4256B-5FT256AI is RoHS non-compliant
• Supply Chain Availability: 1412 units in stock compared to 933 units for the obsolete part

Design integration requires verification of voltage supply compatibility. The LC4256V-5FTN256AC operates at 3V to 3.6V internal supply, compared to the 2.3V to 2.7V specification of the LC4256B-5FT256AI. Applications must confirm that power distribution and voltage regulation circuits support the higher voltage range. The LC4256V-5FTN256AC also operates across a narrower temperature range (0°C to 90°C) compared to the industrial range of the LC4256B-5FT256AI (-40°C to 105°C), requiring validation against application thermal requirements.

Frequently Asked Questions (FAQ)

Q: Can the LC4256V-5FTN256AC directly replace the LC4256B-5FT256AI in existing designs?

A: Direct replacement requires verification of two critical parameters: voltage supply range and operating temperature range. The LC4256V-5FTN256AC operates at 3V to 3.6V internal supply and 0°C to 90°C junction temperature, whereas the LC4256B-5FT256AI operates at 2.3V to 2.7V and -40°C to 105°C. If your application operates within the LC4256V-5FTN256AC specifications, substitution is compatible. If your application requires the extended temperature range or lower voltage operation of the LC4256B-5FT256AI, substitution is not suitable.

Q: Are the package dimensions and pinout identical between these devices?

A: Yes. Both devices use the 256-FTBGA (17x17) package with 256-LBGA case designation. Pinout and mechanical compatibility are identical, allowing direct PCB-level substitution without layout modifications.

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

A: The LC4256B-5FT256AI is RoHS non-compliant, while the LC4256V-5FTN256AC is ROHS3 compliant. For applications subject to environmental regulations or customer requirements mandating RoHS compliance, the LC4256V-5FTN256AC is the appropriate choice.

Q: Are both devices in-system programmable?

A: Yes. Both the LC4256B-5FT256AI and LC4256V-5FTN256AC support in-system programming, maintaining functional equivalence for configuration and reconfiguration workflows.

Q: What is the moisture sensitivity level for both devices?

A: Both devices are classified as MSL 3 with a 168-hour floor life. Identical moisture handling and storage requirements apply to both parts.