SP1255-01UTG Equivalent & Substitute Parts

Part Overview

The SP1255-01UTG is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for surface mount applications in 6-µDFN packaging. This component provides transient voltage protection with a 14.6V reverse standoff voltage and 28V clamping voltage at peak pulse current. The part is classified as obsolete, making identification of suitable substitute components essential for ongoing design support and procurement continuity.

Substiute Parts

SP1255-01UTG

Littelfuse Inc.In Stock: 60265SP1255-01UTG Datasheet

Current PartRFQ

NSPM5131MUTBG

onsemiIn Stock: 2432NSPM5131MUTBG Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SP1255-01UTG is determined by the following critical parameters:

• Unidirectional channel configuration (1 channel required)
• Reverse standoff voltage: 14.6V (Max)
• Peak pulse current capability: 160A (8/20µs)
• Package type: 6-UFDFN Exposed Pad with identical footprint (1.8x2mm)
• Mounting type: Surface Mount
• RoHS3 compliance

The NSPM5131MUTBG from onsemi meets these core substitution criteria. While the clamping voltage differs (21.5V versus 28V), both parts share identical reverse standoff voltage, peak pulse current rating, package geometry, and RoHS compliance status. The lower clamping voltage of the substitute represents a tighter voltage regulation characteristic, which is acceptable in applications where the original 28V clamping specification provides design margin.

Parameter Comparison

Engineering Selection Recommendations

The NSPM5131MUTBG is a qualified substitute for the obsolete SP1255-01UTG based on the following factors:

• Both components maintain identical reverse standoff voltage (14.6V Max) and peak pulse current rating (160A at 8/20µs)
• Identical package geometry (6-UFDFN 1.8x2mm) ensures PCB footprint compatibility
• Both parts are ROHS3 compliant, meeting environmental and regulatory requirements
• The onsemi part is in active production status, ensuring long-term availability and supply chain continuity
• The NSPM5131MUTBG operates across an extended temperature range (-55°C to 125°C junction temperature) compared to the original part (-40°C to 125°C ambient), providing broader thermal operating margin

The primary design consideration is the reduced clamping voltage (21.5V versus 28V). Circuit designs must confirm that the tighter voltage regulation of the substitute part remains within system protection requirements.

Frequently Asked Questions (FAQ)

Q: Can the NSPM5131MUTBG directly replace the SP1255-01UTG without PCB modifications?

A: Yes. Both components use identical 6-UFDFN packaging with 1.8x2mm footprint and exposed pad configuration. No PCB layout changes are required for mechanical and electrical connectivity.

Q: What is the significance of the different clamping voltages (28V vs 21.5V)?

A: The clamping voltage determines the maximum voltage the TVS diode allows across its terminals during a transient event. The substitute part clamps at a lower voltage, providing tighter voltage regulation. This is acceptable if the protected circuit can tolerate 21.5V; however, if the original 28V specification was critical to system protection, circuit validation is necessary.

Q: Are both parts automotive-qualified?

A: The SP1255-01UTG carries AEC-Q101 automotive qualification. The NSPM5131MUTBG does not list automotive qualification in the provided specifications. Applications requiring automotive-grade components should confirm qualification status with onsemi before selection.

Q: What is the difference in operating temperature ranges?

A: The original part specifies -40°C to 125°C ambient temperature (TA), while the substitute specifies -55°C to 125°C junction temperature (TJ). The substitute provides a wider operating range, which is advantageous for thermal margin in high-temperature environments.

Q: Why is the original part listed as obsolete?

A: Littelfuse has discontinued the SP1255-01UTG. The NSPM5131MUTBG is an active product from onsemi, ensuring continued availability and manufacturing support for new designs and legacy system maintenance.