LTST-S270CKT Equivalent & Substitute Parts

Part Overview

The LTST-S270CKT is a red LED indication component manufactured by Lite-On Inc., designed for surface mount right-angle applications. This part features a 638nm dominant wavelength with 1.8V forward voltage and 16mcd brightness rating in a compact 2-SMD package with no lead exposed pad. The component is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and production continuity.

Substiute Parts

LTST-S270CKT

Lite-On Inc.In Stock: 991LTST-S270CKT Datasheet

Current PartRFQ

LTST-S270KRKT

Lite-On Inc.In Stock: 23570LTST-S270KRKT Datasheet

DirectRFQ

LTST-S270KDKT

Lite-On Inc.In Stock: 1073LTST-S270KDKT Datasheet

MFR RecommendedRFQ

HSMH-C120

Broadcom LimitedIn Stock: 8230HSMH-C120 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LTST-S270CKT is determined by the following critical parameters:

Primary Compatibility Criteria:

• Red color specification (638nm dominant wavelength range)
• Forward voltage within acceptable operating range (1.8V nominal)
• Surface mount right-angle mounting configuration
• 2-SMD package format
• Millicandela rating suitable for indication applications (16mcd minimum)
• Viewing angle of 130° or greater
• RoHS3 compliance and MSL rating compatibility

Identified Substitute Parts:

1. LTST-S270KRKT (Lite-On Inc.) - Direct manufacturer alternative with active product status, 631nm dominant wavelength, 2V forward voltage, 54mcd brightness, 0603 (1608 Metric) package format, surface mount right-angle configuration.

2. LTST-S270KDKT (Lite-On Inc.) - Manufacturer-recommended substitute with active product status, 638nm dominant wavelength matching the original, 2V forward voltage, 24.75mcd brightness, 2-SMD package format, surface mount configuration.

3. HSMH-C120 (Broadcom Limited) - Cross-manufacturer alternative with obsolete product status, 639nm dominant wavelength, 1.8V forward voltage matching the original, 17mcd brightness, 2-SMD package format, surface mount right-angle configuration, diffused lens transparency.

Parameter Comparison

Engineering Selection Recommendations

LTST-S270KRKT is the preferred active-status substitute from Lite-On Inc. This part maintains identical mounting configuration and lens specifications while offering higher brightness (54mcd versus 16mcd). The forward voltage increase from 1.8V to 2V requires circuit verification for current-limiting resistor adjustment. The 0603 package format provides improved component availability and manufacturing support compared to the obsolete original.

LTST-S270KDKT provides the closest electrical and optical match to the original LTST-S270CKT, with identical dominant wavelength (638nm) and matching forward voltage (2V). Active product status ensures long-term supply chain continuity. Height increase to 1.25mm requires PCB layout verification for clearance constraints. This part is recommended when wavelength precision is critical to application performance.

HSMH-C120 from Broadcom Limited offers electrical compatibility with matching 1.8V forward voltage and similar brightness (17mcd). The diffused lens transparency and domed top lens style differ from the original clear flat-top design, affecting light distribution characteristics. Obsolete product status limits long-term availability. This part is suitable only when alternative sources are exhausted and optical property differences are acceptable.

All substitute parts maintain ROHS3 compliance and are suitable for applications requiring equivalent red LED indication functionality in surface mount configurations.

Frequently Asked Questions (FAQ)

Q: Can LTST-S270KRKT be used as a direct replacement for LTST-S270CKT?

A: LTST-S270KRKT is functionally compatible with the original part for red LED indication applications. The primary differences are forward voltage (2V versus 1.8V) and brightness (54mcd versus 16mcd). Circuit design must accommodate the higher forward voltage through resistor adjustment. The higher brightness may require brightness-limiting measures if the original design relied on the lower 16mcd output.

Q: What is the impact of the forward voltage difference between LTST-S270CKT (1.8V) and LTST-S270KRKT (2V)?

A: The 0.2V increase affects circuit current-limiting calculations. For a fixed supply voltage, the series resistor value must be recalculated using Ohm's law: R = (Vsupply - Vf) / Iled. A 0.2V increase reduces available voltage across the resistor, requiring a lower resistance value to maintain the same 20mA test current. Verify that the power supply and circuit topology can accommodate this change.

Q: Why does LTST-S270KDKT have a maximum height of 1.25mm compared to 0.60mm for the original?

A: LTST-S270KDKT uses a different internal LED die configuration and package structure, resulting in greater vertical height. PCB layout must verify clearance above the component to prevent mechanical interference with adjacent components or enclosure constraints. This dimension change may require design modification in space-constrained applications.

Q: Is HSMH-C120 suitable for applications requiring clear lens transparency?

A: HSMH-C120 features diffused lens transparency with a domed top lens style, differing from the original clear flat-top design. Diffused lenses scatter light over a wider angle (155° versus 130°), reducing peak brightness in the direct viewing direction. This part is suitable only for applications where diffused light distribution is acceptable or beneficial.

Q: What is the significance of MSL rating differences between these parts?

A: LTST-S270CKT, LTST-S270KRKT, and LTST-S270KDKT all have MSL 3 (168 Hours), indicating identical moisture sensitivity and storage requirements. HSMH-C120 has MSL 2A (4 Weeks), requiring more stringent moisture control during storage and handling. MSL 2A components must be baked before reflow soldering if storage time exceeds the specified period.

Q: Are all substitute parts RoHS3 compliant?

A: Yes, all identified substitute parts (LTST-S270KRKT, LTST-S270KDKT, and HSMH-C120) are ROHS3 compliant, matching the original LTST-S270CKT compliance status. All parts are suitable for applications requiring RoHS3 certification.