LTST-C191EKT Equivalent & Substitute Parts

Part Overview

The LTST-C191EKT is a red 621nm LED indication component in 0603 (1608 Metric) surface mount package manufactured by Lite-On Inc. This part is classified as obsolete, making substitute components necessary for new designs and ongoing production requirements. The component operates at 2V forward voltage with 10mA test current and provides 2mcd luminous intensity with a 130° viewing angle. Equivalent parts must maintain compatibility with the 0603 package footprint and preserve core electrical characteristics for direct circuit substitution.

Substiute Parts

LTST-C191EKT

Lite-On Inc.In Stock: 1205LTST-C191EKT Datasheet

Current PartRFQ

LTST-S270EKT

Lite-On Inc.In Stock: 45140LTST-S270EKT Datasheet

MFR RecommendedRFQ

SM0603HC

Bivar Inc.In Stock: 768SM0603HC Datasheet

MFR RecommendedRFQ

SM0603RC

Bivar Inc.In Stock: 857SM0603RC Datasheet

MFR RecommendedRFQ

SM0603URC

Bivar Inc.In Stock: 21143SM0603URC Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following critical parameters:

• Package Compatibility: All substitute parts must use 0603 (1608 Metric) surface mount package to ensure PCB footprint compatibility
• Color & Wavelength: Red color specification with dominant wavelength in the 621–645nm range maintains visual consistency and application compatibility
• Forward Voltage (Vf): Operating voltage range of 1.8V–2.1V ensures compatibility with existing circuit designs and current-limiting resistor calculations
• Viewing Angle: 130° viewing angle maintained across all substitutes for consistent optical performance
• Mounting Type: Surface mount configuration required for automated assembly compatibility
• Lens Configuration: Rectangle with flat top lens style and clear transparency preserved across substitutes

The four substitute parts listed below meet these criteria and are classified as active products with current manufacturing status and improved availability compared to the obsolete LTST-C191EKT.

Parameter Comparison

Engineering Selection Recommendations

LTST-S270EKT (Lite-On Inc., Active Status): Recommended as the primary substitute. Manufactured by the same supplier as the original part, maintaining design continuity. Operates at identical 2V forward voltage with 621nm dominant wavelength. Higher test current (20mA vs. 10mA) and increased luminous intensity (4mcd vs. 2mcd) provide improved brightness margin. Right-angle mounting configuration offers alternative PCB layout flexibility. Active product status ensures long-term availability and supply chain stability.

SM0603URC (Bivar Inc., Active Status): Suitable for applications requiring higher luminous intensity. Operates at 2.1V forward voltage with 640nm dominant wavelength, within acceptable red LED specification range. Highest luminous intensity rating (55mcd) among substitutes accommodates designs with brightness margin requirements. ROHS3 compliant with active manufacturing status. Requires circuit verification for voltage tolerance.

SM0603RC (Bivar Inc., Active Status): Direct electrical equivalent with 2V forward voltage matching the original part. Lowest luminous intensity (1mcd) among substitutes, suitable for applications where brightness reduction is acceptable or beneficial. ROHS3 compliant with active manufacturing status and high inventory availability (798 pcs).

SM0603HC (Bivar Inc., Active Status): Operates at reduced forward voltage (1.8V) with 643nm dominant wavelength. Moderate luminous intensity (15mcd) provides brightness increase. Requires circuit design verification for voltage compatibility. ROHS3 compliant with active manufacturing status.

Frequently Asked Questions (FAQ)

Q: Can LTST-S270EKT be used as a direct replacement for LTST-C191EKT?

A: Yes. Both parts share identical 0603 package footprint, 2V forward voltage, 621nm dominant wavelength, and 130° viewing angle. The primary difference is mounting configuration (right-angle vs. standard) and increased luminous intensity (4mcd vs. 2mcd). PCB layout must accommodate the right-angle orientation.

Q: What is the impact of different forward voltages among substitutes?

A: Forward voltage variations (1.8V to 2.1V) affect current-limiting resistor calculations in series circuits. Designs using fixed resistor values must verify that voltage drop across the resistor remains within acceptable limits. Circuits with active current regulation are less sensitive to Vf variations.

Q: Are all substitute parts RoHS compliant?

A: The Bivar substitutes (SM0603HC, SM0603RC, SM0603URC) are ROHS3 compliant. The Lite-On LTST-S270EKT does not specify RoHS status in provided documentation. Verify RoHS compliance requirements with your supply chain if mandatory for your application.

Q: How do luminous intensity differences affect circuit design?

A: Luminous intensity (mcd rating) determines perceived brightness. The original LTST-C191EKT provides 2mcd. Substitutes range from 1mcd to 55mcd. Higher intensity parts (SM0603URC at 55mcd) may require reduced current or additional optical diffusion to match original brightness perception. Lower intensity parts (SM0603RC at 1mcd) suit applications where reduced brightness is acceptable.

Q: What are the moisture sensitivity implications?

A: The original part specifies MSL 2A (4 weeks storage limit). Substitutes specify MSL 3 or 4 (168 hours to 72 hours), indicating stricter moisture control requirements. Bivar parts require more careful handling and storage management compared to the original Lite-On component.

Q: Can substitutes be used interchangeably on the same PCB?

A: Footprint compatibility exists for SM0603HC, SM0603RC, and SM0603URC (all standard 0603 mounting). LTST-S270EKT requires right-angle mounting accommodation. Verify PCB layout supports the selected mounting configuration before assembly.