LTST-S320EKT Red Surface Mount Right Angle LED Equivalent & Substitute Parts

Part Overview

The LTST-S320EKT is a red surface mount right angle LED manufactured by Lite-On Inc., designed for indication applications with a 621nm dominant wavelength and 4mcd brightness rating. This component is classified as obsolete, making equivalent substitute parts necessary for ongoing production and maintenance applications. The part operates at 2V forward voltage with a 20mA test current and features a clear lens with 130° viewing angle in a compact 2-SMD, No Lead package measuring 3.00mm L x 2.00mm W x 1.00mm H.

Key Parameters

Parameter	Value
Manufacturer Part Number	LTST-S320EKT
Manufacturer	Lite-On Inc.
Color	Red
Lens Transparency	Clear
Voltage - Forward (Vf) (Typ)	2V
Current - Test	20mA
Millicandela Rating	4mcd
Wavelength - Dominant	621nm
Mounting Type	Surface Mount, Right Angle
Package / Case	2-SMD, No Lead
Size / Dimension	3.00mm L x 2.00mm W
Height (Max)	1.00mm
Viewing Angle	130°
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution eligibility for the LTST-S320EKT is determined by strict alignment across the following critical parameters:

Primary Compatibility Criteria:

Color: Red
Mounting Type: Surface Mount, Right Angle
Package / Case: 2-SMD, No Lead
Size / Dimension: 3.00mm L x 2.00mm W
Voltage - Forward (Vf) (Typ): 2V (±0.3V tolerance acceptable)
Current - Test: 20mA
Lens Transparency: Clear

Secondary Compatibility Criteria:

Wavelength - Dominant: 619nm to 631nm range
Millicandela Rating: Minimum 4mcd
Viewing Angle: 115° to 130°
Height (Max): 1.00mm to 1.20mm

All substitute parts listed meet the primary compatibility criteria. Variations in secondary parameters (brightness, wavelength, viewing angle) remain within functional tolerance for indication applications while maintaining electrical and mechanical interchangeability.

Parameter Comparison

Parameter	LTST-S320EKT	12-21SRC/TR8	5972002607F	APA3010EC	APECVA3010EC	HSMC-C680	HSMS-C680	SML-LXR851SIC-TR	SML-LXR851SRC-TR
Manufacturer	Lite-On Inc.	Everlight Electronics Co Ltd	Dialight	Kingbright	Kingbright	Broadcom Limited	Broadcom Limited	Lumex Opto/Components Inc.	Lumex Opto/Components Inc.
Color	Red	Red	Red	Red	Red	Red	Red	Red	Red
Lens Transparency	Clear	Clear	Diffused	Clear	Clear	Clear	Clear	Clear	Clear
Voltage - Forward (Vf) (Typ)	2V	1.7V	2V	2V	2V	2V	2V	2V	1.7V
Current - Test	20mA	20mA	20mA	20mA	20mA	20mA	20mA	20mA	20mA
Millicandela Rating	4mcd	24.5mcd	125mcd	15mcd	15mcd	62.3mcd	5.1mcd	70mcd	33mcd
Wavelength - Dominant	621nm	619nm	631nm	625nm	625nm	630nm	621nm	—	—
Mounting Type	Surface Mount, Right Angle	Surface Mount, Right Angle	Surface Mount, Right Angle	Surface Mount, Right Angle	Surface Mount, Right Angle	Surface Mount, Right Angle	Surface Mount, Right Angle	Surface Mount, Right Angle	Surface Mount, Right Angle
Package / Case	2-SMD, No Lead	2-SMD, No Lead	2-SMD, No Lead	2-SMD, No Lead	2-SMD, No Lead	2-SMD, No Lead	2-SMD, No Lead	2-SMD, No Lead	2-SMD, No Lead
Size / Dimension	3.00mm L x 2.00mm W	3.00mm L x 2.00mm W	3.00mm L x 2.00mm W	3.00mm L x 2.00mm W	3.00mm L x 2.00mm W	3.00mm L x 1.00mm W	3.00mm L x 1.00mm W	3.00mm L x 2.00mm W	3.00mm L x 2.00mm W
Height (Max)	1.00mm	1.20mm	1.00mm	1.00mm	1.00mm	1.00mm	1.00mm	1.00mm	1.00mm
Viewing Angle	130°	120°	130°	120°	120°	115°	125°	160°	160°
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active
RoHS Status	—	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility):

5972002607F (Dialight microLED®) and APA3010EC / APECVA3010EC (Kingbright) are the preferred substitutes. Both maintain exact electrical specifications (2V forward voltage, 20mA test current) and mechanical compatibility (3.00mm L x 2.00mm W x 1.00mm H). All three are ROHS3 compliant and active products with established supply chains. The 5972002607F offers higher brightness (125mcd) suitable for applications requiring enhanced visibility, while APA3010EC and APECVA3010EC provide moderate brightness (15mcd) closer to the original specification.

Secondary Substitutes (Acceptable with Design Review):

HSMC-C680 and HSMS-C680 (Broadcom Limited) are electrically compatible but feature reduced width (1.00mm W vs. 2.00mm W). These parts maintain 2V forward voltage and 20mA test current specifications. HSMC-C680 provides higher brightness (62.3mcd) while HSMS-C680 closely matches the original brightness (5.1mcd). Both are ROHS3 compliant with superior moisture sensitivity (MSL 2A vs. MSL 3). PCB layout verification is required due to dimensional variance.

Alternative Substitutes (Conditional Use):

12-21SRC/TR8 (Everlight Electronics Co Ltd) operates at reduced forward voltage (1.7V) and requires circuit recalculation for current-limiting resistor values. This part is suitable only for applications with flexible voltage tolerance. SML-LXR851SIC-TR and SML-LXR851SRC-TR (Lumex Opto/Components Inc.) offer wide viewing angles (160°) and are ROHS3 compliant. SML-LXR851SRC-TR operates at 1.7V forward voltage, requiring the same voltage tolerance consideration as the Everlight part.

Compliance Considerations:

All active substitute parts carry ROHS3 compliance certification. The original LTST-S320EKT carries REACH Unaffected status, as do all listed substitutes. All parts are classified under ECCN EAR99 and HTSUS 8541.41.0000.

Frequently Asked Questions (FAQ)

Q: Can I use 5972002607F as a direct replacement for LTST-S320EKT?

A: Yes. The 5972002607F maintains identical electrical specifications (2V forward voltage, 20mA test current) and mechanical compatibility (2-SMD, No Lead package, 3.00mm L x 2.00mm W x 1.00mm H). The primary difference is lens transparency (diffused vs. clear) and higher brightness (125mcd vs. 4mcd). For indication applications, this substitution is direct. Verify that increased brightness does not create visual interference in your application.

Q: What is the difference between APA3010EC and APECVA3010EC?

A: Both parts are manufactured by Kingbright with identical electrical and mechanical specifications (2V forward voltage, 20mA test current, 15mcd brightness, 625nm dominant wavelength, 3.00mm L x 2.00mm W x 1.00mm H). The primary difference is packaging: APA3010EC is supplied in Tape & Reel (TR), while APECVA3010EC is supplied in standard packaging. Select based on your procurement and assembly requirements.

Q: Why do HSMC-C680 and HSMS-C680 have different widths?

A: HSMC-C680 and HSMS-C680 are classified as Chip LED components with 1.00mm width versus the standard 2.00mm width of other substitutes. Both maintain 2V forward voltage and 20mA test current compatibility. The reduced width requires PCB layout verification to ensure mechanical fit within your assembly. These parts offer superior moisture sensitivity (MSL 2A vs. MSL 3) for applications in humid environments.

Q: Can I use 12-21SRC/TR8 or SML-LXR851SRC-TR in my circuit designed for 2V forward voltage?

A: Both 12-21SRC/TR8 and SML-LXR851SRC-TR operate at 1.7V forward voltage, requiring recalculation of current-limiting resistor values. Use these parts only if your circuit design permits voltage adjustment. For fixed-voltage designs, select substitutes rated at 2V forward voltage (5972002607F, APA3010EC, APECVA3010EC, HSMC-C680, HSMS-C680, or SML-LXR851SIC-TR).

Q: Which substitute offers the widest viewing angle?

A: SML-LXR851SIC-TR and SML-LXR851SRC-TR both provide 160° viewing angle, compared to 130° for the original LTST-S320EKT. These parts are suitable for applications requiring wide-angle indication visibility. All other substitutes maintain viewing angles between 115° and 130°.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed carry ROHS3 compliance certification. The original LTST-S320EKT does not specify RoHS status. If RoHS3 compliance is a requirement for your application, select from the active substitute parts: 5972002607F, APA3010EC, APECVA3010EC, HSMC-C680, HSMS-C680, SML-LXR851SIC-TR, or SML-LXR851SRC-TR.

Q: What is the inventory status for these substitute parts?

A: All substitute parts are currently in stock: 12-21SRC/TR8 (723 Pcs), 5972002607F (1117 Pcs), APA3010EC (2709 Pcs), APECVA3010EC (874 Pcs), HSMC-C680 (37810 Pcs), HSMS-C680 (43118 Pcs), SML-LXR851SIC-TR (913 Pcs), and SML-LXR851SRC-TR (1057 Pcs). HSMC-C680 and HSMS-C680 offer the highest inventory availability.

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