3SRD Red Diffused LED T-1 Through Hole - Equivalent & Substitute Parts

Part Overview

The 3SRD is a red diffused LED indicator manufactured by Bivar Inc., designed for through-hole mounting applications requiring red light indication at 40mcd brightness. The 3SRD operates at a forward voltage of 1.7V with a 20mA test current and features a 3mm T-1 lens form factor with 40° viewing angle and 645nm peak wavelength emission.

The primary 3SRD part is classified as Obsolete in product status. Substitute components are necessary to ensure design continuity and maintain supply chain reliability for new production runs and component replenishment in existing applications.

Key Parameters

Parameter	Value
Manufacturer Part Number	3SRD
Manufacturer	Bivar Inc.
Product Status	Obsolete
Color	Red
Lens Transparency	Diffused
Millicandela Rating	40mcd
Lens Size	3mm, T-1
Voltage - Forward (Vf)	1.7V
Current - Test	20mA
Viewing Angle	40°
Mounting Type	Through Hole
Wavelength - Peak	645nm
Package / Case	Radial
Height (Max)	4.50mm

Substitute Part Grouping Explanation

Substitution eligibility for the 3SRD is determined by the following key parameters:

Mounting Type: Must be Through Hole
Package Form: Must be Radial configuration with T-1 or equivalent 3mm round lens
Color & Lens Transparency: Must be Red with Diffused lens
Current Rating: Test current of 20mA
Electrical Compatibility: Forward voltage (Vf) between 1.7V and 2.2V and viewing angle of 40° or greater

Substitute parts are classified into two categories:

Parametric Equivalent: Parts from the same manufacturer (Bivar Inc.) with identical or functionally equivalent electrical and optical specifications. The 3SRD-S (Bulk packaging variant) is classified as a Parametric Equivalent with Active product status and matches all critical electrical parameters.

Similar Manufacturer Parts: Components from alternative manufacturers (Lite-On Inc., Rohm Semiconductor, Everlight Electronics, Kingbright) that maintain compatibility within the allowed parameter ranges. These parts operate within the specified electrical envelope while providing equivalent or enhanced performance characteristics in terms of brightness, wavelength, or viewing angle.

Parameter Comparison

Parameter	3SRD (Main)	3SRD-S	LTL-4261N	SLI-343U8R3F	SLI-343V8RC3F	264-7SURD/S530-A3	WP710A10SRD/J
Manufacturer	Bivar Inc.	Bivar Inc.	Lite-On Inc.	Rohm Semiconductor	Rohm Semiconductor	Everlight Electronics	Kingbright
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
Color	Red	Red	Red	Red	Red	Red	Red
Lens Transparency	Diffused	Diffused	Diffused	Diffused	Diffused	Diffused	Diffused
Millicandela Rating	40mcd	40mcd	60mcd	220mcd	330mcd	125mcd	1300mcd
Lens Size	3mm, T-1	3mm, T-1	3.00mm Dia	3.10mm Dia	3.10mm Dia	2.90mm Dia	3mm, T-1
Voltage - Forward (Vf)	1.7V	1.7V	1.8V	2.2V	2.2V	2V	1.85V
Current - Test	20mA	20mA	20mA	20mA	20mA	20mA	20mA
Viewing Angle	40°	40°	60°	40°	40°	60°	40°
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Wavelength - Peak	645nm	645nm	660nm	—	—	632nm	660nm
Package / Case	Radial	Radial	Radial	Radial	Radial	Radial	Radial
Height (Max)	4.50mm	4.50mm	6.00mm	5.60mm	5.60mm	6.20mm	5.90mm
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: The 3SRD-S (Bulk packaging) is the direct replacement for the obsolete 3SRD. Both parts are manufactured by Bivar Inc. with identical electrical and optical specifications. The 3SRD-S is classified as Active in product status, ensuring supply chain continuity. This part requires no design modifications and maintains full compatibility with existing PCB layouts and circuit designs.

Secondary Recommendations for Design Flexibility:

LTL-4261N (Lite-On Inc.): Active product status with 1.8V forward voltage, 60mcd brightness, and 60° viewing angle. Suitable for applications requiring wider light distribution while maintaining comparable electrical operation.
Rohm Semiconductor Series (SLI-343U8R3F, SLI-343V8RC3F, SLI-343V8R3F): All classified as Active with ROHS3 compliance. These EXCELED™ series components operate at 2.2V forward voltage and provide significantly higher brightness (220mcd to 330mcd). Selection depends on optical transparency requirements: SLI-343U8R3F is diffused at 220mcd, SLI-343V8RC3F is diffused at 330mcd.
WP710A10SRD/J (Kingbright): Active product status with 1.85V forward voltage and 1300mcd brightness. Recommended only for applications where substantial brightness increase is compatible with circuit current limits and thermal management.

All recommended substitutes maintain Through Hole mounting, 20mA test current, and Radial package configuration. ROHS3 compliance is confirmed for all Active substitute parts.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with higher millicandela rating than the original 3SRD?

A: Yes, if your circuit is designed to handle the optical output. Substitute parts with higher brightness (such as SLI-343V8RC3F at 330mcd or WP710A10SRD/J at 1300mcd) are electrically compatible within the 20mA test current specification. However, verify that your application design does not depend on the specific 40mcd brightness level of the 3SRD for proper system operation. Circuit current limiting must remain effective.

Q: Are there dimensional differences I should account for when substituting?

A: Yes. While all substitute parts maintain the 3mm T-1 form factor or equivalent round lens, maximum heights vary from 4.50mm (3SRD-S) to 6.20mm (264-7SURD/S530-A3). Verify that your PCB layout and mechanical constraints accommodate the substitute part's maximum height. All parts use Radial Through Hole mounting with compatible lead spacing.

Q: What forward voltage differences exist between substitutes?

A: Forward voltages range from 1.7V (3SRD, 3SRD-S) to 2.2V (Rohm Semiconductor series). When selecting a substitute, ensure your circuit's current-limiting resistor and power supply voltage are compatible with the specific Vf of the chosen part. A 20mA test current is maintained across all parts.

Q: Which substitute offers the best balance of compatibility and availability?

A: The 3SRD-S provides the highest direct compatibility as a same-manufacturer equivalent with Active product status. For alternative sources, LTL-4261N (Lite-On) offers Active status with minimal electrical difference (1.8V Vf) and enhanced viewing angle (60°). Both parts ensure reliable long-term supply.

Q: Is viewing angle a critical parameter for substitution?

A: Viewing angle affects light distribution but not electrical operation. Substitute parts with wider viewing angles (60°, such as LTL-4261N or 264-7SURD/S530-A3) distribute light over a broader field compared to the 3SRD's 40°. Select based on your application's optical requirements. Narrower angles (40°) concentrate light intensity in a specific direction.

Q: Do all substitute parts meet RoHS compliance?

A: The 3SRD does not specify RoHS status. All Active substitute parts are ROHS3 Compliant, which is standard for current production components. The obsolete 3SRD-S variant does not specify RoHS status in available data, but the newer 3SRD-S (Active, Bulk packaging) is ROHS3 Compliant.

Q: Can I use WP710A10SRD5V as a substitute?

A: WP710A10SRD5V is not recommended for direct substitution. This part operates at 5V forward voltage with only 13mA test current, requiring fundamentally different circuit design and current-limiting calculations compared to the 3SRD's 1.7V operation. This part is classified as Obsolete.

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