3SYD-F

Part Overview

The 3SYD-F is a yellow LED indication component manufactured by Bivar Inc., configured as a discrete 2V radial through-hole LED with T-1 form factor. The part features a diffused yellow lens with 30mcd brightness rating and 35° viewing angle. This product is obsolete and no longer in active production. Locating alternative components with compatible electrical and mechanical specifications is necessary for design continuity and component procurement.

Key Parameters

Parameter	Specification
Manufacturer Part Number	3SYD-F
Manufacturer	Bivar Inc.
Color	Yellow
Lens Size	3mm, T-1
Lens Transparency	Diffused
Lens Style	Round with Domed Top
Voltage - Forward (Vf) (Typ)	2V
Current - Test	20mA
Millicandela Rating	30mcd
Viewing Angle	35°
Wavelength - Peak	590nm
Mounting Type	Through Hole
Package / Case	Radial
Height (Max)	5.30mm
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the 3SYD-F is determined by the following critical parameters: forward voltage (Vf), lens size (T-1 or 3mm), lens transparency (diffused), mounting type (through hole radial), and color (yellow). The substitute parts are grouped into three categories based on voltage compatibility:

Category A - Direct Voltage Match (2V Forward Voltage): Parts operating at 2V forward voltage with comparable mechanical dimensions and yellow diffused optics.

Category B - Alternative Voltage (1.8V, 5V, 12V Forward Voltage): Parts with modified forward voltages requiring circuit design adjustment but maintaining T-1 through-hole radial configuration and yellow diffused characteristics.

Category C - Cross-Color Substitutes: Orange wavelength alternatives (605nm) from the same product series, applicable when color-specific requirements permit substitution.

Parameter Comparison

Parameter	3SYD-F (Original)	264-7UYD/S530-A3	HLMP-1620	HLMP-1719	LTL-4251	LTL-4251N	SLR-332DU3F
Manufacturer	Bivar Inc.	Everlight Electronics Co Ltd	Broadcom Limited	Broadcom Limited	Lite-On Inc.	Lite-On Inc.	Rohm Semiconductor
Color	Yellow	Yellow	Yellow	Yellow	Yellow	Yellow	Orange
Lens Size	3mm, T-1	2.90mm Dia	3mm, T-1	3mm, T-1	3mm, T-1	3mm, T-1	3.20mm Dia
Lens Transparency	Diffused	Diffused	Diffused	Diffused	Diffused	Diffused	Diffused
Lens Style	Round with Domed Top	Round with Domed Top	Round with Domed Top	Round with Domed Top	Round with Domed Top	Round with Domed Top	Round with Domed Top
Voltage - Forward (Vf) (Typ)	2V	2V	5V	1.8V	2.1V	2.1V	2V
Current - Test	20mA	20mA	10mA	2mA	10mA	10mA	10mA
Millicandela Rating	30mcd	125mcd	2.2mcd	2.1mcd	8.7mcd	5.6mcd	10mcd
Viewing Angle	35°	60°	60°	50°	40°	60°	85°
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	Radial	Radial	Radial	Radial	Radial	Radial	Radial
Height (Max)	5.30mm	6.20mm	6.35mm	6.35mm	6.55mm	5.85mm	4.60mm
Wavelength - Peak	590nm	591nm	583nm	-	585nm	585nm	-
Product Status	Obsolete	Active	Active	Active	Active	Active	Not For New Designs
RoHS Status	-	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (2V Voltage Class):

The 264-7UYD/S530-A3 from Everlight Electronics and LTL-4251/LTL-4251N from Lite-On Inc. operate at the same 2V forward voltage as the original 3SYD-F. These parts maintain full electrical compatibility with existing circuit designs and preserve through-hole radial mounting. The Everlight part achieves 125mcd brightness, exceeding the original specification. Lite-On parts operate at 2.1V with reduced brightness specifications. All recommended substitutes maintain ROHS3 compliance and unlimited moisture sensitivity rating.

Alternative Voltage Substitutes (1.8V, 5V, 12V Classes):

Parts from Broadcom Limited (HLMP-1620, HLMP-1621, HLMP-1719 series) and the HLMP-1719-A0002 variant require circuit modifications due to different forward voltages. The HLMP-1719 operates at 1.8V with low test current (2mA), suitable for low-power applications. HLMP-1620 and variants operate at 5V. HLMP-1621 operates at 12V. These selections demand resistor recalculation in associated current-limiting circuits. All Broadcom alternatives maintain ROHS3 compliance and REACH unaffected status.

Cross-Color Substitute:

The SLR-332DU3F from Rohm Semiconductor is an orange LED (605nm) alternative applicable only when design specifications permit color substitution. This part maintains 2V forward voltage compatibility and through-hole radial configuration but is designated Not For New Designs and should be reserved for legacy system repairs.

Frequently Asked Questions (FAQ)

Q: Can I directly replace the 3SYD-F with any of these substitute parts without circuit modification?

A: Direct replacement without modification is limited to parts operating at 2V forward voltage: the 264-7UYD/S530-A3, LTL-4251, and LTL-4251N. These maintain electrical compatibility. All other substitutes require forward voltage adjustment through current-limiting resistor recalculation.

Q: What is the primary difference between LTL-4251 and LTL-4251N?

A: Both parts are manufactured by Lite-On Inc. at 2.1V forward voltage with identical package and lens specifications. The LTL-4251N offers a broader 60° viewing angle compared to the LTL-4251's 40° viewing angle, with slightly reduced brightness (5.6mcd versus 8.7mcd). The LTL-4251N is available in significantly higher inventory volume.

Q: Why is the 3SYD-F listed as obsolete, and what does this mean for my design?

A: Obsolete status indicates that Bivar Inc. no longer manufactures this component. Active substitutes from Everlight Electronics, Lite-On Inc., and Broadcom Limited provide equivalent functionality. All recommended active alternatives maintain identical through-hole mechanical form factor and diffused yellow optics.

Q: Does the increased brightness of the 264-7UYD/S530-A3 (125mcd) affect circuit compatibility?

A: The 264-7UYD/S530-A3 operates at identical 2V forward voltage and 20mA test current as the original 3SYD-F, maintaining direct electrical compatibility. The higher brightness rating does not compromise circuit function; however, design reviews should confirm that increased luminous intensity aligns with intended application requirements.

Q: What packaging options are available for 2V substitute parts?

A: The 264-7UYD/S530-A3 is available in Bulk packaging. The LTL-4251 is available in Bulk packaging, while the LTL-4251N is available in both Bulk and standard distribution formats. All three parts maintain T-1 through-hole radial configuration.

Q: Are all substitute parts RoHS compliant?

A: All active-status substitute parts listed (264-7UYD/S530-A3, HLMP series, LTL-4251, LTL-4251N) are ROHS3 compliant. The SLR-332DU3F is also ROHS3 compliant but carries Not For New Designs status.

Q: What is the significance of the viewing angle differences between substitute parts?

A: The original 3SYD-F specifies 35° viewing angle. Substitute parts range from 40° to 85° viewing angle. Narrower viewing angles concentrate light output in a more focused beam; wider angles distribute light across a broader spatial range. Circuit design and application requirements determine acceptable viewing angle parameters.

Q: Can I use the HLMP-1620-C00A1 or HLMP-1620-C00A2 variants as substitutes?

A: These variants feature right-angle mounting configuration rather than radial through-hole configuration. These parts are mechanically incompatible with the original 3SYD-F footprint and circuit board layout unless the PCB design accommodates right-angle mounting. Both variants operate at 5V forward voltage, requiring circuit modification.

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