LTE-3271B Infrared Emitter 940nm Equivalent & Substitute Parts

Part Overview

The LTE-3271B is an infrared (IR) emitter manufactured by Lite-On Inc., designed for applications requiring 940nm wavelength emission at 100mA forward current. This radial-mounted through-hole component operates across an extended temperature range of -40°C to 85°C and is ROHS3 compliant with unlimited moisture sensitivity rating. The part is currently active in production with 1117 units in stock. Substitute parts become necessary when radial packaging is unavailable, when alternative wavelengths are acceptable for system design, or when different forward voltage specifications better match circuit requirements.

Substiute Parts

LTE-3271B

Lite-On Inc.In Stock: 1171LTE-3271B Datasheet

Current PartRFQ

OP290A

TT Electronics/Optek TechnologyIn Stock: 10349OP290A Datasheet

MFR RecommendedRFQ

OP291A

TT Electronics / Optek TechnologyIn Stock: 3055OP291A Datasheet

MFR RecommendedRFQ

OP292A

TT Electronics/Optek TechnologyIn Stock: 1034OP292A Datasheet

MFR RecommendedRFQ

OP294

TT Electronics / Optek TechnologyIn Stock: 756OP294 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LTE-3271B is determined by the following critical parameters: wavelength tolerance, forward current rating, forward voltage compatibility, viewing angle, operating temperature range, and package form factor. The substitute parts listed (OP290A, OP291A, OP292A, OP294) are all infrared emitters manufactured by TT Electronics/Optek Technology with the following substitution criteria:

Wavelength: All substitutes operate at 890nm, representing a shift from the primary 940nm specification. This wavelength difference is acceptable only in applications where the system design permits alternative IR wavelengths within the 880-950nm band.

Forward Current: Substitutes OP290A, OP291A, and OP292A support 150mA maximum forward current, exceeding the LTE-3271B specification of 100mA. OP294 matches the 100mA rating of the primary part.

Forward Voltage: Substitute parts offer multiple voltage options (1.5V, 1.75V, 2V, 4V) to accommodate different circuit designs. OP294 at 1.5V most closely aligns with the LTE-3271B forward voltage of 1.25V.

Package Form Factor: All substitutes use T 1 3/4 through-hole packaging, differing from the radial package of the LTE-3271B. This represents a mechanical redesign requirement at the board level.

Viewing Angle & Operating Temperature: All substitutes maintain the 50° viewing angle and support -40°C to 100°C operating range, meeting or exceeding the LTE-3271B specifications.

Parameter Comparison

Engineering Selection Recommendations

All substitute parts maintain ROHS3 compliance and unlimited moisture sensitivity rating, ensuring regulatory and environmental compatibility with the LTE-3271B. The extended operating temperature range of -40°C to 100°C in all substitutes provides thermal margin beyond the primary part's -40°C to 85°C specification.

OP294 represents the closest electrical match, with 100mA forward current matching the LTE-3271B and forward voltage of 1.5V within 0.25V of the primary specification. This part requires mechanical redesign due to T 1 3/4 package form factor.

OP292A offers 1.75V forward voltage with 150mA current capacity, suitable for applications where higher current headroom is required and wavelength shift to 890nm is acceptable.

OP291A provides 2V forward voltage with 150mA current capacity, appropriate for designs with higher supply voltages and current margin requirements.

OP290A operates at 4V forward voltage with 150mA current capacity, suitable only for applications with significantly higher supply voltage specifications and where 890nm wavelength is compatible with system requirements.

Selection among substitutes depends on circuit voltage availability, current budget, and wavelength tolerance of the end application. All parts are active production items with established supply availability.

Frequently Asked Questions (FAQ)

Q: Can OP294 directly replace LTE-3271B without circuit modification? A: OP294 matches the electrical specifications (100mA, 1.5V) but requires mechanical redesign. The radial package of LTE-3271B differs from the T 1 3/4 package of OP294, necessitating PCB layout changes and component mounting adjustments.

Q: Why do substitute parts use 890nm wavelength instead of 940nm? A: The substitute parts listed are available alternatives from TT Electronics/Optek Technology. Wavelength selection depends on application requirements. If 940nm is mandatory, alternative suppliers or extended lead times may be necessary.

Q: Are all substitute parts ROHS3 compliant? A: Yes. OP290A, OP291A, OP292A, and OP294 are all ROHS3 compliant with unlimited moisture sensitivity rating, matching the environmental compliance of LTE-3271B.

Q: Which substitute part has the closest forward voltage to LTE-3271B? A: OP294 at 1.5V forward voltage is closest to the LTE-3271B specification of 1.25V, with a difference of 0.25V. This part also matches the 100mA forward current rating.

Q: Can substitutes with 150mA rating be used in circuits designed for 100mA? A: Yes. OP290A, OP291A, and OP292A with 150mA maximum ratings can operate at 100mA or lower. Circuit current limiting must be maintained through appropriate series resistance or current source design.

Q: What is the temperature operating range difference between LTE-3271B and substitutes? A: LTE-3271B operates from -40°C to 85°C. All substitutes extend to -40°C to 100°C, providing an additional 15°C upper temperature margin.

Q: Do substitute parts have the same viewing angle as LTE-3271B? A: Yes. All substitute parts maintain the 50° viewing angle specification, ensuring optical performance consistency in directional IR applications.