Vishay Semiconductor Opto Division TLHY4438

Overview

TLHY4438 from Vishay Semiconductors is a yellow high-efficiency LED in a 3 mm tinted diffused plastic package (T-1), with dominant wavelength 581–594 nm, luminous intensity 1.6–10 mcd at 10 mA, forward voltage 2.4–3.0 V at 20 mA, and ±30° viewing angle - used for status indication and legend lighting in industrial control panels.

For engineers reviewing the TLHY4438 datasheet, TLHY4438 pinout, TLHY4438 application, or TLHY4438 equivalent, this page delivers verified optical/electrical specs, package geometry, real-world use cases, and validated alternative parts for indicator LED selection and BOM optimization.

Technical Context

The TLHY4438 is a GaAsP-on-GaP yellow LED optimized for DC and pulsed operation up to 30 mA continuous forward current and 1 A surge current (tp ≤ 10 μs). Its ±30° half-intensity angle and tinted diffused lens deliver high on-off contrast for visual indication.

It operates across –40 °C to +100 °C ambient temperature, with junction-to-ambient thermal resistance of 400 K/W and maximum reverse voltage of 6 V. Luminous intensity is binned per group (e.g., M: 1.6–3.2 mcd) to ensure uniform appearance in multi-LED assemblies.

Key Specifications

Pinout & Package

TLHY4438 uses a standard 2-pin through-hole Ø3 mm (T-1) package with axial leads. Cathode is identified by flat side on lens housing and shorter lead; anode is longer lead. No internal circuitry - purely passive diode structure.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar yellow LED indicator applications.

Compared with TLHY4405 and TLHO4400, TLHY4438 offers mid-range luminous intensity within the yellow bin while preserving identical thermal, electrical, and mechanical compatibility - making it the balanced choice for general-purpose status indication where color fidelity and moderate brightness are prioritized over peak output or hue variation.

Availability

TLHY4438 is available at Aetrix Electronics and suitable for industrial control panels, medical device interfaces, and test equipment requiring stable component supply, consistent optical binning, and long-term obsolescence management.

Supply support for TLHY4438 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Vishay Semiconductors is a global leader in discrete semiconductors and passive components, specializing in high-reliability optoelectronics, power MOSFETs, and precision resistors.

The TLHY4438 belongs to Vishay's TLH.44.. series of standard indicator LEDs, designed specifically for general-purpose visual signaling in industrial, medical, and instrumentation applications where mechanical robustness and optical consistency are critical.

FAQ

What is the dominant wavelength range of the TLHY4438?

The TLHY4438 has a dominant wavelength range of 581–594 nm, placing it firmly in the yellow portion of the visible spectrum. This specification is measured at 10 mA forward current and enables precise color matching in multi-LED arrays. The TLHY4438's wavelength binning ensures consistent hue across production lots, critical for applications requiring uniform visual coding such as safety signage or regulatory-compliant interfaces.

What is the maximum continuous forward current rating for TLHY4438?

The TLHY4438 is rated for a maximum continuous forward current of 30 mA at 25 °C ambient temperature. This value is defined in the Absolute Maximum Ratings table and must not be exceeded to avoid accelerated degradation or catastrophic failure. Derating is required above 25 °C - for example, at 60 °C ambient, the safe operating current drops to approximately 20 mA based on thermal resistance (400 K/W) and junction temperature limit (100 °C).

Does TLHY4438 have a diffused or clear lens?

The TLHY4438 features a tinted diffused lens housed in a standard Ø3 mm plastic package. The diffusion spreads light evenly across its ±30° viewing angle, eliminating hotspots and improving on-off contrast - essential for legible status indication. The tint enhances color purity by filtering out non-yellow wavelengths, and the diffused surface ensures uniform illumination of legends or indicators without requiring secondary optics.

Can TLHY4438 be driven directly from a 3.3 V microcontroller GPIO?

Yes, TLHY4438 can be driven directly from a 3.3 V microcontroller GPIO when paired with an appropriate current-limiting resistor. With a typical forward voltage of 2.4 V at 20 mA, a ~47 Ω resistor yields ~21 mA drive - safely within both GPIO sink/source capability and the LED's 30 mA absolute maximum. Pulse-width modulation is also supported due to the device's suitability for high peak current operation (1 A surge, tp ≤ 10 μs).

Is TLHY4438 RoHS compliant and halogen-free?

Yes, TLHY4438 complies with RoHS Directive 2011/65/EU and is halogen-free per Vishay's material categorization standards (documented in www.vishay.com/doc?99912). The device contains no lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), or polybrominated diphenyl ethers (PBDE), and all bromine/chlorine content is below 900 ppm. Full compliance documentation is available upon request from Aetrix Electronics.