Hewlett-Packard HLMP-DB00 & HLMP-DB15  
Written by Accutron on 2008-02-13  

Introduced in 1993, the Hewlett-Packard HLMP-DB00 and HLMP-DB15 are among a small number of commercially produced silicon carbide (SiC) blue light emitting diodes. The two devices appear to be internally identical, the only difference being that the -DB00 has a slightly milky, diffuse lens, while the -DB15 is water-clear.

Hewlett-Packard HLMP-DBxx Series Datasheet

Silicon carbide has been known since the 19th century for its electroluminescent properties, and was first developed into a working blue LED in the 1960s. Siemens briefly produced a commercial SiC device in 1977, but a successful product did not arrive until 1989.

A handful of SiC LEDs were produced by several different maufacturers, first Cree then Hewlett-Packard, Lite-On and others, but the coinciding development of superbright gallium nitride (GaN) blue LEDs in the 1990s rapidly obsoleted the much dimmer SiC devices. SiC consequently had a very short market life, and such devices are difficult to obtain today. Silicon carbide lives on as a substrate for GaN and InGaN LEDs, but it is no longer produced as a primary die material. Currently produced members of the Avago HLMP-DBxx series, such as the -DB25 and -KB45, are GaN devices.

In the early years of GaN devices, the virtually indestructible SiC LED retained a niche in industrial and medical applications. Electronics folklore claims that they can survive a lightning strike.

Hewlett-Packard HLMP-DB00, operating at typical brightness.

HLMP-DB00, top view.

Hewlett-Packard HLMP-DB00 and HLMP-DB15, 5mm SiC blue LEDs. Both types can be identified by a small blue dot on the side, so as to not confuse them with typical LEDs of otherwise identical external appearance.

This article is part of the [Discrete Optoelectronics] exhibit.

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