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Vf vs If for Cree Sic Schottky Diode - Measured at cathode-relevant Currents

Posted by Maxamillion (A) on July 5, 2009 at 11:29:41

Since the Vf vs If plot supplied by Cree is really tailored to the higher end of the current range, I decide to measure it at currents relevant to use in cathode biasing. I set up a simple test rig using a AA battery (1.61V measured) and a series of resistors on the + leg of the circuit, to deliver a range of currents to the diode, then measured the voltage across the diode for each current.

The chart above shows the results for the current range of 2.79mA to 65.8mA for the 1A, 600V SiC Schottky Diode, Cree part # CSD01060A. Dynamic resistance looks to be ~1.6 ohms in the range of 10-65mA.

Although the Vf is a bit lower than that of an IR LED at 10mA (.84 vs 1.2V) the dynamic resistance (slope resistance) is more than 3 times less for the SiC Schottky diode, indicating it may be an excellent choice as a cathode bias diode (IR LED data from Morgan Jones' "Valve Amplifiers").

Now if we could just get some comparative noise data on the various diodes... I wonder whether the Schottkys would have an advantage here - they are known to be less noisy in switching applications, but the diodes do not switch on/off in a cathode bias application.

This post is made possible by the generous support of people like you and our sponsors:

Kimber Kable

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