Tag: CREE C3D02060F bias

E282F HP Amp

First and foremost, Merry Christmas! I hope you’re having a great time with your loved ones and good music.

Without a mood for public introspection this time, I have to say that I will celebrate this holiday the best I can. I will be hosting today with a lot of meat, wine and single malt. What else can I do? When I escape from the little ones, will get back to spin some records and hopefully work on the projects.

Merry Christmas to everyone

Headphone Amp Quest Continues

Obviously, I needed to pursue this project further. I’ve been lately listening a lot to HPs as simply is the best choice for me when the young family is in bed. In addition to this, I find the HP setup to force me to connect a bit more to what I’m listening to as I don’t get easily distracted.

Continue reading “E282F HP Amp”

GM-70 SE Amplifier

I keep getting requests about SE amp designs using the 6SF5 driver. Here is what I have come up with for the 6SF5 driving the GM-70. With only one stage you can drive the GM-70 to full power and get 18W out of this lovely transmitting valve: Continue reading “GM-70 SE Amplifier”

C3D02060F Spice Model

As the model for the C3D02060F SiC diode is not available, I decided to venture myself and attempt to build a decent model for Spice. I researched a bit around in the web and found this interesting article about creating your own Spice models for diodes.

Luckily I have the Locky curve tracer and can get the most out of tracing sand devices. I did a quick trace on one of the SiC diodes to capture a good sample set of Vf and If points.

How did I go about to develop the model? Quite simple. I started with ploting the ideal diode response with the Schokley current model. Then I played around with N and Is to fit the curve. Note that this is an iterative manual process, which takes a bit of time but can be done without much difficulty. Finally I created the model in Spice and adjusted Rs by testing manually a pair of Vf/If points. Not perfect, but good enough for what I need:CREE C3D02060F Spice Model

The graph above has the actual tracer plot (“I”), and both the ideal model (“Schokley model”) as well as the output of LTSpice simulation (“Spice”).

This is a great diode for cathode bias when using drivers which need +15mA at least. If you are interested in the model it can be downloaded from here: C3D02060F model. Hope you find this useful.

SiC cathode bias

Playing this afternoon with the SiC C3D02060F, which can happily run +20mA with very low dynamic resistance. Ideal for the 6e5p/6e6p driver I had in mind for the 300B amp:

C3D02060F-1At 20mA of cathode current the forward voltage is 0.85V and dynamic resistance 1.5Ω. If cathode current is 40mA instead the resistance drops down to 1Ω:

C3D02060F-2The 6e5P/6e6P will run comfortably around 30-40mA and bias tends to be around 3.5-3.7V to swing nice volts as needed. Therefore, we will need 4 SiC in series. 4Ω resistance is good enough and not adding much when reflected to the anode…

 

 

Diode cathode bias

 

Playing with the semiconductor curve tracer I did a quick test of potential candidates for diode cathode bias:
Diode Bias Examples

 

The popular HLMP-6000 is a superb LED with its low impedance. The SiC diodes have proved to be a great match with an impedance lower than 2Ω. Bias voltages will be around 0.7-0.8V for low currents. The classic Schottky SB540 has a very low impedance, but its forward voltage is so low that is not practical for diode cathode bias. What surprised me was to see the 1N4007 to be a good match. The impedance is higher than the LEDs or SiCs, but good enough. The green LED on the opposite extent has a significant dynamic resistance over 10Ω.

Interesting to see that a minimum of 2mA should be run through with small signals to ensure the diode operates in the linear region. The higher the better. An arrangement with an extra source of diode current (e.g. LND150 or DN2540 CCS shunting current to the diode) can be used when dealing with lower cathode currents due to the valve being used.

Further tests are required….