Just had a look in my Marantz SR5400 to see what output devices were being used.
The devices used a labled "SAP17" with "no" or "po" which I assume is for npn or pnp. The pcb has labels c,b,e but the package has five pins.
Does anyone know what this device pair is?
Could it be the output device and pre-driver in a single package?
Another theory is that the other two pins are for sensing the junction temperature ( ie a diode ) to compensate the vbe biasing.
I've not pulled the device off board to find out, as it's a brand new amp.
The devices used a labled "SAP17" with "no" or "po" which I assume is for npn or pnp. The pcb has labels c,b,e but the package has five pins.
Does anyone know what this device pair is?
Could it be the output device and pre-driver in a single package?
Another theory is that the other two pins are for sensing the junction temperature ( ie a diode ) to compensate the vbe biasing.
I've not pulled the device off board to find out, as it's a brand new amp.
You have deduced it correctly -- darlington pair with built-in bias diodes. These are made by Sanken. My data sheet lists three pairs from this series -- SAP09, SAP10, and SAP16. So either Marantz is having a custom version made for them, or else you made an error when typing in the number.
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