Each SC is encapsulated in a high thermal conductivity epoxy resin which eliminates problems associated with moisture. All SC power supplies are designed to withstand extremes of shock, vibration, acceleration, and thermal shock in accordance with MIL-STD-810. The power supply is generally mounted to PC boards via five 0.045” diameter pins.
The output voltage of the SC power supply is directly proportional to the input voltage. The power supply will start with input voltage as low as 1.5 V and will not be damaged by inputs as high as 18 VDC. The value of the resistor is such that it dissipates less than 0.1 W. The two output leads are floating and fully isolated from the two input leads by over 1 k Ohm with less than 50pF of coupling capacitance. This permits either positive or negative polarity operation.
There is NO internal connection between the input and output pins. The maximum output current ability is achieved at full output voltage and must be derated linearly as the input voltage decreases. Therefore, a 1kV, 5W unit, which is capable of providing 5 mA will only be able to provide 2.5 mA at 500 V out, indicating that the output power capability is parabolic with respect to output voltage. SC power supplies may be driven from a 3 terminal regulator, or run closed loop with a suitable regulation scheme. The input capacitance is 10µF AC bypass. Their equivalent circuit model is shown below with the following parameters. Voutmax is defined as the maximum output voltage of the power supply with the standard 12 V input.
