Current Sources and Voltage References

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The importance of silicon-gate

pros and cons for each type. Typically, the

vertical

structure supports a higher current

capability (because the channel beneath the gate becomes deeper), and it therefore

has a lower on-resistance. For power devices this is vital, because the physical dis-

tance between source and drain must be large in order to maintain a high voltage-

blocking capability. A FET’s drain-to-source current is inversely proportional to this dis-

tance. It also has a higher level of breakdown voltage (more than 200 volts) than the

JFET, as well as low capacitance and a very-high-frequency response.

The

lateral

structure, on the ...