Test: BiCMOS Inverters - Electrical Engineering (EE) MCQ

 In BiCMOS, bipolar transistors are used to drive output loads. Bipolar transistor can also be used as amplifier, switch or as an oscillator.

 In BiCMOS circuits, MOS switches are used to perform logic functions. The ability to turn the power MOS “ON” and “OFF” allows the device to be used as a very efficient switch with switching speeds much faster than standard bipolar junction transistors.

The nMOS and pMOS transistors used in BiCMOS device operates in enhancement mode. Enhancement mode devices are mostly common switching elements in MOS.

 The inverter has low input impedance. The basic inverter circuit requires a transistor with source connected to ground and a load resistor connected from the drain to positie supply Vdd.

The inverter has low output impedance and low input impedance. These are some of the properties of a BiCMOS inverter.

The inverter has high current driving capability, occupies smaller area and has high noise margins.

For a better performance BiCMOS circuit, the output voltage swing should be reduced. The possible maximum output peak-to-peak voltage obtained without clipping is called as output voltage swing.

BiCMOS inverter needs high load current sinking and sourcing. Sinking provides a grounded connection to the load, whereas sourcing provides a voltage source to the load.

 BiCMOS has higher standby leakage current and thus has high power consumption.

For improved base current discharge, two enhancement type nMOS transistors have to be added.