EE 321L Analog Electronics Laboratory Fall 2010Lab 11MOSFET characteristics and current mirrorPre-Lab1. Read Sedra and Smith section 6.3.1.2. Find the data sheet fo r the CD 4007 MOSFET chip3. Find the maximum allowed voltage range.4. Decide which transistor(s) to use for each of the three sections of the lab, and how toconnect them.5. Provide initial estimates of the size of current sense resistors based on the informationin t he data sheet.In this lab you will characterize MOSFETs and then build a current mirror.Static precautions and other preparationsIn this lab we will use the CD 4007 dual complimentary pair plus inverter MOSFET device.MOSFETs are extremely sensitive to static discharge. Use wrist straps, or otherwise groundyour body and the prototype board befo re handling the chips. Make sure all connectionsare correct before turning on power to the circuit. Do not move wires while the circuit isconnected to power. Ground your body whenever you are handling the chips or when you areinserting wires into the proto board. Any unused pins should be connected to ground. Pin 7should be connected to the most negative voltage in the circuit. Pin 14 should be connectedto the most positive voltage in the circuit. Think and measure before connecting power.1EE 321L Analog Electronics Laboratory Fall 2010IV characteristic of a NMOSIn this section you will plot the IV characteristic. You will plot iD(on the Y-axis) as afunction of vDS(on the X-axis) for several different values of vGS.1. Connect VDDto 10 V and VSSto 0 V.2. Connect the source to ground and the gate to a voltage divider providing (in succession)0.5, 1, 2, and 4 V (feel free to modify these, but the suggestion is one voltage below Vtand several different above Vt).3. Create a triangular wave between 0 and 9 V. Be sure the output does not go below0 V or above 10 V. If the function generator cannot generate the necessary offset, usea op-amp summer. Connect this signal to t he drain.4. Attach a very small resistor between the source and ground. This is called a currentsense resistor. Make sure it is small enough that the volta ge across it is much smallerthan the gate voltage. You may need to experiment with the size of the current senseresistor.5. Plot vDSversus iDin XY mode fo r the different values of vGS.6. Plan and carry out a measurement program to determine Vtand k′WLfrom measure-ments o f vGS, vDS, and iD.IV characteristic of a PMOS1. Plan and carry out a measurement program for the PMOS to obtain k′WLand Vt. Forexample:2. Connect VDD= 0 and VSS= −10 V, and also choose a negative voltage to VG.3. Make the necessary measurements to obtain Vtand k′WL.NMOS current mirrorIn this section you will build a MOSFET current mirror and measure its output resistance.1. Design a nd build a NMOS current mirror. It is laid out similar to the NPN BJT currentmirror we built during the previous lab.2. Measure pairs of values of output current and drain voltage. Plot these values and alsouse them to determine the output resistance of the current
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