Show that the series connection of MOSFETs shown in Fig. 6.21 behaves as a single MOSFET with twice the length of the individual MOSFETs. Again, neglect the body effect.
Show that the bottom MOSFET, Fig. 6.21, in a series connection of two MOSFETs cannot operate in the saturation region. Neglect the body effect. Hint: Show that M1 is always either in cutoff ( VGS1 < VTHN) or triode (VDS1 < VGS1 - VTHN).
Show that the series connection of MOSFETs shown below behaves as a single MOSFET with twice the length of the individual MOSFET. Hint. assume the same W for each device, then set L1=L2=L.
The circuit given below has the feedback biasing arrangement with a 5 V supply and an NMOS device for which RG = 2Mohm, Vt = 1 V and KnW/L = 10 mA/V2. Find the value of RD to establish a drain current of 0.2 mA.
Figure below represents a MOS amplifier using a specific biasing arrangement. The transistor has threshold voltage Vt = 1 V, early voltage VA = 15 V, unCox = 10uA/V2, W = 20um and L = 2um. Assume the coupling capacitors to be sufficiently large so as to acts as short circuits at the signal frequencies. a. Calculate the transconductance, gm. b. Determine the small signal gain of the amplifier. c. What is the minimum VDS required for the transistor to operate in pinch-off point?
D4.72 For the cascode circuit in Figure 4.51 in the text, the transistor parameters are: VTN1 = VTN2 = 1 V, Kn1 = Kn2 = 2 mA/V2 , and lambda1 = lambda2 = 0. (a) Let RS = 1.2 kohm and R1 + R2 + R3 = 500 kohm. Design the circuit such that IDQ = 3 mA and VDSQ1 = VDSQ2 = 2.5 V. (b) Determine the small-signal voltage gain Av = vo/vi.
(5) Qualitatively plot gm as a function of VDS, identify important transition points and mark the different operation regions. (6) Provide a symbolic expression for gm in each region. (7) Which region does the MOSFET need to operate in for amplification? And why.
Q2. Common Source with diode-connected For questions (1)-(5), channel-length modulation and the body effect can be ignored. M1 is in the saturation region. (1) Which region does M2 work in? (2) Provide a symbolic expression for the small-signal gain of the amplifier using Vov1 and Vov2, which are the overdrive voltage of M1 and M2, respectively.