A discrete-circuit source follower driven with Rsig = 100 kΩ has Cgs = 10 pF, Cgd = 1 pF, CL = 10 pF, gmb = 0, and ro very large. The transfer function of the source follower is measured as RL is varied. At what value of RL will the transfer function be maximally flat? At this value of RL the dc gain is found to be 0.9 V/V. What is the 3-dB frequency? What is the value of gm at which the source follower is operating?
A MOSFET common-source amplifier has gm = 2.0 mA/V, ro = 100 KΩ, RD = 10 KΩ, Cgs = 2 pF, Cgd = 0.4 pF. The amplifier is fed from a voltage source with an internal resistance of 500 KΩ and the output is connected to a 10 KΩ load. If the lower cutoff frequency (fL) is 10 KHz, find the Gain-bandwidth product of this amplifier in (dB) KHz (ignore the sign). Approximate your answer to 2 decimal point accuracy.
Figure P9.19 shows a MOS differential amplifer with the drain resistors RD implemented using diode-connected PMOS transistors, Q3 and Q4. Let Q1 and Q2 be matched, and Q3 and Q4 be matched. (a) Find the differential half-circuit and use it to derive an expression for Ad in terms of gm1,2, gm3,4, ro1,2, and ro3,4. (b) Neglecting the effect of the output resistances ro, find Ad in terms of μn, μp, (W/L)1,2 and (W/L)3,4. (c) If μn = 4μp and all four transistors have the same channel length, find (W1,2/W3,4) that results in Ad = 10 V/V.
A CG amplifier is specified to have Cgs = 4 pF, Cgd = 0.2 pF, CL = 2 pF, gm = 5 mA/V, Rsig = 1 kΩ, and RL = 10 kΩ. Neglecting the effects of ro, find the low-frequency gain Vo/Vsig, the frequencies of the poles fP1 and fP2, and hence an estimate of the 3-dB frequency fH.
A CS amplifier modeled with the equivalent circuit of Fig. 10.22(a) is specified to have Cgs = 2 pF, Cgd = 0.1 pF, gm = 4 mA/V, CL = 2 pF, and RL’ = 20 kΩ. Find AM , f3dB, fz , and ft.
A source follower has gm = 5 mA/V, gmb = 0, ro = 20 kΩ, Rsig = 20 kΩ, RL = 2 kΩ, Cgs = 2 pF, Cgd = 0.1 pF, and CL = 1 pF. Find AM , Ro, fZ , the frequencies of the two poles, and an estimate of fH.
Consider a PMOS, as shown in Fig. 1,VDD = 3 V, μpCoxW/L = 20 μA/V2, γp = -0.5 V1/2, ϕf = 0.3 V, λp = -0.01 1/V and Vtpo = -0.8 V. The Circuit is in DCSS. Find the threshold voltage Vtp of the PMOS and the current Ip in this case.
Based on the common source amplifier circuit shown in Fig. Q3a, suppose a limited voltage supply VDD is imposed such that only a single load is allowed to insert between VOUT and ground, (i) suggest the type of load required to have a fairly constant DC current while achieving a reasonably high voltage gain. (ii) draw the small signal model circuit based on Q3a)i), assuming λ ≠ 0 and γ = 0
An IC CG amplifier is fed from a signal source with Rsig = ro/2, where ro is the MOSFET output resistance. It has a current-source load with an output resistance equal to ro. The MOSFET is operated at ID = 100 μA and has gm = 1.5 mA/V, VA = 10 V, Cgs = 0.2 pF, Cgd = 0.015 pF, and Cd b = 20 fF. As well, the current-source load provides an additional 30 fF capacitance at the output node. Find fH.