Various measurements are made on an NMOS amplifier for which the drain resistor RD is 20 kΩ. First, dc measurements show the voltage across the drain resistor, VRD, to be 2 V and the gate-to-source bias voltage to be 0.75 V. Then, ac measurements with small signals show the voltage gain to be −16 V/V. What is the value of V, for this transistor? If the process transconductance parameter kn′ is 400 μA/V2, what is the MOSFET's W/L?
By hand calculation, find the Q-point for the enhanced NMOS transistor shown in Figure 2 with VTO = 1 V and γ = 0. (10 points) Figure 2 The VDD, kn’, W/L, and R values are : VDD = 15V, kn′ = 25μA/V2, W/L = 4/1, R1 = 1MΩ, R2 = 2MΩ, R3 = 47kΩ, and R4 = 10kΩ. (b) Confirm your result of part (a) through SPICE simulation. State the simulated Q-point and compare it with that of hand-calculation. Print and attach the simulation result. (10 points) (c) By interchanging the resistance values between R2 and R1, as well as between R4 and R3, hand calculate the new Q-point. (10 points)
Further, assume that the DC current of M1 and M2 is 1 mA each and that of M3 and M4 is 0.5 mA each. Assume all transistors are in operating in saturation region and the aspect ratio of transistors is as follows: (W/L)1 = 125, (W/L)2 = 250, (W/L)3 = 40, and (W/L)4 = 80. a) Find transconductance (gm) of all the transistors and the drain-source resistance (ro) of the PMOS transistors, that is, ro2 and ro4. [10 marks] b) Find the voltage gains Vout1/Vin and Vout /Vin. . In the following circuit assume: λ(NMOS) = 0 V−1, λ(PMOS) = 0.05 V−1, VDD = 3.0 V, VTH(NMOS) = ∣VTH(PMOS)∣ = 0.5 V, μnCox = 0.1 mA/V2, μpCox = 0.05 mA/V2, and γ(NMOS) = γ(NMOS) = 0.
A certain NMOS transistor has the characteristics shown in (figure 1) Graphically determine the value of gm at the operating point defined by VDSQ = 6 V and VGSQ = 2.5 V Express your answer to three significant figures and include the appropriate units. Graphically determine the value of rd at the operating point defined by VDSQ = 6 V and VGSQ = 2.5 V Express your answer to three significant figures and include the appropriate units.
A bias source is depicted in Figure 10.1 where Q2 is twice the size of Q1. The other transistors are the same size as Q1. (a) State the basic mechanism of this bias source. (b) Derive the variation of the fractional temperature coefficient for the output current. (c) Determine the resistance R2 for the current bias reference circuit to obtain an output of 100μA and the resultant TCF at room temperature (T=300 K). Assume that the resistor temperature coefficient is 1500ppm/∘C. [(c) 180Ω, 1800ppm/∘C]
A differential amplifier depicted in Figure 10.2 comprises 4 transistors where MOS transistors: μnCoxW/L = 0.2×10−3 A/V2, Vt = 0.5 V Bipolar transistors: VCE( sat) = 0.2 V. Assume that the two MOSFETs have an identical aspect (i.e. W/L) ratio and that the two BJTs have identical emitter areas. (d) Show that all the MOSFETs and BJTs are active for the zero-input condition, i.e. Vin = 0. (e) Find the maximum and minimum common-mode input voltages, i.e. the limits of operation where the circuit remains in active operation. [(b)−6.14 V ≤ Vin ≤ 7.5 V]