Calculate the small-signal voltage gain of the common-source amplifier with active load in Fig. 4.16b.Assume that V_DD= 3 V and that all the transistors operate in the active region. Do the calculations for values of I_REFof 1 mA, 100 µA, 10 µA, and 1 µA.

Figure 4.16b:

(a) Common-emitter amplifier with active load. (b) Common-source amplifier with active load.

Assume that the drawn dimensions of each transistor are W=100[1]m and L = 1[1]m. Assume X_d = 0 and use Table 2.4 for other parameters.

(a) At first, assume the transistors operate in strong inversion in all cases.

(b) Repeat part (a) including the effects of weak inversion by using (1.253) with n = 1.5 to calculate the transconductance of M₁. Assume that a transistor operates in weak inversion when its overdrive is less than 2nV_T, as given in (1.255).

(c) Use SPICE to check your calculations for both parts (a) and (b).

Table 2.4:

Transcribed Image Text:

VDp T3 T2 Va2 ds2 = La1 Iout = lan IREF O Vout = Vds1 +0 Vị T1 Value Value n-Channel p-Channel Parameter Symbol Transistor Transistor Units Substrate doping NA, ND 5 x 105 4 x 1016 Atoms/cm Gate oxide thickness lox 80 80 Metal-silicon work function Фия -0.6 -0.1 cm/V-s Channel mobility Minimum drawn channel 450 150 Larwa 0.4 0.4 pm length Source, drain junction depth Source, drain side diffusion Overlap capacitance per unit gate X) La Cd 0.15 0.18 um 0.09 0.09 um 0.35 0.35 fF/um width Threshold adjust implant (box dist) impurity type effective depth х, 0.16 0.16 effective surface Nsi 4 x 106 3 x 1016 Atoms/cm concentration -0.8 100 Nominal threshold voltage V, Napoly 0.6 Polysilicon gate doping 100 Atoms/cm concentration Poly gate sheet resistance Source, drain-bulk junction R, 0.2 0.4 fF/um? capacitances (zero bias) Source, drain-bulk junction capacitance grading 0.5 0.4 coefficient Source, drain periphery capacitance (zero bias) Source, drain periphery capacitance grading coefficient Source, drain junction built-in potential Срио 1.2 2.4 F/μη 0.4 0.3 0.7 0.7 Os Surface-state density 101 Atoms/cm? dX4 dVps Channel-length modulation 0.02 0.04 дm/v parameter