The following circuit shows a MOS Wilson mirror in which Q1 and Q3 are matched, and they have the same (W/L)1 ratio that is 2 times of the (W/L)2 of Q2. All MOSFETs have the same Vt. 1) Derive the relationship between lout and IREF 2) Using small-signal model of the MOSFETs, derive and appreciate the output resistance of the current source, Ro.
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The following circuit shows a MOS Wilson mirror in which Q1 and Q3 are matched, and they have the same (W/L)1 ratio that is 2 times of the (W/L)2 of Q2. All MOSFETs have the same Vt. 1) Derive the relationship between lout and IREF 2) Using small-signal model of the MOSFETs, derive and appreciate the output resistance of the current source, Ro.
![Question 3 (25 marks) Figure 4 shows an amplifier with current mirror as active load. The MOSFETs have the following parameters: Vtn = −Vtp = 0.6 V, Kn′ = 200 μA/V2, Kp′ = 65 μA/V2, VA(NMOS) = 20 V, VA(PMOS) = −10 V, L = 0.4 μm and W = 10 μm. The supply voltage, VDD = 3 V and the reference current, IREF is 0.02 mA. Assume all the transistors are biased in the saturation region. Figure 4 (a) Identify the transistors forming the current mirror. [3 marks] (b) Calculate the output resistances of transistors Q1 and Q2. [6 marks] (c) Given that ID = k′(W/L)(VGS − Vt)2, calculate the gate to source voltage of Q1. [7 marks] (d) Calculate the small-signal voltage gain, vout/Vin. [9 marks]](https://www.doubtrix.com/uploads/editor/9090580396tgyGQJZuQI.png)
