Question

Notify Me Bookmark

VI. Draw the small signal model, including source-drain resistance, and find the small-signal gain (in V/V) for this current-mirror loaded CS transistor amplifier. For all transistors: W/L = 50 Vt = |0.5 V| VA = 20 V IREF = 100 µA µnCox = 100 µA/V^2 µpCox = 50 µA/V^2 iD = 1/2µnCoxW/L(VOV )^2 gm = µnCoxW/L VOV = 2ID/Vov = √2µnCoxW/LID

VI. Draw the small signal model, including source-drain resistance, and find the small-signal gain (in V/V) for this current-mirror loaded CS transistor amplifier. For all transistors: W/L = 50 Vt = |0.5 V| VA = 20 V IREF = 100 µA µnCox = 100 µA/V^2 µpCox = 50 µA/V^2 iD = 1/2µnCoxW/L(VOV )^2 gm = µnCoxW/L VOV = 2ID/Vov = √2µnCoxW/LID

Image text
VI. Draw the small signal model, including source-drain resistance, and find the small-signal gain (in V/V) for this current-mirror loaded CS transistor amplifier. For all transistors: W/L = 50 Vt = |0.5 V| VA = 20 V IREF = 100 µA µnCox = 100 µA/V^2 µpCox = 50 µA/V^2 iD = 1/2µnCoxW/L(VOV )^2 gm = µnCoxW/L VOV = 2ID/Vov = √2µnCoxW/LID

Explanation & Steps

The given circuit is a common-source amplifier with active load as current-mirror formed by PMOS transistors Q2 and Q3. NMOS Q1 is a driver transistor. Input signal is applied at gate terminal of driver transistor. By default, all transistors are assumed to bias in saturaton region. Use following steps to determine voltage gain of the given amplifier circuit.

Step (1): Determine drain current of NMOS Q1/Q2 transistor.

Step (2): Transconductance gm1 of NMOS transistor, Q1.

Step (3): Output resistance ro1 & ro2 of NMOS transistor Q1 & Q2 respectively.

Step (4): Draw small-signal model of the amplifier circuit. Use transconductance and output resistances to calculate small-signal voltage gain, Av.

Detailed Answer

2 0

Please enter your email here. You will get email when this question is answered by our tutor.

Answer
Doubtrix Logo

This Problem has been solved!

You'll get a detailed, step-by-step and expert verified solution.

Join Doubtrix with 7-days free trial

  • Icon Correct & Verified Answers
  • Icon No AI-Generated Answers
  • Icon Video Solution for Difficult Questions
  • Icon Work With Experts to Reach at Correct Answers
Login Sign Up
  • Student Reviews:
  • (2)
  • Correct answers (2)
  • Complete solution (2)
  • Step-by-step solution (2)
  • Fully explained (2)

Similar/Related Questions

Figure 1(a) shows a BJT based current mirror where the BJT current equation is given by: IC = IS′AEe VBE VT(1 + VCE VA) where Is′ = 50 fA, AE is normalized emitter area, thermal voltage VT = 25 mV and early voltage VA → ∞. Further, it is given that IREF = 0.5 mA, Vdd = 5 V and β = 50 for both Q1 and Q2. (a) Derive the equation of mirror ratio MR = Io/IREF. Using this, find Io, VBEI and VCEI if AE1 = 2, AE2 = 2. (25 Marks) (b) Suppose I want to increase the output current by increasing AE2 by 10 times. Recalculate MR = Io/IREF, Io, VBE1 and VCE1 if AE1 = 2,AE2 = 20. Does the output current increase 10 times compared to (a)? Marks) (c) What is the maximum mirror ratio attainable by increasing AE2 ? (10 Marks) Figure 1 2. Now, draw the AC small signal model for this same circuit in Figure 1 and find an algebraic expression for the input resistance, Rin, including the effect of V. 1. Evaluate the value of Rin using the parameters given in part 1(a) and considering VA = 100 V−1. (40 Marks)
Solution
0 0

For the shown PMOS amplifier driving load RL with the following parameters: Vdd = 2.5v RL = 10 kohm Vt = -0.5v lambda = 0.67 v-1 W/L = 10 upCox = 50.0 uA/v2 IBias = 100 uA a) Find the value of VIN for VOUT equal to zero. Hint: Current through the load resistor, RL, is zero b) Write a small signal model for this amplifier in SPICE. Hint: Don't need Vin , and know VIN when VOUT = 0 (part a) which helps calculate gm and g0 (r0 = 1/g0) c) Simulate your model and study the results, can you measure the gain for th given load (RL) ? d) Find its small signal gain Av = VOUT/VIN. Hint: Easy to find as you already have g0, gm, and RL e) Find the range for VOUT that the PMOS stays in the saturation region. f) Find the range for VIN that the PMOS stays in the saturation region. Hint for d and e: VOUT = (-ID-IBias)?RL

For the shown PMOS amplifier driving load RL with the following parameters: Vdd = 2.5v RL = 10 kohm Vt = -0.5v lambda = 0.67 v-1 W/L = 10 upCox = 50.0 uA/v2 IBias = 100 uA a) Find the value of VIN for VOUT equal to zero. Hint: Current through the load resistor, RL, is zero b) Write a small signal model for this amplifier in SPICE. Hint: Don't need Vin , and know VIN when VOUT = 0 (part a) which helps calculate gm and g0 (r0 = 1/g0) c) Simulate your model and study the results, can you measure the gain for th given load (RL) ? d) Find its small signal gain Av = VOUT/VIN. Hint: Easy to find as you already have g0, gm, and RL e) Find the range for VOUT that the PMOS stays in the saturation region. f) Find the range for VIN that the PMOS stays in the saturation region. Hint for d and e: VOUT = (-ID-IBias)?RL

Solution
0 0

Consider the CMOS common-source amplifier in Fig. 7.4(a) for the case VDD = 3 V, Vtn = |Vtp| = 0.6 V, μnCox = 200 μA/V2, and μpCox = 65 μA/V2. For all transistors, L = 0.4 μm and W = 4 μm. Also, VAn = 20 V, |VAp| = 10 V, and IREF = 100 μA. Find the small-signal voltage gain. Also, find the coordinates of the extremities of the amplifier region of the transfer characteristic-that is, points A and B. (a)
Solution
0 0