EE 140 / EE 240A ANALOG INTEGRATED CIRCUITS FALL 2015 C. Nguyen PROBLEM SET #3 Issued: Tuesday, Sep. 15, 2015 Due (at 8 a.m.): Wednesday, Sep. 23, 2015, in the EE 140/240A HW box near 125 Cory. *Unless otherwise stated, assume all the transistors are properly biased in the saturation region. 1. For each of the amplifiers in Fig. PS3-1, !! =20V, ! = ! = 10kΩ, ! = 5V, and !! = - 10V. For all BJTs: = 100, ! = 2pF, and ! = 400MHz. Ignore Early effect and !" . (a) Find the mid-band gain = ! / ! , the 3-dB frequency ! , and the gain-bandwidth product = | ! |. (b) Briefly compare the results obtained from part (a) for the three amplifiers and identify advantages or disadvantages between the three amplifiers. Hint: Consider the following metrics: power consumption, output voltage swing, gain, bandwidth, and GBW. Fig. PS3-1 2. For the amplifier shown in Fig. PS3-2, !! = 5, ! = 1kΩ, ! = 5kΩ, ! =4kΩ, ! = 0.8kΩ, ! = 50Ω, and ! = ! = ∞. All transistors have the same parameters !!! = 0.75V, !" = 15fF/m ! , ! !" = 50A/V ! , = 0, and !" = 0.75fF/m. You can ignore !" and !" . All channel lengths are 0.5m. (a) Calculate ! , ! , and ! such that the overdrive voltage of both ! and ! are 250mV and the voltage at the point A is equal to 2V when no input signal is applied. (b) Find midband voltage gain ! / ! , !" , and !"# . (c) Find the ! of the circuit. Point out which capacitor dominates. V i V CC 0.5mA R s Q 1 R L ∞ V o V i V CC 0.5mA R s Q 1 R L ∞ V o Q 2 V b (a) (b) V i 0.5mA R s Q 1 R L ∞ V o (c) Q 2 1mA V CC V b V EE