MELZG 632: Analog IC Design Assignment 1 Submission Date: 18th August 2019 Note: Until and otherwise stated use the device data given in table at the end of this document and assume 𝑽𝑫𝑫 = 𝟑 𝑽 where necessary. 1. Sketch 𝐼𝑋 and transconductance of the transistor as a function of 𝑉𝑋 for each circuit given as 𝑉𝑋 varies from 0 to 𝑉𝐷𝐷 . 2. Sketch 𝑉𝑜𝑢𝑡 as a function of 𝑉𝑖𝑛 for the circuit given as 𝑉𝑖𝑛 varies from 0 to 𝑉𝐷𝐷 . 3. Sketch 𝑉𝑋 and 𝐼𝑋 as a function of time for the circuit given. The initial voltage of 𝐶1 is equal to 3 V. 4. The transit frequency, 𝑓𝑇 , of a MOSFET is defined as the frequency at which the small-signal current gain of the device drops to unity while the source and drain terminals are held at ac ground. Prove that 𝑓𝑇 = 𝑔𝑚 2𝜋(𝐶𝐺𝐷 + 𝐶𝐺𝑆 ) Note that 𝑓𝑇 does not include the effect of S/D junction capacitance. 5. Explain why the structures cannot operate as current sources even if they are in saturation. 6. An NMOS device is operating in the subthreshold region has a ζ of 1.5. What variation in 𝐶𝐺𝑆 results in a ten-fold change in 𝐼𝐷 ? If 𝐼𝐷 = 10 µ 𝐴, what is 𝑔𝑚 ?