HW7-solution

# HW7-solution - Homework 7 ECE456 Note This assignment has...

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Unformatted text preview: Homework 7 ECE456 Note: This assignment has higher weight than previous assignments. Problem 1: Implement the function below (both the function and its complement) in DCVSL (see page 267 of your textbook). Assume A, B, C, D and their complements are available as inputs. Make sure to use the minimum number of transistors. F= AEGXCD ; (A’+sc).( “5495) lit tramsi‘s {wars 3 Imptdamgn‘l—al‘fdh (,Ul-H’l if”) Homework 7 ECE456 Note: This assignment has higher weight than previous assignments. Problem 2: The following network is a pass transistor logic gate implemented in 1.2um CMOS technology (see ﬁle spice 1.2um CMOS.doc on Vista). 1. Determine the truth table for the circuit. What logic function does it implement? 2. Assuming 0 and 5V inputs, size the PMOS transistor to achieve a V0L=0.3V (hint for this case assume NMOS in linear regime and PMOS in Saturation). 3. If the PMOS were removed, would the circuit still function correctly? Does the PMOS transistor serve any useful purpose? Vdd l . Vout B U I" "Walla Table [email protected] / XNOR i A:\,B:(I‘5 2. V9L=o.3v Wd;p;m to achieve Vail: ﬂow is {Asmgz‘a In aim» Col/SL2 we have JIM “Fallow‘nj CC?- “or; BOTH trmsishm (NMOS ovmd PMOS) almon- 4' “[- of?" “MOS ts {M Ma» (“Ds<"e«s-V-rn) “kw UL1/117!” PMOS is {M gamahmww>vm+vw> Ignon‘nj C)an Jiij Macmillath UPI-'90 1 [an .1 19.6 MM— V‘th; 0‘7113 V .7:— VW r. a 0.73:; v r. mwmaﬁ_ PMos ‘ mPul- 6D} Q (Mould 1401- we haw CL JCm/mSiHm/m (1&6): I,I—-a»¢ ﬂ 1Mﬂw%ww PMos Pram/“(1&5 M Pm”th “‘P‘AAC’HW %%T-ﬂm PM” P _%5T gig CAVOWi—S' Homework 7 ECE456 Note: This assignment has higher weight than previous assignments. Problem 3. Effects of scaling on pass—gate logic. 1. If a process has a 2?sz of 0.4nsec, Reg of 8Kohm, and C of 12fF, what is the optimal number of stages between buffers in a pass—gate chain? 2. Suppose that if the dimensions of this process are shrunk by a factor of S, Reg scales as 1/52, C scales as 1/8, and IM scales as 1/52. What is the expression for optimal number of buffers as a function of S? What is the number ifS=2. Homework 7' ECE456 Note: This assignment has higher weight than previous assignments. Problem 4. For a simple level restorer shown in Fig 6-40 (p. 275) implemented in 1.2um technology, let capacitance at point X to ground CX=5QJT, M, has effective W/L=1.8/1.5, M? has effective W/L=1.8/0.9. Assume the output inverter doesn’t switch, until its input equals VDD/2. a. How long it takes Mn to pull dOWn node X from 5V to 2.5V if AIOV and B=5V (hint: at VFSV, Mn is saturated and M. is off. at VFZSV, both Mn and M,. are in linear region). b. How long it takes MD to pull up nodeX from 0V to 2.5V when A=B=5V. c. What is the value of V5 necessary to pull down Vx to 2.5V when A=0V? ll '\ \ .— v‘ as MOM %:g.—a~£{‘3 =e- ant—{WEDW Al: VISASV bo‘l‘h bfmmgisi-m am 141 5V / /0.74 f VDS‘rQ-SV < V6~S_th° iCap :: Lou - lop 'L = K’n(‘m'j£)n Ug’o‘ﬂﬂls) ‘ Kﬂv—HP [(tapmaﬂm) #2:? Z— ; 245’- 6 MA \> ILRP mg 1 Sis— +:Z‘g '4 gDO/HA £P; CK Av ; SogFXZ'SV 5 0-416 nSec) Bod/LIA 3'11: 79—“ 15mg“? Chm/mm maMmHW ye-IA'H “ed/VIA ICOLPM/Vj £P '3 VISMQC . 415" WW .5 1av) b5V x (0V ._.>- g). XV) T A16 VX : o “71> ICaP: IBM Saar 5 Af Vac: 26V 72, v63, v05: A 3v scrmmm 541‘“ W 2 L I 7 5 J.— ” 5cm w \I d- V 2) AP 0N; Sod- —— ,1 PL)” ( (“S *5 , ; £9.6x10 x2 A (1.§,O.7A)Q’; L)O/HA 2. Chi/7%” we Mme Cﬂwmui W 100% C09QJ_ LCQPJ‘B ; 2‘ ZOO/HA “NM 53.36 Legit} 4» WM vary???) mach/ﬂak?” % Wgrkmdf m5 M09 becomes Na. g ‘nsec I m ' Qt‘qnmb C. WWI/1 V1528)!" bo‘ﬁn Womagns’mrs W l .9 ~22) L} V \fst m A \l ’T *\ 8 8‘! r, 0V .- I V ...
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## This note was uploaded on 09/24/2009 for the course ECE 456 taught by Professor Mohammadi during the Spring '09 term at Purdue.

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HW7-solution - Homework 7 ECE456 Note This assignment has...

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