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Unformatted text preview: ECE164 Analog Integrated Circuitl Design ll Ian Galtonl
Nonernberi E) 2005 EBUl 3802M Homeworld Assignment 6
Due: StOLl am, Thursday) Decemberi 1, M5 Problemsi
L Be—sohnd thd problems on the second midterm examl 1 Consider the following ampliﬁer circuit. You may assume that 1) all nMOS transistors
are identical to each other, 2) all pMOS transistors are identical to each other, 3) al
transistors are in saturation, 4) Rk, << rdsi for all i and k, and 5) the input signa
frequencies are sufﬁciently low that all capacitances can be ignored. Wm Vim a Drain the differentialnnodd small—signa 1131mm oLthe ampliﬁerl bl Derivd expressions for Adm andl Adm_cml (Hintl Fori large values of gmlrds A Adm
shouldl approximatelﬁ dependl onlﬁ on R1 and R2)l 91 Draw the commortrnorld small—signa halfiircuitl oLthe ampliﬁerl
dl Derivd expressions for £1ij and Acm_dml eJ Does this circuit require a common—mode feedback circuit (i.e.l must the [1 and/Oil
Ij current sources be maintained at precise values by feedback circuitrﬁ in orderi
to keeg all the transistors irﬂ saturation)? Explain. 3. This problem relates to the following circuit. The voltage V03 is a bias voltagj
generated by circuitry not shown in the ﬁgure. You may M and M
are identical) that M41 and M5) are identical, and that the inpu‘d signal frequencies are sufficientlﬂ low that all capacitances can be ignoredl Fori Parts a)—e)l M mag assume
that all transistors are irﬂ saturationl a) For this part assume that A = 0, that an : 3MP, tha W4/L4 : W5/L5 : 3W3/L3,
and that VT —VTp. Calculate V04 as a functio of only V03, VTp, and VDD. Does @ depend upon and Explain. Qanl a differential—mode half—circuit be used to calculate AM and Adm_cm fori this
circuitZ Explain youn reasoning, andl iﬂ your ansnrer is yes, draw the small—signal Calenlate Adm] andl Adm_cm fori this circuit. If applicablel dd notl neglectl the body
effectonrdsi fonanmofthetransistorsl Qanl a common—mode half—circuitl be usedl td calculate flij and Acm_dmj for this
circuitZ Explain youn reasoning, andl iﬂ your ansnrer is yes, draw the small—signal
model oLthe cemmortmorle halﬂ circnitl Calenlate Aim and Acm_dm fori this circuitl If applicable, dd notl neglectl the body
effect lei any oLthe transistors Does this circuitl require common—mode feedback (i.e.l dd the m bias voltages
need td be preciselﬂ balanced using a feedback circuit td kete the transistors in saturation)? Explain. What major advantagd does this circuit offeri with respectl td a resistively loadedl
diﬁemntialampliﬁerwhereimwandﬂareabsentandeachmsistorcnnnectsthe
drainl ofeither M on % to V00 .1 ...
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This note was uploaded on 08/26/2010 for the course ECE ece164 taught by Professor Iangalton during the Fall '05 term at UCSD.
 Fall '05
 IANGALTON

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