2007 Spring VLSI Design Mid-term Exam 2:20-4:20pm, 2007/05/11

Transcription

1 7 ri VLI esi Mid-erm xam :-4:m, 7/5/11 efieτ R, where R ad deoe he chael resisace ad he ae caaciace of a ui MO ( W / L μm 1μm ), resecively., he chael resisace of a ui PMO, is wo R P imes R. i.e., R R. The mobiliy of MO, μ, is wice as bi as he mobiliy of PMO, μ P. P 1. (%) If he oolea fucio of a comlex ae is X (( + ) + F)( H + I), he (a) (1%) Please show he schemaic of he MO comlex ae i erms of PMO ad MO OL. (b) (1%) If he ouu of he above comlex full-saic ae is drivi a load of uis, wha will be he wors-case risi ad falli delay iτ uis? I your comuaio, assume ha all MO ad PMO rasisors are ui rasisors ( W / L μm 1μm ), ad he ieral diffusio caaciaces ca be iored. (a) The schemaic of X (( + ) + F)( H + I) is show as follows. Vdd H F I X I H F (b) The wors-case risi ad falli delay are Tr 3R * 1R 6τ 1

2 Tf 5R * 1R 5τ. (6%) We kow ha he oal delay of a iverer buffer chai is + ( 1 F /γ ) The iu ae caaciace of he 1 s iverer,,1, is, 1, ad he ouu load caaciace h L 496. ssume haγ i, i /, i 1, for i iverer, i 1,,...,. (a) (5%) For a sile-sae buffer wih a ui-size iverer, show he oal delay i erms of. (b) (5%) For a four-sae iverer buffer chai, show he oal delay i erms of. (ars wih a ui-size iverer) (c) (5%) The cosumed eery,, of a MO er rasiio ca be aroximaed as. L V For he roblem (b), exress (er MO rasiio) i erms of V ad (o fore i,i he effec of ). (d) (5%) ssume ha f o 3.6 a γ 1. oimal sizi iverer chai sars wih a ui-size iverer. Please decide he oal umber of saes for miimum delay. (e) (6%) Please derive he relaioshi of effecive faou f ad roorioal facor we wa o obai he oimum umber of saes. (a) Toal delay for he sile sae buffer : γ whe 1 ( /1) (b) Toal delay for he four-sae iverer buffer : 4 ( /1) 4 36 (c) Q f F Vdd ( 1+ γ )(1 + f + f + f ) + F 566Vdd. 3 The cosumed eery is b [ ] (d) Oimal sizi buffer chai /1 3 6 If 6, he ( ) / If 7, he ( )

3 Therefore, 7-sae is oimal soluio. (e) l F L F i f i F f l f F F ( + l f l γ f 1 F / γ ) l f γ γ l f l f f l F l f 1 γ )( γ (l f ) ( f ) f ex 1+ ( γ f ) 3. (15%) The oolea fucio of a MO comlex ae is ( + ) +. how he layou (ick iaram) of his ae based o lie-of-diffusio rules. ou ca use oly oe + diffusio ad oe P+ diffusio (o break hem). Please use uler ah o derive he resul ad show he corresodi uler ah i your desi. uler ah : ->->->-> V Layou : V 4. (5%) Please exlai he reaso ha we usually imleme he Pull-U ework wih PMO ad Pull-ow ework wih MO. (ou ca show i by drawi he fiure of he MO iverer.) 3

4 PMO rasisors ca ass a sro 1 bu a weak, ad MO rasisors ca ass a sro bu a weak 1. PU V V V V V V -V T L L P V V V T V L V L 5. (1%) There are five differe sizes of MO iverer aes wih oe MO ad oe PMO, icludi () ( W W ) 1 & ( ) 1, () ( W W ) 5 & ( ) 1, () W W ( ) 1 & ( ) 5, () ( W W ) 1 & ( ), ad () W W ( ) & ( ) 1. Please show he relaive relaioshi bewee ()~() ad (1)~(5) i he below fiure of Volae Trasfer haracerisics urve. (For examle, (1) -> (), () -> (), (3) -> (), (4) -> (), (5) -> () ) Vou (1) () (3) (4) (5) Vi Relaioshi : (5) -> (), (4) -> (), (3) -> (), () -> (), (1) -> (). 6. (6%) Please briefly secify he hree ars of ower cosumio i MO echoloy. (1) yamic ower cosumio : chari & dischari caacior. () hor-circui ower cosumio : shor circui ah bewee suly rails duri swichi. (3) Leakae ower cosumio: leaki diodes & rasisors. 4

5 7. (6%) Please desi a ass-rasisor ework ha imlemes he oolea fucio ou should show he schemaic of he circui. 8. (1%) I order o simly desi a MO iverer, we eed six differe masks, icludi () + diffusio, () + diffusio, () oac, () -well, () Meal, ad (F) Polysilico. Fiure 1 & show he cross-secioal ad verical views of he MO iverer, resecively. Please show he relaive relaioshi bewee ()~(F) ad (1)~(6) i Fiure. (For examle, (1) -> (), () -> (), (3) -> (), (4) -> (), (5) -> (), (6) -> (F)) Fiure 1 (1) (4) (5) () (3) (6) Fiure Relaioshi : (1) -> (), () -> (F), (3) -> (), (4) -> (), (5) -> (), (6) -> (). 5