| OCR Text |
Show gat -array design ar shown in Figures 5.2 and 5.3. Th opamp had a gain of 468 and a unity gain bandwidth of 4.45 Hz. Th phas margin was n1easured to be 147 degrees and th sl w rat was 563.4V fp, . The output voltage swings between -2.85V to -7.9V with an offs t of l. 7In V. Thi slew rate was too slow for the high speed operation of the sig1na-delta 1nodulator. Therefore instead of using an opamp integrator, the use of a simple R int grator in the system was investigated and simulations show that the performance at high speed was very good, which justifies the use of it inspite of its low gain. Another problem with the designed opamp was that it had a voltage offset that increased v 0 L T 0 B L I N IWDE PLOT ;: : : : : : : : : : : : H COHP _OPAHP . I :~ ~:: r:::;::: :t : ;: : I ;: :r ::: :J ;:: : r: : [:: :::r: .,! ;~ ~:~~T- 6 0 . 0 ~ -···· ·:·······:········:·······:········:········:········: · ······:·······~········~·······~····· 1 -j ::::(L T T I: T I · T L .: T !j ..... • • • • • ' + • • • • - : :: 0 : ~: ::: l:.::.:: i: :.::: t.. i::::.: i:: ::.:. i .: :·::: i•: ~ t~ ~\.:::::I:::::: 1 ::I~ ~ . . . . . . . . \ . . I ~ -6 0. 0 ~-·····:· · ······:········:·········~········~········:········j········:·········:\·····:·········:·····t~ • ::::: t:::•r::::::r•:::r:•:•• :I:••::::.:•::•J••::•:•i•::::•r••:••:I:·~1~~~·:11 ... . . . . . . . . . . . \ I .. ::::::~ :r: ,· T·:·:r ::,·· r::: ••r·· :::·::,::,:·ii - 178 . 55~ 1. 0 1 0 0 . 0 t O.OK t.OX lOO.OX lO . OM HER TZ (L OG J tO.OG Figure 5 .2. Bode Plot of Opamp |
