click to buy information furnished by linear integrated systems and micross components is believed to be accurate and reliable. however, no responsibility is assumed for its use; nor for any infringement of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of linear integrated systems. features ? high ? input ? impedance ? i g ? = ? 0.25pa ? max ? high ? gain ? gfs ? = ? 120mho ? min ? low ? power ? operation ? v gs ( off ) ? = ? 2v ? max ? absolute ? maximum ? ratings ?? @ ? 25c ? (unless ? otherwise ? noted) ? maximum ? temperatures ? storage ? temperature ?\ 65c ? to ? +150c ? operating ? junction ? temperature ? +150c ? maximum ? voltage ? and ? current ? for ? each ? transistor ? ? ? note ? 1 ? \ v gss ? gate ? voltage ? to ? drain ? or ? source ? 40v ? \ v dso ? drain ? to ? source ? voltage ? 40v ? \ i g ( f ) ? gate ? forward ? current ? 10ma ? maximum ? power ? dissipation ? device ? dissipation ? @ ? free ? air ? ? ? total ????????????????? 400mw ? @ ? +125c ? matching ? characteristics ? @ ? 25c ? unless ? otherwise ? noted symbol ? characteristics ? value ? units ? conditions ? | ? v ? gs1 \ 2 ? / ? t|max. ? drift ? vs. ? temperature ? 10 ? v/c ? v dg =10v, ? i d =30a ? t a = \ 55c ? to ? +125c ? | ? v ? gs1 \ 2 ? | ? max. ? offset ? voltage ? 10 ? mv ? v dg =10v, ? i d =30a ? electrical ? characteristics ? @ ? 25c ? (unless ? otherwise ? noted) symbol ? characteristics ? min. ? typ. ? max. ? units ? conditions ? bv gss ? breakdown ? voltage ? 40 ? 60 ? \\? v ? v ds ? = ? 0 ?????????????????? i g =1na ? bv ggo ? gate \ to \ gate ? breakdown ? 40 ? \\? \\? v ? ?????? i g ? = ? 1a ??????????????? i d = ? 0 ??????????????? i s = ? 0 ? ? y fss ? transconductance ? full ? conduction ? ? 300 ? ? \\? ? 1500 ? ? mho ? ? v ds ? = ? 10v ????????? v gs = ? 0v ?????? f ? = ? 1khz ? y fs ? typical ? operation ? 120 ? 200 ? 350 ? mho ? ????? v dg ? = ? 10v ?????????? i d = ? 30a ???? f ? = ? 1khz ? ? i dss ? drain ? current ? full ? conduction ? ? 60 ? ? \\? ? 1000 ? ? a ? ? v ds ? = ? 10v ?????????????? v gs = ? 0v ? ? v gs ( off ) ? gate ? voltage ? pinchoff ? voltage ? ? \\? ? \\? ? 2.0 ? ? v ? ? v ds ? = ? 10v ??????????????? i d = ? 1na ? v gs ? operating ? range ? \\? \\? 1.8 ? v ? ???????????? v dg ? = ? 10v ????????????????? i d = ? 30a ? ? i g max. ? gate ? current ? operating ? ? \\? ? \\? ? .25 ? ? pa ? ? ?? v dg ? = ? 10v ??????????????? i d = ? 30a ? \ i g max. ? high ? temperature ? \\? \\? 250 ? pa ? t a ? = ? +125c ? i gss max. ? at ? full ? conduction ? \\? \\? 1.0 ? pa ? v ds ? = ? 0v ????????????? v gs = ? 20v ? \ i gss max. ? high ? temperature ? \\? \\? 1.0 ? na ? t a ? = ? +125c ?? ? y oss ? output ? conductance ? full ? conduction ? ? \\? ? \\? ? 10 ? ? mho ? ? v ds ? = ? 10v ?????????????? v gs = ? 0v ? y os ? operating ? \\? 0.1 ? 3.0 ? mho ?? v dg ? = ?? 10v ????????????? i d = ? 30a ? ? cmr ? common ? mode ? rejection ? \ 20 ? log ? | ?? v ? gs1 \ 2 / ?? v ds | ? ? \\? ? 90 ? ? \\? ? db ? ? ? v ds ? = ? 10 ? to ? 20v ???????? i d = ? 30a ? ?\ 20 ? log ? | ?? v ? gs1 \ 2 / ?? v ds | ? \\? 90 ? \\? db ?? v ds ? = ? 5 ? to ? 10v ?????????? i d = ? 30a ? ? nf ? noise ? figure ? ? \\? ? \\? ? 1 ? ? db ? v dg ? = ? 10v ????? i d ? = ? 30a ????? r g ? = ? 10m ? f ? = ? 10hz ???????????? e n ? voltage ? \\? 20 ? 70 ? nv/ hz ? ???? v dg ? = ? 10v ????? i d ? = ? 30a ?????? f ? = ? 10hz ??? ? ? \\? 10 ? \\? ? ???? v dg ?? = ? 10v ???? i d ? = ? 30a ?????? f ? = ? 1khz ??? ? c iss ? capacitance ? input ? ? \\? ? \\? ? 3.0 ? ? pf ? ? v ds = ? 10v ??????? v gs = ? 0 ????? f ? = ? 1mhz ? c rss ? reverse ? transfer ? \\? \\? 1.5 ? pf ?? the u421 is a high input impedance monolithic dual n-channel jfet u421 high input impedance monolithic dual n-channel jfet available packages: u421 in to-71 & to-78 u421 in pdip & soic u421 available as bare die please contact micross for full package and die dimensions email: chipcomponents@micross.com u421 applications: ? ultra low input current differential amps ? high-speed comparators ? impedance converters the u421 monolithic dual n-channel jfet is designed to provide very high input impedance for differential amplification and impedance matching. among its many unique features, this series offers operating gate current specified at -250 fa. the u421 is a direct replacement for discontinued siliconix u421. the hermetically sealed to-71 & to-78 packages are well suited for military applications. the 8 pin p-dip and 8 pin soic provide ease of manufacturing, and the symmetrical pinout prevents improper orientation. (see packaging information). linear s y stems re p laces discontinued siliconix u421 to-71 / to-78 (top view) p-dip / soic (top view) note 1 ? these ratings are limiting values above which the serviceability of any semiconductor may be impaired
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