IT358 infinitrue technology 1/8 e c t r o n i c s w i t h o u t r e q u i r i ng the additional=15vpower supplies. n i q u e c h a r a c t e r i s t i c s o m m on-m ode voltage range includes ground and the r o s s f r e q u e n c y i s t e m p erature com p ensated l y c o m p e n s a t e d o p a m p s . out also goes to gnd. low power dual opera t ional amplifier i t 3 5 8 description the IT358 consists of two independent ,high gain ,internally frequency com p ensated operational amplifiers which were designed specifically to operate from a single power supply over a wide range of voltages.operation from split power supplies is also possible and the low power supply current drain is independent of the m a gnitude of the power supply voltage. application areas include transducer amplifiers. dc agin blocks and all the conventional op am p circuits which now can be more easily . im plem ented in single power supply system s.for exam ple,the IT358 can be directly operated of f of the standard -5vpower supply voltage which is used in digital systems and will easily provide the required i n t e r f a c e e l u in the linear m o d e t h e i n p u t c output voltage can also swing to grou nd .,even though operate d from onl y a single power supply voltage t h e u n i t y g a i n c the input bias current is also tem p erature com p ensated. adv ant ages t w o i n t e r n a l eliminates need for dual supplies. d v a l l o w s d i r e c t s e n s i n g n e a r g n d a n compatible with all forms of logic. r a t i o n p o w e r d r a i n s u i t a b l e f o r b a t t e r y o p e www..net
IT358 infinitrue technology 2/8 features z internally frequency comp ensated for unity gain z large dc voltage gain: 100 db z wide bandwidth (unity gain): 1 mhz (temperature compensated) z wide power supply range: ? single supply: 3v to 32v ? or dual supplies: 1.5v to 16v z very low supply current drain (500 a)?essentially independent of supply voltage. z low input offset voltage: 2 mv z input common-mode voltage range includes ground z differential input voltage range equal to the power supply voltage z large output voltage swing: 0v to v+- 1.5v block diagram and pin connection absolute maximum ratings (ta=25 c) characteristic value unit supply voltage,v + 32 ? 16 v differential input voltage 32 v input voltage -0.3~32 v dip package 550 power dissipation (note 1) sop package 530 mw output short-circuit to gnd ? one amplifier ? ? note 2 ? ? v + 15v ? ta=25 ??? continuous input current ? v in <-0.3v ? (note 3) 50 ma operating temperature range -25~85 ?? storage temperature range -65~150 ?? a + - b + - 1 2 3 4 5 6 7 8 output a inverting input a non-inverting input a gnd v+ output b inverting input b non-inverting input b www..net
IT358 infintrue technology 3/8 electrical characteristics (unless otherwise specified: v + =5.0v) parameter test conditions min. typ. max. unit input offset voltage ta=25 ??? note 5 ? 2 5 mv input bias current ta=25 ?? , i in(+) or i in ? - ? , v cm =0v ? note 6 ? 45 150 na input offset current ta=25 ??? i in(+) - i in ? - ? ? v cm =0v 3 30 na input common-mode voltage range ta=25 ??? v + =30v ? note 7 ? 0 v + -1.5 v v + =30v 1 2 supply current over full temperature range, r l = f on all op amps v + =5v 0.5 1.2 ma large signal voltage gain v + =15v ? ta=25 ??? r l t 2k : ? for vo=1~11v ? 50 100 v/mv common-mode rejection ratio dc ? ta=25 ??? v cm =0~v + -1.5v 70 85 db power supply rejection ratio dc ? ta=25 ??? v + =5~30v 65 100 db amplifier-to-amplifier coupling ta=25 ??? f=1~20khz ? input referred ? ? note 8 ? -120 db source v in(+) =1v,v in(-) =0v,v + =15v,vo=2v, ta=25 ?? 20 40 ma v in(-) =1v,v in(+) =0v,v + =15v,vo=2v, ta=25 ?? 10 20 ma output current sink v in(-) =1v,v in(+) =0v,v + =15v, vo=200mv,ta=25 ?? 12 50 p a short circuit to ground v + =15v ? ta=25 ??? note 2 ? 40 60 ma input offset voltage ? note 5 ? 7 mv input offset voltage drift rs=0 : 7 p v/ ?? input offset current i in(+) - i in ? - ? 100 na input offset current drift rs=0 : 10 pa/ ?? input bias current i in(+) or i in ? - ? 40 300 na input common-mode voltage range v + =30v ? note 7 ? 0 v + -2 v large signal voltage gain v + =15v ? ? vo = 1 ~ 11 v ? ? r l t 2k : 25 v/mv r l =2k : 26 v v oh v + =30v r l =10k : 27 28 v output voltage swing v ol v + =5v ? r l =10k : 5 20 mv source v in(+) =1v ? v in(-) =0v ? v + =15v ? vo = 2 v 10 20 ma output current sink v in(-) =1v ? v in(+) =0v ? v + =15v ? vo = 2 v 5 8 ma www..net
IT358 infinitrue technology 4/8 note 1 the dissipation is the total of both amplifiers?us e external resistors, where possible, to allow the amplifier to saturate or to reduce the power which is dissipated in the integrated circuit. note 2: short circuits from the output to v + can cause excessive heating and eventual destruction. when considering short circuits to ground, th e maximum output current is approximately 40ma independent of the magnitude of v + . at values of supply voltage in excess of +15v, continuous short-circuits can exceed the power dissipation ratings and cause eventual destruction. destructive dissipation can result from simultane ous shorts on all amplifiers. note 3: this input current will only exist when the voltage at any of the input leads is driven negative. it is due to the collector-base junction of the input pnp transistors becoming forward biased and thereby acting as input diode clamps. in addition to th is diode action, there is also lateral npn parasitic transistor action on the ic chip. this transistor ac tion can cause the output vo ltages of the op amps to go to the v + voltage level (or to ground for a large overd rive) for the time duration that an input is driven negative. this is not destructive and nor mal output states will re-establish when the input voltage, which was negative, again returns to a value greater than -0.3v (at 25c). note 4: with the IT358, all temperature specifications are limited to -25?? d ta d 85?? . note 5: vo=1.4v, rs = 0 : with v + from 5v to 30v; and over the full input common-mode range (0v to v + -1.5v) at 25c note 6: the direction of the input current is out of the ic due to the pnp input stage. this current is essentially constant, independent of the state of the output so no loading change exists on the input lines. note 7: the input common-mode voltage of either input signal voltage should not be allowed to go negative by more than 0.3v (at 25c). the upper end of them common-mode voltage range is v + -1.5v (at 25c), but either or both inputs can go to +32v without damage, independent of the magnitude of v + . note 8: due to proximity of external components, insu re that coupling is not originating via stray capacitance between these external parts. this typica lly can be detected as this type of capacitance increases at higher frequencies. www..net
IT358 infinitrue technology 5/8 typical single-supply application circuit r1 10k r2 1m +v + - 1/2 IT358 +vo in * * r not needed due to temperature independent i in vo(v) +5v 0 v (mv) in gain=1+r2/r1 =101 as shown ?? non-inverting dc gain 0v output ?? + - 1/2 IT358 +vo + - +vo r2 100k r3 91k r1 910k r 100k r 100k r 100k r 100k rl +v in v + +v 1 +v 2 r 100k r 100k +v 3 +v 4 1/2 IT358 where :vo=v1+v2+v3+v4 (v1+v2) ? in dc summing amplifier v ? po w er amplifier in' s + - 1/2 IT358 r1 2k r2 r3 2k r4 3k + - 2v v + + - 2v i1 i2 1ma i2=(r1/r2)*i1 fix ed current s ources + - 1/2 IT358 + - 1/2 IT358 + - 1/2 IT358 c2 330pf r6 470k r3 100k r2 100k r4 10m r1 100k c1 330pf r5 470k r8 100k c3 10uf v in vo v + r7 100k fo=1khz q=50 av =1 00 (40 db) "bi-quad" rc active bandpass filter www..net
IT358 infintrue technology 6/8 application hints the it35 8 is op amps which operate with only a single power supply voltage, have true-differential inputs, and remain in the linear mode with an input common-mode voltage of 0v. these amplifiers operate over a wide range of power supply voltage with little change in performance characteristics. at 25c amplifier operation is possible down to a minimum supply voltage of 2.3 v. precautions should be taken to insure that the power supply for the integrated circuit never becomes reversed in polarity or that the unit is not inadvertently installed backwards in a test socket as an unlimited current surge through the resulting forward diode within the ic could cause fusing of the internal conductors and result in a destroyed unit. large differential input voltages can be easil y accommodated and, as input differential voltage protection diodes are not needed, no large input currents result from large differential input voltages. the differential input voltage may be larger than v + without damaging the device. protection should be provided to prevent the input voltages from going negative more than -0.3v (at 25c). an input clamp diode with a resistor to the ic input terminal can be used. to reduce the power supply current drain, the amplifiers have a class a output stage for small signal levels which converts to class b in a large signal mode. this allows the amplifiers to both source and sink large output currents. therefore both npn and pnp external current boost transistors can be used to extend the power capability of the basic amplifiers. the output voltage needs to raise approximately 1 diode drop above ground to bias the on-chip vertical pnp transistor for output current sinking applications. for ac applications, where the load is capacitive ly coupled to the outp ut of the amplifier, a resistor should be used, from the output of the amplifier to ground to increase the class a bias current and prevent crossover distortion. wh ere the load is direc tly coupled, as in dc applications, there is no crossover distortion. capacitive loads which are applied directly to the output of the am plifier reduce the loop stability margin. values of 50pf can be accomodated using the worst-case non-inverting unity gain connection. large closed loop gains or resistive isolation should be used if larger load capacitance must be driven by the amplifier. output short circuits either to ground or to the positive power supply should be of short time duration. units can be destroyed, not as a result of the short circuit current causing metal fusing, but rather due to the large increase in ic chip dissipation which will cause eventual failure due to excessive function te mperatures. putting direct short-circuits on more than one amplifier at a time will increase the total ic power dissipation to destructive levels, if not properly protected with external dissipation limiting resistors in series with the output leads of the amplifiers. the larger value of output source current which is available at 25c provides a larger output curren t capability at elevated temperatures (see typical performance characteristics) than a standard ic op amp. www..net
IT358 infinitrue technology 7/8 typical performanc e characteristics www..net
IT358 infintrue technology 8/8 www..net
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