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el2176c/EL2276C december 1995, rev b el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable note: all information contained in this data sheet has been carefully checked and is believed to be accurate as of the date of publication; however, this data sheet cannot be a ``controlled document''. current revisions, if any, to these specifications are maintained at the factory and are available upon your request. we recommend checking the revision level before finalization of your design documentation. ? 1995 elantec, inc. features # single (el2176c) and dual (EL2276C) topologies # 1 ma supply current (per amplifier) # 70 mhz b 3 db bandwidth # low cost # fast disable # powers down to 0 ma # single- and dual-supply operation down to g 1.5v # 0.15%/0.15 diff. gain/diff. phase into 150 x # 800v/ m s slew rate # large output drive current: 100 ma (el2176c) 55 ma (EL2276C) # also available without disable in single (el2170c), dual (el2270c) and quad (el2470c) # higher speed el2180c/el2186c family also available (3 ma/ 250 mhz) in single, dual and quad applications # low power/battery applications # hdsl amplifiers # video amplifiers # cable drivers # rgb amplifiers # test equipment amplifiers # current to voltage converters ordering information part no. temp. range package outline y el2176cn b 40 cto a 85 c 8-pin pdip mdp0031 el2176cs b 40 cto a 85 c 8-pin soic mdp0027 EL2276Cn b 40 cto a 85 c 14-pin pdip mdp0031 EL2276Cs b 40 cto a 85 c 14-pin soic mdp0027 general description the el2176c/EL2276C are single/dual current-feedback oper- ational amplifiers which achieve a b 3 db bandwidth of 70 mhz at a gain of a 1 while consuming only 1 ma of supply current per amplifier. they will operate with dual supplies ranging from g 1.5v to g 6v, or from single supplies ranging from a 3v to a 12v. the el2176c/EL2276C also include a disable/power- down feature which reduces current consumption to 0 ma while placing the amplifier output in a high impedance state. in spite of its low supply current, the EL2276C can output 55 ma while swinging to g 4v on g 5v supplies. the el2176c can output 100 ma with similar output swings. these attributes make the el2176c/EL2276C excellent choices for low power and/or low voltage cable-driver, hdsl, or rgb applications. for single, dual and quad applications without disable, consid- er the el2170c (8-pin single), el2270c (8-pin dual) or el2470c (14-pin quad). for higher bandwidth applications where low power is still a concern, consider the el2180c/ el2186c family which also comes in similar single, dual and quad configurations. the el2180c/el2186c family provides a b 3 db bandwidth of 250 mhz while consuming 3 ma of supply current per amplifier. connection diagrams el2176c so, p-dip EL2276C so, p-dip 2176 1 2176 2 manufactured under u.s. patent no. 5,352,989, 5,351,012, 5,418,495
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable absolute maximum ratings (t a e 25 c) voltage between v s a and v s b a 12.6v common-mode input voltage v s b to v s a differential input voltage g 6v current into a in or b in g 7.5 ma internal power dissipation see curves operating ambient temperature range b 40 cto a 85 c operating junction temperature plastic packages 150 c output current (el2176c) g 120 ma output current (EL2276C) g 60 ma storage temperature range b 65 cto a 150 c important note: all parameters having min/max specifications are guaranteed. the test level column indicates the specific device testing actually performed during production and quality inspection. elantec performs most electrical tests using modern high-speed automatic test equipment, specifically the ltx77 series system. unless otherwise noted, all tests are pulsed tests, therefore t j e t c e t a . test level test procedure i 100% production tested and qa sample tested per qa test plan qcx0002. ii 100% production tested at t a e 25 c and qa sample tested at t a e 25 c, t max and t min per qa test plan qcx0002. iii qa sample tested per qa test plan qcx0002. iv parameter is guaranteed (but not tested) by design and characterization data. v parameter is typical value at t a e 25 c for information purposes only. dc electrical characteristics v s e g 5v, r l e 150 x , enable e 0v, t a e 25 c unless otherwise specified parameter description conditions min typ max test units level v os input offset voltage 2.5 15 i mv tcv os average input offset voltage drift measured from t min to t max 5v m v/ c dv os v os matching EL2276C only 0.5 v mv a i in a input current 0.5 5 i m a d a i in a i in matching EL2276C only 20 v na b i in b input current 4 15 i m a d b i in b i in matching EL2276C only 1.5 v m a cmrr common mode rejection ratio v cm e g 3.5 v 45 50 i db b icmr b input current common mode rejection v cm e g 3.5v 4 10 i m a/v psrr power supply rejection ratio v s is moved from g 4v to g 6v 60 70 i db b ipsr b input current power supply rejection v s is moved from g 4v to g 6v 0.5 5 i m a/v r ol transimpedance v out e g 2.5v 150 400 i k x a r in a input resistance v cm e g 3.5v 1 4 i m x a c in a input capacitance 1.2 v pf cmir common mode input range g 3.5 g 4.0 i v 2 td is 3.1in
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable dc electrical characteristics e contd. v s e g 5v, r l e 150 x , enable e 0v, t a e 25 c unless otherwise specified parameter description conditions min typ max test units level v o output voltage swing v s e g 5 g 3.5 g 4.0 i v v s ea 5 single-supply, high 4.0 v v v s ea 5 single-supply, low 0.3 v v i o output current el2176c only 80 100 i ma EL2276C only, per amplifier 50 55 i ma i s supply current enable e 2.0v, per amplifier 1 2 i ma i s(dis) supply current (disabled) enable e 4.5v 0 20 i m a c out(dis) output capacitance (disabled) enable e 4.5v 4.4 v pf r en enable pin input resistance measured at enable e 2.0v, 4.5v 45 85 i k x i ih logic ``1'' input current measured at enable , enable e 4.5v b 0.04 v m a i il logic ``0'' input current measured at enable , enable e 0v b 53 v m a v dis minimum voltage at enable to disable 4.5 i v v en maximum voltage at enable to enable 2.0 i v ac electrical characteristics v s e g 5v, r f e r g e 1.0 k x ,r l e 150 x , enable e 0v, t a e 25 c unless otherwise specified parameter description conditions min typ max test level units b 3dbbw b 3 db bandwidth a v ea 1 70 v mhz b 3dbbw b 3 db bandwidth a v ea 2 60 v mhz sr slew rate v out e g 2.5v, a v ea 2 400 800 iv v/ m s t r ,t f rise and fall time v out e g 500 mv 4.5 v ns t pd propagation delay v out e g 500 mv 4.5 v ns os overshoot v out e g 500 mv 3.0 v % ts 0.1% settling v out e g 2.5v, a v eb 140vns dg differential gain a v ea 2, r l e 150 x (note 1) 0.15 v % dp differential phase a v ea 2, r l e 150 x (note 1) 0.15 v dg differential gain a v ea 1, r l e 500 x (note 1) 0.02 v % dp differential phase a v ea 1, r l e 500 x (note 1) 0.01 v t on turn-on time a v ea 2, v in ea 1v, r l e 150 x (note 2) 40 100 i ns t off turn-off time a v ea 2, v in ea 1v, r l e 150 x (note 2) 1500 2000 i ns cs channel separation EL2276C only, f e 5 mhz 85 v db note 1: dc offset from 0v to 0.714v, ac amplitude 286 mv p-p ,f e 3.58 mhz. note 2: measured from the application of the logic signal until the output voltage is at the 50% point between initial and final values. 3 td is 2.8in td is 2.8in
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable test circuit (per amplifier) 2176 3 simplified schematic (per amplifer) 2176 4 4
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable typical performance curves frequency response (gain) non-inverting 2176 5 frequency response (phase) non-inverting 2176 6 various r f and r g frequency response for 2176 7 response (gain) inverting frequency 2176 8 response (phase) inverting frequency 2176 9 various r l and c l frequency response for 2176 10 transimpedance (r ol ) 2176 11 psrr and cmrr 2176 12 for various c in b frequency response 2176 13 5
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable typical performance curves e contd. noise vs frequency voltage and current 2176 14 distortion vs frequency 2nd and 3rd harmonic 2176 15 vs frequency output voltage 2176 16 various non-inverting gains vs supply voltage for b 3 db bandwith and peaking 2176 17 various inverting gains vs supply voltage for b 3 db bandwith and peaking 2176 18 vs supply voltage output voltage swing 2176 19 voltage supply current vs supply 2176 20 vs supply voltage common-mode input range 2176 21 supply voltage slew rate vs 2176 22 6
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable typical performance curves e contd. die temperature input bias current vs 2176 23 die temperature short-circuit current vs 2176 24 die temperature transimpedance (r ol )vs 2176 25 various non-inverting gains vs die temperature for b 3 db bandwith and peaking 2176 26 various inverting gains vs die temperature for b 3 db bandwith and peaking 2176 27 vs die temperature input offset voltage 2176 28 die temperature supply current vs 2176 29 die temperature input voltage range vs 2176 30 die temperature slew rate vs 2176 31 7
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable typical performance curves e contd. at 3.58 mhz/a v ea 2 phase vs dc input voltage differential gain and 2176 32 at 3.58 mhz/a v ea 1 phase vs dc input offset differential gain and 2176 33 settling accuracy settling time vs 2176 34 small-signal step response 2176 35 large-signal step response 2176 36 maximum power dissipation 8-pin plastic dip vs ambient temperature 2176 37 maximum power dissipation 8-lead so vs ambient temperature 2176 38 8
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable typical performance curves e contd. vs ambient temperature maximum power dissipation 14-pin plastic dip 2176 39 vs ambient temperature maximum power dissipation 14-lead so 2176 40 vs frequency (el2276) channel separation 2176 41 9
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable applications information product description the el2176c/EL2276C are current-feedback op- erational amplifiers that offer a wide b 3db bandwidth of 70 mhz, a low supply current of 1 ma per amplifier and the ability to disable to 0 ma. both products also feature high output current drive. the el2176c can output 100 ma, while the EL2276C can output 55 ma per ampli- fier. the el2176c/EL2276C work with supply voltages ranging from a single 3v to g 6v, and they are also capable of swinging to with in 1v of either supply on the input and the output. be- cause of their current-feedback topology, the el2176c/EL2276C do not have the normal gain- bandwidth product associated with voltage-feed- back operational amplifiers. this allows their b 3 db bandwidth to remain relatively constant as closed-loop gain is increased. this combina- tion of high bandwidth and low power, together with aggressive pricing make the el2176c/ EL2276C the ideal choice for many low-power/ high-bandwidth applications such as portable computing, hdsl, and video processing. for single, dual and quad applications without disable, consider the el2170c (8-pin single), el2270c (8-pin dual) and el2470c (14-pin quad). if more ac performance is required, refer to the el2180c/el2186c family which provides singles, duals, and quads with 250 mhz of bandwidth while consuming 3 ma of supply cur- rent per amplifier. power supply bypassing and printed circuit board layout as with any high-frequency device, good printed circuit board layout is necessary for optimum performance. ground plane construction is high- ly recommended. lead lengths should be as short as possible. the power supply pins must be well bypassed to reduce the risk of oscillation. the combination of a 4.7 m f tantalum capacitor in parallel with a 0.1 m f capacitor has been shown to work well when placed at each supply pin. for good ac performance, parasitic capacitance should be kept to a minimum especially at the inverting input (see the capacitance at the in- verting input section). ground plane construc- tion should be used, but it should be removed from the area near the inverting input to mini- mize any stray capacitance at that node. carbon or metal-film resistors are acceptable with the metal-film resistors giving slightly less peaking and bandwidth because of their additional series inductance. use of sockets, particularly for the so package should be avoided if possible. sock- ets add parasitic inductance and capacitance which will result in some additional peaking and overshoot. disable/power-down the el2176c/EL2276C amplifiers can be dis- abled, placing their output in a high-impedance state. when disabled, each amplifier's supply cur- rent is reduced to 0 ma. each el2176c/ EL2276C amplifier is disabled when its enable pin is floating or pulled up to within 0.5v of the positive supply. similarly, each am- plifier is enabled by pulling its enable pin at least 3v below the positive supply. for g 5v sup- plies, this means that an el2176c/EL2276C am- plifier will be enabled when enable is at 2v or less, and disabled when enable is above 4.5v. although the logic levels are not standard ttl, this choice of logic voltages allows the el2176c/ EL2276C to be enabled by tying enable to ground, even in a 3v single-supply applications. the enable pin can be driven from cmos outputs or open-collector ttl. when enabled, supply current does vary some- what with the voltage applied at enable . for example, with the supply voltages of the el2176c at g 5v, if enable is tied to b 5v (rather than ground) the supply current will in- crease about 15% to 1.15 ma. capacitance at the inverting input any manufacturer's high-speed voltage- or cur- rent-feedback amplifier can be affected by stray capacitance at the inverting input. for inverting gains this parasitic capacitance has little effect because the inverting input is a virtual ground, but for non-inverting gains this capacitance (in conjunction with the feedback and gain resistors) creates a pole in the feedback path of the amplifi- er. this pole, if low enough in frequency, has the same destabilizing effect as a zero in the forward open-loop response. the use of large value feed- 10
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable applications information e contd. back and gain resistors further exacerbates the problem by further lowering the pole frequency. the el2176c/EL2276C have been specially de- signed to reduce power dissipation in the feed- back network by using large 1.0 k x feedback and gain resistors. with the high bandwidths of these amplifiers, these large resistor values would nor- mally cause stability problems when combined with parasitic capacitance, but by internally can- celing the effects of a nominal amount of parasit- ic capacitance, the el2176c/EL2276C remain very stable. for less experienced users, this fea- ture makes the el2176c/EL2276C much more forgiving, and therefore easier to use than other products not incorporating this proprietary cir- cuitry. the experienced user with a large amount of pc board layout experience may find in rare cases that the el2176c/el2276 c have less band- width than expected. in this case, the inverting input may have less parasitic capacitance than expected by the internal compensation circuitry of the el2176c/EL2276C. the reduction of feed- back resistor values (or the addition of a very small amount of external capacitance at the in- verting input, e.g., 0.5 pf) will increase band- width as desired. please see the curves for fre- quency response for various r f and r g , and frequency response for various c in b . feedback resistor values the el2176c/EL2276C have been designed and specified at gains of a 1 and a 2 with r f e 1.0 k x . this value of feedback resistor gives 70 mhz of b 3 db bandwidth at a v ea 1 with about 1.5 db of peaking, and 60 mhz of b 3db bandwidth at a v ea 2 with about 0.5 db of peaking. since the el2176c/EL2276C are cur- rent-feedback amplifiers, it is also possible to change the value of r f to get more bandwidth. as seen in the curve of frequency response for various r f and r g , bandwidth and peaking can be easily modified by varying the value of the feedback resistor. because the el2176c is a current-feedback am- plifier, the gain-bandwidth product is not a con- stant for different closed-loop gains. this feature actually allows the el2176c/EL2276C to main- tain about the same b 3 db bandwidth, regard- less of closed-loop gain. however, as closed-loop gain is increased, bandwidth decreases slightly while stability increases. since the loop stability is improving with higher closed-loop gains, it becomes possible to reduce the value of r f below the specified 1.0 k x and still retain stability, resulting in only a slight loss of bandwidth with increased closed-loop gain. supply voltage range and single- supply operation the el2176c/EL2276C have been designed to operate with supply voltages having a span of greater than 3v, and less than 12v. in practical terms, this means that the el2176c/EL2276C will operate on dual supplies ranging from g 1.5v to g 6v. with a single-supply, the el2176c will operate from a 3v to a 12v. as supply voltages continue to decrease, it be- comes necessary to provide input and output voltage ranges that can get as close as possible to the supply voltages. the el2176c/EL2276C have an input voltage range that extends to with- in 1v of either supply. so, for example, on a sin- gle a 5v supply, the el2176c/EL2276C have an input range which spans from 1v to 4v. the out- put range of the el2176c /EL2276C is also quite large, extending to within 1v of the supply rail. on a g 5v supply, the output is therefore capable of swinging from b 4v to a 4v. single-supply output range is even larger because of the in- creased negative swing due to the external pull- down resistor to ground. on a single a 5v sup- ply, output voltage range is about 0.3v to 4v. video performance for good video performance, an amplifier is re- quired to maintain the same output impedance and the same frequency response as dc levels are changed at the output. this is especially difficult when driving a standard video load of 150 x , be- cause of the change in output current with dc level. until the el2176c/EL2276C, good differ- ential gain could only be achieved by running high idle currents through the output transistors (to reduce variations in output impedance). these currents were typically in excess of the 11
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable applications information e contd. entire 1 ma supply current of each el2176c/ EL2276C amplifier! special circuitry has been in- corporated in the el2176c/EL2276C to reduce the variation of output impedance with current output. this results in dg and dp specifications of 0.15% and 0.15 while driving 150 x at a gain of a 2. video performance has also been measured with a 500 x load at a gain of a 1. under these condi- tions, the el2176c/EL2276C have dg and dp specifications of 0.01% and 0.02 respectively while driving 500 x at a v ea 1. output drive capability in spite of its low 1 ma of supply current, the el2176c is capable of providing a minimum of g 80 ma of output current. similarly, each am- plifier of the EL2276C is capable of providing a minimum of g 50 ma. these output drive levels are unprecedented in amplifiers running at these supply currents. with a minimum g 80 ma of output drive, the el2176c is capable of driving 50 x loads to g 4v, making it an excellent choice for driving isolation transformers in telecommu- nications applications. similarly, the g 50 ma minimum output drive of each EL2276C amplifi- er allows swings of g 2.5v into 50 x loads. driving cables and capacitive loads when used as a cable driver, double termination is always recommended for reflection-free per- formance. for those applications, the back-termi- nation series resistor will decouple the el2176c/ EL2276C from the cable and allow extensive ca- pacitive drive. however, other applications may have high capacitive loads without a back-termi- nation resistor. in these applications, a small se- ries resistor (usually between 5 x and 50 x ) can be placed in series with the output to eliminate most peaking. the gain resistor (r g ) can then be cho- sen to make up for any gain loss which may be created by this additional resistor at the output. in many cases it is also possible to simply in- crease the value of the feedback resistor (r f )to reduce the peaking. current limiting the el2176c/EL2276C have no internal cur- rent-limiting circuitry. if any output is shorted, it is possible to exceed the absolute maximum ratings for output current or power dissipation, potentially resulting in the destruction of the de- vice. power dissipation with the high output drive capability of the el2176c/EL2276C, it is possible to exceed the 150 c absolute maximum junction temperature under certain very high load current conditions. generally speaking, when r l falls below about 25 x , it is important to calculate the maximum junction temperatu re (t jmax ) for the application to determine if power-supply voltages, load con- ditions, or package type need to be modified for the el2176c/EL2276C to remain in the safe op- erating area. these parameters are calculated as follows: t jmax e t max a ( i ja * n * pd max ) [ 1 ] where: t max e maximum ambient temperature i ja e thermal resistance of the package n e number of amplifiers in the pack- age pd max e maximum power dissipation of each amplifier in the package. pd max for each amplifier can be calculated as follows: pd max e (2 * v s * i smax ) a (v s b v outmax ) * (v outmax /r l )) [ 2 ] where: v s e supply voltage i smax e maximum supply current of 1 amplifier v outmax e max. output voltage of the ap- plication r l e load resistance 12
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable typical application circuits low power multiplexer with single-ended ttl input 2176 42 13
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable typical application circuits e contd. inverting 200 ma output current distribution amplifier 2176 43 14
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable typical application circuits e contd. differential line-driver/receiver 2176 44 15
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable typical application circuits e contd. fast-settling precision amplifier 2176 45 16
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable el2176c/EL2276C macromodel * revision a, march 1995 * transimpedance stage * ac characteristics used rf e rg e 1k x ,rl e 150 x * * connections: a input g1 0 18 17 0 1.0 * l b input rol 18 0 400k * ll a vsupply cdp 18 0 1.9pf * lll b vsupply * * llll output * output stage * lllll * .subckt el2176/el 32746 q141819qp * q271820qn * input stage q3 7 19 21 qn * q442022qp e1100301.0 r72164 vis1090v r82264 h2 9 12 vxx 1.0 ios1 7 19 0.4ma r1 2 11 165 ios2 20 4 0.4ma l1 11 12 25nh * iinp 3 0 0.5ua * supply current iinm 2 0 4ua * r12 3 0 4meg ip s741na ** * slew rate limiting * error terms ** h1 13 0 vis 600 ivos 0 23 2ma r2 13 14 1k vxx 23 0 0v d1 14 0 dclamp e4 2 40301.0 d2 0 14 dclamp e5 2 50701.0 * e626040 b 1. 0 * high frequency pole r9 24 23 0.316k * r10 25 23 3.2k e2 30 0 14 0 0.00166666666 r11 26 23 3.2k l3 30 17 0.5uh * c5 17 0 0.69pf * models r5 17 0 300 * * .model qn npn(is e 5e-15 bf e 200 tf e 0.01ns) .model qp pnp(is e 5e-15 bf e 200 tf e 0.01ns) .model dclamp d(is e 1e-30 ibv e 0.266 a bv e 1.3v n e 4) .ends 17 td is 5.2in
el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable el2176c/EL2276C macromodel e contd. 2176 46 18
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el2176c/EL2276C december 1995, rev b el2176c/EL2276C 70 mhz/1 ma current mode feedback amp w/disable general disclaimer specifications contained in this data sheet are in effect as of the publication date shown. elantec, inc. reserves the right to make changes in the circuitry or specifications contained herein at any time without notice. elantec, inc. assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement. elantec, inc. 1996 tarob court milpitas, ca 95035 telephone: (408) 945-1323 (800) 333-6314 fax: (408) 945-9305 european office: 44-71-482-4596 warning e life support policy elantec, inc. products are not authorized for and should not be used within life support systems without the specific written consent of elantec, inc. life support systems are equipment in- tended to support or sustain life and whose failure to perform when properly used in accordance with instructions provided can be reasonably expected to result in significant personal injury or death. users contemplating application of elantec, inc. products in life support systems are requested to contact elantec, inc. factory headquarters to establish suitable terms & conditions for these applications. elantec, inc.'s warranty is limited to replace- ment of defective components and does not cover injury to per- sons or property or other consequential damages. printed in u.s.a. 20

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