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lt1999-10/lt1999-20/ lt1999-50 1 1999fd for more information www.linear.com/lt1999 typical application features description high voltage, bidirectional current sense amplifier the lt ? 1999 is a high speed precision current sense am- plifier, designed to monitor bidirectional currents over a wide common mode range. the lt1999 is offered in three gain options: 10v/v, 20v/v, and 50v/v. the lt1999 senses current via an external resistive shunt and generates an output voltage, indicating both magnitude and direction of the sensed current. the output voltage is referenced halfway between the supply voltage and ground , or an external voltage can be used to set the reference level. with a 2 mhz bandwidth and a common mode input range of C5 v to 80 v, the lt1999 is suitable for monitor - ing currents in h-bridge motor controls, switching power supplies, solenoid currents, and battery charge currents from full charge to depletion. the lt1999 operates from an independent 5 v supply and draws 1.55 ma. a shutdown mode is provided for minimizing power consumption. the lt1999 is available in an 8- lead sop, an 8- lead msop (original pinout), or an 8- lead pinout option engineered for fmea. l , lt , lt c , lt m , linear technology and the linear logo are registered trademarks of linear technology corporation. all other trademarks are the property of their respective owners. applications n buffered output with 3 gain options: 10v/v, 20v/v, 50v/v n gain accuracy: 0.5% max n input common mode voltage range: ?5v to 80v n ac cmrr > 80db at 100khz n input offset voltage: 1.5mv max n C3db bandwidth: 2mhz n smooth, continuous operation over entire common mode range n 4kv hbm tolerant and 1kv cdm tolerant n low power shutdown <10a n C55c to 150c operating temperature range n 8-lead msop and 8-lead so (narrow) packages n 8-lead msop pinout option engineered for fmea n high side or low side current sensing n h-bridge motor control n solenoid current sense n high voltage data acquisition n pwm control loops n fuse/mosfet monitoring full bridge armature current monitor time (10s/div) 2.5v v out (2v/div) v +in (20v/div) 1999 ta01b v out v +in lt1999 4k 0.8k 160k160k 2a 0.8k 4k shdn 5v v + v + v + 5v r s 1999 ta01a +C +C v s 8 12 3 4 76 5 0.1f 0.1f v out r g v +in v Cin v ref v shdn v + v + downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 2 1999fd for more information www.linear.com/lt1999 absolute maximum ratings differential input voltage + in to C in ( notes 1, 3) ................................. 60 v , 10 ms + in to gnd , C in to gnd ( note 2) ............. C5.25 v to 88 v total supply voltage (v + to gnd ) ................................ 6v input voltage pins 6 and 8 ................... v + + 0.3 v , C0.3 v output short - circuit duration ( note 4) ............ indefinite operating ambient temperature ( note 5) lt 1999 c .............................................. C 40 c to 85 c lt 1999 i ................................................ C 40 c to 85 c lt 1999 h ............................................ C 40 c to 125 c lt 1999 mp ......................................... C55 c to 150 c (note 1) original msop pinout 12 3 4 v + +inCin v + 87 6 5 shdnout ref gnd top view ms8 package 8-lead plastic msop t jmax = 150c, ja = 300c/w msop pinout engineered for fmea 12 3 4 +inCin nc v + 87 6 5 shdnout ref gnd top view ms8 package 8-lead plastic msop t jmax = 150c, ja = 300c/w 12 3 4 87 6 5 top view shdnout ref gnd v + +inCin v + s8 package 8-lead plastic so t jmax = 150c, ja = 190c/w pin configuration order information lead free finish tape and reel part marking* package description specified temperature range lt1999cms8-10#pbf lt1999cms8-10#trpbf ltfpb 8-lead plastic msop 0c to 70c lt1999ims8-10#pbf lt1999ims8-10#trpbf ltfpb 8-lead plastic msop C40c to 85c lt1999hms8-10#pbf lt1999hms8-10#trpbf ltfpb 8-lead plastic msop C40c to 125c lt1999mpms8-10#pbf lt1999mpms8-10#trpbf ltfqp 8-lead plastic msop C55c to 150c lt1999cms8-10f#pbf lt1999cms8-10f#trpbf ltgvb 8-lead msop fmea pinout 0c to 70c lt1999ims8-10f#pbf lt1999ims8-10f#trpbf ltgvb 8-lead msop fmea pinout C40c to 85c lt1999hms8-10f#pbf lt1999hms8-10f#trpbf ltgvb 8-lead msop fmea pinout C40c to 125c lt1999mpms8-10f#pbf lt1999mpms8-10f#trpbf ltgvb 8-lead msop fmea pinout C55c to 150c lt1999cs8-10#pbf lt1999cs8-10#trpbf 199910 8-lead plastic so 0c to 70c lt1999is8-10#pbf lt1999is8-10#trpbf 199910 8-lead plastic so C40c to 85c lt1999hs8-10#pbf lt1999hs8-10#trpbf 199910 8-lead plastic so C40c to 125c lt1999mps8-10#pbf lt1999mps8-10#trpbf 99mp10 8-lead plastic so C55c to 150c lt1999cms8-20#pbf lt1999cms8-20#trpbf ltfnz 8-lead plastic msop 0c to 70c lt1999ims8-20#pbf lt1999ims8-20#trpbf ltfnz 8-lead plastic msop C40c to 85c lt1999hms8-20#pbf lt1999hms8-20#trpbf ltfnz 8-lead plastic msop C40c to 125c lt1999mpms8-20#pbf lt1999mpms8-20#trpbf ltfqq 8-lead plastic msop C55c to 150c specified temperature range ( note 6) lt 1999 c .................................................. 0 c to 70 c lt 1999 i ................................................ C 40 c to 85 c lt 1999 h ............................................ C 40 c to 125 c lt 1999 mp ......................................... C55 c to 150 c junction temperature ........................................... 150 c storage temperature range .................. C65 c to 150 c downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 3 1999fd for more information www.linear.com/lt1999 electrical characteristics the l denotes the specifications which apply over the full operating temperature range , 0 c < t a < 70 c for c- grade parts , ?40 c < t a < 85 c for i- grade parts, and ?40 c < t a < 125 c for h- grade parts, otherwise specifications are at t a = 25 c . v + = 5 v , gnd = 0 v , v cm = 12 v , v ref = floating, v shdn = floating, unless otherwise specified. see figure 2. lead free finish tape and reel part marking* package description specified temperature range lt1999cms8-20f#pbf lt1999cms8-20f#trpbf ltgvc 8-lead msop fmea pinout 0c to 70c lt1999ims8-20f#pbf lt1999ims8-20f#trpbf ltgvc 8-lead msop fmea pinout C40c to 85c lt1999hms8-20f#pbf lt1999hms8-20f#trpbf ltgvc 8-lead msop fmea pinout C40c to 125c lt1999mpms8-20f#pbf lt1999mpms8-20f#trpbf ltgvc 8-lead msop fmea pinout C55c to 150c lt1999cs8-20#pbf lt1999cs8-20#trpbf 199920 8-lead plastic so 0c to 70c lt1999is8-20#pbf lt1999is8-20#trpbf 199920 8-lead plastic so C40c to 85c lt1999hs8-20#pbf lt1999hs8-20#trpbf 199920 8-lead plastic so C40c to 125c lt1999mps8-20#pbf lt1999mps8-20#trpbf 99mp20 8-lead plastic so C55c to 150c lt1999cms8-50#pbf lt1999cms8-50#trpbf ltfpc 8-lead plastic msop 0c to 70c lt1999ims8-50#pbf lt1999ims8-50#trpbf ltfpc 8-lead plastic msop C40c to 85c lt1999hms8-50#pbf lt1999hms8-50#trpbf ltfpc 8-lead plastic msop C40c to 125c lt1999mpms8-50#pbf lt1999mpms8-50#trpbf ltfqr 8-lead plastic msop C55c to 150c lt1999cms8-50f#pbf lt1999cms8-50f#trpbf ltgvd 8-lead msop fmea pinout 0c to 70c lt1999ims8-50f#pbf lt1999ims8-50f#trpbf ltgvd 8-lead msop fmea pinout C40c to 85c lt1999hms8-50f#pbf lt1999hms8-50f#trpbf ltgvd 8-lead msop fmea pinout C40c to 125c lt1999mpms8-50f#pbf lt1999mpms8-50f#trpbf ltgvd 8-lead msop fmea pinout C55c to 150c lt1999cs8-50#pbf lt1999cs8-50#trpbf 199950 8-lead plastic so 0c to 70c lt1999is8-50#pbf lt1999is8-50#trpbf 199950 8-lead plastic so C40c to 85c lt1999hs8-50#pbf lt1999hs8-50#trpbf 199950 8-lead plastic so C40c to 125c lt1999mps8-50#pbf lt1999mps8-50#trpbf 99mp50 8-lead plastic so C55c to 150c consult lt c marketing for parts specified with wider operating temperature ranges . * the temperature grade is identified by a label on the shipping container . consult lt c marketing for information on non-standard lead based finish parts. for more information on lead free part marking, go to: http://www.linear.com/leadfree/ for more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ order information symbol parameter conditions min typ max units v sense full-scale input sense voltage (note 7) v sense = v +in C v Cin lt1999-10 lt1999-20 lt1999-50 l l l C0.35 C0.2 C0.08 0.35 0.2 0.08 v v v v cm cm input voltage range l C5 80 v r in(diff) differential input impedance v indiff = 2v/gain l 6.4 8 9.6 k r incm cm input impedance v cm = 5.5v to 80v v cm = C5v to 4.5v l l 5 3.6 20 4.8 6 m k v osi input referred voltage offset l C750 C1500 500 750 1500 v v v osi /t input referred voltage offset drift 5 v/c a v gain lt1999-10 lt1999-20 lt1999-50 l l l 9.95 19.9 49.75 10 20 50 10.05 20.1 50.25 v/v v/v v/v a v error gain error v out = 2v l C0.5 0.2 0.5 % downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 4 1999fd for more information www.linear.com/lt1999 electrical characteristics the l denotes the specifications which apply over the full operating temperature range , 0 c < t a < 70 c for c- grade parts , ?40 c < t a < 85 c for i- grade parts, and ?40 c < t a < 125 c for h- grade parts, otherwise specifications are at t a = 25 c . v + = 5 v , gnd = 0 v , v cm = 12 v , v ref = floating, v shdn = floating, unless otherwise specified. see figure 2. symbol parameter conditions min typ max units i b input bias current i(+in) = i(Cin) (note 8) v cm > 5.5v v cm = C5v v shdn = 0.5v, 0v < v cm < 80v l l l 100 C2.35 137.5 C1.95 0.001 175 C1.5 2.5 a ma a i os input offset current i os = i(+in) C i(Cin) (note 8) v cm > 5.5v v cm = C5v v shdn = 0.5v, 0v < v cm < 80v l l l C1 C10 C2.5 1 10 2.5 a a a psrr supply rejection ratio v + = 4.5v to 5.5v l 68 77 db cmrr sense input common mode rejection v cm = C5v to 80v v cm = C5v to 5.5v v cm = 12v, 7v p-p , f = 100khz, v cm = 0v, 7v p-p , f = 100khz l l l l 96 96 75 80 105 120 90 100 db db db db e n differential input referred noise voltage density f = 10khz f = 0.1hz to 10hz 97 8 nv/ hz v p-p ref rr ref pin rejection, v + = 5.5v v ref = 3.0v v ref = 3.25v v ref = 3.25v lt1999-10 lt1999-20 lt1999-50 l l l 62 62 62 70 70 70 db db db r ref ref pin input impedance v shdn = 0.5v l l 60 0.15 80 0.4 100 0.65 k m v ref open circuit voltage v shdn = 0.5v l l 2.45 1 2.5 2.5 2.55 2.75 v v v refr ref pin input range (note 9) lt1999-10 lt1999-20 lt1999-50 l l l 1.25 1.125 1.125 v + C 1.25 v + C 1.125 v + C 1.125 v v v i shdn pin pull-up current v + = 5.5v, v shdn = 0v l C6 C2 a v ih shdn pin input high l v + C 0.5 v v il shdn pin input low l 0.5 v f 3db small signal bandwidth lt1999-10 lt1999-20 lt1999-50 2 2 1.2 mhz mhz mhz sr slew rate 3 v/s t s settling time due to input step, v out = 2v 0.5% settling 2.5 s t r common mode step recovery time v cm = 50v, 20ns (note 10) lt1999-10 lt1999-20 lt1999-50 0.8 1 1.3 s s s v s supply voltage (note 11) l 4.5 5 5.5 v i s supply current v cm > 5.5v v cm = C5v v + = 5.5v, v shdn = 0.5v, v cm > 0v l l l 1.55 5.8 3 1.9 7.1 10 ma ma a r o output impedance i o = 2ma 0.15 i src sourcing output current r load = 50 to gnd l 6 31 40 ma i snk sinking output current r load = 50 to v + l 15 26 40 ma v out swing output high (with respect to v + ) r load = 1k to mid-supply r load = open l l 125 5 250 125 mv mv swing output low (with respect to v C ) r load = 1k to mid-supply r load = open l l 250 150 400 225 mv mv t on turn-on time v shdn = 0v to 5v 1 s t off turn-off time v shdn = 5v to 0v 1 s downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 5 1999fd for more information www.linear.com/lt1999 electrical characteristics the l denotes the specifications which apply over the full operating temperature range, ?55c < t a < 150c for mp-grade parts, otherwise specifications are at t a = 25c. v + = 5v, gnd = 0v, v cm = 12v, v ref = floating, v shdn = floating, unless otherwise specified. see figure 2. symbol parameter conditions min typ max units v sense full-scale input sense voltage (note 7) v sense = v +in C v Cin lt1999-10 lt1999-20 lt1999-50 l l l C0.35 C0.2 C0.08 0.35 0.2 0.08 v v v v cm cm input voltage range l C5 80 v r in(diff) differential input impedance v indiff = 2v/gain l 6.4 8 9.6 k r incm cm input impedance v cm = 5.5v to 80v v cm = C5v to 4.5v l l 5 3.6 20 4.8 6 m k v osi input referred voltage offset l C750 C2000 500 750 2000 v v v osi /t input referred voltage offset drift 8 v/c a v gain lt1999-10 lt1999-20 lt1999-50 l l l 9.95 19.9 49.75 10 20 50 10.05 20.1 50.25 v/v v/v v/v a v error gain error v out = 2v l C0.5 0.2 0.5 % i b input bias current i(+in) = i(Cin) (note 8) v cm > 5.5v v cm = C5v v shdn = 0.5v, 0v < v cm < 80v l l l 100 C2.35 137.5 C1.95 0.001 180 C1.5 10 a ma a i os input offset current i os = i(+in) C i(Cin) (note 8) v cm > 5.5v v cm = C5v v shdn = 0.5v, 0v < v cm < 80v l l l C1 C10 C10 1 10 10 a a a psrr supply rejection ratio v + = 4.5v to 5.5v l 68 77 db cmrr sense input common mode rejection v cm = C5v to 80v v cm = C5v to 5.5v v cm = 12v, 7v p-p , f = 100khz, v cm = 0v, 7v p-p , f = 100khz l l l l 96 96 75 80 105 120 90 100 db db db db e n differential input referred noise voltage density f= 10khz f = 0.1hz to 10hz 97 8 nv/ hz v p-p ref rr ref pin rejection, v + = 5.5v v ref = 2.75v v ref = 3.25v v ref = 3.25v lt1999-10 lt1999-20 lt1999-50 l l l 62 62 62 70 70 70 db db db r ref ref pin input impedance v shdn = 0.5v l l 60 0.15 80 0.4 100 0.65 k m v ref open circuit voltage v shdn = 0.5v l l 2.45 0.25 2.5 2.5 2.55 2.75 v v v refr ref pin input range (note 9) lt1999-10 lt1999-20 lt1999-50 l l l 1.5 1.125 1.125 v + C 1.25 v + C 1.125 v + C 1.125 v v v i shdn pin pull-up current v + = 5.5v, v shdn = 0v l C6 C2 a v ih shdn pin input high l v + C 0.5 v v il shdn pin input low l 0.5 v f 3db small signal bandwidth lt1999-10 lt1999-20 lt1999-50 2 2 1.2 mhz mhz mhz sr slew rate 3 v/s t s settling time due to input step, v out = 2v 0.5% settling 2.5 s downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 6 1999fd for more information www.linear.com/lt1999 electrical characteristics note 1: stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. exposure to any absolute maximum rating condition for extended periods may affect device reliability and lifetime. note 2: pin 2 (+ in) and pin 3 (C in) are protected by esd voltage clamps which have asymmetric bidirectional breakdown characteristics with respect to the gnd pin ( pin 5). these pins can safely support common mode voltages which vary from C5.25 v to 88 v without triggering an esd clamp . note 3: exposure to differential sense voltages exceeding the normal operating range for extended periods of time may degrade part performance. a heat sink may be required to keep the junction temperature below the absolute maximum rating when the inputs are stressed differentially. the amount of power dissipated in the lt1999 due to input overdrive can be approximated by: p diss = v + in ? v ? in ( ) 2 8k note 4: a heat sink may be required to keep the junction temperature below the absolute maximum rating.note 5: the lt1999 c/ lt1999 i are guaranteed functional over the operating temperature range C40 c to 85 c . the lt1999 h is guaranteed functional over the operating temperature range C40 c to 125 c . the lt1999mp is guaranteed functional over the operating temperature range C55 c to 150 c. junction temperatures greater than 125c will promote accelerated aging. the lt1999 has a demonstrated typical life beyond 1000 hours at 150c. note 6: the lt1999c is guaranteed to meet specified performance from 0c to 70c. the lt1999c is designed, characterized, and expected to meet specified performance from C40c to 85c but is not tested or qa sampled at these temperatures. the lt1999i is guaranteed to meet specified performance from C40c to 85c. the lt1999h is guaranteed to meet specified performance from C40c to 125c. the lt1999mp is guaranteed to meet specified performance from C55c to 150c. note 7: full-scale sense (v sense ) gives indication of the maximum differential input that can be applied with better than 0.5% gain accuracy. gain accuracy is degraded when the output saturates against either power supply rail. v sense is verified with v + = 5.5v, v cm = 12v, with the ref pin set to its voltage range limits. the maximum v sense is verified with the ref pin set to its minimum specified limit, verifying the gain error is less than 0.5% at the output. the minimum v sense is verified with the ref pin set to its maximum specified limit, verifying the gain error at the output is less than 0.5%. see note 9 for more information. note 8: i b is defined as the average of the input bias currents to the +in and Cin pins (pins 2 and 3). a positive current indicates current flowing into the pin. i os is defined as the difference of the input bias currents. i os = i(+in) C i(Cin) note 9: the ref pin voltage range is the minimum and maximum limits that ensures the input referred voltage offset does not exceed 3mv over the i, c, and h temperature ranges, and 3.5mv over the mp temperature range. note 10: common mode recovery time is defined as the time it takes the output of the lt1999 to recover from a 50v, 20ns input common mode voltage transition, and settle to within the dc amplifier specifications. note 11: operating the lt1999 with v + < 4.5v is possible, although the lt1999 is not tested or specified in this condition. see the applications information section. symbol parameter conditions min typ max units t r common mode step recovery time v cm = 50v, 20ns (note 10) lt1999-10 lt1999-20 lt1999-50 0.8 1 1.3 s s s v s supply voltage (note 11) l 4.5 5 5.5 v i s supply current v cm > 5.5v v cm = C5v v + = 5.5v, v shdn = 0.5v, v cm > 0v l l l 1.55 5.8 3 1.9 7.1 25 ma ma a r o output impedance i o = 2ma 0.15 i src sourcing output current r load = 50 to gnd l 3 31 40 ma i snk sinking output current r load = 50 to v + l 10 26 40 ma v out swing output high (with respect to v + ) r load = 1k to mid-supply r load = open l l 125 5 250 125 mv mv swing output low (with respect to v C ) r load = 1k to mid-supply r load = open l l 250 150 400 225 mv mv t on turn-on time v shdn = 0v to 5v 1 s t off turn-off time v shdn = 5v to 0v 1 s the l denotes the specifications which apply over the full operating temperature range, ?55c < t a < 150c for mp-grade parts, otherwise specifications are at t a = 25c. v + = 5v, gnd = 0v, v cm = 12v, v ref = floating, v shdn = floating, unless otherwise specified. see figure 2. downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 7 1999fd for more information www.linear.com/lt1999 typical performance characteristics input bias current vs input common mode input bias current vs temperature input impedance vs input common mode voltage v cm (v) C5 i b (ma) 0.5 0 C1.0C1.5 C0.5C2.0 45 25 65 1999 g07 75 80 35 15 5 55 v + = 5v temperature (c) C55 i b (a) 146 144140 134 136 138 142132 70 20 120 1999 g08 145 45 C5 C30 95 v cm = 80v v cm = 5.5v v shdn = open v indiff = 0v v + = 5v v cm (v) C5 impedance (k) 100000 10000 100 10 1000 1 45 25 65 1999 g09 75 35 15 5 55 common mode inputimpedance differential input impedance supply current vs shdn pin voltage shutdown supply current vs temperature shutdown input bias current vs input common mode supply current vs input common mode supply current vs temperature supply current vs supply voltage v cm (v) C5 i s (ma) 76 4 2 53 1 0 45 25 65 1999 g01 75 80 35 15 5 55 v + = 5v temperature (c) C55 i s (ma) 1.81.7 1.5 1.61.4 70 20 120 1999 g02 145 45 C5 C30 95 v + = 5.5v v + = 4.5v v shdn = open v indiff = 0v v cm = 12v supply voltage (v) 0 i s (ma) 4.03.0 1.0 2.0 3.51.5 2.5 0 0.5 2 4 1999 g03 5 1 3 v cm = 12v 150c130c 90c 25c C45c C55c v shdn (v) 0 i s (ma) 10 0.1 1 0.001 0.01 2 4 1999 g04 5 1 3 t a = 25c t a = 150c t a = C55c v + = 5v v cm = 12v temperature (c) C55 i s (a) 10 84 2 60 70 20 120 1999 g05 145 45 C5 C30 95 v + = 5.5v v + = 4.5v v shdn = 0v v indiff = 0v v cm = 12v v cm (v) 0 i b (na) 1000 10 100 1 40 80 1999 g06 100 20 60 v + = 5v v shdn = 0v v sense = 0v t a = 70c t a = 90c t a = 150c t a =110c t a =130c downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 8 1999fd for more information www.linear.com/lt1999 typical performance characteristics lt1999-10 small signal frequency response gain error vs temperature gain error vs input common mode voltage input referred voltage offset vs temperature and gain option input referred voltage offset vs input common mode voltage temperature (c) C55 v osi (v) 1500 1000C500 C1000 500 0 C1500 70 20 120 1999 g10 145 45 C5 C30 95 lt1999-10 lt1999-20 lt1999-50 v cm = 12v 12 units plotted v cm (v) C5 v osi (v) 1500 1000C500 C1000 500 0 C1500 45 25 65 1999 g11 75 35 15 5 55 v + = 5v t a = 25c 12 units plotted lt1999-10 lt1999-20 lt1999-50 temperature (c) C55 gain error (%) 0.500.25 C0.25 0 C0.50 70 20 120 1999 g15 145 45 C5 C30 95 v cm = 12v 12 units plotted lt1999-10 lt1999-20 lt1999-50 v cm (v) C5 gain error (%) 0.50 0.25 C0.25 0 C0.50 45 25 65 1999 g16 75 35 15 5 55 v + = 5v t a = 25c 12 units plotted lt1999-10 lt1999-20 lt1999-50 frequency (khz) 1 gain (db) phase (deg) 30 15 0 C5 10 2520 5 C10 180 45 C90 C135 0 13590 C45 C180 10 1000 1999 g12 10000 100 v out = 0.5v p-p at 1khz gain phase lt1999-50 small signal frequency response lt1999-20 small signal frequency response frequency (khz) 1 gain (db) phase (deg) 35 20 50 15 3025 10 C5 180 45 C90 C135 0 13590 C45 gain C180 10 1000 1999 g13 10000 100 v out = 0.5v p-p at 1khz phase frequency (khz) 1 gain (db) phase (deg) 40 2510 5 20 3530 15 0 180 45 C90 C135 0 13590 C45 gain phase C180 10 1000 1999 g14 10000 100 v out = 0.5v p-p at 1khz downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 9 1999fd for more information www.linear.com/lt1999 typical performance characteristics cmrr vs frequency cmrr vs frequency frequency (khz) 1 cmrr (db) 120100 8020 40 60 0 1000 1999 g23 10000 100 10 v cm = 12v v + = 5v t a = 25c 6 units plotted lt1999-10 lt1999-20 lt1999-50 lt1999-50 2v step response settling time lt1999-10 2v step response settling time lt1999-20 2v step response settling time lt1999-50 pulse response time (2s/div) v sense (0.1v/div) v out (1v/div) 1999 g19 v out v sense v out time (1s/div) v out (v) output error (v) 4.5 3.51.5 2.50.5 4.02.0 3.01.0 0.100 0.050C0.050 0C0.100 0.075C0.025 0.025C0.075 1999 g20 output error v out v out (v) output error (v) 4.5 3.51.5 2.50.5 4.02.0 3.01.0 0.20 0.10C0.01 0C0.20 0.15C0.05 0.05C0.15 output error time (1s/div) C1 4 2 6 1999 g21 7 3 10 5 9 10 8 v out (v) output error (v) 4.53.5 1.5 2.50.5 4.02.0 3.01.0 0.5000.250 C0.250 0C0.500 0.375C0.125 0.125C0.375 time (1s/div) 1999 g22 v out output error lt1999-10 pulse response lt1999-20 pulse response time (2s/div) v sense (0.5v/div) v out (1v/div) 1999 g17 v out v sense time (2s/div) v sense (0.2v/div) v out (1v/div) 1999 g18 v out v sense frequency (khz) 1 cmrr (db) 120100 8020 40 60 0 1000 100 1999 g24 10000 10 v cm = 0v v + = 5v t a = 25c 6 units plotted lt1999-10 lt1999-20 lt1999-50 downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 10 1999fd for more information www.linear.com/lt1999 lt1999-10 common mode rising edge step response v out (0.5v/div) v cm (25v/div) time (0.5s/div) 1999 g25 v cm , t rise 20ns v out lt1999-10 common mode falling edge step response v out (0.5v/div) v cm (25v/div) time (0.5s/div) 1999 g26 v cm , t fall 20ns v out v out (0.5v/div) v cm (25v/div) time (0.5s/div) 1999 g27 v cm , t rise 20ns v out lt1999-20 common mode rising edge step response lt1999-20 common mode falling edge step response v out (0.5v/div) v cm (25v/div) time (0.5s/div) 1999 g28 v cm , t fall 20ns v out typical performance characteristics lt1999-50 common mode rising edge step response lt1999-50 common mode falling edge step response v out (0.5v/div) v cm (25v/div) time (0.5s/div) 1999 g29 v cm , t rise 20ns v out v out (0.5v/div) v cm (25v/div) time (0.5s/div) 1999 g30 v cm , t fall 20ns v out downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 11 1999fd for more information www.linear.com/lt1999 typical performance characteristics lt1999 input referred noise density vs frequency frequency (khz) 0.001 0.01 0.1 noise density (nv / hz ) 1000 100 10 1000 1999 g31 10000 10 1 temperature (c) C55 i sc (ma) 4020 3010 C20 0 C40 C10C30 70 20 120 1999 g32 145 45 C5 C30 95 sinking sourcing temperature (c) C55 ref pin voltage (v) 3.0 2.51.0 2.0 0 1.50.5 70 20 120 1999 g33 145 45 C5 C30 95 shdn mode active mode v + = 5v short-circuit current vs temperature ref open circuit voltage vs temperature shdn pin current vs shdn pin voltage and temperature turn-on/turn-off time vs shdn voltage v out vs v sense i s (1ma/div) shdn pin voltage (5v/div) time (1s/div) 1999 g35 v shdn i s shutdown v cm = 12v v sense (v) C0.25 v out (v) 64 51 2 3 C1 C0.05 0.15 1999 g36 0.25 C0.15 0.05 v ref = 2.5v lt1999-10 lt1999-20 lt1999-50 0 v shdn (v) 0 i shdn (a) C2C4 C1 0 C3 2 4 5 1999 g34 1 3 t a = 150c t a = 25c t a = C55c v + = 5v v cm = 12v v out vs v sense over the sense absmax range v sense (v) C60 v out (v) 64 51 2 3 C1 C30 30 1999 g37 60 0 0 v out phase reversal for v sense < C25v v ref = 2.5v lt1999-10 lt1999-20 lt1999-50 downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 12 1999fd for more information www.linear.com/lt1999 pin functions v + ( pins 1, 4/ pin 4): power supply voltage. pins 1 and 4 are tied internally together. the specified range of opera- tion is 4.5 v to 5.5 v, but lower supply voltages ( down to approximately 4 v) is possible although the lt1999 is not tested or characterized below 4.5 v. see the applications information section.+in (pin 2/pin 1): positive sense input pin. ?in (pin 3/pin 2): negative sense input pin. nc (na/pin 3)gnd (pin 5/pin 5): ground pin. ref ( pin 6/ pin 6): reference pin input. the ref pin sets the output common mode level and is set halfway between v + and gnd using a divider made of two 160 k resistors. the default open circuit potential of the ref pin is mid-supply. it can be overdriven by an external voltage source cable of driving 80 k to a mid-supply potential ( see the electrical characteristics table for its specified input voltage range). out ( pin 7/ pin 7): voltage output. v out = a v ? (v sense v osi ), where a v is the gain, and v osi is the input referred offset voltage. the output amplifier has a low impedance output and is designed to drive up to 200 pf capacitive loads directly. capacitive loads exceeding 200 pf should be decoupled with an external resistor of at least 100. shdn ( pin 8/ pin 8): shutdown pin. when pulled to within 0.5v of gnd ( pin 5), will place the lt1999 into low power shutdown . if the pin is left floating, an internal 2 a pull- up current source will place the lt1999 into the active (amplifying) state. (lt1999-xx/lt1999-xxf) downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 13 1999fd for more information www.linear.com/lt1999 shdn v + v + v + v+ 160k160k 1999 bd 2a lt1999-xxf +C + C r g 0.8k 4k 0.8k 8 7 2 1 3 4 6 5 4k nc shdn v + v + v + v + v+ 160k160k 1999 bd 2a lt1999 +C + C r g 0.8k 4k 0.8k 8 7 2 1 3 4 6 5 4k block diagram figure 1. simplified block diagram test circuit 5v 1999 f02 0.1f v out v in(diff) +C v cm v ref v shdn + C + C + C lt1999f 4k 0.8k 160k160k 2a 0.8k 4k nc shdn v + v + +C +C 8 1 23 4 76 5 r g 0.1f v + v + 5v 5v 1999 f02 0.1f v out v in(diff) +C v cm v ref v shdn + C + C + C lt1999 4k 0.8k 160k160k 2a 0.8k 4k shdn v + v + v + +C +C 8 2 1 34 76 5 r g 0.1f v + v + figure 2. test circuit downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 14 1999fd for more information www.linear.com/lt1999 the lt1999 current sense amplifier provides accurate bidirectional monitoring of current through a user - selected sense resistor. the voltage generated by the current flowing in the sense resistor is amplified by a fixed gain of 10 v/v, 20v/v or 50 v/v ( lt1999-10, lt1999-20, or lt1999-50 respectively) and is level shifted to the out pin. the volt - age difference and polarity of the out pin with respect to ref ( pin 6) indicates magnitude and direction of the current in the sense resistor. theory of operation refer to the block diagram (figure 1). case 1: v + < v cm < 80v for input common mode voltages exceeding the power supply, one can assume d1 of figure 1 is completely off. the sensed voltage ( v sense ) is applied across pin 2 (+ in) and pin 3 (C in) to matched resistors r + in and r C in ( nomi- nally 4 k each). the opposite ends of r + in and r C in are forced to equal potentials by transconductor g in , which convert the differentially sensed voltage into a sensed current. the sensed current in r + in and r C in is combined, level-shifted, and converted back into a voltage by trans- resistance amplifier a o and resistor r g . amplifier a o pro- vides high open loop gain to accurately convert the sensed current back into a voltage and to drive external loads. the theoretical output voltage is determined by the sensed voltage (v sense ), and the ratio of two on-chip resistors: v out ? v ref = v sense ? r g r in where r in = r + in + r ? in 2 nominally 4k for the lt1999-10, r g is nominally 40 k . for the lt1999-20, r g is nominally 80 k, and for the lt1999-50, r g is nomi- nally 200k. applications information the voltage difference between the out pin and the ref pin represent both polarity and magnitude of the sensed voltage. the noninverting input of amplifier a o is biased by a resistive 160 k to 160 k divider tied between v + and gnd to set the default ref pin bias to mid-supply.case 2: ?5v < v cm < v + for common mode inputs which transition or are set below the supply voltage, diode d1 will turn on and will provide a source of current through r +s and r C s to bias the inputs of transconductance amplifier g in at least 2.25 v above gnd. the transition is smooth and continuous; there are negligible changes to either gain or amplifier voltage off - set. the only difference in amplifier operation is the bias currents provided by d1 through r +s and r C s are steered through the input pins, otherwise amplifier operation is identical. the inputs to transconductance amplifier g in are still forced to equal potentials forcing any differential volt- ages appearing at the + in and C in pins into a differential current. this differential current is combined, level - shifted , and converted back into a voltage by trans-resistance amplifier a o and resistor r g . resistors r +s and r C s are trimmed to match r + in and r C in respectively, to prevent common mode to differential conversion from occurring (to the extent of the matched trim) when the input com - mon mode transitions below v + . as described in case 1, the output is determined by the sense voltage and the ratio of two on-chip resistors: v out ? v ref = v sense ? r g r in where r in = r + in + r ? in 2 downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 15 1999fd for more information www.linear.com/lt1999 applications information input common mode range the lt1999 was optimized for high common mode re- jection. its input stage is balanced and fully differential, designed to amplify differential signals and reject common mode signals. there is negligible crossover distortion due to sense voltage reversals. the amplifier is most linear in the zero-sense region. with the v + supply configured within the specified and tested range (4.5 v < v + < 5.5 v), the lt1999s common mode range extends from C5 v to 80 v. pushing + in and Cin beyond the limits specified in the absolute maximum table can turn on the voltage clamps designed to protect the +in and Cin pins during esd events. it is possible to operate the lt1999 on power supplies as low as 4 v ( although it is not tested or specified below 4.5v). operating the lt1999 on supplies below 4 v will produce erratic behavior. when operating the lt1999 with supplies as low as 4 v, the common mode range for inputs which extend below gnd is reduced. refer to the block diagram ( figure 1). for inputs driven below v + , diode d1 conducts. for proper operation, the input to the transconductor v(g + in ) must be biased at approximately 2.25v above the gnd pin. v(g + in ) sits on the centertap of a voltage divider comprised of r + s and r + in v(g C in ) likewise sits in the middle of the voltage divider comprised of r C s , and r C in ). the voltage on v(g + in ) input is given by the following equation: v(g + in ) = v + in ? r + s r + s + r + in + v + ? v d1 ( ) ? r + in r + s + r + in setting v(g + in ) = 2.25 v, the ratio ( r + in /r + s ) to 5, and v d1 equal to 0.8 v ( cold temperatures), a plot of the lower input common mode range plotted against supply is shown in figure 3. output common mode range the lt1999s output common mode level is set by the voltage on the ref pin. the ref pin sits in the middle of a 160 k to 160 k voltage divider connected between v + and gnd which sets the default open circuit potential of the ref pin to mid-supply. it can be overdriven by an external voltage source capable of driving 80 k tied to a mid-supply potential. see the electrical characteristics table for the ref pins specified input voltage range. differential sampling of the out pin with respect the ref pin provides the best noise immunity. measurements of the output voltage made differentially with respect to the ref pin will provide the highest power supply and com - mon mode rejection . otherwise, power supply or gnd pin disturbances are divided by the ref pins voltage divider and appear directly at the noninverting input of the trans- resistance amplifier a o and are not rejected. if not driven by a low impedance (<100), the ref pin should be filtered with at least 1 nf of capacitance to a low impedance, low noise ground plane. this external capacitance will also provide a charge reservoir during high frequency sampling of the ref pin by adc inputs attached to this pin. figure 3. lower input common mode vs supply voltage supply voltage (v) 4 v cm(lower limit) (v) C2.0C2.5 C3.0 C4.0 C5.0 C3.5C4.5 C5.5 C6.0 4.75 4.25 5.25 1999 f03 5.5 4.5 5 below ground inputcommon mode range limited by v + supply voltage below ground inputcommon mode range limited by esd clamps typical esd clamp voltage downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 16 1999fd for more information www.linear.com/lt1999 applications information shutdown capability if shdn ( pin 8) is driven to within 0.5 v of gnd, the lt1999 is placed into a low power shutdown state in which the part will draw about 3 a from the v + supply. the input pins (+ in and C in) will draw approximately 1 na if biased within the range of 0 v to 80 v ( with no differential voltage applied). if the input pins are pulled below the gnd pin, each input appears as a diode tied to gnd in series with approximately 4 k of resistance. the ref pin appears as approximately 0.4 m tied to a mid-supply potential. the output appears as reverse biased diodes tied between the output to either v + or gnd pins. emi filtering and layout practicesan internal 1 st order differential lowpass noise / emi suppression filter with a C3 db bandwidth of 10 mhz ( ap - proximately 5 the lt1999s C3 db bandwidth) is included to help improve the lt1999s emi susceptibility and to assist with the rejection of high frequency signals beyond the bandwidth of the lt1999 that may introduce errors. the pole is set by the following equation: f filt = 1/( ? (r + in + r C in )? c f ) 10mhz both the resistors and capacitors have a 15% variation so the pole can vary by approximately 30% over manu- facturing process and temperature variations.the layout for lowest emi/noise susceptibility is achieved by keeping short direct connections and minimizing loop areas ( see figure 4). if the user-supplied sense resistor cannot be placed in close proximity to the lt1999, the surface area of the loop comprising connections of + in to r sense and back to C in should be minimized. this requires routing pcb traces connecting + in to r sense and C in to r sense adjacent with one another with minimal separation. the metal traces connecting + in to the sense resistor and C in to the sense resistor should match and use the same trace width. bypassing the v + pin to the gnd pin with a 0.1 f capacitor with short wiring connection is recommended. figure 4. recommended layout supply bypass capacitor * keep loop area comprising r sense , +in and Cin pins as small as possible. ** ref bypass tied to a low noise, low impedance signal ground plane. ? optional 10pf capacitor to prevent dv/dt edges on input coupling to floating shdn pin. ** * from dc source to load r sense differentialanalog out ? 1999 f03 12 3 4 87 6 5 shdn out ref gnd v + +inCin v + downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 17 1999fd for more information www.linear.com/lt1999 applications information the ref pin should be either driven by a low source im- pedance (<100) or should be bypassed with at least 1 nf to a low impedance, low noise, signal ground plane ( see figure 4). larger bypass capacitors on both v + pins, and the ref pin, will extend enhanced ac cmrr, and psrr performance to lower frequencies . bypassing the ref pin to a quiet ground plane filters the v + pin or gnd pin noise that is sensed by the ref pin voltage divider and applied to the noninverting input of output amplifier a o . any com- mon i ? r drops generated by pulsating ground currents in common with the ref pin filter capacitor can compromise the filtering performance and should be avoided. if the shdn pin is not driven and is left floating, routing a pcb trace connecting pins 1 and 8 under the part will act as a shield, and will help limit edge coupling from the inputs ( pins 2 and 3) to the shdn pin. periodic pulses on the inputs with fast edges may glitch the high impedance shdn pin, periodically putting the part into low power shutdown. additional precaution against this may be taken by adding an optional small (~10 pf) capacitor may be tied between v + (pin 1) and pin 8. finally, when connecting the lt1999 inputs to the sense resistor, it is important to use good kelvin sensing prac - tices ( sensing the resistor in a way that excludes pcb trace i ? r voltage drops). for sense resistors less than 1, one might consider using a 4- wire sense resistor to sense the resistive element accurately. selection of the current sense resistor the external sense resistor selection presents a delicate trade-off between power dissipation in the resistor and current measurement accuracy.in high current applications, the user may want to minimize the power dissipated in the sense resistor. the sense re - sistor current will create heat and voltage loss, degrading efficiency . as a result, the sense resistor should be as small as possible while still providing adequate dynamic range required by the measurement. the dynamic range is the ratio between the maximum accurately produced signal generated by the voltage across the sense resistor, and the minimum accurately reproduced signal. the minimum accurately reproduced signal is primarily dictated by the voltage offset of the lt1999. the maximum accurately reproduced signal is dictated by the output swing of the lt1999. thus the dynamic range for the lt1999 can be thought of the maximum sense voltage divided by the input referred voltage offset or: dynamic range = v out(max) gain ? v osi the above equation tells us that the dynamic range is inversely proportional to the gain of the lt1999 . thus, if accuracy is of greater importance than efficiency or power loss, the lt1999-10 used with the highest valued sense resistor possible is recommended . if efficiency, heat generated, and power loss in the resistive shunt is the primary concern, the lt1999-50 and the lowest value sense resistor possible is recommended . the lt1999-20 is available for applications somewhere in between these two extremes. downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 18 1999fd for more information www.linear.com/lt1999 applications information pinout option engineered for fmea (failure mode and effects analysis) the lt1999 family of ics is available with an 8- lead msop pinout option engineered for fmea ( failure mode and effects analysis ): ( lt1999-10f, lt1999-20f and the lt1999-50f). see figure 5 below. the lt1999-xxf is designed to meet the most stringent automotive requirements and to satisfactorily survive single faults due to the most common pcb defects : 1) open pins due to cold solder joints and 2) adjacent pin short circuits due to adjacent pin solder bridging. the no-connect pin (pin 3) has been inserted between the input pin (C in) and the v + supply pin to isolate the input voltages which may range from C5 v to 80 v from solder bridging to the v + supply ( typically 5 v). pin 3 is not connected internally to the die and should be left unconnected. the purpose of the fmea is to emulate single faults and determine whether or not they are destructive and / or lead to conditions which could damage surrounding components. the lt1999 - xxf is configured as shown in figure?2, with an input common mode of either 12 v or 0 v . each pin is systematically shorted to its adjacent pin ( emulating solder bridging) and the resulting effects recorded. each pin is then opened ( emulating a cold solder joint) with the resulting effects recorded . in all instances, the lt1999-xxf recovers when these fault conditions are removed. furthermore, the output pin (out) has been verified to never exceed the pins nominal output range of 0v to 5v during fault testing. table 1 lists the behavior which results from shorting adjacent pins and table 2 details the behavior from open - ing any pin. shdn nc v + v + v + v+ 2k r +in r Cin 300 c f 4pf 0.8k0.8k 160k160k 1999 f05a 2a out ref +inCin gnd + C +C g r g 2k 2k 4.5k 2k 8 7 2 1 3 4 6 5 figure 5. simplified block diagram of the lt1999-xxf downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 19 1999fd for more information www.linear.com/lt1999 applications information table 1: behavior due to adjacent pin-to-pin shorts for the lt1999-10f, lt1999-20f, or the lt1999-50f adjacent pin short test: (v + = 5v, tested at v cm = 0v, v cm = 12v, v cm = 80v) pin # adjacent pins shorted recovery when fault is removed behavior 1 C 2 +in C Cin yes v out approaches the voltage on pin v ref . 2 C 3 Cin C nc yes the circuit behaves normally. 3 C 4 nc C v+ yes the circuit behaves normally. 5 C 6 gnd C ref yes v out follows the voltage on pin 6 or 0v. 6 C 7 ref C out yes v out approaches 5.0v 7 C 8 out C shdn yes supply current drops by 5%. table 2: behavior due to open pins for the lt1999-10f, lt1999-20f, or the lt1999-50f open pin test (v + = 5v, tested at v cm = 0v, v cm = 12v, v cm = 80v) pin # pin opened recovery when fault is removed behavior 1 +in yes v out may go to either v + or gnd, depending on the voltage applied to Cin. generally, for C5v< Cin< 4v, out will be near 5v. for Cin > 5v, out will be near 0v. in the range of 4v < Cin < 5v, out may go to either v + or gnd, depending on the voltage applied to Cin. the open input (+in) is biased internal to the ic to one diode below v + . 2 Cin yes v out may go to either v + or gnd, depending on the voltage applied to +in. generally, for C5v < +in < 4v, out will be near 0v. for +in > 5v, out will be at 5v. in the range of 4v < Cin < 5v, out may go to either v+ or gnd, depending on the voltage applied to +in. the open input (Cin) is biased internal to the ic to one diode below v + . 3 nc yes the circuit behaves normally. 4 v + yes the circuit will behave as if powered off. 5 gnd yes out, ref will float up towards 3.9v. 6 ref yes the circuit behaves normally with more broadband noise on out. 7 out yes no v out signal. 8 shdn yes the low power shutdown feature will not function, otherwise the circuit behaves normally in the active state. fmea information in this document (not limited to, but including the description of behavior under specific pin-connection conditions) is provided for convenience only. ultimately, the end-user is responsible for verifying proper and reliable operation in each actual application. linear technology assumes no liability whatsoever with providing this information. downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 20 1999fd for more information www.linear.com/lt1999 applications information v out v ref v shdn lt1999 4k 0.8k 160k160k 2a 0.8k 4k shdn v + v + v + +C +C 8 12 3 4 76 5 r g v + v + v s 5v 1999 f05 0.1f 0.1f fuse steeringdiode load i load r sense off on 5v v out v +in v Cin v ref v shdn figure 6. using the lt1999 to monitor a fuse fuse monitor the inputs can be overdriven without fear of damaging the lt1999. this makes the lt1999 ideal for monitoring fuses if either + in or C in are shorted to ground while the other is at the full common mode supply voltage ( see figure?6). if the fuse in figure?6 opens with the + in tied to the positive supply, the load will pull C in to gnd. the output will be forced to the positive v + supply rail. if it is desired that the output be near ground if the fuse opens, it is a simple matter of swapping the inputs. precautions should be followed: first, when the inputs are stressed differentially due to the fuse blowing open, a large voltage drop will be placed across the + in to C in pins, dissipating power in the precision on-chip input resistors. precaution should be taken to prevent junction temperatures from exceeding the absolute maximum ratings ( see note 3 in the electrical characteristics section). secondly, if the load is inductive, and the fuse blows open without a clamp diode, energy stored in the inductive load will be dissipated in the lt1999, which could cause damage. a simple steering diode as shown in figure ?6 will prevent this from happen- ing, and will protect the lt1999 from damage.finally , the user should be aware that in fuse monitoring applications with the sense voltage ( v sense = v + in C v C in ) being driven in excess of C25 v, the output of the lt1999 will undergo phase reversal (see figure?7). figure 7. a plot of the lt1999?s output voltage vs v sense (v sense = v +in ? v ? in ). in applications where the sense voltage is driven in excess of ?25v, the output of the lt1999 will undergo phase reversal v sense (v) C60 v out (1v/div) C30 C45 C15 30 1999 f06 60 15 45 0 v out phase reversal for v sense < C25v v ref = 2.5v downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 21 1999fd for more information www.linear.com/lt1999 typical applications solenoid current monitor the solenoid of figure 8 consists of a coil of wire in an iron case with permeable plunger that acts as a movable element. when the mosfet turns on, the diode is reversed biased off, and current flows through r sense to actuate the solenoid. if the mosfet is turned off, the current in the mosfet is interrupted, but the energy stored in the solenoid causes the diode to turn on and current to freewheel in the loop consisting of the diode, r sense and the solenoid.figure 8 shows the lt1999 monitoring currents in a ground referenced solenoid used when the coil is hard tied to the case, and is tied to ground. figure 9 shows a supply referenced solenoid whose coil is insulated from the case. the lt1999 will interface equally well to either of these two configurations. bidirectional pwm motor monitor pulse width modulation is commonly used to efficiently vary the average voltage applied across a dc motor. the h-bridge topology of figure 10 allows full 4- quadrant control: clockwise control, counter - clockwise control , clockwise regeneration, and counter-clockwise regen - eration. the lt1999 in conjunction with a non-inductive current shunt is used to monitor currents in the rotor . the lt1999 can be used to detect stuck rotors, provide detection of overcurrent conditions in general, or provide current mode feedback control. figure 11 shows a plot of the output voltage of the lt1999. figure 8. solenoid current monitor for ground tied solenoid. the common mode inputs to the lt1999 switch between v s and one diode drop below ground lt1999 4k 0.8k 160k160k 2a 0.8k 4k shdn v + v + v + +C +C 8 12 3 4 76 5 r g v + v + time (50ms/div) v out (0.5v/div) v +in (10v/div) 5v v s 5v 1999 f07a 1999 f07b 0.1f 0.1f solenoid r sense v +in v shdn v out v ref v Cin on off v out v +in solenoid plunger pulls in solenoid releases 2.5v downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 22 1999fd for more information www.linear.com/lt1999 figure 9. solenoid current monitor for non-grounded solenoids. this circuit performs the same function as figure 7 except one end of the solenoid is tied to v s . the common mode voltage of inputs of the lt1999 switch between ground and one diode drop above v s typical applications lt1999 4k 0.8k 160k160k 2a 0.8k 4k shdn v + +C +C 8 23 76 5 r g v + v + 5v v s 5v 1999 f08a 1 4 0.1f 2.5v 0.1f solenoid r sense v out v ref v shdn on off v + v + v +in v Cin time (50ms/div) v out (0.5v/div) v +in (10v/div) v out v +in solenoid plunger pulls in solenoid releases 1999 f08b downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 23 1999fd for more information www.linear.com/lt1999 typical applications figure 10. armature current monitor for dc motor applications figure 11. lt1999 output waveforms for the circuit of figure 10 1999 f09 v bridge v +in v Cin r sense 0.025 10f pwm inputdirection brake input 24v 5v 5v gnd 5v pwm in outaoutb c41000f 24v motor h-bridge lt1999-20 4k 0.8k 160k160k 2a 0.8k 4k shdn +? +? 80k v + v + v + v + 0.1f 0.1f 87 6 v shdn v out v ref 23 14 v + 5 time (20s/div) v out (2v/div) v +in (20v/div) 1999 f10 v out v +in 2.5v downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 24 1999fd for more information www.linear.com/lt1999 package description please refer to http:// www .linear.com/designtools/packaging/ for the most recent package drawings. msop (ms8) 0213 rev g 0.53 0.152 (.021 .006) seating plane note:1. dimensions in millimeter/(inch) 2. drawing not to scale 3. dimension does not include mold flash, protrusions or gate burrs. mold flash, protrusions or gate burrs shall not exceed 0.152mm (.006") per side 4. dimension does not include interlead flash or protrusions. interlead flash or protrusions shall not exceed 0.152mm (.006") per side 5. lead coplanarity (bottom of leads after forming) shall be 0.102mm (.004") max 0.18 (.007) 0.254 (.010) 1.10 (.043) max 0.22 C 0.38 (.009 C .015) typ 0.1016 0.0508 (.004 .002) 0.86 (.034) ref 0.65 (.0256) bsc 0 C 6 typ detail a detail a gauge plane 1 2 3 4 4.90 0.152 (.193 .006) 8 7 6 5 3.00 0.102 (.118 .004) (note 3) 3.00 0.102 (.118 .004) (note 4) 0.52 (.0205) ref 5.10 (.201) min 3.20 C 3.45 (.126 C .136) 0.889 0.127 (.035 .005) recommended solder pad layout 0.42 0.038 (.0165 .0015) typ 0.65 (.0256) bsc ms8 package 8-lead plastic msop (reference ltc dwg # 05-08-1660 rev g) .016 C .050 (0.406 C 1.270) .010 C .020 (0.254 C 0.508) 45 0 C 8 typ .008 C .010 (0.203 C 0.254) so8 rev g 0212 .053 C .069 (1.346 C 1.752) .014 C .019 (0.355 C 0.483) typ .004 C .010 (0.101 C 0.254) .050 (1.270) bsc 1 2 3 4 .150 C .157 (3.810 C 3.988) note 3 8 7 6 5 .189 C .197 (4.801 C 5.004) note 3 .228 C .244 (5.791 C 6.197) .245 min .160 .005 recommended solder pad layout .045 .005 .050 bsc .030 .005 typ inches (millimeters) note:1. dimensions in 2. drawing not to scale 3. these dimensions do not include mold flash or protrusions. mold flash or protrusions shall not exceed .006" (0.15mm) 4. pin 1 can be bevel edge or a dimple s8 package 8-lead plastic small outline (narrow .150 inch) (reference ltc dwg # 05-08-1610 rev g) downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 25 1999fd for more information www.linear.com/lt1999 information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. revision history rev date description page number a 5/11 revised +in and Cin pin descriptions in pin functions section 12 b 3/12 revised voltage output swing low specification (v out ) under a loaded condition of 1k? to mid-supply. updated figure 4 to multicolor. 4, 6 16 c 2/15 addition of msop pinout option engineered for fmea correction to av specification for lt1999-50 from 48.75 to 49.75 update to pin functions to include pinout option engineered for fmeaaddition of new application information "pinout option engineered for fmea" addition of figure 5 and renumbering of figures 6 to 11 addition of table 1 and table 2 all 5 12 18, 19 18 to 23 19 d 6/15 lt1999f added to figure 1 (simplified block diagram) lt1999f added to figure 2 (test circuit) additional test condition (v cm = 80) added to table 1 and table 2 note added regarding the use of fmea information 1314 19 19 downloaded from: http:///
lt1999-10/lt1999-20/ lt1999-50 26 1999fd for more information www.linear.com/lt1999 linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 l fax : (408) 434-0507 l www.linear.com ? linear technology corporation 2010 lt 0615 rev d ? printed in usa typical application part number description comments lt1787/lt1787hv precision, bidirectional high side current sense amplifier 2.7v to 60v operation, 75v offset, 60a current draw lt6100 gain-selectable high side current sense amplifier 4.1v to 48v operation, pin-selectable gain: 10v/v, 12.5v/v, 20v/v, 25v/v, 40v/v, 50v/v ltc6101/ ltc6101hv high voltage high side current sense amplifier 4v to 60v/5v to 100v operation, external resistor set gain, sot23 ltc6102/ltc6102hv zero drift high side current sense amplifier 4v to 60v/5v to 100v operation, 10v offset, 1s step response, msop8/dfn packages ltc6103 dual high side precision current sense amplifier 4v to 60v, gain configurable, 8-pin msop package ltc6104 bidirectional, high side current sense 4v to 60v, gain configurable, 8-pin msop package lt6106 low cost, high side precision current sense amplifier 2.7v to 36v, gain configurable, sot23 package lt6105 precision, extended input range current sense amplifier C0.3 to 44v, gain configurable, 8-pin msop package ltc4150 coulomb counter/battery gas gauge indicates charge quantity and polarity lt1990 precision, 100a gain selectable amplifier 2.7v to 36v operation, cmrr > 70db, input voltage = 250v lt1991 250v input range difference amplifier 2.7v to 36v operation, 50v offset, cmrr > 75b, input voltage = 60v lt1637/lt1638 1.1/1.2mhz, 0.4 v/s over-the- top , rail-to-rail input and output amplifier 0.4v/s slew rate, 230a per amplifier related parts 1999 ta02 5v 0.1f lt1999-10 4k 0.8k 160k160k 2a 0.8k 4k v + +C shdn +C v out 40k v ref v shdn v + v + v + v + 4 0.1f 5v charger load 0.025 bat42v v cc v ref 0.1f +in 10f cssck sdo ltc2433-1 v out +? 5v ?in 0.1f 23 1 5 76 8 v +in v ?in battery charge current and load current monitor v out = 0.25v/a, maximum measured current 9.5a (408) 432-1900 l fax : (408) 434-0507 l www.linear.com/lt1999 downloaded from: http:///

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