for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim?s website at www.maxim integrated .com. general description the max4173 low-cost, precision, high-side current-sense amplifier is available in a tiny sot23-6 package. it features a voltage output that eliminates the need for gain-setting resistors and it is ideal for today? notebook computers, cell phones, and other systems where cur- rent monitoring is critical. high-side current monitoring is especially useful in battery-powered systems, since it does not interfere with the ground path of the battery charger. the input common-mode range of 0 to +28v is independent of the supply voltage and ensures that the current-sense feedback remains viable even when con- nected to a battery in deep discharge. the max4173? wide 1.7mhz bandwidth makes it suitable for use inside battery charger control loops. the combination of three gain versions and a user- selectable external sense resistor sets the full-scale current reading. this feature offers a high level of inte- gration, resulting in a simple and compact current- sense solution. the max4173 operates from a single +3v to +28v sup- ply, typically draws only 420? of supply current over the extended operating temperature range (-40? to +85?), and is offered in the space-saving sot23 package. applications notebook computersportable/battery-powered systems smart battery packs/chargers cell phones power-management systems general system/board-level current monitoring pa bias control precision current sources features ? low-cost, compact current-sense solution ? high accuracy +2v to +28v common-moderange, functional down to 0v, independent of supply voltage ? three gain versions available +20v/v (max4173t)+50v/v (max4173f) +100v/v (max4173h) ? ?.5% full-scale accuracy ? ?mv input offset voltage (max4173t) ? wide 1.7mhz bandwidth (max4173t) ? 420? supply current ? available in space-saving sot23 package low-cost, sot23, voltage-output, high-side current-sense amplifier max4173t/f/h r sense 0 to +28v i load v sense v cc out gnd rs+ +3v to +28v rs- load/ battery a/d converter 0.1 f typical operating circuit part max4173teut+tmax4173tesa+ pin-package 6 sot238 so ordering information -40? to +85? -40? to +85? temp range sot top mark aabn max4173feut+t -40? to +85? 6 sot23 aabo max4173fesa+ -40? to +85? 8 so max4173heut+t -40? to +85? 6 sot23 aabp max4173hesa+ -40? to +85? 8 so 20 20 gain (v/v) 50 50 100 100 pin configurations appear at end of data sheet. + denotes a lead(pb)-free/rohs-compliant package. t = tape and reel. max4173 19-1434; rev 5; 4/11 downloaded from: http:/// available
low-cost, sot23, voltage-output, high-side current-sense amplifier absolute maximum ratings electrical characteristics (v rs+ = 0 to +28v, v cc = +3v to +28v, v sense = 0v, t a = t min to t max , r load = unless otherwise noted. typical values are at t a = +25?.) (note 1) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. v cc , rs+, rs- to gnd .......................................... -0.3v to +30v out to gnd .............................................. -0.3v to (v cc + 0.3v) output short-circuit to v cc or gnd ......................... continuous differential input voltage (v rs+ - v rs- ) ............................. ?.3v current into any pin......................................................... ?0ma continuous power dissipation (t a = +70?) 8-pin so (derate 5.88mw/? above +70?)............... 471mw sot23-6 (derate 8.7mw/? above +70?)................. 696mw operating temperature range .......................... -40? to +85? storage temperature range ............................ -65? to +150? lead temperature (soldering, 10s) ................................ +300? soldering temperature (reflow) ...................................... +260? parameter symbol conditions min typ max units operating voltage range v cc guaranteed by psr test 3 28 v common-mode input range v cmr (note 2) 0 28 v common-mode rejection cmr v rs+ > +2.0v 90 db supply current i cc v rs+ > +2.0v, v cc > 12v 0.42 1.0 ma leakage current i rs+ , i rs- v cc = 0v, v rs+ = 28v 0.3 3 ? v rs+ > +2.0v 0 50 i rs+ v rs+ +2.0v -350 50 v rs+ > +2.0v 0 100 input bias current i rs- v rs+ +2.0v -700 100 ? full-scale sense voltage v sense v sense = v rs+ - v rs- 150 mv v sense = +100mv, v cc = +12v, v rs+ = +12v ?.5 5.75 v sense = +100mv, v cc = +12v, v rs+ = +12v, t a = +25? 0.5 3.25 v sense = +100mv, v cc = +28v, v rs+ = +28v 0.5 5.75 v sense = +100mv, v cc = +12v, v rs+ = +0.1v -9 ?4 total out voltage error(note 3) v cc = +12v, v rs+ = +12v, v sense = +6.25mv (note 4) ?.5 % max4173t, v cc = +3.0v, v rs+ = 28v, v sense = 250mv 0.8 1.2 max4173f, v cc = +7.5v, v rs+ = 28v, v sense = 250mv 0.8 1.2 out high voltage (note 5) (v cc - v oh ) max4173h, v cc = +15v, v rs+ = 28v, v sense = 250mv 0.8 1.2 v t a = +25? 1.2 5 out low voltage v ol max4173teut,v cc = +5v, v rs+ = 0.89v, v sense = 0mv t a = -40? to +85? 40 mv 2 maxim integrated max4173 downloaded from: http:///
low-cost, sot23, voltage-output, high-side current-sense amplifier note 1: all devices are 100% production tested at t a = +25?. all temperature limits are guaranteed by design. note 2: guaranteed by total output voltage error test. note 3: total out voltage error is the sum of gain and offset voltage errors. note 4: +6.25mv = 1/16 of +100mv full-scale voltage. note 5: v sense such that output stage is in saturation. note 6: v os is extrapolated from the gain accuracy tests. note 7: the device does not experience phase reversal when overdriven. electrical characteristics (continued)(v rs+ = 0 to +28v, v cc = +3v to +28v, v sense = 0v, t a = t min to t max , r load = unless otherwise noted. typical values are at t a = +25?.) (note 1) parameter symbol conditions min typ max units max4173t,v sense = +100mv 1.7 max4173f,v sense = +100mv 1.4 max4173h,v sense = +100mv 1.2 bandwidth bw v rs+ = +12v, v cc = +12v, c load = 5pf v sense = +6.25mv (note 4) 0.6 mhz max4173t 20 max4173f 50 gain a v max4173h 100 v/v t a = +25? 0.5 ?.5 ? a v max4173t/f v sense = +10mv to +150mv,v cc = v rs+ = 12v t a = -40? to +85? 4.0 t a = +25? 0.5 ?.5 gain accuracy ? a v max4173h v sense = +10mv to +100mv,v cc = v rs+ = 12v t a = -40? to +85? 4.0 % t a = +25? 0.3 ? input offset voltage(note 6) v os max4173teut,v rs+ = 12v t a = -40? to +85? ? mv v sense = +6.25mv to +100mv 400 out settling time to 1% offinal value v cc = +12v, v rs+ = 12v, c load = 5pf v sense = +100mv to +6.25mv 800 ns out output resistance r out 12 k max4173t, v sense = 80mv, v rs+ +2v 60 84 max4173f, v sense = 32mv, v rs+ +2v 60 91 power-supply rejection psr max4173h, v sense = 16mv, v rs+ +2v 60 95 db power-up time to 1% offinal value v sense = +100mv, c load = 5pf 10 ? saturation recovery time v cc = +12v, v rs+ = 12v (note 7) 10 ? maxim integrated 3 max4173 downloaded from: http:///
low-cost, sot23, voltage-output, high-side current-sense amplifier 370 390380 410400 430420 440 01 0 1 5 5 202530 supply current vs. supply voltage max4173 toc01 supply voltage (v) supply current ( a) max4173t max4173f max4173h 200 300250 450400 350 550500 150 -50 -5 10 -35-20 2540557085 supply current vs. temperature max4173 toc02 temperature (?) supply current ( a) max4173t max4173f max4173h 0 0.40.2 0.80.6 1.21.0 1.4 0 1.0 1.5 0.5 2.0 2.5 28 supply current vs. rs+ voltage max4173 toc03 v rs+ (v) supply current (ma) max4173t max4173h max4173f -0.60 -0.45 -0.30 -0.15 0 0.15 0.30 0.45 0.60 01 0 5 15202530 total output error vs. supply voltage max4173 toc04 supply voltage (v) total output error (%) max4173f v sense = 100mv max4173t max4173h 0 -100 100 1k 10k 100k 1m 10m power-supply rejection vs. frequency -80 max4173 toc07 frequency (hz) psr (db) -60 -40 -20 -10-90 -70 -50 -30 -6 -2-4 20 4 6 01 0 1 5 5 202530 total output error vs. supply voltage max4173 toc05 supply voltage (v) total output error (%) max4173f v sense = 6.25mv max4173h max4173t -2 0 -1 21 3 4 0 100 50 150 200 total output error vs. full-scale sense voltage max4173 toc06 v sense (mv) total output error (%) max4173f v cc = 28v max4173h max4173t -10 -8 -6 -4 -2 0 2 4 6 01 0 5 15202530 total output error vs. common-mode voltage max4173 toc08 common-mode voltage (v) total output error (%) max4173f max4173t max4173h typical operating characteristics (v cc = +12v, v rs+ = +12v, v sense = +100mv, t a = +25?, unless otherwise noted.) -1.2 -0.4-0.8 0 0.4 0.8 1.2 -50 -20 -5 10 -35 2540557085 gain accuracy vs. temperature max4173 toc09 temperature (?) gain accuracy (%) max4173f max4173h max4173t 4 maxim integrated max4173 downloaded from: http:///
low-cost, sot23, voltage-output, high-side current-sense amplifier typical operating characteristics (continued) (v cc = +12v, v rs+ = +12v, v sense = +100mv, t a = +25?, unless otherwise noted.) -2.0 -1.0-1.5 0.5 0 -0.5 1.51.0 2.0 -50 -5 10 -35 -20 25 40 55 70 85 total output error vs. temperature max4173 toc10 temperature (?) total output error (%) max4173h max4173t max4173f 2 s/div max4173t large-signal transient response (v sense = 6mv to 100mv) in (45mv/div) out (500mv/div) 6mv 100mv2v 0.120v max4173 toc11 c l = 5pf 2 s/div max4173f large-signal transient response (v sense = 6mv to 100mv) in (45mv/div) out (2v/div) 6mv 100mv5v 0.3v max4173 toc12 c l = 5pf 2 s/div max4173h large-signal transient response (v sense = 6mv to 100mv) in (45mv/div) out (3v/div) 6mv 100mv10v 0.6v max4173 toc13 c l = 5pf 2 s/div max4173t small-signal transient response (v sense = 95mv to 100mv) in (5mv/div) out (50mv/div) 95mv 100mv2.0v 1.9v max4173 toc14 c l = 5pf 2 s/div max4173f small-signal transient response (v sense = 95mv to 100mv) in (5mv/div) out (100mv/div) 95mv 100mv5v 4.75v max4173 toc16 c l = 5pf maxim integrated 5 max4173 downloaded from: http:///
low-cost, sot23, voltage-output, high-side current-sense amplifier pin description typical operating characteristics (continued) (v cc = +12v, v rs+ = +12v, v sense = +100mv, t a = +25?, unless otherwise noted.) 2 s/div max4173h small-signal transient response (v sense = 95mv to 100mv) in (5mv/div) out (200mv/div) 95mv 100mv10v 9.5v max4173 toc15 c l = 5pf 5 s/div start-up delay (v cc = 0 to 4v) (v sense = 100mv) in (2v/div) out (1v/div) 0v 4v2v 0v max4173 toc17 6 load-side connection for the external sense resistor rs- 5 function name so pin sot23 1 supply voltage input. bypass to gnd with a 0.1? capacitor. v cc 3 4 voltage output. v out is proportional to v sense ( v rs+ - v rs- ). output impedance is approximately 12k ? . out 6 3 ground gnd 1, 2 8 power-side connection to the external sense resistor rs+ 4 2, 5, 7 no connection. not internally connected. n.c. 6 maxim integrated max4173 downloaded from: http:///
low-cost, sot23, voltage-output, high-side current-sense amplifier detailed description the max4173 high-side current-sense amplifier fea-tures a 0 to +28v input common-mode range that is independent of supply voltage. this feature allows the monitoring of current out of a battery in deep discharge and also enables high-side current sensing at voltages greater than the supply voltage (v cc ). the max4173 operates as follows: current from the source flows through r sense to the load (figure 1). since the internal-sense amplifier? inverting input has highimpedance, negligible current flows through rg2 (neglecting the input bias current). therefore, the sense amplifier? inverting-input voltage equals v source - (i load )(r sense ). the amplifier? open-loop gain forces its noninverting input to the same voltage asthe inverting input. therefore, the drop across rg1 equals (i load )(r sense ). since i rg1 flows through rg1, i rg1 = (i load )(r sense ) / rg1. the internal current mirror multiplies i rg1 by a current gain factor, , to give i rgd = i rg1 . solving i rgd = (i load )(r sense ) / rg1. assuming infinite output impedance, v out = (i rgd ) (rgd). substituting in for i rgd and rearranging, v out = (rgd / rg1)(r sense i load ). the parts gain equals rgd / rg1. therefore, v out = (gain) (r sense ) (i load ), where gain = 20 for max4173t, gain = 50 for max4173f, and gain = 100 for max4173h. set the full-scale output range by selecting r sense and the appropriate gain version of the max4173. applications information recommended component values the max4173 senses a wide variety of currents withdifferent sense resistor values. table 1 lists common resistor values for typical operation of the max4173. choosing r sense to measure lower currents more accurately, use a highvalue for r sense . the high value develops a higher sense voltage that reduces offset voltage errors of theinternal op amp. in applications monitoring very high currents, r sense must be able to dissipate the i 2 r losses. if the resistor? rated power dissipation is exceeded, its value may driftor it may fail altogether, causing a differential voltage across the terminals in excess of the absolute maxi- mum ratings. if i sense has a large high-frequency component, mini- mize the inductance of r sense . wire-wound resistors have the highest inductance, metal-film resistors aresomewhat better, and low-inductance metal-film resis- tors are best suited for these applications. using a pcb trace as r sense if the cost of r sense is an issue and accuracy is not critical, use the alternative solution shown in figure 2.this solution uses copper pc board traces to create a sense resistor. the resistivity of a 0.1-inch-wide trace of 2-ounce copper is approximately 30m ? /ft. the resis- tance-temperature coefficient of copper is fairly high(approximately 0.4%/?), so systems that experience a wide temperature variance must compensate for this effect. in addition, do not exceed the maximum power dissipation of the copper trace. for example, the max4173t (with a maximum load cur- rent of 10a and an r sense of 5m ? ) creates a full-scale v sense of 50mv that yields a maximum v out of 1v. r sense in this case requires about 2 inches of 0.1 inch- wide copper trace. output impedance the output of the max4173 is a current source driving a12k ? resistance. resistive loading added to out reduces the output gain of the max4173. to minimizeoutput errors for most applications, connect out to a high-impedance input stage. when output buffering is required, choose an op amp with a common-mode input range and an output voltage swing that includes ground when operating with a single supply. the op r sense v source 0 to +28v +3v to +28v rgd = 12k v out i rg1 i rgd i load r g1 r g2 rs- rs+ out gnd to load battery v cc current mirror a1 max4173 figure 1. functional diagram maxim integrated 7 max4173 downloaded from: http:///
low-cost, sot23, voltage-output, high-side current-sense amplifier amp? supply voltage range should be at least as highas any voltage the system may encounter. the percent error introduced by output loading is determined with the following formula: where r load is the external load applied to out. current source circuit figure 3 shows a block diagram using the max4173with a switching regulator to make a current source. % 100 r 12k r 1 error load load = ?+ ? ? ? ? ? ? table 1. recommended component values max4173t v sense r sense +3v to +28v 0.1 f rs+ + 0.3 in. copper input load/battery 0.3 in. copper 0.1 in. copper rs- gnd out v cc _ figure 2. max4173 connections showing use of pc board figure 3. current source max4173 r sense i load 0 to +28v v sense v cc out v in gnd rs+ +3v to +28v 0.1 f rs- load/ battery low-cost switching regulator 10.0 100 5.0 50 2.0 10 10 20 10.0 100 5.0 50 2.0 5 20 20 10.0 100 5.0 50 2.0 1 100 20 10.0 100 5.0 50 1000 current-sense resistor r sense (m ? ? ) 20 gain 2.0 0.1 full-scale output voltage (full-scale v sense = 100mv) v out (v) full-scale load current i load (a) 8 maxim integrated max4173 downloaded from: http:///
rs- n.c. out 12 8 7 rs+ n.c. n.c. gnd v cc 3 4 6 5 max4173 so + pin configurations low-cost, sot23, voltage-output, high-side current-sense amplifier 5 rs- gnd gnd rs+ v cc 1 + 6 out max4173 234 sot23 top view package type package code outline no. land pattern no. 8 so s8+4 21-0041 90-0096 6 sot23 u6+2 21-0058 90-0175 package information for the latest package outline information and land patterns(footprints), go to www.maxim-ic.com/packages . note that a ?? ?? or ??in the package code indicates rohs status only.package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. maxim integrated 9 max4173 downloaded from: http:///
low-cost, sot23, voltage-output, high-side current-sense amplifier revision history revision number revision date description pages changed 4 6/10 clarified 0v to 2v is not a high-accuracy range for the device, added lead-freeoptions and soldering temperature 1, 2 5 4/11 updated v rs+ conditions to synchronize with tested material 2, 3 max4173 downloaded from: http:/// 0 d [ l p , q w h j u d w h g 5 l r 5 r e o h v 6 d q - r v h & $ 8 6 $ maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidance. ? maxim integrated the maxim logo and maxim integrated are trademarks of maxim integrated products, inc.
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