? semiconductor components industries, llc, 2012 november, 2012 ? rev. 2 1 publication order number: CAT2300/d CAT2300 sensefet current monitor for 0.9 v - 1.5 v bus description CAT2300 is a controller for sensefet ? mosfet current monitoring in high-side switch applications. CAT2300 provides current mirroring and on/off control for sensefet mosfets. exact control and matching of the sense output of the sensefet with the kelvin voltage insures accurate current monitoring over a couple of decades of current. designed for use with ntmfs4833nst1g, ntmfs4854nst1g or similar sensefet mosfets from on semiconductor, CAT2300 is the single chip alternative to discrete circuits for monitoring and controlling 0.9 v ? 1.5 v power busses. when teamed with a sensefet, CAT2300 will track currents up to 25 a and resolve currents below 100 ma. CAT2300 provides logic level on/off control of the power mosfet and its own internal circuitry, reducing power consumption to virtually zero milliwatts. packaged in a space saving low profile 2 x 3 mm tdfn, CAT2300 operates over the full industrial temperature range of ? 40 c to +85 c. features ? precision current measurement of 0.9 v ? 1.5 v power supply rails ? on/off power fet control with soft ? start ? sense current mirroring to 70 ma (equal to 25 a flowing in the power bus) ? user adjustable current to voltage conversion ratio ? 150 v typical matching between kelvin and sense leads ? less than 1 a current consumption in shutdown mode ? this device is pb ? free, halogen free/bfr free and rohs compliant typical applications ? portable computers ? backplane bus control ? power distribution figure 1. system application sensefet power bus enable system load CAT2300 i measure http://onsemi.com see detailed ordering and shipping information in the package dimensions section on page 7 of this data sheet. ordering information pin configuration tdfn ? 8 vp2 suffix case 511ak sense ks kelvin gate 1 gnd v dd en i meas (top view) marking diagram f3t = specific device code l = assembly location code aa = assembly lot number = (last two digits) y = production year (last digit) m = production month (1 ? 9, o, n, d) = pb ? free microdot f3t laa ym device package shipping ? ordering information CAT2300 tdfn 3,000 / tape & reel marking f3t ?for information on tape and reel specifications, including part orientation and tape sizes, please refer to our tape and reel packaging specification brochure, brd8011/d.
CAT2300 http://onsemi.com 2 vreg gnd sense ks kelvin gate en 250 a 1 0 figure 2. simplified block diagram i meas + ? v dd table 1. pin function description pin no. pin name function 1 sense connects to sense pin of sensefet and directs sensed current to imeas output. 2 ks kelvin sense; a kelvin connection for the current mirror control amplifier. this connection must be made directly to sense on the sensefet package. do not share any trace length with CAT2300?s sense lead. 3 kelvin connects to kelvin pin of the sensefet. serves as the reference point for sense lead biasing. 4 gate connects to gate of the sensefet and controls sensefet operation. 5 gnd electrical ground for ic. 6 v dd external voltage supply for driving the gate of the sensefet and power supply for CAT2300 internal circuitry via an internal voltage regulator. 7 en enable: high true logic input. turns on sensefet and CAT2300?s internal circuitry. a logic low on en grounds gate, shutting off the sensefet and shuts down the internal current source and mirroring circuitry. 8 i meas sensed current output. a resistor between i meas and ground develops a voltage proportional to the current flowing through the sensefet. pad backside paddle is internally connected to gnd. this pad may be left floating but if connected with pcb it must be to the ground plane of circuitry which is also grounded. table 2. absolute maximum ratings (note 1) parameter symbol value unit v dd v dd 6.5 v gate 15 ma v k , en, sense, ks, kelvin, i meas 6.5 v junction temperature 150 c stresses exceeding maximum ratings may damage the device. maximum ratings are stress ratings only. functional operation above t he recommended operating conditions is not implied. extended exposure to stresses above the recommended operating conditions may af fect device reliability. 1. guaranteed by design. table 3. recommended operating conditions parameter symbol value unit v k v k 0.9 to 1.5 v v dd v dd 5 v maximum junction temperature t junction 125 c ambient temperature range t ambient ? 40 to +85 c
CAT2300 http://onsemi.com 3 table 4. package thermal performance package symbol test conditions min typ max unit tdfn ? 8 ja 1 oz copper thickness, 100 mm 2 160 c/w jc 35 soic ? 8 ja 1 oz copper thickness, 100 mm 2 160 c/w jc 25 table 5. dc electrical characteristics (v k = 0.9 ? 1.5 v; v dd = +5 v; t ambient = ? 40 c to +85 c, t junction = ? 40 c to +125 c, unless otherwise specified.) parameter symbol test conditions limits units min typ max kelvin voltage v k 0.9 1.5 v gate drive input voltage v dd 4.5 5.5 v supply current on v dd pin i vdd en = logic 0 1 a en = logic 1 65 77 100 a gate drive sourcing i gate v gate = v dd ? 1 v ? 235 ? 280 ? 330 a gate drive sinking v gate = 0.6 v 7 9.6 13 ma offset voltage v os v os = v kelvin ? v sense v k = 0.9 v to 1.5 v 150 300 v input bias current; kelvin and ks inputs i k 100 150 na power supply rejection ratio psrr 70 db i meas output current i meas 0 70 ma output voltage of i meas amplifier v o_im 0 v k ? 0.1 v logic low level input voltage v il en 0.9 1.1 1.26 v high level input voltage v ih en 1.4 1.65 1.9 v hysteresis 0.55 v low level input current i il en, v dd = 0 v or 5.5 v 2 a high level input current i ih en, v dd = 0 v or 5.5 v 2 a table 6. ac operating characteristics (v k = 0.9 v ? 1.5 v; v dd = 5 v; t ambient = ? 40 c to +85 c, t junction = ? 40 c to +125 c, unless otherwise specified.) parameter symbol test conditions limits units min typ max i meas output rise time t r 20 , 100 pf, v k = 1.5 v i sense : 2 ma ? 70 ma 38 s i meas output fall time t f 33 s i meas settling time t s en = logic 0 1, i sense = 1 ma 30 s en = logic 0 1, i sense = 70 ma 50 s
CAT2300 http://onsemi.com 4 typical performance characteristics figure 3. load step: 1 a ? 10 a 50 s / div i bus v meas pin description sense sense connects directly to the sensefet? s sense pin and directs the sensed current to the i meas output. sense is controlled by an amplifier with a fet follower stage to maintain sense at exactly the kelvin voltage, thus insuring accuracy of the sensefet?s mirror current. ks ks = kelvin sense; a kelvin connection for the mirroring amplifier. current measurement accuracy is dependent upon the voltage match between the sensefet?s sense and kelvin leads. to minimize voltage losses in the pcb trace between ca t2300 and the sensefet, a kelvin connection for the control amplifier is provided. ks must be a dedicated connection, shared by no other circuitry , and tied directly to the sense pin on of the sensefet. figure 4. current sense sensefet sensefet sensefet careful layout is critical in achieving full sensefet perfomance. pcb trace resistance can no longer be ignored as it can be in typical low current circuit designs. microvolt offsets ( v) produce meaningful errors in current ratio tracking. a few milliohms of trace resistance carrying a few milliamps of current produces microvolts of potential difference between CAT2300 and the sensefet. to circumvent this error CAT2300 provides a kelvin lead (ks) for monitoring the sensefet?s sense pin. under no circumstances should the ks connection share any portion of the current path between the sense pins of CAT2300 and the sensefet. doing so will degrade measurement accuracy. kelvin kelvin connects directly to the sensefet?s kelvin pin and acts the reference voltage for CAT2300?s mirroring circuit. it too must be a dedicated connection, shared by no other circuitry. gate gate connects to the sensefet?s gate pin and controls the sensefet?s operation. gate is controlled by en: a logic 1 turns the sensefet on, a logic 0 turns it off. when on, voltage is applied to the sensefet?s gate via a current source inside CAT2300. by controlling the gate drive current a controlled turn-on is achieved. faster turn-on times can be done by adding a supplemental current source to augment the internal current source. placing a resistor between v dd and gate will provide extra current and boost turn-on speeds. for a softer turn-on characteristic, add capacitance between the sensefet?s gate and source pins; approximately 1 nf for every ms of increased delay. when switching off the sensefet, gate provides a strong pull-down, 7.5 ma typical, so the sensefet will be switched off quickly.
CAT2300 http://onsemi.com 5 v dd v dd provides gate drive for the sensefet and power for CAT2300?s internal circuitry and must be +5 v. i meas i meas is the mirror current output. placing a resistor between i meas and ground produces a voltage proportional to i bus . the maximum voltage producible at imeas is the kelvin voltage (v k ) ? 0.1 v. this sets a limitation on the maximum value of r meas . r meas v k 0.1 v i sense csr v k 0.1 v i bus where: csr = current sensing ratio taken from the sensefet data sheet. i bus = max current through the sensefet. en enable is a high true logic input controlling the sensefet?s on/off state. a logic high on en turns the switch on; a logic low turns it off. bus turn-on time is controlled by the fet?s input gate capacitance and the drive current applied to the gate. to minimize power consumption en disables the internal gate drive current source and current mirroring circuitry whenever the sensefet is off. vreg CAT2300 ntmf4834ns gnd sense sense ks kelvin kelvin source drain gate gate en 250 a 1 0 figure 5. typical application v dd i bus v in v out i sense i meas v meas + ?
CAT2300 http://onsemi.com 6 package dimensions tdfn8, 2x3 case 511ak ? 01 issue a pin#1 identification e2 e a3 eb d a2 top view side view bottom view pin#1 index area front view a1 a l d2 notes: (1) all dimensions are in millimeters. (2) complies with jedec mo-229. symbol min nom max a 0.70 0.75 0.80 a1 0.00 0.02 0.05 a3 0.20 ref b 0.20 0.25 0.30 d 1.90 2.00 2.10 d2 1.30 1.40 1.50 e 3.00 e2 1.20 1.30 1.40 e 2.90 0.50 typ 3.10 l 0.20 0.30 0.40 a2 0.45 0.55 0.65
CAT2300 http://onsemi.com 7 ordering information part number temperature range package quantity per reel (note 5) package marking CAT2300vp2 ? gt3 ? 40 c to +85 c tdfn 3,000 f3t 2. all packages are rohs ? compliant (lead ? free, halogen ? free). 3. the standard lead finish is nipdau pre ? plated (ppf). 4. for additional package and temperature options, please contact your nearest on semiconductor sales office. 5. for information on tape and reel specifications, including part orientation and tape sizes, please refer to our tape and reel packaging specifications brochure, brd8011/d. on semiconductor and are registered trademarks of semiconductor co mponents industries, llc (scillc). scillc owns the rights to a numb er of patents, trademarks, copyrights, trade secrets, and other intellectual property. a list ing of scillc?s product/patent coverage may be accessed at ww w.onsemi.com/site/pdf/patent ? marking.pdf. scillc reserves the right to make changes without further notice to any products herein. scillc makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does scillc assume any liability arising out of the application or use of any product or circuit, and s pecifically disclaims any and all liability, including without limitation special, consequential or incidental damages. ?typical? parameters which may be provided in scillc data sheets and/ or specifications can and do vary in different applications and actual performance may vary over time. all operating parame ters, including ?typicals? must be validated for each customer application by customer?s technical experts. scillc does not convey any license under its patent rights nor the right s of others. scillc products are not designed, intended, or a uthorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in whic h the failure of the scillc product could create a situation where personal injury or death may occur. should buyer purchase or us e scillc products for any such unintended or unauthorized appli cation, buyer shall indemnify and hold scillc and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unin tended or unauthorized use, even if such claim alleges that scil lc was negligent regarding the design or manufacture of the part. scillc is an equal opportunity/affirmative action employer. this literature is subject to all applicable copyrig ht laws and is not for resale in any manner. publication ordering information n. american technical support : 800 ? 282 ? 9855 toll free usa/canada europe, middle east and africa technical support: phone: 421 33 790 2910 japan customer focus center phone: 81 ? 3 ? 5817 ? 1050 CAT2300/d sensefet is a registered trademark of semiconductor components industries, llc literature fulfillment : literature distribution center for on semiconductor p.o. box 5163, denver, colorado 80217 usa phone : 303 ? 675 ? 2175 or 800 ? 344 ? 3860 toll free usa/canada fax : 303 ? 675 ? 2176 or 800 ? 344 ? 3867 toll free usa/canada email : orderlit@onsemi.com on semiconductor website : www.onsemi.com order literature : http://www.onsemi.com/orderlit for additional information, please contact your local sales representative
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