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? semiconductor components industries, llc, 2014 1 publication order number: november 2014- rev. 2 LV8714TA/d LV8714TA dual stepper motor driver with ultra-small micro steps the lv8714 is a fully integrated dual bipolar/unipolar stepper motor driver with ultra-small micro step drive capability. alte rnatively, it can be used to drive four dc motors independently. the device includes low r ds(on) (upper + lower = 0.9 ? ) type mosfets based quad h-bridges with gate drivers and can drive up to 1.5a per h-bridge. synchronous rectification control is implemented for all h-bridges to lower power dissipation during a mosfet switching. the device implements constant-current control using pwm at 125 khz (typ.) switching frequency that enables the least noise motor drive solution. a built-in linear regulator powers internal logic circuit directly from the motor supply voltage, v m, thus eliminating need fo r any external regulator. a proprietary internal current sens ing mechanism is implemented that eliminates up to four exte rnal current sense power resistors and improves the system energy efficiency significantly. external v ref input signal for each h-bridge controls the drive step size and can achieve over 256 micro step resolution. individual controls signals (enax and inx) are provided for controlling each h-bridge channel independently with forward and reverse direction control. to enhance energy efficiency further, the device can be put into a power saving standby mode, when idle. features ? integrated quad h-bridges with independent controls o dual bipolar/unipolar stepper motor or quad dc motor drive o forward and reverse direction control ? low r ds(on) (upper + lower = 0.9 ? ) type mosfets ? proprietary internal current sensing o eliminates up to four external current sense power resistors ? over 256 micro step resolution with external v ref inputs ? single supply operation with a built-in internal regulator ? no external component for driving internal mosfets ? constant-current control with 125 khz (typ.) pwm switching frequency ? low power standby mode when idle ? synchronous rectification to reduce power dissipation ? in-built system protection features such as: o under-voltage o over-current o over-temperature typical applications ? surveillance camera ? stage light ? scanner ? printer www.onsemi.com 48-pin tqfp with exposed pad 7 mm x 7 mm marking diagram ordering information ordering code: LV8714TA-nh package tqfp48 ep (pb-free / halogen free) shipping (qty / packing) 1000 / tape & reel xxxxxxxxxx xxxxxxxxxx awlyywwg xxxxx = specific device code a = assembly location wl = wafer lot yy = year ww = work week g= pb ? free package 1
LV8714TA www.onsemi.com 2 block diagram figure 1. LV8714TA block diagram
LV8714TA www.onsemi.com 3 application circuit examples 37 nc 38 pgnd2 39 nc 40 out2a 41 nc 42 out2b 43 out1b 44 nc 45 out1a 46 nc 47 pgnd1 48 nc 1 2 ena1 3 in1 4 vref1 5 rcs1 6 ps 7 vreg3 8 rcs3 9 vref3 10 in3 11 ena3 12 vm3 24 23 22 21 20 19 18 17 16 15 14 13 nc pgnd4 nc out4a nc out4b out3b nc out3a nc pgnd3 nc 36 35 34 33 32 31 30 29 28 27 26 25 ena2 in2 vref2 rcs2 gnd nc rcs4 vref4 in4 ena4 vm4 vm2 vm1 1.5k ? 1.5k ? 1.5k ? 1.5k ? 47f 12v 0.1f logic input logic input logic input logic input logic input m m figure 2. two bipolar stepper motor drive using LV8714TA
LV8714TA www.onsemi.com 4 37 nc 38 pgnd2 39 nc 40 out2a 41 nc 42 out2b 43 out1b 44 nc 45 out1a 46 nc 47 pgnd1 48 nc 1 2 ena1 3 in1 4 vref1 5 rcs1 6 ps 7 vreg3 8 rcs3 9 vref3 10 in3 11 ena3 12 vm3 24 23 22 21 20 19 18 17 16 15 14 13 nc pgnd4 nc out4a nc out4b out3b nc out3a nc pgnd3 nc 36 35 34 33 32 31 30 29 28 27 26 25 ena2 in2 vref2 rcs2 gnd nc rcs4 vref4 in4 ena4 vm4 vm2 vm1 1.5k ? 1.5k ? 1.5k ? 1.5k ? 47f 12v 0.1f logic input logic input logic input logic input logic input m m m m figure 3. four brushed dc motor drive using LV8714TA
LV8714TA www.onsemi.com 5 figure 4. two unipolar stepper motor drive using LV8714TA
LV8714TA www.onsemi.com 6 pin assignment 37 nc 38 pgnd2 39 nc 40 out2a 41 nc 42 out2b 43 out1b 44 nc 45 out1a 46 nc 47 pgnd1 48 nc 24 23 22 21 20 19 18 17 16 15 14 13 nc pgnd4 nc out4a nc out4b out3b nc out3a nc pgnd3 nc figure 5. pin assignment
LV8714TA www.onsemi.com 7 pin function discription pin no. pin name description 1 vm1 motor power supply pin for channel 1 2 ena1 enable control pin of channel 1 3 in1 input control pin of channel 1 4 vref1 reference voltage input pin of channel 1 5 rcs1 current sense resi stor pin of channel 1 6 ps power save mode selection pin 7 vreg3 internal 3.3v voltage regulator pin 8 rcs3 current sense resi stor pin of channel 3 9 vref3 reference voltage input pin of channel 3 10 in3 input control pin of channel 3 11 ena3 enable control pin of channel 3 12 vm3 motor power supply pin for channel 3 13 nc no connection 14 pgnd3 channel 3 power ground pin 15 nc no connection 16 out3a channel 3 phase output a pin 17 nc no connection 18 out3b channel 3 phase output b pin 19 out4b channel 4 phase output b pin 20 nc no connection 21 out4a channel 4 phase output a pin 22 nc no connection 23 pgnd4 channel 4 power ground pin 24 nc no connection 25 vm4 motor power supply pin for channel 4 26 ena4 enable control pin of channel 4 27 in4 input control pin of channel 4 28 vref4 reference voltage input pin of channel 4 29 rcs4 current sense resi stor pin of channel 4 30 nc no connection 31 gnd ground pin 32 rcs2 current sense resi stor pin of channel 2 33 vref2 reference voltage input pin of channel 2 34 in2 input control pin of channel 2 35 ena2 enable control pin of channel 2 36 vm2 motor power supply pin for channel 2 37 nc no connection 38 pgnd2 channel 2 power ground pin 39 nc no connection 40 out2a channel 2 phase output a pin 41 nc no connection 42 out2b channel 2 phase output b pin 43 out1b channel 1 phase output b pin 44 nc no connection 45 out1a channel 1 phase output a pin 46 nc no connection 47 pgnd1 channel 1 power ground pin 48 nc no connection
LV8714TA www.onsemi.com 8 maximum ratings (note 1) parameter symbol value unit motor supply voltage (note 2) v m 18 v logic input voltage (note 3) v in 6 v output peak current per channel (note 4) i o(peak) 1.75 a output current per channel i o(max) 1.5 a allowable power dissipation (note 5) pd 4.86 w storage temperature t stg ? 55 to 150 ? c junction temperature t j 150 oc moisture sensitivity level (msl) (note 6) msl 3 - lead temperature soldering pb-free versions (10sec or less) (note 7) t sld 260 oc 1. stresses exceeding those listed in the absolute maximum rating table may damage the device. if any of these limits are exceeded , device functionality should not be assumed, damag e may occur and reliability may be affected. 2. motor power supply pins are vm1, vm2, vm3 and vm4. 3. logic input pins are ps, ena1, in1, ena2, in2, ena3, in3, ena4 and in4. 4. condition for measuring the output peak cu rrent is that total time duration 10 ms (pwm duty cycle = 20%) at each channel. 5. specified circuit board : 90mm ? 90mm ? 1.6mm, glass epoxy 4-layer board, with backside mounting. it has 1 oz internal power and ground planes and 1/2 oz copper traces on top and bottom of the board. please refer to thermal test conditions of page 23. 6. moisture sensitivity level (msl): 3 per ipc/jedec standard: j-std-020a 7. for information, please refer to our soldering and mounting techniques reference manual, solderrm/d http://www.onsemi.com/pub_link/collateral/solderrm-d.pdf thermal characteristics parameter symbol value unit thermal resistance, junction-to-ambient (note 5) r ja 25.7 oc/w thermal resistance, junction-to-case (top) (note 5) r jt 6 oc/w figure 6. power dissipation vs am bient temperature characteristic 0.00 1.00 2.00 3.00 4.00 5.00 6.00 -20 0 20 40 60 80 100 allowable power dissipation, pd (w) ambient temperature, t a ( ? c) 4.86 2.52 4-layer circuit board with backside mounting
LV8714TA www.onsemi.com 9 recommended operating ranges (note8) parameter symbol ratings unit motor supply voltage range (note 2) v m 4 to 16.5 v logic input voltage range (note 3) v in ? 0.3 to 5.5 v vref input voltage range v ref 0 to 1.5 v ambient temperature t a ? 20 to 85 oc 8. functional operation above the stresses listed in the recommended o perating ranges is not implied. extended exposure to stresse s beyond the recommended operating ranges limits may affect device reliability. electrical charactericals t a =25oc, v m = 12v, vref=0.6v unless otherwise noted. (note 9) parameter symbol condition min typ max unit standby mode current i mstn i m1 (vm1)+i m2 (vm2)+i m3 (vm3)+i m4 (vm4), ps=?l?, no load 0 1 a supply current i m i m1 (vm1)+i m2 (vm2)+i m3 (vm3)+i m4 (vm4), ps=?h?, no load 3.2 4.2 ma thermal shutdown temperature tsd guaranteed by design 150 180 ? c thermal hysteresis width ? tsd guaranteed by design 40 ? c regulator reg3 output voltage v reg3 3 3.3 3.6 v output output on resistance ronu i o = ? 1.5a, upper side 0.6 0.85 ? ronl i o =1.5a, lower side 0.3 0.5 ? output leakage current i oleak v m =16.5v 10 a diode forward voltage v f i f = ? 1.5a 1.2 1.6 v logic input logic pin input current i inl ps,ena1,in1,ena2,in2,ena3,in3,ena4,in4 ,v in =0.8v 4.8 8 13.3 a i inh ps,ena1,in1,ena2,in2,ena3,in3,ena4,in4 ,v in =3.3v 20 33 55 a logic input voltage high v inh ps,ena1,in1,ena2,in2,ena3,in3,ena4,in4 2.0 5.5 v low v inl 0 0.8 v pwm current control vref pin input current i ref vref1,vref2,vref3,vref4 v ref =1.5v ? 0.5 a current detectionreference voltage v refdet vref1,vref2,vref3,vref4 v ref =0.6v 0.18 0.2 0.22 v pwm (chopping) frequency fchop 100 125 150 khz output current detection current ircs rcs1,rcs2,rcs3,rcs4,io=0.5a,rsc=0v 115 125 137 a 9. product parametric performance is indicated in the electrical characteristics for t he listed test conditions, unless otherwise noted. product performance may not be indicated by the electrical characteristics if operated under different conditions.
LV8714TA www.onsemi.com 10 typical characteristics 0.00 0.10 0.20 0.30 0.40 0.50 024681012141618 i mstn (ua) v m (v) figure 7. standby mode supply current vs vm voltage 0 0.5 1 1.5 2 2.5 3 3.5 4 2 4 6 8 10 12 14 16 18 v reg3 (v) v m (v) figure 9. reg3 output voltage vs vm voltage 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 0.5 1 1.5 ron ( ? ) i out (a) figure 11. output on resistance vs output current (vm=12v) outxa_ronu outxa_ronl outxb_ronu outxb_ronl 0 0.5 1 1.5 2 2.5 3 3.5 2 4 6 8 10 12 14 16 18 i m (ma) v m (v) figure 8. supply current vs vm voltage 0 0.5 1 1.5 2 2.5 3 3.5 4 0 5 10 15 20 25 30 35 v reg3 (v) i reg3 (ma) figure 10. reg3 output voltage vs reg3 output current 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 -25 0 25 50 75 100 125 ronu+ronl ( ? ) temperature ( ? c) figure 12. output on resistance vs temperature (vm=12v)
LV8714TA www.onsemi.com 11 typical characteristics 0 0.2 0.4 0.6 0.8 1 1.2 0 0.5 1 1.5 v f (v) i out (a) figure 13. diode forward voltage vs output current vfu vfl 0 10 20 30 40 50 60 0123456 i in (ua) v in (v) figure 15. ena1-4 pin input current vs ena1-4 input voltage ena1 ena2 ena3 ena4 0.0 0.5 1.0 1.5 2.0 4 6 8 1012141618 v in (v) v m (v) figure 17. ps pin h/l-level input voltage vs vm voltage vinh vinl 0 10 20 30 40 50 60 70 0123456 i in (ua) v in (v) figure 14. ps pin input current vs ps pin input voltage 0 10 20 30 40 50 60 0123456 i in (ua) v in (v) figure 16. in1-4 pin input current vs in1-4 input voltage in1 in2 in3 in4 0.0 0.5 1.0 1.5 2.0 4 6 8 10 12 14 16 18 v in (v) v m (v) figure 18. ena1-4 h/l-level input voltage vs vm voltage ena1_vinh ena2_vinh ena3_vinh ena4_vinh ena1_vinl ena2_vinl ena3_vinl ena4_vinl vinh vinl
LV8714TA www.onsemi.com 12 typical characteristics 0.0 0.5 1.0 1.5 2.0 4 6 8 1012141618 v in (v) v m (v) figure 19. in1-4 h/l-level input voltage vs vm voltage in1_vinh in2_vinh in3_vinh in4_vinh in1_vinl in2_vinl in3_vinl in4_vinl 110 112 114 116 118 120 3 8 13 18 pwm (chopping) frq (khz) v m (v) figure 21. pwm (chopping) frq vs vm voltage -18 -16 -14 -12 -10 -8 -6 -4 -2 0 0 0.5 1 1.5 2 i ref (na) vref1-4 (v) figure 20. vrefx pin input current vs v ref voltage vref1 vref2 vref3 vref4 0 100 200 300 400 500 00.511.5 ircs (ua) i out (a) figure 22. output detection current vs i out (rcs=0v) out1a out1b out2a out2b out3a out3b out4a out4b vinh vinl
LV8714TA www.onsemi.com 13 functional description power supply pins (vm1, vm2, vm3 and vm4) the lv8714 has four power supply pins, vm1, vm2, vm3, and vm4, connected internally. hence, it is must that all power supply pins are connected to the same power supply rail externally. vm1 also supplies power to internal circuits through an internal voltage regulator. it is highly recommended to provide a decoupling capacitor of 47f close to the vm1 pin. internal 3.3v voltage regulator pin (vreg3) an internal 3.3v voltage regulator acts a power source for internal logic, oscillator, and protection circuits. output of this regulator is connected to the vreg3 pin. do not use the vreg3 pin to drive any external load. it is recommended to connect a 0.1f decoupling capacitor to the vreg3 pin. internal regulator (vm-3.3v) an vm-3.3v regulator is integrated in the lv8714. this regulator provides required biasing for upper mosfets of each channel. power save mode selection pin (ps) when the lv8714 is idle, to save power, it can be put to a power saving, standby mode by applying logic low to the ps pin. while in the standby mode, all internal circuits of the lv8714 including voltage regulators are put into inactive state. table 1 shows mode selection of the lv8714 using the ps pin logic input at ps pin mode internal ci r cuits low or open standb y inactive high operating active table 1: lv8714 mode selection using the ps pin figure 23 shows an equivalent internal circuit of the ps pin input. vm1 63k ? gnd 37k ? 500k ? ps figure 23. equivalent circuit of the ps pin channel control pins (enax, inx) each channel of the lv8714 is controlled independently by corresponding enax and inx pins. figure 24 shows an equivalent internal circuit of these input pins. gnd vreg3 100k ? 2.9k ? enax inx figure 24. equivalent circuit of enax, inx motor drive output pins (outxx) the lv8714 has quad built-in h-bridges for driving stepper or dc motors. each h-bridge (channel) is made up of upper side p-mosfets and lower side n-mosfets. output of each channel is connected to outxa or outxb pins. when a channel is configured to drive a stepper motor in forward direction, outxa becomes high output and in reverse direction, outxb becomes high output. reference voltage input pins (vrefx) step size of a stepper motor drive is controlled by providing a reference voltage signal at vrefx pin for each channel. resolution of the vrefx input enables ultra-small micro step driv e of a stepper motor in combination with the inx input. the coil current is proportional to the analog voltage amplitude at the vrefx pin. figure 25 shows an equivalent circuit of vrefx input pins. gnd vreg3 2.9k ? vrefx figure 25. equivalent circuit of vref1-4 current sense resist or pins (rcsx) the lv8714 implements a proprietary current sense mechanism for each channel and doesn?t require any external current sense power resistor, thus providing
LV8714TA www.onsemi.com 14 loss-less current control that improves the energy efficiency of the system. to control a coil current, the individual rcsx pin is provided for each channel. a resistor connected at this rcsx pin decides the coil current. the coil current is sensed internally and fed back to rcs pin with the ratio of 1/4000. and, the output du ty cycle adjusted such that the rcsx voltage level is equal to 1/3 of the vrefx pin voltage. figure 26 shows the equivalent circuit of current control. figure 26. equivalent circuit of current control equation 1 is utilized to calculate the coil current, i out. 4000 ? 3 1 where, i out = coil current [a] r cs = resistance between rcsx and gnd [ ? ] v ref = input voltage at the vrefx pin [v] for example, in case of 1 k 0.6 the coil current is 4000 0.6 3 1000 0.8
LV8714TA www.onsemi.com 15 detailed description stepper motor direction control the stepper motor rotation direction is determined by phase lead/lag relation between inx inputs of the lv8714 as shown in table 2 and table 3. inx ena1, ena2 phase direction 0-90 90-180 180-270 270-360 in1 h l l h h forward in2 h h l l h in1 h h l l h reverse in2 h l l h h table 2: stepper motor direction control by in1 and in2 inx ena3, ena4 phase direction 0-90 90-180 180-270 270-360 in3 h l l h h forward in4 h h l l h in3 h h l l h reverse in4 h l l h h table 3: stepper motor direction control by in3 and in4 dc motor dir ection control the lv8714 utilizes enax and inx to control the dc motor rotation direction as shown in table 4. input signal output direction enax inx outxa outxb l ? off off h l high low forward h h low high reverse x represents a channel number table 4: dc motor direction control by enax and inx stepper motor coil current control stepper motor coil current is controlled in proportional to vrefx and rcsx as shown in equation 1 previously. two phase outputs (a and b) for each stepper motor are controlled by combination of inx and vrefx inputs as shown in table 5. input output (coil current) inx vrefx enax amplitude polarity low analog high proportional to vrefx a to b high analog high proportional to vrefx b to a table 5: stepper motor coil current control figure 27 and 28 show example waveforms of output current with in response to vrefx, enax and inx input. figure 27. example waveforms for full step (forward) control
LV8714TA www.onsemi.com 16 figure 28. example waveforms for 1/256 step (forward) control pwm constant-current control the lv8714 implements constant-current control drive by applying pwm switching to the output pin. when the coil current becomes equal to the set target value (as determined by equation 1), the constant current control mechanism ge ts activated and performs a repetitive sequence of charge ? slow decay ? fast decay (fixed 2s) ? charge? as shown in figure 29. the period for each sequence is fixed at 8s(typ.). figure 29 shows timing chart of pwm based constant-current control.
LV8714TA www.onsemi.com 17 coil current pwm cycle charge set current slow decay current control mode blanking time out1a out1b fast decay 1us 2us 8us figure 29. timing chart of pwm based constant-current three modes of constant-current control each pwm cycle of constant-current control is made up of three distinct interval s ? charge, slow decay and fast decay. example: current direction a to b charge: voltage is applied to the coil until the coil current becomes equal to the target (a = high, b = low). slow decay: output a and b are shorted internally resulting in circular current (a = low, b = low). fast decay: inverted bias is applied to discharge the coil current (a = low, b = high) that results in decreases of the coil current. these intervals (charge, slow decay and fast decay) are results of mosfet switc hing as shown in figure 30.
LV8714TA www.onsemi.com 18 figure 30. mosfet switching sequence for constant-current control whenever, there is a switch from the upper mosfet to the lower mosfet of the same leg, the fixed dead time of 0.375s is provided to avoid turning on both mosfets on at the same time. during this time, the coil current flows through the body diode of the mosfet as seen in (2), (4) and (6) events in figure 30. table 6 and table 7 show status of mosfets during various intervals in a pwm cycle for different current polarities. outxa outxb output tr charge slow decay fast decay u1 on off off u2 off off on l1 off on on l2 on on off table 6: mosfet switching sequence for outxa ? outxb polarity outxb outxa output tr charge slow decay fast decay u1 off off on u2 on off off l1 on on off l2 off on on table 7: mosfet switching sequence for outxb ? outxa polarity figure 31 shows example waveforms of the stepper motor with 1/16 step and constant-current control. figure 32 shows example waveforms of three events ? charge, slow decay and fast decay. charge increases current switch from charge to slow decay switch from slow decay to fast decay current regeneration by fast decay switch from fast decay to charge current regeneration by slow decay
LV8714TA www.onsemi.com 19 constant current control is synchronized to the internal pwm period 8 ? s (typ). figure 31. pwm based constant-current control waveforms of the stepper motor with 1/16 step figure 32. one full pwm cycle of the constant-current control 2 ? 1/16 step vm=12v vref1/2=0.23v (iout 0.2a) rcs1/2=1.5k ? in1=in2 125hz rcoil=15 ? 8 ? ? s/div out1b 10v/div out1a 10v/div 2 4 3 out1b 10v/div out1a 10v/div 3 out1a motor current 0.2a/div in1 5v/div in2 5v / div 2 1 4 2ms/div in2 in1 in2 5v / div 2ms/div 2 1 4 out1a motor current 0.2a/div in2 5v / div in2 out1a motor current 0.2a/div in2 4 5 ? ? 0.1a) rcs1/2=1.5k ? in1=in2=100hz rcoil=15 ? out1b output voltage 10v/div out1a output voltage 10v/div 2 4 3 fast decay charge slow deca y setting current out1a motor current 0.1a/div 2 ? s/div
LV8714TA www.onsemi.com 20 blanking time as the lv8714 switches from fast decay to charge, switching noise can lead to wrong reading by the comparator that is comparin g the coil current against the target current. to filter out this switching noise, a fixed 1s blanking time is provided at the beginning of the charge interval. during this blanking time, the comparator ignores the coil current reading and thus avoid false switching to the slow decay interval, if the comparator detects the coil current higher than the target current. power-on reset (por) sequence at startup, when vm1 4v and ps = high, it takes 50s for the internal 3.3v regulator to provide stable output. after the 3.3v regulator is in the active state, enax needs to be pulled high to enable respective channel output. it is recommended that vrefx input is never floating and the required input signal is applied at least 10s before enax is pulled high. figure 33 shows por and fault handling sequence. cold ? start ps ? high? enable ? internal ? voltage ? regulator ? reg3 (*1) enax ? high? (*2) driver ? active ocp ? det ected shutdown ? output ps ? high? tsd ? detected shutdown ? output ps ? high? y n y n t j ? < ? 140c (*4) n y over ? current ? protection thermal ? shutdown n y n y (*1) ? it ? takes ? 50s ? to ? settle ? to ? the ? target ? voltage. (*2) ? vrefx ? and ? inx ? input ? must ? be ? applied ? for ? 10s ? before ? ena ? = ? high (*3) ? minimum ? 10s ? of ? ps=low ? duration ? is ? required. (*4) ? tsd ? detection ? criterion ? is ? 180c ? with ? 40c ? hysteresis por ? and ? fault ? handling ? operation ? flow supply ? vm1 disable ? internal ? voltage ? regulator ? reg3 (*3) reg3 ? > ? 3v? low ? voltage ? shutdown y n figure 33. por and fault handling sequence system protection functions the lv8714 has built-in protection functions such as over-current (ocp), over-temperature (thermal shutdown, tsd), and under-voltage (low-voltage shutdown, lvs) protectio ns. these integrated protections make the lv8714 based system solution highly reliable without need for any external protection circuit. table 8 shows summary of lv8714 protection functions with recovery mechanisms. priority fault event condition outxx logic regulator recovery 1 low voltage shutdown lvs vreg3 ? 2.6v off reset < 2.6v vm1 4.0v 2 thermal shutdown tsd junction temperature > 180c off active on auto-recover when t j 140oc 3 over-current protection ocp upper side fet current > 2.6a lower side fet current > 2.0a off active on toggle ps input high ? low ( 10 ? s) ? high table 8: summary of lv8714 protection functions with recovery mechanisms
LV8714TA www.onsemi.com 21 low voltage shutdown (lvs) the integrated lvs protection enables safe shutdown of the system when the vm1 dr ops. the vreg3 voltage is monitored and the lvs is activated when the vreg3 voltage drops below 2.6v (typ.). it turns off output fets and logic circuits are pu t into the reset state. the lv8714 recovers from the lvs automatically when vm1 4v. thermal shutdown (tsd) the built-in tsd protection prevents damage to the lv8714 from excessive heat. to avoid false trigger, the tsd protection is activated when the die t j exceeds 180oc. once activated, it shuts down output fets while keeping the rest of circuit in the active state. when t j falls below 140oc, the output stage is reactivated under control of input signals inx, and enax. over-current protection (ocp) the on-chip ocp protection of the lv8714 triggers when current above the threshold is detected internally. once detected for 2s, output fets are turned off and the internal timer is triggered to count 128s (typ.) of the timer latch period. at the end of the timer latch period, output fets are turned on again 2s. if during this time, over-current is detected again, then the fault is latched and fets are turned off. fets can now be turned on again only when over-current condition is removed and the ps pin is toggled (high -> low ( 10s) -> high). timing chart of the ocp is as shown in figure 34. figure 34. timing chart of ocp fault detection h-bridge output state internal counte r 2s output on output off over-current detected release 1st counte r start 1st counte r stop 1st counte r start 1st counte r stop 2nd counte r start 2nd counte r stop time r latch period (typ : 128 s ) 2s output on output off over-current detected over-current detected
LV8714TA www.onsemi.com 22 example of over-current detection: short to power short to gnd load short
LV8714TA www.onsemi.com 23 pcb guidelines vm and ground routing make sure to short-circuit vm1, vm2, vm3 and vm4 externally by a low impedance route on one side of pcb. as high current flows into pgnd, connect it to gnd through a low impedance route. exposed pad the exposed pad is connected to the frame of the lv8714. therefore, do not co nnect it to anywhere else other than ground. if gnd and pgnd are in the same plane, connect the exposed pad to the ground plane. else, if gnd and pgnd are separated, connect the exposed pad to gnd. nc pin utilization nc pins are not connected in ternally inside the lv8714. if the power track that is connected to vm, outputs and gnd is wide, the power track can be connected to nc pins. thermal test conditions size: 90mm 90mm 1.6mm (four layer pcb) material: glass epoxy copper wiring density: l1 = 80% / l4 = 85% second layer is vm power supply layer. third layer is gnd layer l1 : copper wiring pattern diagram (top) l4 : copper wiring pattern diagram (bottom) figure 35. pattern diagram of top and bottom layer recommendation the thermal data provided is for the thermal test condition where 90% or more of the exposed die pad is soldered. it is recommended to derate critical rating parameters for a safe design. electrical parameters that are recommended to be derated are operating voltage, operating current, junction temperature, and device power dissipation. the recommended derating for a safe design is as shown below: ? maximum 80% or less for operating voltage ? maximum 80% or less for operating current ? maximum 80% or less for junction temperature check solder joints and verify reliability of solder joints for critical areas such as exposed die pad, power pins and grounds. any void or deterioration, if observed, in solder joint of these critical areas parts, may cause deterioration in thermal conduction and that may lead to thermal destruction of the device.
LV8714TA www.onsemi.com 24 package dimensions seating 0.20 h a bottom view top view side view d b e 0.08 c c e plane 48x 0.05 1 37 48 25 13 4x note 9 note 7 note 7 note 7 notes 4 & 6 notes 4 & 6 note 9 4x 12 tips detail a note 3 d a e1 d1 a-b d 0.20 c a-b d d2 e2 0.20 c a-b d b detail a a2 a1 h l m l2 tqfp48 ep 7x7, 0.5p case 932f issue c dim min max millimeters a 0.95 1.25 a1 0.05 0.15 d1 7.00 bsc b 0.17 0.27 d 9.00 bsc d2 4.90 5.10 e 0.50 bsc l 0.45 0.75 m 0 7 l2 0.25 bsc soldering footprint* 0.29 48x recommended dimensions: millimeters notes: 1. dimensions and tolerancing per asme y14.5m, 1994. 2. controlling dimension: millimeters. 3. dimension b does not include dambar protrusion. dambar protrusion shall be 0.08 max. at mmc. dambar cannot be located on the lower radius of the foot. minimum space between protrusion and adjacent lead is 0.07. sions or gate burrs. mold flash, protrusions or gate burrs shall not exceed 0.25 per side. dimensions d1 and e1 are maximum plastic body size including mold mismatch. 5. the top package body size may be smaller than the bottom package size by as much as 0.15. 6. datums a-b and d are determined at datum plane h. 7. a1 is defined as the vertical distance from the seating 8. dimensions d and e to be determined at datum plane c. a2 0.90 1.20 e1 7.00 bsc e 9.00 bsc e2 4.90 5.10 5.30 9.36 5.30 9.36 0.50 pitch 1.13 48x *for additional information on our pb-free strategy and soldering details, please download the on semiconductor soldering and mounting t echniques reference manual, solderrm/d. 1
LV8714TA www.onsemi.com 25 on semiconductor and the on logo are registered trademarks of semiconductor components industries, llc (scillc) or its subsidiaries in the united st ates and/or other countries. scillc owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. a lis ting of scillc?s product/patent coverage may be accessed at www.onsemi.com/site/pdf/patent-marking.pdf . scillc reserves the right to make changes with out further notice to any products herein. scillc makes no warranty, representation or guarantee regarding the suitability of its products for any parti cular purpose, nor does scillc assume any liability arising out of the application or use of any product or circuit, and specifically 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 specific ations can and do vary in different applications and actual performance may vary over time. all operating parameters, including ?typicals? must be validated fo reach customer application by customer?s technical experts. scillc does not convey any license under its patent rights nor the rights of others. scillc pro ducts are not designed, intended, or authorized for use as com ponents in systems int ended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the scillc product could create a situation where personal injury or death may occur. should buyer purchase or use scillc products for any such unintended or unauthorized application, 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 ar ising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that sci llc was negligent regarding the design or manufacture of the part. scillc is an equal opportunity/affirmative action employer. this literature is subject t oall applicable copyright laws and is not for resale in any manner.

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