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automotive datasheet rev. 1.0, 2009-05-05 BTS3256D 10 m ? smart power single channel low side swit ch with restart and variable slew rate hitfet? smart low side power switch
datasheet 2 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d table of contents table of contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1 overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 bts 3256d block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 voltage and current naming definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.1 pin assignment bts 3256d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2 pin definitions and functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 general product characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.1 absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.2 functional range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.3 thermal resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5 supply and input stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.1 supply circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.1.1 under voltage lock out / po wer on reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.2 input circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.3 electrical characteristics - supply and input stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6power stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6.1 output on-state resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6.2 output timings and slopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 6.3 inductive output clamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 6.4 electrical characteristics - power stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7 control and diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 7.1 readout of fault information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 7.2 adjustable slew rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 7.3 electrical characteristics - di agnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 8 protection functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 8.1 thermal protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 8.2 over voltage protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 8.3 short circuit protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 8.4 electrical characteristics - protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 9 application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 9.1 dimensioning of serial resistor at in pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 9.2 further application informat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 10 package outlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 11 revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 table of contents
type package bts 3256d pg-to-252-5-11 datasheet 3 rev. 1.0, 2009-05-05 smart low side power switch BTS3256D bts 3256d pg-to-252-5-11 1overview the bts 3256d is a single channel low-side power switch in pg-to-252-5-11 package providing embedded protective functions. this hitfet? is designed for automotive and industrial applications with outstanding protection and control features. the power transistor is a n-channel vertical power mosfet. the device is controlled by a chip in smart power technology. basic features ? slew rate control by dedicated pin enabling emc optimized switching or pwm operation ? max. switching frequency 12khz ? clear detection of digital fault signal also du ring fast pwm operation due to restart delay time ? thermal and overload protection with time controlled auto restart behavior ? time and power limited ac tive current limitation ? minimum r ds(on) achieved with 3.3v or 5v logic input ? electrostatic discha rge protection (esd) ? very low leakage current ? green product (rohs compliant) ? aec (automotive electronics coun cil) stress test qualification table 1 basic electrical data operating voltage v sop 5.5 v.... 30 v over voltage protection v d (az) 40 v maximum on state resistance at t j = 150c r ds(on,max) 20 m ? typical on state resistance at t j = 25c r ds(on,typ) 10 m ? nominal load current i d(nom) 7.5 a minimum current limitation i d(lim) 42 a
datasheet 4 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d overview digital diagnostic features ? over temperature ? over load ?short circuit ? clear detection due to a restart delay time protection functions ? enhanced short circuit protection with time and power limited acti ve current limitation ? under voltage lock out ? over temperature with time and temperature controlled auto restart ? over load with power and time controlled auto restart ? esd protection application ? all types of resistive, in ductive and capacitive loads ? suitable for loads with inru sh current, such as motors , coils, solenoids or lamps ? suitable for emc optimized swit ching in slow operation mode ? suitable for higher speed pwm controlled loads in fast operation mode ? replacement of electromechanical relays, fuses and discrete circuits ? micro controller compatible low side power switch with digital feedback for 12v loads detailed description the bts 3256d is an autorestart single channel low-si de power switch in pg-to-252-5-11 package providing embedded protective functions. the device is able to swit ch all kind of resistive, inductive and capacitive loads. the esd protection of the v s and in/fault pin is referenced to gnd. the bts 3256d is supplied by the v s pin. this pin should be connected to a reverse protected battery line. the supply voltage is monitored by the under voltage lock out ci rcuit. the gate driving unit allows the device to operate in the lowest ohmic range independent of the input signal level, 3.3 v or 5 v . for slow pwm application the device offers smooth turn-on and off due to the embedded edge shaping function, to reduce emc noise. furthermore the srp pin can be used to customize the slew rate of the device in a wide range. the device is designed for driving automotive loads like mo tors,valves, coils or bulbs in continous or pwm mode. the over voltage protection is for protection during load- dump or inductive turn off conditions. the power mosfet is limiting the drain-so urce voltage to a specified level. this func tion is available even without any supply. the over temperature protection preven ts the device from overheating due to overload and/or bad cooling conditions. in order to reduce the device stress the edge shaping is disabled during thermal shutdown. after thermal shutdown the device stays off for the specified restart delay time to enable a clear feedback readout on the microcontroller. after this time th e device follows the in signal state. at high dynamic overload conditions, such as short circuit, the device will eith er turn off immedi ately due to the implemented over power limitatio n, or limit the current for a specified time and then switch off for the restart delay time. shutdown of the device is triggered if the powe r dissipation during limitation is above the over power threshold. the short circuit shutdown is a timed restart fu nction. the device will stay of f for the specified time and afterwards follow the in signal state. in order to reduce the device stress the edge shaping is disabled during protective turn off.
datasheet 5 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d bts 3256d block diagram 2 bts 3256d block diagram figure 1 block diagram for the BTS3256D 2.1 voltage and curren t naming definition following figure shows all the terms us ed in this data sheet, with associated convention for positive values. figure 2 terms drain gnd gate driving unit over- voltage protection esd protection in / fault over- temperature protection overload protection srp v s short circuit protection blockdiagram.emf ? under voltage lockout slew rate control terms.emf v in v d gnd i gnd drain v bb r l in / fault v s v s i d i in i s v bb gnd srp v sr p
datasheet 6 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d pin configuration 3 pin configuration 3.1 pin assignment bts 3256d figure 3 pin configuration 3.2 pin definitions and functions pin symbol function 1 v s supply voltage; connected to battery voltage with reverse protection diode and filter against emc 2in control input and status feedback; digital input 3.3 v or 5 v logic. 3, tab drain drain output; protected low side power output channel, usually connected via load to battery 4srp slew rate preset; used to define slew rate, see chapter 7.2 for details 5gnd ground; power ground, pin connection needs to carry the load current from drain drain drain (top view ) gnd 5 6 ( tab) 4 3 2 1 srp in v s pinconfiguration.emf
datasheet 7 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d general product characteristics 4 general product characteristics 4.1 absolute maximum ratings note: stresses above the ones listed here may cause perm anent damage to the device. exposure to absolute maximum rating conditions for extended periods may affect device reliability. note: integrated protection functions are designed to prevent ic destruction under fault conditions described in the data sheet. fault conditions are considered as ?outside? normal operating range. protection functions are not designed for continuous repetitive operation. absolute maximum ratings 1) t j = -40 c to +150 c all voltages with respect to ground, positive current flowing into pin (unless otherwise specified) 1) not subject to production test, specified by design. pos. parameter symbol limit values unit conditions min. max. voltages 4.1.1 supply voltage v s -0.3 30 v ? 4.1.2 supply voltage during active clamping v s(pulse) -0.3 45 2) 2) not for dc operation, only for short pulse (i.e. loaddump) for a total of 100 h in full device life. v? 4.1.3 drain voltage v d -0.3 40 3) 3) active clamped. v? 4.1.4 drain voltage for short circuit protection v d(sc) 030v 4) 4) the device can not be switched on if v d > v d(sc) 4.1.5 logic input voltage v in -0.3 5.5 v ? 4.1.6 slew rate preset maximum voltages v srp -0.3 5.5 v 5) 5) srp pin is driven by an internal current source, so active dr iving from outside is not required,it may affect lifetime and co uld cause parameter shifts outside the range given in datasheet energies 4.1.7 unclamped sing le pulse inductive energy e as 00.3j i d = 22 a; v bb = 30 v temperatures 4.1.8 junction temperature t j -40 150 c? 4.1.9 storage temperature t stg -55 150 c? esd susceptibility 4.1.10 esd resistivity v esd kv hbm 6) 6) esd susceptibility, hbm accordin g to eia/jesd 22- a114b, section4 on input pins (in,srp,vs) in -4 4 on drain and gnd pins out -8 8
datasheet 8 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d general product characteristics 4.2 functional range note: within the functional range the ic operates as de scribed in the circuit description. the electrical characteristics are specifi ed within the conditions given in the re lated electrical ch aracteristics table. 4.3 thermal resistance pos. parameter symbol limit values unit conditions min. max. 4.2.1 supply voltage v s 5.5 30 v ? 4.2.2 supply current in on i s ?3ma? pos. parameter symbol limit values unit conditions min. typ. max. 4.3.1 junction to case 1) 1) not subject to production test, specified by design r thjc ? 0.9 1.1 k/w ? 4.3.2 junction to ambient 1) r thja ? 80 ? k/w @min. footprint ? 45 ? k/w @ 6 cm2 cooling area, see figure 4
datasheet 9 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d general product characteristics figure 4 typical transient thermal impedance z thja = f(t p ) , pulse d = tp/t, t a = 25 c device on 50 mm 50 mm 1.5 mm epoxy pcb fr4 with 6 cm 2 (one layer, 70 m thick) copper area for drain connection. pcb mounted vertical without blown air. z thja s 0.1 1 10 k/w t p zth.emf 0.2 0.1 0.5 single pulse 0. 01 0.02 0. 05 100 10 -3 10 -2 10 -1 10 -6 10 -5 10 -4 11010 2 10 3
datasheet 10 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d supply and input stage 5 supply and input stage 5.1 supply circuit the supply pin v s is protected against esd pulses as shown in figure 5 . due to an internal voltage regulator the device can be supplied from a reverse polarity protected battery line. figure 5 supply circuit 5.1.1 under voltage lock out / power on reset in order to ensure a stable device behavior und er all allowed conditio ns the supply voltage v s is monitored by the under voltage lock out circuit. all device functions are onl y given for supply voltages above under voltage lockout. there is no failure feedback for v s < v suvon . figure 6 under voltage lock out 5.2 input circuit figure 7 shows the input circuit of the bts 3256d. it?s ensured that the device switches off in case of open input pin. a zener structure protects the input circuit against esd pulses. as the bts 3256d has a supply pin, the operation of the power mos can be maintained regardless of the voltage on the in pin, therefore a digital status feedback down to logic low is realized. for readout of the fault information, please refer to diagnosis ?readout of fault information? on page 20 . supply .em f 5.5 v .. 30 v gnd v s z d regulator bts3256 d v suvon v suvoff functional off device uvlo.emf
datasheet 11 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d supply and input stage figure 7 input circuit input.em f gnd in/fault 1. 0ma : 3. 0ma 20a : 100a
datasheet 12 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d supply and input stage 5.3 electrical characteristi cs - supply and input stages v s = 5.5 v to 30 v, t j = -40 c to +150 c all voltages with respect to ground, positive current flowing into pin (unless otherwise specified) pos. parameter symbol limit values unit conditions min. typ. max. under voltage lockout 5.3.1 uv-switch-on voltage v suvon ??5.6v? 5.3.2 uv-switch-off voltage v suvoff 4.0 ? 5.5 v ? 5.3.3 uv-switch-off hysteresis v suvhy ?0.2?v v suvon - v suvoff digital input / fault feedback 5.3.4 low level voltage v inl -0.3 ? 0.8 v ? 5.3.5 high level voltage v inh 2.0 ? 5.5 v ? 5.3.6 input pull down current i in 20 50 100 a v in = 5.3 v; no fault condition 5.3.7 input pull down current in fault i in-fault 123ma v in = 5.3 v; all fault conditions
datasheet 13 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d power stage 6 power stage the power stage is built by a n-chann el vertical power mosfet (dmos). 6.1 output on-state resistance the on-state resistance depends on the junction temperature t j . figure 8 shows this dependence for the typical on-state resistance r ds(on) . figure 8 typical on-state resistance r dson = f( t j ), v s = 10 v, v in = high figure 9 typical on-state resistance r dson = f( v s ), v in = high, t ambient = 25 c 6 8 10 12 14 16 18 -50 -25 0 25 50 75 100 125 150 175 typ. rdson_tj.emf t [ c ] r ds(on) [ m ? ] 6 11 16 21 26 31 0102030 r ds(on) [ m ? ] v s [ v ] rdson_vs.emf typ .
datasheet 14 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d power stage 6.2 output timings and slopes a high signal on the input pin causes the power mosfet to switch on with a dedica ted slope which is optimized for low emc emission. figure 10 shows the timing definition. figure 10 definition of power output timing for resistive load in order to minimize the emission during switching, the bt s 3256d limits the slopes during turn on and off at slow slew rate settings. for best performanc e of the edge shaping, the supply pin v s should be connected to battery voltage. for supply voltages other than nominal battery, the edge shaping can differ from the values in the electrical characteristics table below. 6.3 inductive output clamp when switching off inductive loads with lo w-side switches, the drain source voltage v d rises above battery potential, because the inductance intends to continue driving the current. the bts 3256d is equipped with a voltage clamp me chanism that keeps the drain-source voltage v d at a certain level. see figure 11 for more details. figure 11 output clamp in low high t on t off t v d v bb outputtiming.em t t ond 10 % 90 % t o ffd |dv/dt| s haping |dv/dt| s haping |dv/dt|on |dv/dt|off 80 % 20 % |dv/dt| s haping output_clamp_curcuit .emf gnd drain
datasheet 15 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d power stage figure 12 switching off an inductive load while demagnetization of inductive loads, energy has to be dissipated in the bts 3256d. this energy can be calculated with following equation: following equation simplifies under assumption of r l = 0 figure 13 shows the inductance / current co mbination the bts 3256d can handle. for maximum single avalanche energy please also refer to e as value in ?energies? on page 7 . in low high t t von v bb t i d v daz over tem peratur e or shor t cir cuit detected inductive_output_clamp .emf ev d(az) v bb v ? d (az) r l -------------------------------- ln ? 1 r l i l ? v bb v ? daz () --------------------------------- ? ?? ?? ?? i l + l r l ------ ?? = e 1 2 -- - li l 2 1 v bb v bb v ? d(az) ------------------------------- - ? ?? ?? ?? ? =
datasheet 16 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d power stage figure 13 maximum allowed inductance values for single switch off (eas) l= f (i l ), t j,start = 150 c, v bb =30v, r l = 0 ? 0,01 0,10 1,00 10,00 10 i d [ a ] l [ mh ] max. 50 eas .emf
datasheet 17 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d power stage 6.4 electrical character istics - power stage v s = 5.5 v to 30 v, t j = -40 c to +150 c all voltages with respect to ground, positive current flowing into pin (unless otherwise specified) pos. parameter symbol limit values unit conditions min. typ. max. power supply 6.4.1 on-state resistance r ds(on) ?10?m ? t j = 25 c; i d = 20 a; v in = high v s = 10 v ?1620m ? t j = 150 c; i d = 20 a; v in = high v s = 10 v 6.4.2 nominal load current 1) i d(nom) 7.5 8.7 ? a t j < 150 c; t a 85 c smd 2) ; v in = high; v s 10 v; v ds = 0.5 v 6.4.3 iso load current 1) i d(iso) 31 33 ? a t j < 150 c; t c = 85 c; v in = high v s 10 v; v ds = 0.5 v; 6.4.4 off stat e drain current i dss ?612 a v d = 32 v; v in = low 6.4.5 ? 1 2 a 1) t j = 85 c; v d = 13.5 v; v in = low dynamic characteristics 6.4.6 power up settling time t init ?1025svs > 6v first rising edge on in pin. timings with fastest slew rate setting 6.4.7 turn-on delay t ond_fast ?410 s r l = 2.2 ? ; r srp = open; v bb = v s = 13.5 v; see figure 10 6.4.8 turn-on time t on_fast ?1122 s r l = 2.2 ? ; r srp = open; v bb = v s = 13.5 v; see figure 10 6.4.9 turn-off delay t offd_fast 41015 s r l = 2.2 ? ; r srp = open; v bb = v s = 13.5 v; see figure 10
datasheet 18 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d power stage 6.4.10 turn-off time t off_fast 91624 s r l = 2.2 ? ; r srp = open; v bb = v s = 13.5 v; see figure 10 6.4.11 slew rate on -d v d /d t on_fast 1.2 2.2 3.8 v/ s r l = 2.2 ? ; r srp = open; v bb = v s = 13.5 v; see figure 10 6.4.12 slew rate off d v d /d t off_fast 1.2 2.2 3.8 v/ s r l = 2.2 ? ; r srp = open; v bb = v s = 13.5 v; see figure 10 6.4.13 slew rate during edge shaping |dv/dt| shaping_fast ?0.66? v/ s 1) r l = 2.2 ? r srp = open; v bb = v s = 13.5 v; see figure 10 timings with slowest slew rate setting 6.4.14 turn-on delay t ond_slow ?2260 s r l = 2.2 ? ; r srp = gnd; v bb = v s = 13.5 v see figure 10 6.4.15 turn-on time t on_slow ?85200 s r l = 2.2 ? ; r srp = gnd; v bb = v s = 13.5 v see figure 10 6.4.16 turn-off delay t offd_slow ?75110 s r l = 2.2 ? ; r srp = gnd; v bb = v s = 13.5 v see figure 10 6.4.17 turn-off time t off_slow 40 150 220 s r l = 2.2 ? ; r srp = gnd; v bb = v s = 13.5 v see figure 10 v s = 5.5 v to 30 v, t j = -40 c to +150 c all voltages with respect to ground, positive current flowing into pin (unless otherwise specified) pos. parameter symbol limit values unit conditions min. typ. max.
datasheet 19 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d power stage 6.4.18 slew rate on -d v d /d t on_slow 0.08 0.2 0.6 v/ s r l = 2.2 ? ; r srp = gnd; v bb = v s = 13.5 v see figure 10 6.4.19 slew rate off d v d /d t off_slow 0.08 0.2 0.6 v/ s r l = 2.2 ? ; r srp = gnd; v bb = v s = 13.5 v see figure 10 6.4.20 slew rate during edge shaping |dv/dt| shaping_slow ? 0.088 ? v/ s 1) r l = 2.2 ? ; r srp = gnd; v bb = v s = 13.5 v see figure 10 inverse diode 6.4.21 inverse diode forward voltage v d -0.3 -1.0 -1.5 v i d = -12 a; v s = 0 v; v in = 0.0 v 1) not subject to production test, specified by design. 2) device mounted according to eia/jesd 52_2, fr4, 50 50 1.5 mm; 35 cu, 5 sn; 6 cm 2 . pcb mounted without blown air v s = 5.5 v to 30 v, t j = -40 c to +150 c all voltages with respect to ground, positive current flowing into pin (unless otherwise specified) pos. parameter symbol limit values unit conditions min. typ. max.
datasheet 20 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d control and diagnosis 7 control and diagnosis the BTS3256D provides digital fault feedback on the in pin without the need of an adc. additonally the device features an adjustable slew rate via the srp pin. 7.1 readout of fault information the bts 3256d provides digital status information via an increased current on the in / fault pin. the voltage on this pin is pulled down to logic low when a fitting serial resistor is used. an example for the required circuitry is shown in figure 14 . the increased current i in(fault) is one order of magnitude above the normal operation current i in . a 3k3 for a 3.3v c or 5k6 for a 5v c is recommended. for detailed calculation please refer to ?dimensioning of serial resistor at in pin? on page 26 . . figure 14 readout of feedback info rmation and xor logic in micro 7.2 adjustable slew rate in order to optimize electromagnitic emission, the switch ing speed of the mosfet can be adjusted by connecting an external resistor between srp pin and gnd. this allo ws for balancing between electromagnetic emissions and power dissipation. r srp-min represents the minimum slew rate slew rate min and r srp-max represents the maximum slew rate slew rate max . a short to gnd causes the minimum slew rate slew rate min. open pin condition causes the maximum slew rate slew rate max . figure 15 shows the relation between the resistor value and the slew rate of bts 3256d. in/fault bts3256 micro contr oller v cc v s gnd gnd do di v di i do i in r1 v cc gnd v bb =1 0 0 0 fault fault_readout .emf
datasheet 21 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d control and diagnosis 7.3 electrical charact eristics - diagnostic figure 15 typical relation between slew rate and resistor values used on r srp (v bat =13.5v) v s = 5.5 v to 30 v, t j = -40 c to +150 c all voltages with respect to ground, positive current flowing into pin (unless otherwise specified) pos. parameter symbol limit values unit conditions min. typ. max. slew rate control 7.3.1 slew rate min slew rate min 0.08 0.2 0.6 v/s r srp = 0 ohm v s = 13.5 v; ohmic load 7.3.2 slew rate 15k slew rate 15k 0.2 0.6 ? v/s r srp = 15 kohm v s = 13.5 v; ohmic load 7.3.3 slew rate 30k slew rate 30k 0.7 1.45 ? v/s r srp = 30 kohm v s = 13.5 v; ohmic load 7.3.4 slew rate max slew rate max 1.2 2.2 3.8 v/s srp pin open v s = 13.5 v; ohmic load 0 0,5 1 1,5 2 2,5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 slew rate [ v/s ] r srp [ k ? ] slewrate.emf
datasheet 22 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d protection functions 8 protection functions the device provides embedded protection functions ag ainst over temperature, over load and short circuit. note: integrated protection functions are designed to prevent ic destruction under fault conditions described in the data sheet. fault conditions are cons idered as ?outside? normal operation. 8.1 thermal protection the device is protected against over temperature resulting from overload and / or bad cooling conditions. the bts 3256d has a thermal restart function. when overh eating occurs, the device sw itches off for the restart delay time t restart . after this time the device restarts if the temp erature is below threshold and the in has logic high level. the fault feedback is activated during over temperature situation. see figure 16 for the restart behavior. the diagram naming refers to figure 14 . figure 16 status feedback via input current at over temperature 8.2 over voltage protection the bts 3256d is equipped with a voltage clamp me chanism that keeps the drain-source voltage v d at a certain level. this stage is also used for inductive clamping. see ?inductive output clamp? on page 14 for details. in low high t therm al shutdown low high t t t j t jsd i in i innom t 0 i in fa u lt ? t jsd after delay time , in is high over temperature is gone don?t care thermal_fault_autorestart.emf v di t restart
datasheet 23 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d protection functions 8.3 short circuit protection the condition short circuit is an overload condition of the device. in a short circuit condition, the resulting d i / d t is a function of the short circuit resistance. the BTS3256D incorporates 2 shut down strategies for maximum robustness in the presence of short circuits: - immediate shut down in the case of low ohmic shorts by power detection exceeding p max - over temperature shut down in the case of an overload condition the additional feature of this device is a limitation of the load current to i lim for a maximum time of t lim . if the condition is normalized in a shorter time than t lim , the device stays on, if not the device switch off for t restart and tries to restart in case the in pin is still high. from first switch off the fault fe edback will be activated during t restart and continues until the in pin goes low or normal condition is reached. figure 18 shows the behavior mentioned above. in this exam ple first a shorted load occurs which causes the device to limit the current. the device stays on, becaus e the load current returns to normal condition before t restart . in the second switch on, the short circuit is permanent and the device switches off after maximum limiting time, stays off for the blanking time regardless of the input pi n condition and then stays of f according to the in pin low condition. the definitions of voltages and currents are in respect to figure 14 . the behavior of v di also depends on r in . figure 17 typical power limitation behavior i ds / v ds 10 20 30 40 50 60 70 0102030 i d [ a ] v drain [ v ] power_limitation.emf safe operation area protective shut down
datasheet 24 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d protection functions figure 18 short circuit during on state, typical behavior for ohmic loads the case when the device switches on into an existi ng short circuit - short circuit type 1- is shown in figure 17 . the test setup for short circuit characterization is shown in figure 19 . the bts 3256d is a low side switch. therefore it can be assumed that the micro controlle r and device gnd connection have a low impedance. all impedance in the short circuit path is merged in the short circuit resistance r sc and short circuit inductance l sc . figure 19 test setup for short circuit characterization test v in low high inrush overload v di low high i d i lim i in i innom 0 i in fa u lt i dnom t lim don?t care overload situation t t over load shut off protection_behaviour.emf t restart t lim t t gnd drain bts3 25 6 gnd v bb r sc l sc i d control circuit in v s vcc 5v srp short_circuit_schematic.emf r srp
datasheet 25 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d protection functions 8.4 electrical charact eristics - protection v s = 5.5 v to 30 v, t j = -40 c to +150 c all voltages with respect to ground, positive current flowing into pin (unless otherwise specified) pos. parameter symbol limit values unit conditions min. typ. max. thermal protection 8.4.1 thermal shut down junction temperature t jsd 150 175 1) 1) not subject to production test, specified by design. ? c? 8.4.2 thermal hysteresis ? t jsd ?10?k 1) over voltage protection 8.4.3 drain source clamp voltage v d(az) 40 44 - v i d = 10 ma; v s = 0.0 v; v in = 0.0 v ? 4549v i d = 8 a; v s = 0.0 v; v in = 0.0 v short circuit protection 8.4.4 current limitation level i d(lim) 42 55 72 a ohmic load 8.4.5 max. power switch off threshold p max 300 400 650 w ? 8.4.6 max. time for current limitation before shut off t lim 3.5 5 6.5 ms 2) resistive load 2) in case of inductive loads the device needs to increase the vds voltage during current limitation. this can trigger the over power pr otection switch off earlier as t lim . 8.4.7 restart delay time t restart 50 70 100 ms ?
datasheet 26 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d application information 9 application information note: the following information is given as a hint for the implementation of the device only and shall not be regarded as a description or warranty of a certain functionality, condition or quality of the device. 9.1 dimensioning of serial resistor at in pin in order to use the digital feedback function of the device, there must be a serial resistor used between the in pin and the driver (micro controller). to calculate this serial resistor on t he input pin, three device conditions and of course the driver (micro controller) abilities need to be taken into account. figure 20 shows the circuit used for reading out the digital status. figure 20 circuitry to readout fault information note: this is a very simplified example of an application ci rcuit. the function must be verified in the real application. conditions to be meet by the circuitry: during normal operation v in must be higher than v inh,min to switch on. during fault condition the max. capab ility of the driver (micro controller) must not be exceeded and the logic low level at di must be ensured by a volt age drop over the serial resistor r in while the device faul t current is flowing. conditions in formulas: ? c output current,min > c high,max / r in > i infault_min with c output current,min referring to the c maximum output current capability with c high,max referring to the maximal high output voltage of the c driving stage this condition is valid during status feedback operation mode ? v in = c high,min - ( r in * i in,max ) > v inh,min with c high,min referring to the minimal high output voltage of the c driving stage this condition is valid during normal operation mode in/fault do di i do i in r in 1.0ma : 3.0ma 20a : 100a fault infor m ation m icr ocontr oller bts3256 v rin gnd v do v di gnd v cc v s gnd v cc v bb fault_r1dim.emf r srp srp
datasheet 27 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d application information ? c high,max - ( r in * i in-fault,min ) < c(di) l,max with c(di) l,max referring to the maximum logic low voltage of the c input stage the maximum current is either defined by the bts 3256d or the c driving stage this condition is valid during status feedback operation mode out of this conditions the minimum and ma ximum resistor values can be calculated. for a typical 5v micro controller with outp ut current capability in the 3 ma range, a resistor range from 7.5 k ? down to 4.5 k ? can be used. for a typical 3.3v micro controller a range from 4.6 k ? to 2.5 k ? is suitable. 9.2 further application information ? for further information you may contact http://www.infineon.com/hitfet
datasheet 28 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d package outlines 10 package outlines figure 21 pg-to-252-5-11 (plastic green thin outline package) green product (rohs compliant) to meet the world-wide customer requirements for environmentally friendly products and to be compliant with government regulations the device is available as a green product. green products are rohs-compliant (i.e pb-free finish on leads and suitable for pb-free soldering according to ipc/jedec j-std-020). gpt09161 5.4 0.1 -0.10 6.5 +0.15 a 0.5 9.9 6.22 -0.2 1 0.1 0.15 0.8 0.15 max 0.1 per side 5x0.6 1.14 4.56 +0.08 -0.04 0.9 2.3 -0.10 +0.05 b 0.51 min 0.1 1 +0.08 -0.04 0.5 0...0.15 b a 0.25 m 0.1 all metal surfaces tin plated, except area of cut. (4.17) you can find all of our packages, so rts of packing and others in our infineon internet page ?products?: http://www.infineon.com/products . dimensions in mm
datasheet 29 rev. 1.0, 2009-05-05 smart low side power switch hitfet - bts 3256d revision history 11 revision history version date changes rev. 1.0 2009-05-05 released datasheet
edition 2009-05-05 published by infineon technologies ag 81726 munich, germany ? infineon technologies ag 2009. all rights reserved. legal disclaimer the information given in this docu ment shall in no event be regarded as a guarantee of conditions or characteristics (?beschaffenheitsgarantie?). with respect to any examples or hints given herein, any typical values stated herein and/or any information regarding the app lication of the device, infi neon technologies hereby disclaims any and all warranties a nd liabilities of any kind, including without limitation warranties of non-infringement of intellectual property rights of any third party. information for further information on technology , delivery terms and conditions and prices please contact your nearest infineon technologies office ( www.infineon.com ). warnings due to technical requirements components may contain da ngerous substances. for information on the types in question please contact your nearest infineon technologies office. infineon technologies components may only be used in life-support devices or systems with the express written approval of infineon technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system, or to affect the safe ty or effectiveness of that device or system. life support devices or systems are intended to be implanted in the hu man body, or to support an d/or maintain and sustain and/or protect human life. if they fail, it is reasonable to assume that the health of the user or other persons may be endangered.

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