PROFET® BTS650P Smart Highside High Current Power Switch Features Product Summary Overvoltage protection Output clamp Operating voltage On-state resistance Load current (ISO) Short circuit current limitation Current sense ratio • Overload protection • Current limitation • Short circuit protection • Overtemperature protection • Overvoltage protection (including load dump) • Clamp of negative voltage at output • Fast deenergizing of inductive loads 1) • Low ohmic inverse current operation • Reverse battery protection • Diagnostic feedback with load current sense • Open load detection via current sense • Loss of Vbb protection2) • Electrostatic discharge (ESD) protection Vbb(AZ) 62 V VON(CL) 42 V Vbb(on) 5.0 ... 34 V RON 6.0 mΩ IL(ISO) 70 A IL(SC) 130 A IL : IIS 14 000 TO-220AB/7 Application • Power switch with current sense diagnostic feedback for 12 V and 24 V DC grounded loads • Most suitable for loads with high inrush current like lamps and motors; all types of resistive and inductive loads • Replaces electromechanical relays, fuses and discrete circuits 7 7 1 1 SMD Standard General Description N channel vertical power FET with charge pump, current controlled input and diagnostic feedback with load current sense, integrated in Smart SIPMOS chip on chip technology. Fully protected by embedded protection functions. 4 & Tab Voltage source Voltage sensor Overvoltage Current Gate protection limit protection Charge pump Level shifter Rectifier 3 IN Logic ESD I IN + V bb R bb OUT Limit for unclamped ind. loads Output Voltage detection 1,2,6,7 IL Current Sense Load Temperature sensor IS PROFET I IS Load GND 5 VIN V IS R IS Logic GND 1 ) 2) With additional external diode. Additional external diode required for energized inductive loads (see page 9). Semiconductor Group Page 1 of 16 1998-Nov.-2 BTS650P Pin Symbol Function 1 OUT O Output to the load. The pins 1,2,6 and 7 must be shorted with each other 3 especially in high current applications! ) 2 OUT O Output to the load. The pins 1,2,6 and 7 must be shorted with each other especially in high current applications!3) 3 IN I Input, activates the power switch in case of short to ground 4 Vbb + Positive power supply voltage, the tab is electrically connected to this pin. In high current applications the tab should be used for the Vbb connection 4 instead of this pin ). 5 IS S Diagnostic feedback providing a sense current proportional to the load current; zero current on failure (see Truth Table on page 7) 6 OUT O Output to the load. The pins 1,2,6 and 7 must be shorted with each other especially in high current applications!3) 7 OUT O Output to the load. The pins 1,2,6 and 7 must be shorted with each other especially in high current applications!3) Maximum Ratings at Tj = 25 °C unless otherwise specified Parameter Supply voltage (overvoltage protection see page 4) Supply voltage for short circuit protection, Tj,start =-40 ...+150°C: (see diagram on page 10) Load current (short circuit current, see page 5) Load dump protection VLoadDump = VA + Vs, VA = 13.5 V RI5) = 2 Ω, RL = 0.54 Ω, td = 200 ms, IN, IS = open or grounded Operating temperature range Storage temperature range Power dissipation (DC), TC ≤ 25 °C Inductive load switch-off energy dissipation, single pulse Vbb = 12V, Tj,start = 150°C, TC = 150°C const., IL = 20 A, ZL = 7.5 mH, 0 Ω, see diagrams on page 10 Electrostatic discharge capability (ESD) Symbol Vbb Vbb Values 42 34 Unit V V self-limited A 75 V Tj Tstg Ptot -40 ...+150 -55 ...+150 170 °C EAS 1.5 J 4 kV +15 , -250 +15 , -250 mA IL VLoad dump6) VESD W Human Body Model acc. MIL-STD883D, method 3015.7 and ESD assn. std. S5.1-1993, C = 100 pF, R = 1.5 kΩ Current through input pin (DC) Current through current sense status pin (DC) IIN IIS see internal circuit diagrams on page 7 and 8 3) 4) 5) 6) Not shorting all outputs will considerably increase the on-state resistance, reduce the peak current capability and decrease the current sense accuracy Otherwise add up to 0.7 mΩ (depending on used length of the pin) to the RON if the pin is used instead of the tab. RI = internal resistance of the load dump test pulse generator. VLoad dump is setup without the DUT connected to the generator per ISO 7637-1 and DIN 40839. Semiconductor Group Page 2 1998-Nov.-2 BTS650P Thermal Characteristics Parameter and Conditions Thermal resistance Symbol 7 chip - case: RthJC ) junction - ambient (free air): RthJA SMD version, device on PCB8): min --- Values typ max -- 0.75 60 -33 Unit K/W Electrical Characteristics Parameter and Conditions Symbol at Tj = -40 ... +150 °C, Vbb = 12 V unless otherwise specified Load Switching Capabilities and Characteristics On-state resistance (Tab to pins 1,2,6,7, see IL = 20 A, Tj = 25 °C: measurement circuit page 7) VIN = 0, IL = 20 A, Tj = 150 °C: IL = 90 A, Tj = 150 °C: 9) Vbb = 6V , IL = 20 A, Tj = 150 °C: Nominal load current10) (Tab to pins 1,2,6,7) ISO 10483-1/6.7: VON = 0.5 V, Tc = 85 °C 11) Nominal load current10), device on PCB8)) TA = 85 °C, Tj ≤ 150 °C VON ≤ 0.5 V, Maximum load current in resistive range (Tab to pins 1,2,6,7) VON = 1.8 V, Tc = 25 °C: see diagram on page 13 VON = 1.8 V, Tc = 150 °C: 12) Turn-on time IIN to 90% VOUT: to 10% VOUT: Turn-off time IIN RL = 1 Ω , Tj =-40...+150°C Slew rate on 12) (10 to 30% VOUT ) RL = 1 Ω , TJ = 25 °C Slew rate off 12) (70 to 40% VOUT ) RL = 1 Ω , TJ = 25 °C RON Values min typ max 6.0 10.5 10.7 17 -- mΩ -55 4.4 7.9 -10 70 IL(NOM) 13.6 17 -- A IL(Max) 250 150 100 30 ----- --420 110 dV/dton -- 0.7 -- V/µs -dV/dtoff -- 1.1 -- V/µs RON(Static) IL(ISO) ton toff -- Unit A A µs 7) Thermal resistance RthCH case to heatsink (about 0.5 ... 0.9 K/W with silicone paste) not included! Device on 50mm*50mm*1.5mm epoxy PCB FR4 with 6cm2 (one layer, 70µm thick) copper area for Vbb connection. PCB is vertical without blown air. 9) Decrease of Vbb below 10 V causes slowly a dynamic increase of RON to a higher value of RON(Static). As long as VbIN > VbIN(u) max, RON increase is less than 10 % per second for TJ < 85 °C. 10) Not tested, specified by design. 11) TJ is about 105°C under these conditions. 12) See timing diagram on page 14. 8 ) Semiconductor Group Page 3 1998-Nov.-2 BTS650P Inverse Load Current Operation On-state resistance (Pins 1,2,6,7 to pin 4) VbIN = 12 V, IL = - 20 A Tj = 25 °C: RON(inv) see diagram on page 10 Tj = 150 °C: Nominal inverse load current (Pins 1,2,6,7 to Tab) IL(inv) VON = -0.5 V, Tc = 85 °C11 Drain-source diode voltage (Vout > Vbb) -VON IL = - 20 A, IIN = 0, Tj = +150°C Operating Parameters Operating voltage (VIN = 0) 9, 13) Undervoltage shutdown 14) Undervoltage start of charge pump see diagram page 15 Overvoltage protection15) Tj =-40°C: Ibb = 15 mA Tj = 25...+150°C: Standby current Tj =-40...+25°C: IIN = 0 Tj = 150°C: 6.0 10.5 -- mΩ 55 4.4 7.9 70 -- 0.6 -- V Vbb(on) VbIN(u) 5.0 1.5 -3.0 34 4.5 V V VbIN(ucp) VbIN(Z) 3.0 60 62 --- 4.5 -66 15 25 6.0 --25 50 V V Ibb(off) -- A µA ) If the device is turned on before a V -decrease, the operating voltage range is extended down to VbIN(u). bb For all voltages 0 ... 34 V the device is fully protected against overtemperature and short circuit. 14) VbIN = Vbb - VIN see diagram on page 7. When VbIN increases from less than VbIN(u) up to VbIN(ucp) = 5 V (typ.) the charge pump is not active and VOUT ≈Vbb - 3 V. 15) See also VON(CL) in circuit diagram on page 9. 13 Semiconductor Group Page 4 1998-Nov.-2 BTS650P Parameter and Conditions Symbol at Tj = -40 ... +150 °C, Vbb = 12 V unless otherwise specified Protection Functions Short circuit current limit (Tab to pins 1,2,6,7) VON = 12 V, time until shutdown max. 350 µs Tc =-40°C: Tc =25°C: Tc =+150°C: Short circuit shutdown delay after input current positive slope, VON > VON(SC) Unit IL(SC) IL(SC) IL(SC) --65 110 130 115 td(SC) 80 -- 350 µs 14 16.5 20 V VON(CL) 39 42 47 V VON(SC) Tjt ∆Tjt -150 -- 6 -10 ---- V °C K -- -- 32 V -- 5.4 8.9 7.0 12.3 mΩ -- 120 -- Ω min. value valid only if input "off-signal" time exceeds 30 µs Output clamp 16) (inductive load switch off) Values min typ max IL= 40 mA: -VOUT(CL) -180 -- A see diagram Ind. and overvolt. output clamp page 8 Output clamp (inductive load switch off) at VOUT = Vbb - VON(CL) (e.g. overvoltage) IL= 40 mA Short circuit shutdown detection voltage (pin 4 to pins 1,2,6,7) Thermal overload trip temperature Thermal hysteresis Reverse Battery 17 Reverse battery voltage ) -Vbb On-state resistance (Pins 1,2,6,7 to pin 4) Tj = 25 °C: RON(rev) Vbb = -12V, VIN = 0, IL = - 20 A, RIS = 1 kΩ Tj = 150 °C: Rbb Integrated resistor in Vbb line ) This output clamp can be "switched off" by using an additional diode at the IS-Pin (see page 8). If the diode is used, VOUT is clamped to Vbb- VON(CL) at inductive load switch off. 17) The reverse load current through the intrinsic drain-source diode has to be limited by the connected load (as it is done with all polarity symmetric loads). Note that under off-conditions (I IN = I IS = 0) the power transistor is not activated. This results in raised power dissipation due to the higher voltage drop across the intrinsic drain-source diode. The temperature protection is not active during reverse current operation! Increasing reverse battery voltage capability is simply possible as described on page 9. 16 Semiconductor Group Page 5 1998-Nov.-2 BTS650P Parameter and Conditions Symbol at Tj = -40 ... +150 °C, Vbb = 12 V unless otherwise specified Diagnostic Characteristics Current sense ratio, static on-condition, kILIS = IL : IIS18, VON < 1.5 V ), VIS <VOUT - 5V, VbIN > 4.0 V see diagram on page 12 Values min typ max Unit IL = 90 A,Tj =-40°C: kILIS Tj =25°C: Tj =150°C: IL = 20 A,Tj =-40°C: Tj =25°C: Tj =150°C: IL = 10 A,Tj =-40°C: Tj =25°C: Tj =150°C: IL = 4 A,Tj =-40°C: Tj =25°C: Tj =150°C: IIS=0 by IIN =0 (e.g. during deenergizing of inductive loads): 12 500 12 500 11 500 12 500 12 000 11 500 12 500 11 500 11 500 11 000 11 000 11 200 14 200 13 700 13 000 14 500 14 000 13 400 15 000 14 300 13 500 18 000 15 400 14 000 16 000 16 000 14 500 17 500 16 500 15 000 19 000 17 500 15 500 28 500 22 000 19 000 IIS,lim 6.5 -- -- mA Sense current saturation IIN = 0: IIS(LL) VIN = 0, IL ≤ 0: IIS(LH) Current sense overvoltage protection Tj =-40°C: VbIS(Z) Ibb = 15 mA Tj = 25...+150°C: 19) Current sense settling time ts(IS) --- -2 0.5 -- µA 60 62 -- -66 -- --500 V µs Input Input and operating current (see diagram page 13) IIN(on) -- 0.8 1.5 mA -- -- 80 µA Current sense leakage current IN grounded (VIN = 0) Input current for turn-off20) IIN(off) 18) If VON is higher, the sense current is no longer proportional to the load current due to sense current saturation, see IIS,lim . 19) Not tested, specified by design. 20) We recommend the resistance between IN and GND to be less than 0.5 kΩ for turn-on and more than 500kΩ for turn-off. Consider that when the device is switched off (IIN = 0) the voltage between IN and GND reaches almost Vbb. Semiconductor Group Page 6 1998-Nov.-2 BTS650P Truth Table Normal operation Very high load current Currentlimitation Short circuit to GND Overtemperature Short circuit to Vbb Open load Negative output voltage clamp Inverse load current Input current Output Current Sense level level IIS L H L H 0 nominal H H IIS, lim H H 0 L H L H L H L H L L L L L H H 22 Z ) H L 0 0 0 0 0 21 <nominal ) 0 0 0 L H H H 0 0 Remark =IL / kilis, up to IIS=IIS,lim up to VON=VON(Fold back) IIS no longer proportional to IL VON > VON(Fold back) if VON>VON(SC), shutdown will occure L = "Low" Level H = "High" Level Overtemperature reset by cooling: Tj < Tjt (see diagram on page 15) Short circuit to GND: Shutdown remains latched until next reset via input (see diagram on page 14) Terms RON measurement layout I bb 4 VbIN l ≤ 5.5mm VON Vbb IL V 3 bb IN RIN OUT PROFET IS 5 V IN I IN 1,2,6,7 VbIS VIS Vbb force I IS Out Force Sense contacts contacts (both out pins parallel) VOUT DS R IS Typical RON for SMD version is about 0.2 mΩ less than straight leads due to l ≈ 2 mm Two or more devices can easily be connected in parallel to increase load current capability. 21 22 ) Low ohmic short to Vbb may reduce the output current IL and can thus be detected via the sense current IIS. ) Power Transistor "OFF", potential defined by external impedance. Semiconductor Group Page 7 1998-Nov.-2 BTS650P Input circuit (ESD protection) Current sense status output V bb Vbb ZD V R bb V Z,IS R bb ZD Z,IN IS V bIN IN I IS I R IN V IN When the device is switched off (IIN = 0) the voltage between IN and GND reaches almost Vbb. Use a mechanical switch, a bipolar or MOS transistor with appropriate breakdown voltage as driver. VZ,IN = 66 V (typ). Short circuit detection Fault Condition: VON > VON(SC) (6 V typ.) and t> td(SC) (80 ...350 µs). VIS IS VZ,IS = 66 V (typ.), RIS = 1 kΩ nominal (or 1 kΩ /n, if n devices are connected in parallel). IS = IL/kilis can be driven only by the internal circuit as long as Vout - VIS > 5 V. If you want measure load currents up to IL(M), RIS Vbb - 5 V should be less than . IL(M) / Kilis Note: For large values of RIS the voltage VIS can reach almost Vbb. See also overvoltage protection. If you don't use the current sense output in your application, you can leave it open. Inductive and overvoltage output clamp + Vbb VZ1 + Vbb VON VON VZG OUT OUT Logic unit PROFET Short circuit detection IS DS VOUT VON is clamped to VON(Cl) = 42 V typ. At inductive load switch-off without DS, VOUT is clamped to VOUT(CL) = -19 V typ. via VZG. With DS, VOUT is clamped to Vbb VON(CL) via VZ1. Using DS gives faster deenergizing of the inductive load, but higher peak power dissipation in the PROFET. Semiconductor Group Page 8 1998-Nov.-2 BTS650P Overvoltage protection of logic part + Vbb V R IN Z,IN V Provide a current path with load current capability by using a diode, a Z-diode, or a varistor. (VZL < 72 V or VZb < 30 V if RIN=0). For higher clamp voltages currents at IN and IS have to be limited to 250 mA. R bb Z,IS Vbb disconnect with energized inductive load IN Logic V OUT Version a: PROFET IS R IS V bb V V Z,VIS RV IN bb PROFET OUT Signal GND Rbb = 120 Ω typ., VZ,IN = VZ,IS = 66 V typ., RIS = 1 kΩ nominal. Note that when overvoltage exceeds 71 V typ. a voltage above 5V can occur between IS and GND, if RV, VZ,VIS are not used. Reverse battery protection IS V ZL Version b: - Vbb Rbb V IN Vbb bb OUT RIN IN PROFET OUT Power Transistor Logic IS IS DS D RIS Signal GND V Zb RL RV Power GND RV ≥ 1 kΩ, RIS = 1 kΩ nominal. Add RIN for reverse battery protection in applications with Vbb above 1 1 1 16 V17); recommended value: + + = RIN RIS RV 0.1A 1 0.1A if DS is not used (or = if DS RIN |Vbb| - 12V |Vbb| - 12V is used). To minimize power dissipation at reverse battery operation, the summarized current into the IN and IS pin should be about 120mA. The current can be provided by using a small signal diode D in parallel to the input switch, by using a MOSFET input switch or by proper adjusting the current through RIS and RV. Semiconductor Group Note that there is no reverse battery protection when using a diode without additional Z-diode VZL, VZb. Version c: Sometimes a neccessary voltage clamp is given by non inductive loads RL connected to the same switch and eliminates the need of clamping circuit: Page 9 V Vbb bb IN PROFET RL OUT IS 1998-Nov.-2 BTS650P Inverse load current operation Maximum allowable load inductance for a single switch off L = f (IL ); Tj,start = 150°C, Vbb = 12 V, RL = 0 Ω Vbb V bb L [µH] - IL IN + PROFET OUT 1000000 V OUT + IS - 100000 IIS V IN - V IS R IS 10000 The device is specified for inverse load current operation (VOUT > Vbb > 0V). The current sense feature is not available during this kind of operation (IIS = 0). With IIN = 0 (e.g. input open) only the intrinsic drain source diode is conducting resulting in considerably increased power dissipation. If the device is switched on (VIN = 0), this power dissipation is decreased to the much lower value RON(INV) * I2 (specifications see page 4). Note: Temperature protection during inverse load current operation is not possible! 1000 100 10 1 1A Inductive load switch-off energy dissipation 10 A 100 A 1000 A IL [A] E bb Externally adjustable current limit E AS V ELoad bb i L(t) V bb IN PROFET OUT IS I IN ZL RIS { EL L RL ER If the device is conducting, the sense current can be used to reduce the short circuit current and allow higher lead inductance (see diagram above). The device will be turned off, if the threshold voltage of T2 is reached by IS*RIS . After a delay time defined by RV*CV T1 will be reset. The device is turned on again, the short circuit current is defined by IL(SC) and the device is shut down after td(SC) with latch function. Vbb Energy stored in load inductance: V bb 2 EL = 1/2·L·I L IN While demagnetizing load inductance, the energy dissipated in PROFET is OUT IS RV EAS= Ebb + EL - ER= ∫ VON(CL)·iL(t) dt, Rload with an approximate solution for RL > 0 Ω: IN Signal IL· L IL·RL EAS= (V + |VOUT(CL)|) ln (1+ |V ) 2·RL bb OUT(CL)| Semiconductor Group PROFET Page 10 T1 Signal GND CV T2 R IS Power GND 1998-Nov.-2 BTS650P Options Overview Type BTS 550P 555 650P Overtemperature protection with hysteresis Tj >150 °C, latch function23) Tj >150 °C, with auto-restart on cooling Short circuit to GND protection X switches off when VON>6 V typ. (when first turned on after approx. 180 µs) X X Overvoltage shutdown - - X 24 X ) X X24) X X X Output negative voltage transient limit to Vbb - VON(CL) to VOUT = -19 V typ ) Latch except when V -V bb OUT < VON(SC) after shutdown. In most cases VOUT = 0 V after shutdown (VOUT ≠ 0 V only if forced externally). So the device remains latched unless Vbb < VON(SC) (see page 5). No latch between turn on and td(SC). 24) Can be "switched off" by using a diode DS (see page 8) or leaving open the current sense output. 23 Semiconductor Group Page 11 1998-Nov.-2 BTS650P Characteristics Current sense versus load current: IIS = f(IL), TJ= -40 ... +150 °C IIS [mA] Current sense ratio: IIS = f(IL), TJ= 25 °C kILIS 7 22000 6 20000 5 18000 max max 4 16000 3 min typ 14000 2 min 1 12000 0 10000 0 20 40 60 0 80 20 40 60 80 IL [A] Current sense ratio: KILIS = f(IL),TJ = -40°C kilis IL [A] Current sense ratio: KILIS = f(IL),TJ = 150°C kilis 30000 22000 28000 20000 26000 24000 18000 22000 20000 16000 max 14000 typ 12000 min max 18000 16000 typ 14000 min 12000 10000 10000 0 20 40 60 80 0 IL [A] Semiconductor Group Page 12 20 40 60 80 IL [A] 1998-Nov.-2 BTS650P Typ. input current IIN = f (VbIN), VbIN = Vbb - VIN IIN [mA] Typ. current limitation characteristic IL = f (VON, Tj ) IL [A] 450 1.6 400 1.4 350 1.2 300 VON > VON(S C) only for t < td(S C) (otherwis e immediate s hutdown) 1 250 0.8 200 T J = 25°C 150 0.6 100 0.4 T J = -40°C 50 T J = 150°C 0.2 0 0 VON(F B) 5 10 15 20 VON [V] In case of VON > VON(SC) (typ. 6 V) the device will be switched off by internal short circuit detection. 0 0 20 40 60 80 VbIN [V] Typ. on-state resistance RON = f (Vbb, Tj ); IL = 20 A; VIN = 0 RON [mOhm] 14 static dynamic 12 10 Tj = 150°C 8 85°C 6 25°C 4 -40°C 2 0 0 5 10 15 40 Vbb [V] Semiconductor Group Page 13 1998-Nov.-2 BTS650P Timing diagrams Figure 2b: Switching an inductive load: Figure 1a: Switching a resistive load, change of load current in on-condition: IIN IIN VOUT dV/dtoff VOUT 90% t on dV/dton t off 10% IL tslc(IS) Load 1 IIS IL t slc(IS) Load 2 IIS t tson(IS) t t soff(IS) The sense signal is not valid during a settling time after turn-on/off and after change of load current. Figure 3a: Short circuit: shut down by short circuit detection, reset by IIN = 0. Figure 2a: Switching motors and lamps: IIN IIN IL IL(SCp) VOUT td(SC) IIL IIS VOUT>>0 VOUT=0 t IIS t Shut down remains latched until next reset via input. Sense current saturation can occur at very high inrush currents (see IIS,lim on page 6). Semiconductor Group Page 14 1998-Nov.-2 BTS650P Figure 4a: Overtemperature Reset if Tj<Tjt IIN IIS Auto Restart VOUT Tj t Figure 6a: Undervoltage restart of charge pump, overvoltage clamp VOUT VIN = 0 VON(CL) dynamic, short Undervoltage not below VbIN(u) 6 4 IIN = 0 2 V ON(CL) 0 0 VbIN(u) Semiconductor Group VbIN(ucp) Page 15 1998-Nov.-2 BTS650P Package and Ordering Code All dimensions in mm Standard TO-220AB/7 BTS650P Ordering code Q67060-S6308-A2 Published by Siemens AG, Bereich Halbleiter Vetrieb, Werbung, Balanstraße 73, D-81541 München Siemens AG 1998. All Rights Reserved Attention please! As far as patents or other rights of third parties are concerned, liability is only assumed for components, not for applications, processes and circuits implemented within components or assemblies. The information describes a type of component and shall not be considered as warranted characteristics. Terms of delivery and rights to change design reserved. For questions on technology, delivery and prices please contact the Semiconductor Group Offices in Germany or the Siemens Companies and Representatives worldwide (see address list). Due to technical requirements components may contain dangerous substances. For information on the types in question please contact your nearest Siemens Office, Semiconductor Group. Siemens AG is an approved CECC manufacturer. Packing: Please use the recycling operators known to you. We can also help you - get in touch with your nearest sales office. By agreement we will take packing material back, if it is sorted. You must bear the costs of transport. For packing material that is returned to us unsorted or which we are not obliged to accept, we shall have to invoice you for any costs incurred. Components used in life-support devices or systems must be 25 expressly authorised for such purpose! Critical components ) of the Semiconductor Group of Siemens AG, may only be used in life 26 supporting devices or systems ) with the express written approval of the Semiconductor Group of Siemens AG. SMD TO 220AB/7, Opt. E3180 Ordering code BTS650P E3180A T&R: Q67060-S6308-A4 Footprint: 10.8 9.4 16.15 4.6 0.47 0.8 8.42 25) 26) Semiconductor Group Page 16 A critical component is a component used in a life-support device or system whose failure can reasonably be expected to cause the failure of that life-support device or system, or to affect its safety or effectiveness of that device or system. Life support devices or systems are intended (a) to be implanted in the human body or (b) support and/or maintain and sustain and/or protect human life. If they fail, it is reasonably to assume that the health of the user or other persons may be endangered. 1998-Nov.-2