234 www.littelfuse.com tvs diode arrays electronic protection array for esd and overvoltage protection SP721 the SP721 is an array of scr/diode bipolar structures for esd and over-voltage protection to sensitive input circuits. the SP721 has 2 protection scr/diode device structures per input. there are a total of 6 available inputs that can be used to protect up to 6 external signal or bus lines. over-voltage protection is from the in (pins 1 - 3 and pins 5 - 7) to v+ or v-. the scr structures are designed for fast triggering at a threshold of one +v be diode threshold above v+ (pin 8) or a -v be diode threshold below v- (pin 4). from an in input, a clamp to v+ is activated if a transient pulse causes the input to be increased to a voltage level greater than one v be above v+. a similar clamp to v- is activated if a negative pulse, one v be less than v-, is applied to an in input. standard esd human body model (hbm) capability is: features ?esd interface capability for hbm standards - mil std 3015.7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15kv - iec 61000-4-2, direct discharge, - single input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4kv (level 2) - two inputs in parallel . . . . . . . . . . . . . . . . . . . . . . . . . . 8kv (level 4) - iec 61000-4-2, air discharge . . . . . . . . . . . . . . . . . . 15kv (level 4) ?high peak current capability - iec 61000-4-5 (8/20?). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ?a - single pulse, 100? pulse width . . . . . . . . . . . . . . . . . . . . . . . . ?a - single pulse, 4? pulse width . . . . . . . . . . . . . . . . . . . . . . . . . . ?a ?designed to provide over-voltage protection - single-ended voltage range to . . . . . . . . . . . . . . . . . . . . . . . . +30v - differential voltage range to. . . . . . . . . . . . . . . . . . . . . . . . . . . ?5v ?fast switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2ns rise time ?low input leakages . . . . . . . . . . . . . . . . . . . . . . . . 1na at 25 o c typical ?low input capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3pf typical ?an array of 6 scr/diode pairs ?operating temperature range . . . . . . . . . . . . . . . . . . . . -40 o c to 105 o c applications ?microprocessor/logic input protection ?data bus protection ?analog device input protection ?voltage clamp functional block diagram 4 v+ v- in 3, 5-7 in in 1 8 2 refer to figure 1 and table 1 for further detail. refer to application notes an9304 and an9612 for additional information. pinout SP721 (pdip, soic) top view hbm standard mode r c esd (v) iec 61000-4-2 air 330 ? 150pf >15kv direct 330 ? 150pf >4kv direct, dual pins 330 ? 150pf >8kv mil-std-3015.7 direct, in-circuit 1.5k ? 100pf >15kv ordering information part no. temp. range ( o c) package pkg. no. min. order SP721ap -40 to 105 8 ld pdip e8.3 2000 1960 2500 SP721ab -40 to 105 8 ld soic m8.15 SP721abt -40 to 105 8 ld soic tape and reel m8.15 in in in v- 1 2 3 4 8 7 6 5 v+ in in in
235 www.littelfuse.com 5 tvs diode arrays tvs diode arrays SP721 electronic protection array for esd and overvoltage protection absolute maximum ratings continuous supply voltage, (v+) - (v-). ........................ +35v forward peak current, i in to v cc , i in to gnd (refer to figure 6). ................................. 2a, 100? esd ratings and capability (figure 1, table 1) load dump and reverse battery (note 2) thermal information thermal resistance (typical, note 1) ja ( o c/w) pdip package . ...........................................160 soic package . ..........................................170 maximum storage temperature range . .................. .-65 o c to 150 o c maximum junction temperature (plastic package) . . . .. ............. ..150 o c maximum lead temperature (soldering 10s). ......................... .300 o c (soic lead tips only) parameter symbol test conditions min typ max units operating voltage range, v supply = [(v+) - (v-)] v supply - 2 to 30 - v forward voltage drop in to v- in to v+ v fwdl v fwdh i in = 1a (peak pulse) - - 2 2 - - v v input leakage current i in -20 5 +20 na quiescent supply current i quiescent - 50 200 na equivalent scr on threshold note 3 - 1.1 - v equivalent scr on resistance v fwd /i fwd ; note 3 - 1 - ? input capacitance c in -3-pf input switching speed t on -2-ns notes: 2. in automotive and battery operated systems, the power supply lines should be externally protected for load dump and reverse b attery. when the v+ and v- pins are connected to the same supply voltage source as the device or control line under protection, a current limiti ng resistor should be connected in series between the external supply and the SP721 supply pins to limit reverse battery current to within the rat ed maximum limits. bypass capacitors of typically 0.01 f or larger from the v+ and v- pins to ground are recommended. 3. refer to the figure 3 graph for definitions of equivalent ?cr on threshold and ?cr on resistance? these characteristics a re given here for thumb-rule information to determine peak current and dissipation under eos conditions. esd capability esd capability is dependent on the application and defined test standard.the evaluation results for various test standards and methods based on figure 1 are shown in table 1. for the ?odified mil-std-3015.7 condition that is defined as an ?n-circuit method of esd testing, the v+ and v- pins have a return path to ground and the SP721 esd capability is typically greater than 15kv from 100pf through 1.5k ? . by strict definition of mil-std-3015.7 using ?in-to-pin device testing, the esd voltage capability is greater than 6kv. the mil-std-3015.7 results were determined from at&t esd test lab measurements. the hbm capability to the iec 61000-4-2 standard is greater than 15kv for air discharge (level 4) and greater than 4kv for direct discharge (level 2). dual pin capability (2 adjacent pins in parallel) is well in excess of 8kv (level 4). for esd testing of the SP721 to eiaj ic121 machine model (mm) standard, the results are typically better than 1kv from 200pf with no series resistance. caution: stresses above those listed in ?bsolute maximum ratings may cause permanent damage to the device. this is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. note: 1. ja is measured with the component mounted on an evaluation pc board in free air. electrical specifications t a = -40 o c to 105 o c, v in = 0.5v cc , unless otherwise specified h.v. supply v d in dut c d r 1 iec 1000-4-2: r 1 50 to 100m ? r d charge switch discharge switch mil-std-3015.7: r 1 1 to 10m ? figure 1. electrostatic discharge test standard type/mode r d c d v d mil-std-3015.7 modified hbm 1.5k ? 100pf 15kv standard hbm 1.5k ? 100pf 6kv iec 61000-4-2 hbm, air discharge 330 ? 150pf 15kv hbm, direct discharge 330 ? 150pf 4kv hbm, direct discharge, two parallel input pins 330 ? 150pf 8kv eiaj ic121 machine model 0k ? 200pf 1kv table 1. esd test conditions
236 www.littelfuse.com tvs diode arrays electronic protection array for esd and overvoltage protection figure 2. low current scr forward voltage drop curve figure 3. high current scr forward voltage drop curve 600 800 1000 1200 forward scr voltage drop (mv) 100 80 60 40 20 0 forward scr current (ma) t a = 25 o c single pulse 2.5 2 1.5 1 0.5 0 forward scr current (a) t a = 25 o c single pulse v fwd i fwd 0123 forward scr voltage drop (v) equiv. sat. on threshold ~ 1.1v figure 4. typical applica tion of the SP721 as an input clamp for over-voltage, greater than 1v be above v+ or less than -1v be below v- +v cc input drivers SP721 input protection circuit (1 of 6 shown) or signal sources in 5 - 7 in 1 - 3 SP721 v- to +v cc linear or digital ic interface v+ +v cc SP721
237 www.littelfuse.com 5 tvs diode arrays tvs diode arrays SP721 electronic protection array for esd and overvoltage protection peak transient current capability of the SP721 the peak transient current capability rises sharply as the width of the current pulse narrows. destructive testing was done to fully evaluate the SP721 |