microsemi scottsdale division 8700 e. thomas rd. po box 1390, scottsdale, az 85252 us a, (480) 941 - 6300, fax: (480) 947 - 1503 copyright ? 2001 mscxxxx.pdf 08 - 13 - 2002 rev h www. microsemi . com t ite lamp sm14lv1.7c tvsarray ? scott sdale division electrical characteristics per line @ 25c unless otherwise specified v br @100 a volts v rwm volts i r +25 c a i r +50 c a cap @ 3v pf cap @10v pf cap @15v pf v f @ i f 100ma volts v f (surge) @ i pp = 8 a 6/70 s volts part number device marking min max max @v r max @v r typ typ typ max max sm14lcv1.7c lv1.7c 35 30 25 30 100 20 45 30 27 0.5 1.70 device pin out configuration tite clamp ? tvs series so - 14 package applications rs - 232 - b rs - 422 - a rs - 423 - a rs - 485 features ultra low clamp for sensitive i/o ports clamps voltage to 1.7v max above signal level operates over range from 3v through 30v protects 10 lines uni and bi - directional to voltag e bus ul 94v - o flammability classification maximum ratings operating temperature: - 55c to +50c storage temperature: - 55c to +125c forward surge current: 8a (6/70s) minimum reverse breakdown voltage ( v br ): 35v working peak reverse voltage v rwm to 30v continuous forward current, i f : 400ma power dissipation, (p d ): 500mw derating factor: 4.0 mw/c mechanical molded soic 14 pin surface mount weight 2.5 grams (approximate) marking: logo, date code pin 1 defined by dot p ackaging tape & reel per eia standard 481 2,500 pieces per 13 inch reel (standard) carrier tube 50 pcs (optional) inches millimeters dim min max min max a 0.336 0.344 8.53 8.74 b 0.150 0.158 3.81 4.01 c 0.228 0.244 5.79 6.19 e 0.011 0.021 0.28 0.53 f 0.004 0.010 0.10 0.20 g 0.053 0.069 1.35 1.75 h 0.006 0.010 0.15 0.25 j 0.189 0.206 4.80 5.23 k 0.016 0.050 0.41 1.27 sm14lv1.7c outline
microsemi scottsdale division 8700 e. thomas rd. po box 1390, scottsdale, az 85252 us a, (480) 941 - 6300, fax: (480) 947 - 1503 copyright ? 2001 mscxxxx.pdf 08 - 13 - 2002 rev h www. microsemi . com t ite lamp sm14lv1.7c tvsarray ? scott sdale division application notes for using the sm14lv1.7c titeclamp tm tvsarray tm the sm14lv1.7c titeclamp tvsarray is a 10 wire protector designed for clamping voltage spikes to lowest possible levels between the signal lin e and the vcc supply or ground. this device incorporates microsemi's proprietary "self programmable" feature that provides exceedingly tight clamping of only 1.7v maximum above signal line voltages ranging from 3.0v up through 30v. destructive over - current is diverted through the plus and minus vcc rails or ground for negative transients. one size fits all downsizing of on chip components to sub - micron dimensions has improved performance, reduced component size and cost at the expense of lower failure vol tage thresholds . the demand has surfaced for improved protection across data lines in highly automated manufacturing, monitoring and control systems. these environments are usually harsh and subject to conducted and induced transient voltages originating f rom sources including motors, solenoids and welders. the connection points are shown in figure 1. pins 1 and 14 are connected to +vcc, with pins 7 & 8 being either - vcc or ground. the lines are spread out for purposes of illustrating the connections; howe ver, the traces between signal lines and the tvs should be at an absolute minimum to reduce parasitic reluctance which causes overshoot per faraday's laws of induction, v=l(di/dt). in figure 2, the segment for a single wire is detailed for improved illustr ation. a scaled illustration of clamping on a 12v signal line example is shown in figure 3. this depicts a small but acceptable rise in voltage above the signal during worse case transient conditions. precauti ons in component placement and board layout: 1. place the sm14lv1.7c directly at the board/signal line interface. 2. keep all traces short for both signal lines and vcc (and ground if applicable). 3. eliminate ground loops. if the reader has further tec hnical questions, please contact microsemi - scottsdale applications engineering at 480 - 941 - 6433 or 480 - 941 - 6524. 7 6 5 4 3 2 1 8 9 10 11 12 13 14 1 2 3 4 5 10 9 8 6 7 t ite lamp + v cc - v cc or gnd line installation figure 1. to signal line + vcc - vcc or gnd single line detail figure 2. clamp performance 12 v signal voltage v t 1.7v max clamp level figure 3. sm14lv1.7c
|
