february 1999 ?revised july 2008 specifications are subject to change without notice. customers should verify actual device performance in their specific applications. tisp83121d unidirectional p & n-gate protector tisp83121d dual-gate unidirectional overvoltage protector device symbol overvoltage protection for dual-voltage ringing slics C programmable protection configurations up to 100 v C typically 5 lines protected by: two tisp83121d + diode steering networks high surge current C 150 a, 10/1000 s C 250 a, 10/700 s C 500 a, 8/20 s pin compatible with the lcp3121 C 50 % more surge current C functional replacement in diode steering applications small outline surface mount package how to order 8-soic package (top view) description the tisp83121d is a dual-gate reverse-blocking unidirectional thyristor designed for the protection of dual-voltage ringing slics (subscriber line interface circuits) against overvoltages on the telephone line caused by lightning, a.c. power contact and induction. the device chip is a four-layer npnp silicon thyristor structure which has an electrode connection to every layer. for negative overvoltage protection the tisp83121d is used in a common anode configuration with the voltage to be limited applied to the cathode (k) terminal and the negative reference potential applied to the gate 1 (g1) terminal. for positive overvoltage protection the tisp83121d is used in a common cathode configuration with the voltage to be limited applied to the anode (a) terminal and the positive reference potential applied to the gate 2 (g2) terminal. md6xayb 1 2 3 4 5 6 7 8 k a a k k k g1 g2 for operation at the rated current values connect pins 1, 4, 5 and 8 together. k g1 g2 sd6xak a a the tisp83121d is a unidirectional protector and to prevent reverse bias, requires the use of a series diode between the protec ted line conductor and the protector. further, the gate reference supply voltage requires an appropriately poled series diode to prevent the supply from being shorted when the tisp83121d crowbars. under low level power cross conditions the tisp83121d gate current will charge the gate reference supply. if the reference supp ly cannot absorb the charging current its potential will increase, possibly to damaging levels. to avoid excessive voltage levels a clamp (zener or avalanche breakdown diode) may be added in shunt with the supply. alternatively, a grounded collector emitter-follower may be u sed to reduce the charging current by the transistors h fe value. this monolithic protection device is made with an ion-implanted epitaxial-planar technology to give a consistent protection per formance and be virtually transparent to the system in normal operation. *rohs directive 2002/95/ec jan 27 2003 including annex ............................................... ul recognized component * r o h s c o m p l i a n t device package carrier tisp83121 d (8-pin small-outline) r (embossed tape reeled) tisp83121dr-s order as
february 1999 ?revised july 2008 specifications are subject to change without notice. customers should verify actual device performance in their specific applications. electrical characteristics, t j = 25 c (unless otherwise noted) tisp83121d unidirectional p & n-gate protector absolute maximum ratings thermal characteristics parameter test conditions min typ max unit i d off-state current v d =70v, i g =0 1 a i drm repetitive peak off- state current v d =v drm = 100 v, i g =0, 0 c to 70 c10 a i h holding current i t = 1 a, di/dt = -1a/ms t j = 0 to 70 c t j = 25 c t j = 70 c 90 60 300 ma i r reverse current v r =0.3v 1ma i g1t gate g1 trigger current i t =+1a, t p(g) =20 s +200 ma i g2t gate g2 trigger current i t =+1a, t p(g) =20 s -180 ma v g1t g1-k trigger voltage i t =+1a, t p(g) =20 s+1.8v v g2t g2-a trigger voltage i t =+1a, t p(g) =20 s-1.8v c ak anode-cathode off- state capacitance f=1mhz, v d =1v rms, v d =5v, i g = 0 (see note 3) 100 pf note 3: these capacitance measurements employ a three terminal capacitance bridge incorporating a guard circuit. the unmeasured device terminals are a.c. connected to the guard terminal of the bridge. parameter test conditions min typ max unit r ja junction to free air thermal resistance t a t tsm(900) = 25 c, eia/jesd51-3 pcb, eia/jesd51-2 environment, i = i 105 c/w rating symbol value unit repetitive peak off-state voltage, 0 c to 70 cv drm 100 v non-repetitive peak on-state pulse current (see notes 1 and 2) i tsp a 10/1000 (gr-1089-core, open-circuit voltage wave shape 10/1000 150 5/310 (ccitt k20/21, open-circuit voltage wave shape 7 kv, 10/700 250 8/20 s s s) s) s) s (ansi c62.41, open-circuit voltage wave shape 1.2/50 500 non-repetitive peak on-state current, 50 hz, halfwave rectified sinewave, (see notes 1 and 2) 100 ms 1 s 900 s i tsm 22 8 3 a junction temperature t j -40 to +150 c storage temperature range t stg -65 to +150 c notes: 1. initially the protector must be in thermal equilibrium with 0 c < t j < 70 c. the surge may be repeated after the device returns to its initial conditions. for operation at the rated current value, pins 1, 4, 5 and 8 must be connected together. 2. above 70 c, derate linearly to zero at 150 c lead temperature.
february 1999 ?revised july 2008 specifications are subject to change without notice. customers should verify actual device performance in their specific applications. parameter measurement information tisp83121d unidirectional p & n-gate protector figure 1. voltage-current characteristic pm6xagb quadrant i anode positive switching characteristic quadrant iii anode negative reverse characteristic i h +v -i -v i d v r i r v drm +i reference volta ge v gt
february 1999 ?revised july 2008 specifications are subject to change without notice. customers should verify actual device performance in their specific applications. applications information tisp83121d unidirectional p & n-gate protector multiple line overvoltage protection figure 2 shows two tisp83121d devices protecting many lines. line conductor positive overvoltage protection is given by the ste ering diode array connected to the anode of the upper tisp83121d and the tisp83121d itself. the tisp83121d gate reference voltage is the po sitive battery supply, +v bat . the initial limiting voltage will be the sum of the voltages of the battery, the forward biased conductor diode, the gate trigger of the tisp83121d and the forward biased reference voltage blocking diode. typically the conductor voltage will be init ially limited at 2.5 v above the +v bat value. figure 2. n line positive and negative overvoltage protection k a g1 tisp83121d g2 k a g1 tisp83121d g2 0 -ve reference voltage ai8xa a +ve reference voltage line 1 in line n in r1 t1 rn tn slic 1 slic n r r r r r r +v bat -v bat line conductor negative overvoltage protection is given by the diode steering array connected to the cathode of the lower tisp8 3121d and the tisp83121d itself. the tisp83121d gate reference voltage is the negative battery supply, -v bat . the initial limiting voltage will be the sum of the voltages of the battery, the forward biased conductor diode, the gate trigger of the tisp83121d and the forward biased r eference voltage blocking diode. typically the conductor voltage will be initially limited at 2.5 v below the -v bat value. when a tisp83121d crowbars and grounds all conductors of the appropriate polarity, the device current will be the sum of all th e slic output currents. this will usually exceed the tisp83121d holding current. to switch off the tisp83121d and restore normal operation, t he grounded condition of the slic output must be detected and the slic outputs turned off. the 150 a rating of the tisp83121d allows a large number of lines to be protected against currents caused by lightning. for exa mple, if a recommendation k.20 10/700 generator was connected to all lines, together with 350 v primary protection and a series conductor resistance (r) of 25 ? , the maximum conductor current before the primary protection operated would be 350/25 = 14 a or 28 a per line. for a total ret urn current of about 150 a the number of lines would be 150/28 = 5. at this current level, 5x28 = 140 a, the generator voltage woul d be140((25+25)/10+15) = 2800 v. another limitation is long term power cross. the long term power cross capability of the tisp831 21d is 3 a peak or 2.1 a rms. if the line conductor overcurrent protection was given by a ptc thermistor which tripped at 0.2 a, the maxim um number of conductors becomes 2.1/0.2 = 10 or 5 lines.
february 1999 ?revised july 2008 specifications are subject to change without notice. customers should verify actual device performance in their specific applications. tisp83121d unidirectional p & n-gate protector battery supply impedance in many designs, the battery supply voltages are generated by switching mode power supplies. this type of power supply cannot b e charged like a battery. feeding a charging current to a switching mode power supply will usually cause the supply to stop switching and the voltage to rise. the gate current of the tisp83121d is a charging current for the supply. to avoid the supply voltage from rising and dama ging the connected slics, an avalanche diode voltage clamp can be connected across the supply (figure 3. (a)). another approach is to reduce the gate charging current for the supply by a transistor buffer (figure 3. (b)). if the transisto r gain was 50, a 200 ma gate current would be reduced to a supply charging current of 200/50 = 4 ma. in both cases, the dissipation in the contr ol devices can be substantial and power capability needs to be taken into account in device selection. figure 3. reference voltage control by (a) breakdown diodes or (b) by transistor buffers -ve reference voltage +ve reference voltage 0 ai8xab +v bat -v bat (b) k a g1 tisp83121d g2 -ve reference vol tage +ve reference vol tage 0 +v bat -v bat k a g1 tisp83 121d g2 k a g1 g2 tisp83121d k a g1 g2 tisp83121d (a) tisp is a trademark of bourns, ltd., a bourns company, and is registered in u.s. patent and trademark office. bourns is a registered trademark of bourns, inc. in the u.s. and other countries.
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