supertex inc. md0100 supertex inc. www.supertex.com doc.# dsfp-md0100 c070113 features ? up to 100v input voltage protection ? low on resistance - 15 typical ? fast switching speed ? effectively, a simple two terminal device ? no external supplies needed applications ? medical ultrasound imaging ? ndt applications ? fast resettable fuses ? high side switches ? data acquisition general description the supertex md0100 is a high voltage, two terminal, bi- directional, current-limiting protection device. the two terminals are interchangeable. it is designed to protect a low noise receiver from the high voltage transmit pulses in ultrasound applications and is commonly referred to as a t/r (transmit and receive) switch. the md0100 can be considered as a normally closed switch with a typical switching resistance of 15 that allows small signals to pass. once the voltage drop across the two terminals exceeds a nominal value of 2.0v, the device will start to turn off. in the off state, the md0100 can withstand up to 100v across its terminals. a small amount of current, typical of 200a, is allowed to low through. the applications for the md0100 are not limited to just ultrasound. it can also be used for resettable fuses to protect power lines, output short circuit protection, and data acquisition. the md0100 is available in the sot-89 package as a single channel device for ease of assembly. it is also available in a 4.0x4.0mm 8-lead dfn package as a two channel device for high density requirements. typical application circuit high voltage protection t/r switch transmitter piezot ransducers b a receiver t x r x high voltage switches +90v -90v t/r switch md0100 logic control and signal processing downloaded from: http:///
2 md0100 supertex inc. www.supertex.com doc.# dsfp-md0100 c070113 absolute maximum ratings 1 pin coniguration product marking 8-lead dfn (top view) (pads are at bottom of device) com1 com2 8 7 6 5 1 2 3 4 com1com1 com2 com2 a1b1 a2 b2 a com b com m10yw y = last digit of year sealed w = code for week sealed = ?green? packaging sot-89 sot-89 package may or may not include the following marks: si or package may or may not include the following marks: si or 0100 ywll y = last digit of year sealedw = code for week sealed ll = lot number = ?green? packaging 8-lead dfn parameter value v a-b , differential voltage drop 0 to 110v maximum junction temperature +125c storage temperature range -65c to 150c power dissipation, 8-lead dfn 2 1.1w power dissipation, sot-89 2 1.6w notes: 1. absolute maximum ratings are those values beyond which damage to the device may occur. functional operation under these conditions is not implied. continuous operation of the device at the absolute rating level may affect device reliability. all voltages are referenced to device ground. 2. mounted on fr4 board, 25mm x 25mm x 1.57mm ordering information part number package options packing MD0100DK6-G (dual channel) 8-lead (4x4) dfn 3000/reel md0100n8-g(single channel) 3-lead to-243aa (sot-89) 2000/reel typical thermal resistance package ja 8-lead dfn 44 o c/w 3-lead to-243aa (sot-89) 133 o c/w -g denotes a lead (pb)-free / rohs compliant package electrical characteristics (t j = 25oc, unless otherwise speciied) sym parameter min typ max units conditions v a-b max. differential input voltage from a to b 100 - - v i a-b = 500a r sw switch on resistance from a to b - 15 - i a-b = 5.0ma v trip v a-b trip point to turn off - 1.0 2.0 v --- v off switch turn off voltage - 2.0 - v i a-b = 1.0ma i a-b(off) switch off current - 200 300 a v a-b = 100v i peak peak switching current - 60 - ma see fig. 8 downloaded from: http:///
3 md0100 supertex inc. www.supertex.com doc.# dsfp-md0100 c070113 block diagram switch control com a b typical i-v characteristics i a-b -v off -v trip +100v i a-b = -200a -100v i a-b = +200a v a-b r sw = 15 +i peak -i peak +v trip +v off +1.0ma +1.0ma electrical characteristics (t j = 25oc, unless otherwise speciied) sym parameter min typ max units conditions t off turn off time - - 20 ns see fig. 2, 3 & 4 t on turn on time - - 20 ns see fig. 5, 6 & 7 c sw(on) switch on capacitance from a to b - 21 - pf sw = on c sw(off) switch off capacitance from a to b - 15 - pf v sw = 25v bw small signal bandwidth - 100 - mhz r load = 50 t j operating junction temperature -40 - +125 c --- downloaded from: http:///
4 md0100 supertex inc. www.supertex.com doc.# dsfp-md0100 c070113 functional description the supertex md0100 can be considered as a normally closed switch controlled by a switch control. (refer to the block diagram.) the switch control monitors the voltage drop across terminals a and b. if the voltage difference is greater than 2.0v, the t/r switch will start to open. once in the open state, there is a small amount of current lowing through the t/r switch, 200ua, to detect if the high voltage is still present or not. the t/r switch will not close until the voltage across terminal a and b drops within 2.0v. a pair of back-to-back diodes from the receive side of the switch to ground are needed to complete the circuit and to allow the initial peak current (about 60ma) to low through the switch so it can drop 2.0v. if the diodes are not present, then there is no current path and the voltage drop across terminal a and b will be less than 2.0v, so the switch will remain in the closed position. the other purpose of the diode is to clamp voltage spikes to 0.7v during transmit cycle. a low voltage diode, for ex - ample 1.0v diode, is suficient since it will only see 0.7v. a bav99t dual diode from diodes, inc. was used in our test circuit. on resistance when the voltage across terminals a and b is within 2.0v, the switch is in the receive mode, and the r on is typically 15. once the voltage across terminals a and b is greater than 2.0v, the switch is in the transmit mode and blocks the high voltage pulses from passing through to the receiver and damaging it. the md0100 does not require any power supply. there are only two active pins; one connects to the transmitter side and the other one connects to the receiver side. switch capacitance the typical switch on capacitance (c sw(on) ) is 21pf. this is measured from a to b or b to a when the switch is on. the switch off capacitance is a function of the voltage across the t/r switch. the c sw(off) is about 12 to 19 pf for 10v to 100v of the transmit voltage. please see figure 1 for the c-v curve of the c sw(off) . figure 1: c sw(off) vs v sw t on and t off time the t on and t off of the md0100 are less than 20ns, which provide a fast switch between the transmit mode and the receive mode. the t on and t off are input rise/fall time depen - dent. the md0100 turns on and off faster when the rise and fall times of the transmit pulse are faster. on the other hand, the switch turns on and off slower if the rise and fall times of the transmit pulse are slower. the t off and t on set up are shown in figure 2 and figure 5 respectively. figure 2: test set up for t off 10 11 12 13 14 15 16 17 18 19 20 0 10 20 30 40 50 60 70 80 90 v sw (v ) c sw (pf) tx +10v 0v 10 transmitter md0100 v b v a 500ns downloaded from: http:///
5 md0100 supertex inc. www.supertex.com doc.# dsfp-md0100 c070113 v a v b +10v +2v 10% 2v 10% figure 4 shows the actual waveform and measurement of the t off . t off is measured from 2v of the v a to 10% of the v b . from the above waveform, the t off is 11ns. tx transmitter md0100 2v +10v 0v 15 v b v a 500ns figure 5: test set up for t on figure 3: t off timing diagram figure 4: t off at v a = 10v v a v b +10v 0v2v 0v +2v 1v figure 6: t on timing diagram 1v 2v figure 7: t on at v a = 10v figure 7 shows the actual waveform and measurement of the t on . the t on is measured from 2v of the v a to 1v of the v b . from the above waveform, the t on is 6.6ns. a b md0100 i peak v 0 - 5v t r = 10ms figure 8: test set up for i peak downloaded from: http:///
6 md0100 supertex inc. www.supertex.com doc.# dsfp-md0100 c070113 tx +90v -90v 1k md0100 ch1 ch2 100ns v b v a transmitter figure 9: typical application circuit figure 11: typical waveform figure 11 shows v a and v b in the same voltage scale, 2.0v/ div. figure 10: typical waveform figure 10 shows the waveforms of v a and v b of the test cir - cuit shown in figure 9. there is a small bump of about 0.5v at the tail of the v b signal because the transmit signal falls into the 2.0v range, and the md0100 turns back on again. figure 11 shows a magniied view of the v a . downloaded from: http:///
7 md0100 supertex inc. www.supertex.com doc.# dsfp-md0100 c070113 pin description (sot-89) name description a switch terminal a com leave loating b switch terminal b pin description (8-lead dfn) pin name description 1 a1 switch terminal a1 2 b1 switch terminal b1 3 a2 switch terminal a2 4 b2 switch terminal b2 5 com2 leave loating 6 com2 7 com1 leave loating 8 com1 heat slug 1 com1 leave loating heat slug 2 com2 leave loating downloaded from: http:///
8 md0100 supertex inc. www.supertex.com doc.# dsfp-md0100 c070113 8-lead dfn package outline (k6) 4.00x4.00mm body, 1.00mm height (max), 1.00mm pitch (dual pad) symbol a a1 a3 b d d2 e e2 e k1 l l1 dimension (mm) min 0.80 0.00 0.20 ref 0.25 3.90 1.35 3.90 1.35 1.00 bsc 0.50 ref 0.40 0.00 0 o nom 0.90 - 0.30 4.00 1.45 4.00 1.45 0.50 - - max 1.00 0.05 0.35 4.10 1.55 4.10 1.55 0.60 0.15 14 o drawings not to scalesupertex doc. #: dspd-8dfnk64x4p100, version c010813 bottom view e2 vi ew b note 1 (index area d/2 x e/2) 1 8 note 1 e2 d2 k1 k1/2 seating plane top vi ew side view a a1 d e e b a3 l l1 vi ew b note 1 (index area d/2 x e/2) note 3 note 2 1 8 d2 notes: 1. a pin 1 identiier must be located in the index area indicated. the pin 1 identiier can be: a molded mark/identiier; an embedded metal marker; or a printed indicator. 2. depending on the method of manufacturing, a maximum of 0.15mm pullback (l1) may be present. 3. the inner tip of the lead may be either rounded or square. downloaded from: http:///
supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such applications unless it receives an adequate ?product liability indemnification insurance agreement.? supertex inc . does not assume responsibility for use of devices described, and limits its liabilit y to the replacement of the devices determined defective due to workmanship. no responsibility is assumed for possible omissions and inaccuracies. circuitry and specifications are subject to change without notice. for the latest product specifications refer to the supertex inc . (website: http//www .supertex.com) ?2013 supertex inc. all rights reserved. unauthorized use or reproduction is prohibited. supertex inc. 1235 bordeaux drive, sunnyvale, ca 94089 t el: 408-222-8888 www.supertex.co m 9 md0100 (the package drawing(s) in this data sheet may not relect the most current speciications. for the latest package outline information go to http://www.supertex.com/packaging.html .) doc.# dsfp-md0100 c070113 3-lead to-243aa (sot-89) package outline (n8) symbol a b b1 c d d1 e e1 e e1 h l dimensions (mm) min 1.40 0.44 0.36 0.35 4.40 1.62 2.29 2.00 ? 1.50 bsc 3.00 bsc 3.94 0.73 ? nom - - - - - - - - - - max 1.60 0.56 0.48 0.44 4.60 1.83 2.60 2.29 4.25 1.20 jedec registration to-243, variation aa, issue c, july 1986. ? this dimension differs from the jedec drawing drawings not to scale . supertex doc. #: dspd-3to243aan8, version f111010. b b1 d d1 e h e1 c a 1 2 3 e e1 top vi ew side view l downloaded from: http:///
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