surface mount rf schottky diodes in sot-363 (sc-70, 6 lead) technical data features ? unique configurations in surface mount sot-363 package C increase flexibility C save board space C reduce cost ? hsms-28 x k grounded center leads provide up to 10 db higher isolation ? matched diodes for consistent performance ? better thermal conductivity for higher power dissipation package lead code identification (top view) description these schottky diodes are specifi- cally intended for analog and digital applications, including dc biased detecting; mixing; switching; sampling; clipping and clamping; and wave shaping. this series offers a wide range of specifications and package configurations for design versatility. the benefit of this added flexibility translates into more board space and reduced cost. available in various package configurations, these families of diodes provide low cost solutions to a wide variety of design problems. hewlett-packards manufacturing techniques assure that when multiple diodes are mounted into a single sot-363 package, they are taken from adjacent sites on the wafer, assuring the highest possible degree of match. hsms-280k/ l/m/n/p/r hsms-281k/l hsms-282k/ l/m/n/p/r common cathode quad m unconnected trio l bridge quad p common anode quad n ring quad r 123 654 high isolation unconnected pair k 123 654 123 654 123 654 123 654 123 654 gu 1 2 3 6 5 4 pin connections and package marking notes: 1. package marking provides orientation and identification. 2. see electrical specifications for appropriate package marking. applications ? hsms-282 a good general purpose diode, specifically for: C dc biased detection at < 2.5 ghz C moderate voltage clipping and clamping C mixing applications < 3 ghz ? hsms-280 a in high voltage clipping and clamping applications ? hsms-281 a low 1/f @ 1 ghz mixing
2 electrical specifications, t c = +25 c, single diode [1] minimum maximum maximum maximum typical part package breakdown forward forward reverse maximum dynamic number marking lead voltage voltage voltage leakage capacitance resistance hsms- code [2] code configuration v br (v) v f (mv) v f (v) @ i r (na) @ c t (pf) r d ( w ) i f (ma) v r (v) 280k ak k high isolation 70 400 1.0 15 200 50 2.0 35 unconnected pair 280l al l unconnected trio 2.0 35 280m h m common cathode quad 280n n n common anode quad 280p ap p bridge quad 280r o r ring quad 281k bk k high isolation 20 400 1.0 35 200 15 1.2 15 unconnected pair 281l bl l unconnected trio 282k ck k high isolation 15 340 0.7 30 100 1 1.0 12 unconnected pair 282l cl l unconnected trio 282m hh m common cathode quad 282n nn n common anode quad 282p cp p bridge quad 282r oo r ring quad test conditions i r = 10 m ai f = 1 ma [3] v f = 0 v i f = 5 ma f = 1 mhz [4] notes: 1. effective carrier lifetime ( t ) for all these diodes is 100 ps maximum measured with krakauer method at 5 ma, except hsms-282 a which is measured at 20 ma. 2. package marking code is laser marked. 3. d v f for diodes in trios and quads is 15.0 mv maximum at 1.0 ma. 4. d c to for diodes in trios and quads is 0.2 pf maximum. absolute maximum ratings, t c = 25oc symbol parameter unit absolute maximum [1] i f forward current (1 m s pulse) amp 1 p iv peak inverse voltage v same as v br t j junction temperature c 150 t stg storage temperature c -65 to 150 q jc thermal resistance [2] c/w 140 notes: 1. operation in excess of any one of these conditions may result in permanent damage to the device. 2. t c = +25 c, where t c is defined to be the temperature at the pack- age pins where contact is made to the circuit board. esd warning: handling precautions should be taken to avoid static discharge.
3 typical performance, t c = 25 c (unless otherwise noted), single diode figure 2. forward current vs. forward voltage at temperatures? hsms-281 a series. 0 0.1 0.3 0.2 0.5 0.6 0.4 0.8 0.7 0.9 i f ?forward current (ma) v f ?forward voltage (v) figure 1. forward current vs. forward voltage at temperatures? hsms-280 a series. 0.01 10 1 0.1 100 t a = +125 c t a = +75 c t a = +25 c t a = ?5 c 0 0.1 0.3 0.2 0.5 0.6 0.4 0.8 0.7 i f ?forward current (ma) v f ?forward voltage (v) 0.01 10 1 0.1 100 t a = +125 c t a = +75 c t a = +25 c t a = ?5 c figure 3. forward current vs. forward voltage at temperatures? hsms-282 a series. 0 0.10 0.20 0.30 0.50 0.40 i f ?forward current (ma) v f ?forward voltage (v) 0.01 10 1 0.1 100 t a = +125 c t a = +75 c t a = +25 c t a = ?5 c figure 4. reverse current vs. reverse voltage at temperatures? hsms-280 a series. 0102030 50 40 i r ?reverse current (na) v r ?reverse voltage (v) 1 1000 100 10 100,000 10,000 t a = +125 c t a = +75 c t a = +25 c figure 5. reverse current vs. reverse voltage at temperatures? hsms-281 a series. 05 15 i r ?reverse current (na) v r ?reverse voltage (v) 10 1 1000 100 10 100,000 10,000 t a = +125 c t a = +75 c t a = +25 c figure 6. reverse current vs. reverse voltage at temperatures? hsms-282 a series. 05 15 i r ?reverse current (na) v r ?reverse voltage (v) 10 1 1000 100 10 100,000 10,000 t a = +125 c t a = +75 c t a = +25 c
4 typical performance, t c = 25 c (unless otherwise noted), single diode, continued figure 7. dynamic resistance vs. forward current. 0.1 1 100 r d ?dynamic resistance ( ) i f ?forward current (ma) 10 1 10 1000 100 hsms-2800 series hsms-2810 series hsms-2820 series figure 8. total capacitance vs. reverse voltage?sms-280 a series. 0102030 50 40 c t ?capacitance (pf) v r ?reverse voltage (v) 0 1.5 1 0.5 2 figure 9. total capacitance vs. reverse voltage?sms-281 a series. 02 6 41012 816 14 c t ?capacitance (pf) v r ?reverse voltage (v) 0 0.75 0.50 0.25 1.25 1 figure 10. total capacitance vs. reverse voltage?sms-282 a series. 02 8 6 c t ?capacitance (pf) v r ?reverse voltage (v) 4 0 0.6 0.4 0.2 1 0.8
5 applications information introduction product selection hewlett-packards family of six- lead schottky products provides unique solutions to many design problems. the first step in choosing the right product is to select the diode type. all of the products in the hsms-282 a family use the same diode chip, and the same is true of the hsms-281 a and hsms-280 a families. each family has a different set of characteristics which can be compared most easily by consulting the spice parameters in table 1. a review of these data shows that the hsms-280 a family has the highest breakdown voltage, but at the expense of a high value of series resistance (r s ). in applica- tions which do not require high voltage the hsms-282 a family, with a lower value of series resistance, will offer higher current carrying capacity and better performance. the hsms- 281 a family is a hybrid schottky (as is the hsms-280 a ), offering lower 1/f or flicker noise than the hsms-282 a family. in general, the hsms-282 a family should be the designers first choice, with the -280 a family reserved for high voltage applica- tions and the hsms-281 a family for low flicker noise applications. six lead applications the hsms-28 x l is an uncon- nected trio of schottky diodes. it can be used as a fast sp3t switch, as shown in figure 11. figure 11. sp3t switch. the unconnected trio can also be used to clamp three data lines, as shown in figure 12. note that either polarity of clamping can be provided. figure 12. clamping three lines. the hsms-28 x m six lead product is designed to clamp four data lines to ground, protecting against positive noise spikes, as shown in figure 13. 3 4 2 1 figure 13. clamping four lines. similarly, the hsms-28 x n com- mon anode quad can be used to clamp four data lines against negative noise spikes, as shown in figure 14. 3 4 2 1 figure 14. clamping four lines. the hsms-28 x p is open bridge quad is designed for sampling circuits, as shown in figure 15. note that the bridge is closed at opposite ends by external connec- tions (a trace on the circuit board). sample point sampling pulse figure 15. sampling circuit. table 1. typical spice parameters. parameter units hsms-280 a hsms-281 a hsms-282 a b v v75 25 15 c j0 pf 1.6 1.1 0.7 e g ev .69 .69 .69 i bv a 10e-5 10e-5 10e-4 i s a 3 e-8 4.8 e-9 2.2 e-8 n 1.08 1.08 1.08 r s w 30 10 6.0 p b (v j ) v 0.65 0.65 0.65 p t (xti) 2 2 2 m 0.5 0.5 0.5
6 the differential detector is often used to provide temperature compensation for a schottky detector, as shown in figure 16. matching network differential amplifier bias figure 16. differential detector. these circuits depend upon the use of two diodes having matched v f characteristics over all operating temperatures. this is best achieved by using two diodes in a single package, such as the sot-143 hsms-2825 as shown in figure 17. to differential amplifier v s detector diode reference diode pa hsms-2825 figure 17. conventional differential detector. in high power differential detec- tors, rf coupling from the detec- tor diode to the reference diode produces a rectified voltage in the latter, resulting in errors. isolation between the two diodes can be obtained by using the hsms-282k diode with leads 2 and 5 grounded. the difference between this product and the conventional hsms-2825 can be seen in figure 18. hsms-2825 sot-143 hsms-282k sot-363 34 654 1 12 23 figure 18. comparing two diode pairs. the hsms-282k, with leads 2 and 5 grounded, offers isolation from rf coupling between the diodes. this product is used in a differential detector as shown in figure 19. to differential amplifier v s detector diode reference diode pa hsms-282k figure 19. high isolation differential detector. in order to achieve the maximum isolation, the designer must take care to minimize the distance from leads 2 and 5 and their respective ground via holes. in addition, the ground strip will isolate the input rf and reference lines, as shown in figure 20. hsms-282k rf input ref figure 20. diode mounting, hsms-282k. tests were run on the hsms-282k and the conventional hsms-2825 pair, with the results shown in figure 21. -35 -25 -15 -5 15 5 37 db 47 db output voltage (mv) input power (dbm) 0.5 1000 100 10 1 5000 frequency = 900 mhz hsms-2825 ref. diode rf diode v out square law response hsms-282k ref. diode figure 21. comparing hsms-282k with hsms-2825. the line marked rf diode, v out is the transfer curve for the detector diode both the hsms-2825 and the hsms-282k exhibited the same output voltage. the data were taken over the 50 db dynamic range shown. to the right is the output voltage (transfer) curve for the reference diode of the hsms-2825, showing 37 db of isolation. to the right of that is the output voltage due to rf leakage for the reference diode of the hsms-282k, demonstrating 10 db higher isolation than the conventional part.
7 such differential detector circuits generally use single diode detectors, either series or shunt mounted diodes. the voltage doubler (hp application note 956-4) offers the advantage of twice the output voltage for a given input power. the two concepts can be combined into the differential voltage doubler, as shown in figure 22. matching network bias differential amplifier figure 22. differential voltage doubler, hsms-282p. here, all four diodes are matched in their v f characteristics, because they came from adjacent sites on the wafer. the hsms-28 x r is an open ring quad, useful in double balanced mixers as shown in figure 23. as was the case with the bridge product, the quad is closed using external connections. lo in rf in if out figure 23. double balanced mixer. the advantage of an open ring quad can be seen in figure 24, where two hsms-28 x r products are used to make an eight diode double balanced mixer having very low distortion. lo in rf in if out figure 24. low distortion mixer. other configurations of six lead schottky products can be used to solve circuit design problems while saving space and cost. thermal considerations the obvious advantage of the sot-363 over the sot-143 is combination of smaller size and two extra leads. however, the copper leadframe in the sot-363 has a thermal conductivity four times higher than the alloy 42 leadframe of the sot-143, which enables it to dissipate more power. the maximum continuous junc- tion temperature for these three families of schottky diodes is 150 c under all operating condi- tions. the following equation, equation (1), applies to the thermal analysis of diodes: t j = (v f i f + p rf ) q jc + t a equation (1). where t j = junction temperature t a = diode case temperature q jc = thermal resistance v f i f = dc power dissipated p rf = rf power dissipated note that q jc , the thermal resis- tance from diode junction to the foot of the leads, is the sum of two component resistances, q jc = q pkg + q chip equation (2). package thermal resistance for the sot-363 package is approxi- mately 100 c/w, and the chip thermal resistance for these three families of diodes is approxi- mately 40 c/w. the designer will have to add in the thermal resistance from diode case to ambient a poor choice of circuit board material or heat sink design can make this number very high. equation (1) would be straightfor- ward to solve but for the fact that diode forward voltage is a func- tion of temperature as well as forward current. the equation, equation (3), for v f is: 11600 (v f C i f r s ) nt i f = i s e C 1 equation (3). where n = ideality factor t = temperature in k r s = diode series resistance and i s (diode saturation current) is given by 2 1 1 n C 4060 ( t C 298 ) i s = i 0 ( t ) e 298 equation (4). equations (1) and (3) are solved simultaneously to obtain the value of junction temperature for given values of diode case temperature, dc power dissipation and rf power dissipation.
8 assembly instructions sot-363 pcb footprint a recommended pcb pad layout for the miniature sot-363 (sc-70, 6 lead) package is shown in figure 25 (dimensions are in inches). this layout provides ample allowance for package placement by automated assembly equipment without adding parasitics that could impair the performance. 0.026 0.075 0.016 0.035 figure 25. pcb pad layout (dimensions in inches). time (seconds) t max temperature ( c) 0 0 50 100 150 200 250 60 preheat zone cool down zone reflow zone 120 180 240 300 figure 26. surface mount assembly profile. smt assembly reliable assembly of surface mount components is a complex process that involves many material, process, and equipment factors, including: method of heating (e.g., ir or vapor phase reflow, wave soldering, etc.) circuit board material, conductor thickness and pattern, type of solder alloy, and the thermal conductivity and thermal mass of components. components with a low mass, such as the sot-363 package, will reach solder reflow temperatures faster than those with a greater mass. hps sot-363 diodes have been qualified to the time-temperature profile shown in figure 26. this profile is representative of an ir reflow type of surface mount assembly process. after ramping up from room temperature, the circuit board with components attached to it (held in place with solder paste) passes through one or more preheat zones. the preheat zones increase the temperature of the board and components to prevent thermal shock and begin evaporat- ing solvents from the solder paste. the reflow zone briefly elevates the temperature sufficiently to produce a reflow of the solder. the rates of change of tempera- ture for the ramp-up and cool- down zones are chosen to be low enough to not cause deformation of the board or damage to compo- nents due to thermal shock. the maximum temperature in the reflow zone (t max ) should not exceed 235 c. these parameters are typical for a surface mount assembly process for hp sot-363 diodes. as a general guideline, the circuit board and components should be exposed only to the minimum temperatures and times necessary to achieve a uniform reflow of solder.
9 outline sot-363 (sc-70 6 lead) package dimensions part number ordering information part number no. of devices container hsms-28 xa -tr2* 10000 13" reel hsms-28 xa -tr1* 3000 7" reel hsms-28 xa -blk* 100 antistatic bag * where x = 0, 1 or 2 a = k, l, m, n, p or r for hsms-280 a , hsms-282 a k or l for hsms-281 a 2.20 (0.087) 2.00 (0.079) 1.35 (0.053) 1.15 (0.045) 1.30 (0.051) ref. xx 0.650 bsc (0.025) 2.20 (0.087) 1.80 (0.071) 0.10 (0.004) 0.00 (0.00) 0.25 (0.010) 0.15 (0.006) 1.00 (0.039) 0.80 (0.031) 0.20 (0.008) 0.10 (0.004) 0.30 (0.012) 0.10 (0.004) 0.30 ref. 10 0.425 (0.017) typ. dimensions are in millimeters (inches) package marking code
tape dimensions and product orientation for outline sot-363 (sc-70, 6 lead) p p 0 p 2 f w c d 1 d e a 0 8 max. t 1 (carrier tape thickness) t t (cover tape thickness) 5 max. b 0 k 0 description symbol size (mm) size (inches) length width depth pitch bottom hole diameter a 0 b 0 k 0 p d 1 2.24 0.10 2.34 0.10 1.22 0.10 4.00 0.10 1.00 + 0.25 0.088 0.004 0.092 0.004 0.048 0.004 0.157 0.004 0.039 + 0.010 cavity diameter pitch position d p 0 e 1.55 0.05 4.00 0.10 1.75 0.10 0.061 0.002 0.157 0.004 0.069 0.004 perforation width thickness w t 1 8.00 0.30 0.255 0.013 0.315 0.012 0.010 0.0005 carrier tape cavity to perforation (width direction) cavity to perforation (length direction) f p 2 3.50 0.05 2.00 0.05 0.138 0.002 0.079 0.002 distance width tape thickness c t t 5.4 0.10 0.062 0.001 0.205 0.004 0.0025 0.00004 cover tape device orientation user feed direction cover tape carrier tape reel end view 8 mm 4 mm top view ## ## ## ## note: ?#?represents package marking code. package marking is right side up with carrier tape perforations at top. conforms to electronic industries rs-481, ?aping of surface mounted components for automated placement.?standard quantity is 3,000 devices per reel. www.hp.com/go/rf for technical assistance or the location of your nearest hewlett-packard sales office, distributor or representative call: americas/canada: 1-800-235-0312 or 408-654-8675 far east/australasia: call your local hp sales office. japan: (81 3) 3335-8152 europe: call your local hp sales office. data subject to change. copyright ? 1998 hewlett-packard co. obsoletes 5966-2049e 5968-2356e (12/98)
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