hsms-2700, 2702, 270b, 270c, 270p high performance schottky diode for transient suppression data sheet features ? ultra-low series resistance for higher current handling ? picosecond switching ? low capacitance ? lead-free applications rf and computer designs that require circuit protection, high-speed switching, and voltage clamping. package lead code identi?cation (top view) description the hsms-2700 series of schottky diodes, commonly referred to as clipping /clamping diodes, are optimal for circuit and waveshape preservation applications with high speed switching. ultra-low series resistance, r s , makes them ideal for protecting sensitive circuit elements against higher current transients carried on data lines. with picosecond switching, the hsms-270x can respond to noise spikes with rise times as fast as 1 ns. low ca- pacitance minimizes waveshape loss that causes signal degradation. hsms-270x dc electrical speci?cations, t a = +25c [1] part number hsms- package marking code [2] lead code con?guration package maximum forward voltage v f (mv) minimum breakdown voltage v br (v) typical capacitance c t (pf) typical series resistance r s () maximum e?. carrier lifetime (ps) -2700 j0 0 single sot-23 550 [3] 15 [4] 6.7 [5] 0.65 100 [6] -270b b sot-323 (3-lead sc-70) -2702 2 sot-23 -270c j2 c series sot-323 (3-lead sc-70) -270p jp p bridge quad sot-363 (6-lead sc-70) notes: 1. t a = +25c, where t a is de?ned to be the temperature at the package pins where contact is made to the circuit board. 2. package marking code is laser marked. 3. i f = 100 ma; 100% tested 4. i r = 100 a; 100% tested 5. v f = 0; f =1 mhz 6. measured with karkauer method at 20 ma; guaranteed by design. series 2, c single 0, b 1212123 654 33 bridge quad
2 absolute maximum ratings, t a = 25oc symbol parameter unit absolute maximum [1] hsms-2700/-2702 hsms-270b/270c/270p i f dc forward current ma 350 750 i f-peak peak surge current (1s pulse) a 1.0 1.0 p t total power dissipation mw 250 825 p inv peak inverse voltage v 15 15 t j junction temperature c 150 150 t stg storage temperature c -65 to 150 -65 to 150 jc thermal resistance, junction to lead c/w 500 150 note: 1. operation in excess of any one of these conditions may result in permanent damage to the device. linear and non-linear spice model parameter unit value bv v 25 cjo pf 6.7 eg ev 0.55 ibv a 10e-4 is a 1.4e-7 n 1.04 rs 0.65 pb v 0.6 pt 2 m 0.5 spice parameters r s 0.08 pf spice model 2 nh
3 typical performance figure 2. forward current vs. forward voltage at temperature for hsms-270b and hsms-270c. 0 0.1 0.3 0.2 0.5 0.4 0.6 i f C forward current (ma) v f C forward voltage (v) figure 1. forward current vs. forward voltage at temperature for hsms-2700 and hsms-2702. 0.01 10 100 1 0.1 300 t a = +75 c t a = +25 c t a = C25 c figure 3. junction temperature vs. forward current as a function of heat sink temperature for the hsms-2700 and hsms-2702. note: data is calculated from spice parameters. figure 5. total capacitance vs. reverse voltage. 0510 20 c t C total capacitance (pf) v f C reverse voltage (v) 15 1 3 2 7 4 6 5 t a = +75 c t a = +25 c t a = C25 c 050 150 100 300 250 200 350 t j C junction temperature ( c) i f C forward current (ma) 0 140 120 100 80 60 40 20 160 max. safe junction temp. figure 4. junction temperature vs. current as a function of heat sink temperature for hsms-270b and hsms-270c. note: data is calculated from spice parameters. t a = +75 c t a = +25 c t a = C25 c 0 150 450 300 600 750 t j C junction temperature ( c) i f C forward current (ma) 0 140 120 100 80 60 40 20 160 max. safe junction temp. 0 0.1 0.3 0.2 0.5 0.4 0.8 0.7 0.6 i f C forward current (ma) v f C forward voltage (v) 0.01 10 100 1 0.1 500 t a = +75 c t a = +25 c t a = C25 c
4 package dimensions outline sot-23 tape dimensions and product orientation for outline sot-23 device orientation for outlines sot-23/323 0.039 1 0.039 1 0.079 2.0 0.031 0.8 dimensions in inches mm 0.035 0.9 9 max a 0 p p 0 d p 2 e f w d 1 ko 8 max b 0 13.5 max t1 description symbol size (mm) size (inches) length width depth pitch bottom hole diameter a 0 b 0 k 0 p d 1 3.15 0.10 2.77 0.10 1.22 0.10 4.00 0.10 1.00 + 0.05 0.124 0.004 0.109 0.004 0.048 0.004 0.157 0.004 0.039 0.002 cavity diameter pitch position d p 0 e 1.50 + 0.10 4.00 0.10 1.75 0.10 0.059 + 0.004 0.157 0.004 0.069 0.004 perforation width thickness w t1 8.00 + 0.30 C 0.10 0.229 0.013 0.315 + 0.012 C 0.004 0.009 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 between centerline recommended pcb pad layout for avagos sot-23 products no t e: " ab " represen t s package marking code. " c " represen t s da t e code. end v i ew 8 mm 4 mm t op v i ew abc abc abc abc user f eed d i rec ti on cover t ape carr i er t ape reel e b e2 e1 e1 c e xxx l d a a1 notes: xxx-package marking drawings are not to scale dimensions (mm) min. 0.79 0.000 0.30 0.08 2.73 1.15 0.89 1.78 0.45 2.10 0.45 max. 1.20 0.100 0.54 0.20 3.13 1.50 1.02 2.04 0.60 2.70 0.69 symbol a a1 b c d e1 e e1 e2 e l
5 package dimensions outline sot-323 (sc-70 3 lead) 0.026 0.039 0.079 0.022 dimensions in inches recommended pcb pad layout for avagos sc70 3l/sot-323 products e b e1 e1 c e xxx l d a a1 notes: xxx-package marking drawings are not to scale dimensions (mm) min. 0.80 0.00 0.15 0.08 1.80 1.10 1.80 0.26 max. 1.00 0.10 0.40 0.25 2.25 1.40 2.40 0.46 symbol a a1 b c d e1 e e1 e l 1.30 typical 0.65 typical outline sot-363 (sc-70 6 lead) e he d e a1 b a a2 l c dimensions (mm) min. 1.15 1.80 1.80 0.80 0.80 0.00 0.15 0.08 0.10 max. 1.35 2.25 2.40 1.10 1.00 0.10 0.30 0.25 0.46 symbol e d he a a2 a1 e b c l 0.650 bcs
6 tape dimensions and product orientation for outline sot-323/363 (sc-70 3 and 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) 8 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 2.40 0.10 2.40 0.10 1.20 0.10 4.00 0.10 1.00 + 0.25 0.094 0.004 0.094 0.004 0.047 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 0.254 0.02 0.315 0.012 0.0100 0.0008 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
7 applications information schottky diode fundamentals the hsms-270x series of clipping/clamping diodes are schottky devices. a schottky device is a rectifying, metal-semiconductor contact formed between a metal and an n-doped or a p-doped semiconductor. when a metal-semiconductor junction is formed, free electrons ?ow across the junction from the semiconductor and ?ll the free-energy states in the metal. this ?ow of electrons creates a depletion or potential across the junction. the di?erence in energy levels between semiconductor and metal is called a schottky barrier. p-doped, schottky-barrier diodes excel at applications requiring ultra low turn-on voltage (such as zero-biased rf detectors). but their very low, breakdown-voltage and high series-resistance make them unsuitable for the clipping and clamping applications involving high forward currents and high reverse voltages. therefore, this discussion will focus entirely on n-doped schottky diodes. under a forward bias (metal connected to positive in an n-doped schottky), or forward voltage, v f , there are many electrons with enough thermal energy to cross the barrier potential into the metal. once the applied bias exceeds the built-in potential of the junction, the forward current, i f , will increase rapidly as v f increases. when the schottky diode is reverse biased, the potential barrier for electrons becomes large; hence, there is a small probability that an electron will have su?cient thermal energy to cross the junction. the reverse leakage current will be in the nanoampere to microampere range, depending upon the diode type, the reverse voltage, and the temperature. in contrast to a conventional p-n junction, current in the schottky diode is carried only by majority carriers (electrons). because no minority-carrier (hole) charge storage e?ects are present, schottky diodes have carrier lifetimes of less than 100 ps. this extremely fast switching time makes the schottky diode an ideal recti?er at fre- quencies of 50 ghz and higher. another signi?cant di?erence between schottky and p-n diodes is the forward voltage drop. schottky diodes have a threshold of typically 0.3 v in comparison to that of 0.6 v in p-n junction diodes. see figure 6. through the careful manipulation of the diameter of the schottky contact and the choice of metal deposited on the n-doped silicon, the important characteristics of the diode (junction capacitance, c j ; parasitic series resistance, r s ; breakdown voltage, v br ; and forward voltage, v f ,) can be optimized for speci?c applications. the hsms- 270x series and hbat-540x series of diodes are a case in point. both diodes have similar barrier heights; and this is indicated by corresponding values of saturation current, i s . yet, di?erent contact diameters and epitaxial-layer thickness result in very di?erent values of c j and r s . this is seen by comparing their spice parameters in table 1. table 1. hsms-270x and hbat-540x spice parameters. parameter hsms- 270x hbat- 540x bv 25 v 40 v cj0 6.7 pf 3.0 pf eg 0.55 ev 0.55 ev ibv 10e-4 a 10e-4 a is 1.4e-7 a 1.0e-7 a n 1.04 1.0 rs 0.65 2.4 pb 0.6 v 0.6 v pt 2 2 m 0.5 0.5 at low values of i f 1 ma, the forward voltages of the two diodes are nearly identical. however, as current rises above 10 ma, the lower series resistance of the hsms- 270x allows for a much lower forward voltage. this gives the hsms-270x a much higher current handling capabil- ity. the trade-o? is a higher value of junction capacitance. the forward voltage and current plots illustrate the di?erences in these two schottky diodes, as shown in figure 7. pn current 0.6 v + C bias voltage pn junction capacitance metal n current 0.3v + C bias voltage schottky junction capacitance i f C forward current (ma) v f C forward voltage (v) .01 10 1 .1 300 100 0 0.1 0.3 0.2 0.5 0.4 0.6 hsms-270x hbat-540x figure 6. figure 7. forward current vs. forward voltage at 25c.
8 because the automatic, pick-and-place equipment used to assemble these products selects dice from adjacent sites on the wafer, the two diodes which go into the hsms-2702 or hsms-270c (series pair) are closely matched without the added expense of testing and binning. current handling in clipping/clamping circuits the purpose of a clipping/clamping diode is to handle high currents, protecting delicate circuits downstream of the diode. current handling capacity is determined by two sets of characteristics, those of the chip or device itself and those of the package into which it is mounted. tained at a low limit even at high values of current. maximum reliability is obtained in a schottky diode when the steady state junction temperature is maintained at or below 150c, although brief excursions to higher junction temperatures can be tolerated with no signi?cant impact upon mean-time-to-failure, mttf. in order to compute the junction temperature, equations (1) and (3) below must be simultaneously solved. 0 0.1 0.2 0.3 0.5 0.4 v f C forward voltage (v) i f C forward current (ma) 0 3 2 1 6 4 5 r s = 7.7 r s = 1.0 i f = i s e C1 11 600 (v f C i f r s ) n t j ( 1 ) i s = i 0 e t j 2 9 8 2 n 1 t j 1 2 9 8 C 4060 C (2) t j = v f i f jc + t a (3) figure 8. two schottky diodes are used for clipping/clamping in a circuit. consider the circuit shown in figure 8, in which two schottky diodes are used to protect a circuit from noise spikes on a stream of digital data. the ability of the diodes to limit the voltage spikes is related to their ability to sink the associated current spikes. the importance of current handling capacity is shown in figure 9 , where the forward voltage generated by a forward current is compared in two diodes. figure 9. comparison of two diodes. the ?rst is a conventional schottky diode of the type generally used in rf circuits, with an r s of 7.7 . the second is a schottky diode of identical characteristics, save the r s of 1.0 . for the conventional diode, the relatively high value of r s causes the voltage across the diodes terminals to rise as current increases. the power dissipated in the diode heats the junction, causing r s to climb, giving rise to a runaway thermal condition. in the second diode with low r s , such heating does not take place and the voltage across the diode terminals is main- where: i f = forward current i s = saturation current v f = forward voltage r s = series resistance t j = junction temperature i o = saturation current at 25c n = diode ideality factor jc = thermal resistance from junction to case (diode lead) = package + chip t a = ambient (diode lead) temperature equation (1) describes the forward v-i curve of a schottky diode. equation (2) provides the value for the diodes satu- ration current, which value is plugged into (1). equation (3) gives the value of junction temperature as a function of power dissipated in the diode and ambient (lead) temperature. the key factors in these equations are: r s , the series resis- tance of the diode where heat is generated under high current conditions; chip , the chip thermal resistance of the schottky die; and package , or the package thermal resistance. r s for the hsms-270x family of diodes is typically 0.7 and is the lowest of any schottky diode available from avago. chip thermal resistance is typically 40c/w; the thermal resistance of the iron-alloy-leadframe, sot-23 package is typically 460c/w; and the thermal resistance of the copper-leadframe, sot-323 package is typically 110c/w. the impact of package thermal resistance on the current handling capability of these diodes can be seen in figures 3 and 4. here the computed values of junction temperature vs. forward current are shown current limiting pull-down (or pull-up) long cross-site cable noisy data-spikes vs 0v voltage limited to vs + vd 0 v C vd
part number ordering information part number no. of devices container hsms-2700-blkg hsms-2700-tr1g hsms-2700-tr2g 100 3,000 10,000 antistatic bag 7" reel 13" reel hsms-2702-blkg hsms-2702-tr1g hsms-2702-tr2g 100 3,000 10,000 antistatic bag 7" reel 13" reel hsms-270b-blkg hsms-270b-tr1g hsms-270b-tr2g 100 3,000 10,000 antistatic bag 7" reel 13" reel hsms-270c-blkg hsms-270c-tr1g hsms-270c-tr2g 100 3,000 10,000 antistatic bag 7" reel 13" reel HSMS-270P-blkg HSMS-270P-tr1g 100 3,000 antistatic bag 7" reel for product information and a complete list of distributors, please go to our web site: www.avagotech.com avago, avago technologies, and the a logo are trademarks of avago technologies limited in the united states and other countries . data subject to change. copyright ? 2005-2010 avago technologies limited. all rights reserved. obsoletes 5989-0473en av02-1366en - july 7, 2010 for three values of ambient temperature. the sot-323 products, with their copper leadframes, can safely handle almost twice the current of the larger sot-23 diodes. note that the term ambient temperature refers to the temperature of the diodes leads, not the air around the circuit board. it can be seen that the hsms-270b and hsms-270c products in the sot-323 package will safely withstand a steady-state forward current of 550 ma when the diodes terminals are maintained at 75c. for pulsed currents and transient current spikes of less than one microsecond in duration, the junction does not have time to reach thermal steady state. moreover, the diode junction may be taken to temperatures higher than 150c for short time-periods without impacting device mttf. because of these factors, higher currents can be safely handled. the hsms-270x family has the highest current handling capability of any avago diode.
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