high performance schottky diode for transient suppression technical data features ? ultra-low series resistance for higher current handling ? low capacitance ? low series resistance applications rf and computer designs that require circuit protection, high- speed switching, and voltage clamping. package lead code identification (top view) description the hbat-5400 series of schottky diodes, commonly referred to as clipping/clamping diodes, are optimal for circuit and waveshape preservation applications with high speed switching. low series resistance, r s , makes them ideal for protecting sensitive circuit elements against high current transients carried on data lines. with picosecond switching, the hbat-540x can respond to noise spikes with rise times as fast as 1 ns. low capacitance minimizes waveshape loss that causes signal degradation. hbat-5400/-5402 hbat-540b/-540c series 2, c single 0, b 12 3 12 3 hbat-540x dc electrical specifications, t a = +25 c [1] maximum minimum typical maximum part package forward breakdown typical series eff. carrier number marking lead voltage voltage capacitance resistance lifetime hbat- code [2] code configuration package v f (mv) v br (v) c t (pf) r s ( w ) t (ps) -5400 v0 0 single sot-23 -540b b sot-323 (3-lead sc-70) -5402 2 sot-23 -540c v2 c series sot-323 (3-lead sc-70) 800 [3] 30 [4] 3.0 [5] 2.4 100 [6] notes: 1. t a = +25 c, where t a is defined 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 f = 100 m a; 100% tested 5. v f = 0; f =1 mhz 6. measured with karkauer method at 20 ma guaranteed by design.
2 absolute maximum ratings, t a = 25oc symbol parameter unit absolute maximum [1] hbat-5400/-5402 hbat-540b/-540c i f dc forward current ma 220 430 i f- peak peak surge current (1 m s pulse) a 1.0 1.0 p t total power dissipation mw 250 825 p inv peak inverse voltage v 30 30 t j junction temperature c 150 150 t stg storage temperature c -65 to 150 -65 to 150 q jc thermal resistance, junction to lead c/w 500 150 notes: 1. operation in excess of any one of these conditions may result in permanent damage to the device. r s 0.08 pf spice model 2 nh linear and non-linear spice model spice parameters parameter unit value bv v 40 cjo pf 3.0 eg ev 0.55 ibv a 10e-4 is a 1.0e-7 n 1.0 rs w 2.4 pb v 0.6 pt 2 m 0.5
3 typical performance figure 2. forward current vs. forward voltage at temperature for hbat-540b and hbat-540c. 0 0.1 0.3 0.2 0.5 0.4 0.6 i f ?forward current (ma) v f ?forward voltage (v) figure 1. forward current vs. forward voltage at temperature for hbat-5400 and HBAT-5402. 0.01 10 100 1 0.1 300 t a = +75 c t a = +25 c t a = ?5 c t a = +75 c t a = +25 c t a = ?5 c 0 100 300 200 500 400 600 t j ?junction temperature ( c) i f ?forward current (ma) 0 140 120 100 80 60 40 20 160 figure 3. junction temperature vs. current as a function of heat sink temperature for hbat-5400 and HBAT-5402. note: data is calculated from spice parameters. figure 5. total capacitance vs. reverse voltage. 0 5 10 20 c t ?total capacitance (pf) v r ?reverse voltage (v) 15 1.0 2.0 1.5 3.0 2.5 max. safe junction temp. t a = +75 c t a = +25 c t a = ?5 c 0 50 150 100 200 250 t j ?junction temperature ( c) i f ?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 hbat-540b and hbat-540c. note: data is calculated from spice parameters. t j ?junction temperature ( c) i f ?forward current (ma) 0 0.2 0.6 0.4 1.0 0.8 1.4 1.2 0.01 10 100 1 0.1 500 t a = +75 c t a = +25 c t a = ?5 c
4 package dimensions outline sot-23 t c w f e embossment p 2 10 pitches cumulative tolerance on tape 0.2 mm ( 0.008) user feed direction p 0 d 0 cover tape t p 1 d 1 k description symbol size (mm) size (inches) length width depth pitch bottom hole diameter a b k p 1 d 1 3.15 0.15 2.65 0.25 1.30 0.10 4.00 0.10 1.00 min. 0.124 0.006 0.104 0.010 0.051 0.004 0.157 0.004 0.04 min. cavity diameter pitch position d 0 p 0 e 1.55 + 0.10/-0 4.00 0.10 1.75 0.10 0.061 + 0.004/-0 0.157 0.004 0.069 0.004 perforation width thickness w t 8.00 0.2 0.30 0.05 0.315 0.008 0.012 0.002 carrier tape cavity to perforation (width direction) cavity to perforation (length direction) f p 2 3.50 0.10 2.00 0.05 0.138 0.004 0.079 0.002 distance between centerline width tape thickness c t 5.40 0.25 0.064 0.01 0.205 0.010 0.003 0.0004 cover tape b center lines of cavity a tape dimensions and product orientation for outline sot-23 3 1 2 x x package marking code side view top view end view dimensions are in millimeters (inches) 1.02 (0.040) 0.89 (0.035) 0.50 (0.024) 0.45 (0.018) 1.40 (0.055) 1.20 (0.047) 2.65 (0.104) 2.10 (0.083) 3.06 (0.120) 2.80 (0.110) 2.04 (0.080) 1.78 (0.070) 1.02 (0.041) 0.85 (0.033) 0.152 (0.006) 0.066 (0.003) 0.10 (0.004) 0.013 (0.0005) 0.69 (0.027) 0.45 (0.018) 0.54 (0.021) 0.37 (0.015)
5 package dimensions outline sot-323 (sc-70 3 lead) 2.20 (0.087) 2.00 (0.079) 1.35 (0.053) 1.15 (0.045) 1.30 (0.051) ref. 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) xx package marking code tape dimensions and product orientation for outline sot-323 (sc-70 3 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
6 applications information schottky diode fundamentals the hbat-540x 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 flow across the junction from the semiconductor and fill the free-energy states in the metal. this flow of electrons creates a depletion or potential across the junction. the differ- ence 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 involv- ing 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 poten- tial 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 sufficient 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. because no minority carrier charge storage effects are present, schottky diodes have carrier lifetimes of less than 100 ps and are extremely fast switching semiconductors. schottky diodes are used as rectifiers at frequencies of 50 ghz and higher. another significant difference 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. pn current 0.6 v + bias voltage pn junction capacitance metal n current 0.3 v + bias voltage schottky junction capacitance 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 specific applica- tions. 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 satura- tion current, i s . yet, different contact diameters and epitaxial- layer thickness result in very different values of junction capacitance, c j and r s . this is portrayed by their spice param- eters in table 1. table 1. hbat-540x and hsms-270x spice parameters. hbat- hsms- parameter 540x 270x bv 40 v 25 v cj0 3.0 pf 6.7 pf eg 0.55 ev 0.55 ev ibv 10e-4 a 10e-4 a is 1.0e-7 a 1.4e-7 a n 1.0 1.04 rs 2.4 w 0.65 w 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 capability. the trade-off is a higher value of junction capacitance. the forward voltage and current plots illustrate the differences in these two schottky diodes, as shown in figure 7.
7 i f ?forward current (ma) v f ?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 7. forward current vs. forward voltage at 25 c. 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 HBAT-5402 or hbat-540c (series pair) are closely matched without the added expense of testing and binning. current handling in clipping/ clamping circuits the purpose of a clipping/clamp- ing diode is to handle high cur- rents, 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. current limiting pull-down (or pull-up) long cross-site cable noisy data-spikes vs 0v voltage limited to vs + vd 0 v ?vd 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. the first is a conventional schottky diode of the type gener- ally used in rf circuits, with an r s of 7.7 w . the second is a schottky diode of identical characteristics, save the r s of 1.0 w . for the conventional diode, the relatively high value of r s causes the voltage across the diodes termi- nals 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 maintained 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 150 c, although brief excursions to higher junction temperatures can be tolerated with no significant impact upon mean-time-to-failure, mttf. in order to compute the junction temperature, equations (1) and (3) below must be simulta- neously solved. i f = i s e ? 11600 ( v f ?i f r s ) nt j (1) i s = i 0 e t j 298 2 n 1 t j 1 298 ?060 (2) t j = v f i f q jc + t a (3) 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 25 c n = diode ideality factor q jc = thermal resistance from junction to case (diode lead) = q package + q chip t a = ambient (diode lead) temperature equation (1) describes the for- ward v-i curve of a schottky diode. equation (2) provides the value for the diodes saturation 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. 0 0.1 0.2 0.3 0.5 0.4 v f ?forward voltage (v) i f ?forward current (ma) 0 3 2 1 6 4 5 r s = 7.7 r s = 1.0 figure 9. comparison of two diodes.
the key factors in these equations are: r s , the series resistance of the diode where heat is generated under high current conditions; q chip , the chip thermal resistance of the schottky die; and q package , or the package thermal resistance. r s for the hbat-540x family of diodes is typically 2.4 w , other than the hsms-270x family, this is the lowest of any schottky diode available. chip thermal resistance is typically 40 c/w; the thermal resistance of the iron-alloy- leadframe, sot-23 package is typically 460 c/w; and the thermal resistance of the copper- leadframe, sot-323 package is typically 110 c/w. the impact of 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 5967-6156e 5968-2349e (10/98) part number ordering information part number no. of devices container hbat-5400-blk 100 antistatic bag hbat-5400-tr1 3,000 7" reel hbat-5400-tr2 10,000 13" reel HBAT-5402-blk 100 antistatic bag HBAT-5402-tr1 3,000 7" reel HBAT-5402-tr2 10,000 13" reel hbat-540b-blk 100 antistatic bag hbat-540b-tr1 3,000 7" reel hbat-540b-tr2 10,000 13" reel hbat-540c-blk 100 antistatic bag hbat-540c-tr1 3,000 7" reel hbat-540c-tr2 10,000 13" reel package thermal resistance on the current handling capability of these diodes can be seen in figures 3 and 4. here the com- puted values of junction tempera- ture vs. forward current are shown for three values of ambient temperature. the sot-323 prod- ucts, 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 hbat-540b and hbat-540c products in the sot-323 package will safely withstand a steady-state forward current of 330 ma when the diodes terminals are maintained at 75 c. 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 150 c for short timeperiods without impacting device mttf. because of these factors, higher currents can be safely handled. the hbat-540x family has the second highest current handling capability of any hp diode, next to the hsms-270x series.
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