? semiconductor components industries, llc, 2002 may, 2002 ? rev. 6 682 publication order number: m1ma151at1/d preferred device these silicon epitaxial planar diodes are designed for use in ultra high speed switching applications. these devices are housed in the sc ? 59 package which is designed for low power surface mount applications. ? fast t rr , < 3.0 ns ? low c d , < 2.0 pf ? available in 8 mm tape and reel use m1ma151/2at1 to order the 7 inch/3000 unit reel. use m1ma151/2at3 to order the 13 inch/10,000 unit reel. maximum ratings (t a = 25 c) rating symbol value unit reverse voltage m1ma151at1 v r 40 vdc m1ma152at1 80 peak reverse voltage m1ma151at1 v rm 40 vdc m1ma152at1 80 forward current i f 100 madc peak forward current i fm 225 madc peak forward surge current i fsm (note 3) 500 madc thermal characteristics rating symbol max unit power dissipation p d 200 mw junction temperature t j 150 c storage temperature t stg ? 55 to + 150 c 3. t = 1 sec preferred devices are on semiconductor recommended choices for future use and best overall value. http://onsemi.com preferred devices are recommended choices for future use and best overall value. sc ? 59 suffix case 318d sc ? 59 package single silicon switching diodes 40/80 v ? 100 ma surface mount marking diagram 2 1 3 mx m x = a for 151 b for 152 m = date code
m1ma151at1, m1ma152at1 http://onsemi.com 683 electrical characteristics (t a = 25 c) characteristic symbol condition min max unit reverse voltage leakage current m1ma151at1 i r v r = 35 v ? 0.1 adc m1ma152at1 v r = 75 v ? 0.1 forward voltage v f i f = 100 ma ? 1.2 vdc reverse breakdown voltage m1ma151at1 v r i r = 100 a 40 ? vdc m1ma152at1 80 ? diode capacitance c d v r = 0, f = 1.0 mhz ? 2.0 pf reverse recovery time (figure 1) t rr (note 4) i f = 10 ma, v r = 6.0 v, r l = 100 , i rr = 0.1 i r ? 3.0 ns 4. t rr test circuit t p = 2 s t r = 0.35 ns i f = 10 ma v r = 6 v r l = 100 ? recovery time equivalent test circuit input pulse output pulse figure 1. reverse recovery time equivalent test circuit
m1ma151at1, m1ma152at1 http://onsemi.com 684 p d = t j(max) ? t a r ja p d = 150 c ? 25 c 370 c/w = 338 milliwatts ? the soldering temperature and time should not exceed 260 c for more than 10 seconds. ? when shifting from preheating to soldering, the maxi- mum temperature gradient should be 5 c or less. ? after soldering has been completed, the device should be allowed to cool naturally for at least three minutes. gradual cooling should be used as the use of forced cooling will increase the temperature gradient and re- sult in latent failure due to mechanical stress. ? mechanical stress or shock should not be applied dur- ing cooling * soldering a device without preheating can cause exces- sive thermal shock and stress which can result in damage to the device. information for using the sc ? 59 surface mount package minimum recommended footprint for surface mounted applications surface mount board layout is a critical portion of the total design. the footprint for the semiconductor packages must be the correct size to insure proper solder connection sc ? 59 power dissipation the power dissipation of the sc ? 59 is a function of the pad size. this can vary from the minimum pad size for sol- dering to the pad size given for maximum power dissipa- tion. power dissipation for a surface mount device is deter- mined by t j(max) , the maximum rated junction temperature of the die, r ja , the thermal resistance from the device junction to ambient; and the operating temperature, t a . us- ing the values provided on the data sheet, p d can be calcu- lated as follows. the values for the equation are found in the maximum ratings table on the data sheet. substituting these values into the equation for an ambient temperature t a of 25 c, one can calculate the power dissipation of the device which in this case is 338 milliwatts. the 370 c/w assumes the use of the recommended foot- print on a glass epoxy printed circuit board to achieve a power dissipation of 338 milliwatts. another alternative would be to use a ceramic substrate or an aluminum core board such as thermal clad ? . using a board material such as thermal clad, the power dissipation can be doubled us- ing the same footprint. interface between the board and the package. with the correct pad geometry, the packages will self align when subjected to a solder reflow process. soldering precautions the melting temperature of solder is higher than the rated temperature of the device. when the entire device is heated to a high temperature, failure to complete soldering within a short time could result in device failure. therefore, the following items should always be observed in order to minimize the thermal stress to which the devices are sub- jected. ? always preheat the device. ? the delta temperature between the preheat and solder- ing should be 100 c or less.* ? when preheating and soldering, the temperature of the leads and the case must not exceed the maximum tem- perature ratings as shown on the data sheet. when us- ing infrared heating with the reflow soldering method, the difference should be a maximum of 10 c.
m1ma151at1, m1ma152at1 http://onsemi.com 685 figure 2. typical solder heating profile for any given circuit board, there will be a group of con- trol settings that will give the desired heat pattern. the op- erator must set temperatures for several heating zones, and a figure for belt speed. taken together, these control set- tings make up a heating ? profile ? for that particular circuit board. on machines controlled by a computer, the comput- er remembers these profiles from one operating session to the next. figure 7 shows a typical heating profile for use when soldering a surface mount device to a printed circuit board. this profile will vary among soldering systems but it is a good starting point. factors that can affect the profile include the type of soldering system in use, density and types of components on the board, type of solder used, and the type of board or substrate material being used. this pro- file shows temperature versus time. solder stencil guidelines prior to placing surface mount components onto a printed circuit board, solder paste must be applied to the pads. a solder stencil is required to screen the optimum amount of solder paste onto the footprint. the stencil is made of brass or stainless steel with a typical thickness of 0.008 inches. the stencil opening size for the surface mounted package should be the same as the pad size on the printed circuit board, i.e., a 1:1 registration. typical solder heating profile the line on the graph shows the actual temperature that might be experienced on the surface of a test board at or near a central solder joint. the two profiles are based on a high density and a low density board. the vitronics smd310 convection/infrared reflow soldering system was used to generate this profile. the type of solder used was 62/36/2 tin lead silver with a melting point between 177 ? 189 c. when this type of furnace is used for solder re- flow work, the circuit boards and solder joints tend to heat first. the components on the board are then heated by con- duction. the circuit board, because it has a large surface area, absorbs the thermal energy more ef ficiently, then dis- tributes this energy to the components. because of this ef- fect, the main body of a component may be up to 30 degrees cooler than the adjacent solder joints.
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