8170 thompson road cicero, n.y. 13039 m.s.kennedy corp. (315) 699-9201 features: 5020 series iso-9001 certified by dscc high current, super low dropout fixed voltage regulators extremely low dropout voltage: 0.50v @ 20 amps available in 3.3v, 5.0v and 12.0v versions output voltages are internally set to 1% ttl level enable pin externally programmable current limit low quiescent current available fully qualified to mil-prf-38534 output current to 20 amps regulation dropout fault pin description: the msk 5020 series voltage regulators are available in a +3.3v, +5.0v or +12.0v fixed output configuration. all three boast ultra low dropout specifications due to the utilization of a mosfet output pass transistor with extremely low rds(on). dropout voltages of 0.50v at 20 amps are typical, in this configuration, which drives efficiency up and power dissipation down. accuracy is guaranteed with a 1% initial output voltage tolerance that varies only 2% with temperature. a ttl level can be used to enable/disable the device and a regulation dropout fault pin provides a means of monitoring the output level. the msk 5020 series is packaged in a thermally efficient 12 pin power dip. 1 rev.a 8/98 mil-prf-38534 certified equivalent schematic typical applications pin-out information high efficiency, high current linear regulators constant voltage/current regulators system power supplies switching power supply post regulators enable n/c ground filter capacitor input fault 1 2 3 4 5 6 output output sense vsc vsc case connection 12 11 10 9 8 7
output voltage typ. 0.5 - 0.002 0.5 0.5 - 0.5 - 20 10 45 0.5 1.2 1.2 20 10 0.5 v in 0.09 - v in v en i out t j input voltage (wrt v out ) enable voltage output current junction temperature 36v -0.3v to 36v 20a within soa +175c t st t ld t c storage temperature range lead temperature range (10 seconds) case operating temperature msk5020 series msk5020b series absolute maximum ratings -65c to +150c 300c -25c to +85c -55c to +125c group a subgroup 1 2,3 1 1 1 2,3 1 2,3 1,2,3 1,2,3 - - 1 1 1 1 - - - - % % v v % % % % ma m a db c/w v v m a m a ms v v ma high low high low output voltage tolerance dropout voltage load regulation line regulation quiescent current ripple rejection 2 thermal resistance 2 enable input voltage enable input current output settling time fault output voltage fault output sink current range parameter msk 5020 series msk 5020(b) series electrical specifications 1 test conditions min. - - - - - - - - - - - - 2.4 - - - - - - 1 typ. 0.5 1.0 0.002 0.50 0.5 0.5 0.5 0.5 20 10 45 0.5 1.2 1.2 20 10 0.5 v in 0.09 - max. 1.0 2.0 0.010 0.75 1.0 2.0 1.0 1.0 30 50 - 0.6 - 0.8 50 25 - - - 10 min. - - - - - - - - - - - - 2.4 - - - - - - 1 max. 1.0 - 0.010 1.0 1.0 - 1.0 - 30 50 - 0.6 - 0.8 50 25 - - - 10 units 3 2 1 2 3 4 5 6 7 8 9 notes: output decoupled to ground using 33f minimum capacitor and rsc=0 w unless otherwise specified. this parameter is guaranteed by design but need not be tested. typical parameters are representative of actual device performance but are for reference only. all output parameters are tested using a low duty cycle pulse to maintain t j = t c . industrial grade devices shall be tested to subgroup 1 only unless otherwise specified. military grade devices ('b' suffix) shall be 100% tested to subgroups 1,2 and 3. subgroup 1 subgroup 2 subgroup 3 please consult the factory if alternate output voltages are required. after application of enable pulse. fault pin connected to v in through a 5.1k w resistor for msk5020-5.0. t a =t c =+25c t a =t c =+125c t c =t c =-55c part number msk5020-3.3 msk5020-5.0 msk5020-12 high low 8 2 9 2 2 rev.a 8/98 i out =0a; v in =v out +3v i out = 0a i out =20a v in =v out +3v 0a i out 20a (v out +1.5v) v in ( v out +15v) i out =0a v en =5v; v in =v out +3v; i out =0a v en =0v; v in =v out +3v; i out =0a f=120hz junction to case to within 10mv (i out =0a) i fault =1ma 2 7 +12.0v +3.3v +5.0v
to select a heat sink for the msk 5020, the following formula for convective heat flow must be used. application notes the output voltage ripple of the msk 5020 series voltage regu- lators can be minimized by placing a filter capacitor from the output to ground. the optimum value for this capacitor may vary from one application to the next and is best determined by experimentation. transient load response can also be improved by placing a 33uf or larger capacitor directly across the load. minimizing output ripple: to implement current limiting, a sense resistor (rsc) must be placed from pin 5 to pins 8,9 and 10 as shown in the typical connection diagram. when the voltage drop across the sense resistor reaches 35mv, the internal control loop limits the out- put current only enough to maintain 35mv across the sense resistor. the device is not disabled. the following formula may be used to find the correct value of sense resistance: r sc =35mv/i lim if current limit is not required simply connect the vsc pins di- rectly to the input voltage along with the sense pin. refer to the typical connection diagram for an illustration. current limit connections the output pass transistors in the msk 5020 are rated to dissi- pate nearly 200 watts. the limiting factor of this device is ef- fective dissipation of heat generated under such conditions. for example, to dissipate 200 watts, calculations show that the msk 5020 would have to be bolted to the underbelly of a submarine submerged in the artic ocean! careful consideration must be paid to heat dissipation and junction temperature when applying this device. power dissipation: 37w = 37 watts first, the power dissipation must be calculated as follows: power dissipation = (vin - vout) x iout next, the user must select a maximum junction temperature. the absolute maximum allowable junction temperature is 175c. the equation may now be rearranged to solve for the required heat sink to ambient thermal resistance (r q sa). example; an msk 5020-3.3 is configured for vin = +7v and vout = +3.3v. iout is a continuous 10a dc level. the ambient tem- perature is +25c. the maximum desired junction temperature is 150c. r q jc = 0.5c/w and r q cs = 0.15c/w typically. power dissipation = (7v - 3.3v) x (10a) solve for r q sa: r q sa = 150c - 25c - 0.5c/w - 0.15c/w in this example, a heat sink with a thermal resistance of no more than 2.73c/w must be used to maintain a junction tempera- ture of no more than 150c. governing equation: tj = pd x (r q jc + r q cs + r q sa) + ta where: tj = junction temperature pd = total power dissipation r q jc = junction to case thermal resistance r q cs = case to heat sink thermal resistance r q sa = heat sink to ambient thermal resistance ta = ambient temperature heat sink selection: for all applications, the user must connect a 1.0uf capacitor from pin 4 directly to ground. this capacitor is part of the cir- cuit which drives the gate of the internal mosfets. approxi- mately three times the voltage seen on the input will appear across this capacitor. careful attention must be paid to capaci- tor voltage rating since voltages larger than the power supply are present. filter capacitor: pin 6 of the msk 5020 series is the fault pin. when the output voltage drops 6% or more below its nominal value, the voltage level on the fault pin drops to a logic low (typically less than 0.1 volts). this pin can be used to drive a light emitting diode or other external circuitry as long as the current is limited to less than 10.0ma (see typical connection diagram). the fault pin is an open collector output so the high state output voltage will be equal to the pull up voltage since no current flows under these conditions. fault pin connections the msk 5020 series of voltage regulators are equipped with a ttl compatible enable pin. a ttl high level on this pin acti- vates the internal bias circuit and powers up the device. a ttl low level on this pin places the controller in shutdown mode and the device draws only 10a of quiescent current. this pin can be pulled up to v in if the enable function is not desired. enable/disable pin: in voltage regulator applications where very large load currents are present, the load connection is very important. the path connecting the output of the regulator to the load must be ex- tremely low impedance to avoid affecting the load regulation specifications. any impedance in this path will form a voltage divider with the load. the same holds true for the connection from the low end of the load to ground. for best load regulation, the low end of the load must be connected directly to pin 3 of the msk 5020 and not to a ground plane inches away from the hybrid. load connections: for best results, the ground pin should be connected directly to the load (see next note). this effectively reduces the ground loop effect and eliminates excessive voltage drop in the sense leg. it is also important to keep the output connection between the regulator and the load as short as possible since this directly affects the load regulation. for example, if 20 gauge wire were used which has a resistance of about .008 ohms per foot, this would result in a drop of 80mv/ft at a load current of 10 amps. load regulation: the case of the msk 5020 is connected to pin seven of the package but isolated from the internal circuitry allowing direct attachment of the heat sink to the case. it may be necessary in some applications to ground the case to limit noise or eliminate oscillations on the output. pin seven can be left as a no connect if the designer chooses. case connections: 3 rev.a 8/98
typical performance curves 4 rev.a 8/98
typical connection diagram the above connection diagram illustrates an msk 5020-3.3 regulator. q1 turns on the fault l.e.d. when pin 6 of the hybrid drops to a logic low. current into pin 6 is limited to approximately 1ma by the 12k w resistor from pin 5 to pin 6. the optimum value of capacitance c out may vary from one application to the next depending on the load applied. 33f is a good starting point. the enable input is ttl compatible but can be tied to the input voltage when shutdown is not needed. r sc should be selected for the desired current limit. see current limit connections application note. 5 rev.a 8/98
the information contained herein is believed to be accurate at the time of printing. msk reserves the right to make changes to its products or specifications without notice, however, and assumes no liability for the use of its products. mechanical specifications m.s. kennedy corp. 8170 thompson rd., cicero, new york 13039-9393 tel. (315) 699-9201 fax (315) 699-8023 msk5020-3.3 b screening blank= industrial; b= mil-prf-38534 output voltage 3.3=+3.3v; 5.0=+5.0v; 12.0=+12.0v general part number the above example is a +3.3v, military regulator. ordering information 6 rev.a 8/98 esd triangle indicates pin 1. note: all dimensions are .010 inches unless otherwise labeled.
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