78xxsr series 3.3v/5v/12v outputs high-ef? ciency switching regulators with lm78xx pinouts for full details go to www.murata-ps.com/rohs www.murata-ps.com/dpm www.murata-ps.com email: sales@murata-ps.com 05 apr 2011 mdc_78xxsr series.b06 page 1 of 6 murata power solutions 7805sr-c (5v output), 7812SR-C (12v output) and 7803sr-c (3.3v output) step-down switching regulators are modern drop-in replacements for older, inef? cient, lm7805 and lm7812 linear regulators. the 78xxsr's are pin- and size-compat- ible with industry-standard to-220 sip packages. a 260khz switching frequency provides for ef? ciencies as high as 95%. full-load (up to 0.5a) operation from 9v, 12v, 24v, or 36v supplies at ambient temperatures up to +70c requires no heat sinks, no temperature derating, no forced-air cooling, and no external capacitors. 78sr switching regulators provide many signi? cant improvements over their linear coun- terparts: lower quiescent current (3ma vs. 5 ma), higher input voltage (40v vs. 32v), and better output accuracy (2% vs. 5%). all these features combine to make 78sr regulators ideal for new or existing lm7805 & lm7812 applications requiring full-load operation at elevated voltages. $ technical notes 1. input/output (i/o) filtering: as shown in the noise and ripple graphs, 78sr switching regulators exhibit excellent low-noise performance with no external i/o capacitors. however, if additional noise reduction is required, be sure to use low-esr capacitors that are rated for continuous operation (with an additional 20% safety margin) at the highest system voltages and temperatures. adding external output capacitors will also improve the units load-transient response. applications in which 78sr regulators are located more than 24 inches (61cm) from the input power supply should include an external 47uf/50v (or greater) aluminum electrolytic capacitor, connected as close as possible to the regulators +vin and gnd terminals (pins 1 and 2). an external input capacitor is particularly important if the input voltage is applied to the regulator via a mechanical switch or relay. contact bounce at turn-on can produce large inductive current-spikes, and these current spikes can generate damaging voltage transients at the regulators input terminals. 2. input fusing: 78sr switching regulators are not internally fused. if fusing their input and/or output terminals is required, use the data shown in the ef? ciency curves as a guide to selecting an appropriate slow-blow fuse. 3. input-output isolation: 78sr regulators internal input and output circuits share a common connection (gnd, pin 2); there is no electrical isolation between the input (pin 1) and output (pin 3) terminals. 4. overvoltage protection: 78sr switching regulators do not provide input or output overvoltage protection. in the extremely rare situation in which a catastrophic failure occurs, the output voltage may rise to excessively high levels. if your load must be protected against all possible overvoltage situations, external voltage-limiting circuitry must be provided. 5. operation at 40vdc: operating with inputs up to 40vdc is permissible if, for inputs between 36 and 40vdc, the maximum load current is reduced to 0.35a for 7805sr-c and 7803sr-c, and to 0.3a for 7812SR-C. under no circumstances should the input voltage be allowed to exceed 45vdc. mps part no. output output input voltage current voltage standard pin package 7803sr-c +3.3vdc 0.5a +7.5-36vdc 7805sr-c +5.0vdc 0.5a +7.5-36vdc 7812SR-C +12.0vdc 0.4a +15-36vdc horizontal pin package 7803srh-c +3.3vdc 0.5a +7.5-36vdc 7805srh-c +5.0vdc 0.5a +7.5-36vdc 7812srh-c +12.0vdc 0.4a +15-36vdc ordering information features 3.3v/0.5a, 5v/0.5a or 12v/0.4a outputs; pin and size-compatible with lm7805 & lm7812 regulators up to 95% ef? ciency C no heat sinks or thermal derating required two sip-packages ? t existing to-220 footprints: - vertical-pin models occupy less than 0.1 square in. - optional horizontal pins provide 0.350 in. installed height +7.5-36vdc operating input range; low 3ma quiescent current built-in ? lter capacitors C no external components required C40 to +70c operation at full load; short-circuit protection excellent load (0.2%) and line (0.3%) regulation ideal for powering instrumentation from 9v/12v/24v/28v supplies or batteries can be used with unregulated dc supplies protection
78xxsr series 3.3v/5v/12v outputs high-ef? ciency switching regulators with lm78xx pinouts www.murata-ps.com/dpm email: sales@murata-ps.com 05 apr 2011 mdc_78xxsr series.b06 page 2 of 6 technical notes (continued) 6. soldering & handling precautions: all units are designed to be hand soldered to pc-boards using no-clean solders (+260c, 5 seconds max.). water-soluble solders can also be used, but the units must be washed and dried using processes appropriate to the type of solder employed. see the mechanical speci? cations section for pin 1 orientation and recommended plated-through hole dimensions. while 78sr regulators easily withstand a 2kv esd discharge to any ter- minal (using human body model), they should always be treated as esd sensitive devices. 7. horizontal-pin models (78xxsrh-c): 78xxsrh-c switching regulators are pin-compatible replacements for to-220 style lm78xx linear regula- tors that are installed with their metal tabs lying ? at on the surface of the pc-board. however, because the surface of inductor l1 on 78xxsrh-c models is electrically conductive, it must not be allowed to come in con- tact with any exposed pc-board traces, other than power ground (gnd). while the 2-mil-thick (0.05mm) polyester label attached to l1 provides some degree of electrical insulation (only if l1 sits perfectly ? at on the pc-board), it is recommended that a 0.020 (0.5mm) clearance be main- tained between l1 and all exposed pc-board traces. 8. dropout voltage: 78sr series regulators described in this data sheet specify a minimum input voltage at which full-load accuracy and output regulation are guaranteed (7.5v for 7803sr-c and 7805sr-c, and 15.0v for 7812SR-C). however, these devices will stay in regulation at lower input voltages if they are operated at less than their rated loads. the following dropout-voltage data, derived from sample testing performed at an ambient temperature of +25c with resistive loads, should be used for information purposes only. for these tests, a unit was considered to be out of regulation when its output changed by more +/C0.005vdc from its nominal value. all voltages were measured directly at the regulators i/o pins. input/output models 7803sr-c 7805sr-c 7812SR-C output voltage +3.3vdc +5.0vdc +12.0vdc rated output current 0.5a 0.5a 0.4a output voltage accuracy 2% 2% 2% input voltage range ? +7.5-36vdc +7.5-36vdc +15-36vdc line regulation (100% load) 0.3% 0.3% 0.3% load regulation (0-100% load) 0.2% 0.2% 0.2% quiescent current 3ma typ., 5ma max. input current see performance curves ef? ciency see performance curves transient response see performance curves input & output noise see performance curves short circuit protection ? continuous isolation none overvoltage protection none undervoltage protection none environmental models 7803sr-c 7805sr-c 7812SR-C operating temperature C40 to +70c storage temperature C40 to +85c cooling free air convection humidity (non-condensing) 0 to 85% physical mechanical see mechanical speci? cations package open-frame sip pins 0.025 (0.64mm) square, tin-plated bronze weight 0.08 ounces (2.2g) pin soldering +260c for 5 seconds ? see technical note 5. ? while these regulators can withstand a continuous short-circuit across their output terminals, they will experience a signi? cant temperature rise. extended short-circuit operation will adversely affect the units reliability. 0% load 25% load 50% load 100% load 7803sr-c 6.0v 6.2v 6.2v 6.3v 7805sr-c 6.3v 6.2v 6.2v 6.8v 7812SR-C 12.8v 13.0v 12.8v 13.0v performance/functional speci? cations typical at t a = +25c typical dropout voltage
78xxsr series 3.3v/5v/12v outputs high-ef? ciency switching regulators with lm78xx pinouts www.murata-ps.com/dpm email: sales@murata-ps.com 05 apr 2011 mdc_78xxsr series.b06 page 3 of 6 7805sr-c vin = 12v, i load = 50ma typical performance curves t a = +25c, v in as indicated noise and ripple - 10% and 100% load, 20mhz bandwidth 7805sr-c vin = 12v, i load = 500ma 7812SR-C vin = 24v, i load = 40ma 7812SR-C vin = 24v, i load = 400ma 7803sr-c vin = 12v, i load = 50ma 7803sr-c vin = 12v, i load = 500ma
78xxsr series 3.3v/5v/12v outputs high-ef? ciency switching regulators with lm78xx pinouts www.murata-ps.com/dpm email: sales@murata-ps.com 05 apr 2011 mdc_78xxsr series.b06 page 4 of 6 transient response - 90% load step 7803sr-c 10% to 100% load step 7803sr-c 100% to 10% load step 7805sr-c 10% to 100% load step 7805sr-c 100% to 10% load step 7812SR-C 10% to 100% load step 7812SR-C 100% to 10% load step v in = 9v v in = 9v v in = 9v v in = 9v v in = 18v v in = 18v
78xxsr series 3.3v/5v/12v outputs high-ef? ciency switching regulators with lm78xx pinouts www.murata-ps.com/dpm email: sales@murata-ps.com 05 apr 2011 mdc_78xxsr series.b06 page 5 of 6 7812SR-C ef? ciency 7812SR-C input current 7805sr-c ef? ciency 7803sr-c ef? ciency 7803sr-c input current 7805sr-c input current 50 55 60 65 70 75 80 85 90 8 1012141618202224262830323436 input voltage efficiency input voltage input current (amps) loa loa loa loa loa loa input voltage efficiency input voltage nput current (amps) loa loa loa loa loa loa input voltage efficiency input voltage input current (amps) loa loa loa loa loa loa ef? cience curves
78xxsr series 3.3v/5v/12v outputs high-ef? ciency switching regulators with lm78xx pinouts murata power solutions, inc. makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. the descriptions contained her ein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. speci? cations are subject to cha nge without notice. ? 2011 murata power solutions, inc. www.murata-ps.com/locations email: sales@murata-ps.com murata power solutions, inc. 11 cabot boulevard, mans? eld, ma 02048-1151 u.s.a. iso 9001 and 14001 registered 05 apr 2011 mdc_78xxsr series.b06 page 6 of 6 mechanical dimensions: inches (mm) tolerances: 2 pl dec 0.02 (0.51) 3 pl dec 0.010 (0.254) pc-board hole: 0.037 - 0.043 (0.94 - 1.09) dia. pins: 0.025 (0.64) sq. 0.100 (2.54) centers horizontal package (h pin option) 0.15 (3.8) min. 0.37 (9.3) max. l1 output (+v out ) gnd input (+v in ) 1 2 3 0.07 (1.8) l1 l1 1 1 0.75 (19.1) 0.41 (10.4) output (+v out ) pc-board hole: 0.037 - 0.043 (0.94 - 1.09) dia. gnd input (+v in ) 0.23 (5.7) pins: 0.025 (0.64) sq. 0.100 (2.54) centers 0.15 (3.8) min. 0.19 (4.8) 123 l1 standard package low-pro? le package
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