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$ features standard quarter-brick package/pinout outputs from 1.5 to 48v up to 125w low profle 0.42" height 24 and 48vdc nominal inputs fully isolated, 2250vdc (basic) insulation designed for rohs compliance output overvoltage/short-circuit protected on/off control, trim and sense functions high effciency to 92% protected against temp. and voltage limits ul/iec/en60950-1 safety approvals qual/halt/emi tested ordering guide summary model v o u t range i o u t range v in range effciency all models 1.2v to 48v 2.5a to 40a 18-36v or 36-75v up to 92.%, model dependent input characteristics parameter typ. @ 25c, full load notes voltage range 18-36 or 36-75 volts 24v or 48v nominal current, full power up to 5.6 amps model dependent isolation 2kvdc to 2250v model dependent remote on/off control switch or fet control positive or negative logic output characteristics parameter typ. @ 25c, full load notes voltage 1.5 to 48 volts 10% trimmable current 2.5 to 40 amps fullscale no minimum load accuracy down to 1% of v nom most models ripple & noise (to 20mhz) down to 35mvp-p model dependent line and load regulation down to 0.125%/0.25% model dependent overcurrent protection 150% of i out max. with hiccup auto-restart overtemperature protection +125 c effciency (minimum) see performance specifcations general specifications parameter typ. @ 25c, full load notes dynamic load response down to 50sec model dependent operating temperature range C40 to +110c with baseplate, see derating curve safety ul/iec/en 60950-1 and csa c22.2-no.234 mechanical characteristics with baseplate 1.45 x 2.30 x 0.5 inches (36.83 x 58.42 x 12.7 mm) without baseplate 1.45 x 2.30 x 0.42 inches (36.83 x 58.42 x 10.67 mm) see performance specifcations, page 2 p b lead-free construction/attach typical unit for effcient, fully isolated dc power in the small - est space, murata power solutions' uvq series quarter bricks offer output voltages from 1.5 to 48 volts with currents up to 40 amps. uvqs operate over a wide temperature range (up to +70c at 200 lfm airfow) at full-rated power. the optional mounting baseplate extends this to all practical temperature ranges at full power. uvqs achieve these impressive specifcations while delivering excellent electrical performance. overall noise is 35mvp-p (3.3v models) with fast step response (down to 50 sec). these converters offer high stability even with no load and tight out - put regulation. the unit is fully protected against input over and undervoltage, output overcur - rent and short circuit. an on-board temperature sensor shuts down the converter if thermal limits are reached. protection uses the hiccup (auto restart) method. a convenient remote on/off control input oper - ates by external digital logic, relay or transistor input. to compensate for longer wiring and to retain output voltage accuracy at the load, uvqs include a sense input to dynamically correct for ohmic losses. a trim input may be connected to a users adjustment potentiometer or trim resistors for output voltage calibration closer than the standard accuracy. uvqs include industry-standard safety certi - fcations and basic i/o insulation provides 2250 volt input/output isolation. radiation emission testing is performed to widely-accepted emc standards. contact mps for details on halt quali - fcation testing. the uvqs may be considered as higher performance replacements for some mps usq models. product overview mdc_uvq models.b04 page 1 of 25 uvq series low profle, isolated quarter brick 2.5C40 amp dc/dc converters for full details go to www.murata-ps.com/rohs www.murata-ps.com technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000
? these are partial model numbers. please refer to the full model number struc - ture for complete ordering part numbers. ? min. i o u t = 3 amps. ? all specifcations are at nominal line voltage and full load, +25 c unless other - wise noted. see detailed specifcations. output capacitors are 1uf ceramic || 10 uf electrolytic. input cap is 22 uf, low esr, except uvq-24/4.5 is 33uf and uvq-48/2.5 uses no input cap. i/o caps are necessary for our test equipment and may not be needed for your application. ? i o u t = 14 amps max. with v in = 18-19.5 volts. uvq pin 9 baseplate connection the uvq series may include an optional installed baseplate for extended thermal management. various uvq models (see list below) are also available with an additional pin 9 on special order which connects to the baseplate but is electrically isolated from the rest of the converter. please refer to the mechani - cal drawings. pin 9 offers a positive method of controlling the electrical potential of the baseplate, independent of the converter. some baseplate models cannot include pin 9 and in such cases, the baseplate is grounded by the mounting bolts. or consider adding an external lugged washer with a grounding terminal. the baseplate may be ordered by adding a b to the model number tree and pin 9 will be pre-installed by adding a 9. the two options are separate. please refer to the ordering guide. do not order pin 9 without the baseplate. note that pin 9 converters may be on limited forecast, requiring minimum order quantities and scheduled deliveries. models available with pin 9: uvq-12/10-d48 uvq-1.5/40-d24 models which are not available with pin 9: uvq-5/20-d24 and Cd48 uvq-3.3/30-d24 uvq-3.3/35-d48 uvq-2.5/35-d24 uvq-2.5/40-d48 other models which are not listed will be reviewed for future pin 9 accomo - dation. ordering guide root models output input effciency) package (case, pinout) v o u t (volts) i o u t (amps) power (watts) r/n (mvp-p) ? regulation (max.) ? v i n nom. (volts) range (volts) i i n , no load (ma) i i n , full load (amps) typ. max. line load min. typ. uvq-1.2/40-d48 1.2 40 48 tbd tbd tbd tbd 48 36-75 tbd tbd tbd tbd c59, p32 uvq-1.5/40-d24 1.5 40 60 30 60 0.075% 0.05% 24 18-36 80 2.84 86.5% 88% c59, p32 uvq-1.5/40-d48 1.5 40 60 tbd tbd tbd tbd 48 36-75 tbd tbd tbd tbd c59, p32 uvq-1.8/40-d48 1.8 40 72 tbd tbd tbd tbd 48 36-75 tbd tbd tbd tbd c59, p32 uvq-2.5/35-d24 2.5 35 87.5 35 60 0.05% 0.05% 24 18-36 100 4.14 86% 88% c59, p32 uvq-2.5/40-d48 60 0.05% 0.05% 48 36-75 100 2.37 87% 88% uvq-3.3/30-d24 3.3 30 99 65 0.1% 0.25% 24 18-36 180 4.58 88.5% 90% uvq-3.3/35-d48 40 0.05% 0.25% 48 36-75 130 2.7 87% 89% uvq-5/20-d24 5 20 100 30 50 0.05% 0.05% 24 18-36 180 4.53 91% 92% uvq-5/20-d48 20 25 0.05% 0.05% 48 36-75 80 2.31 88.5% 90% uvq-12/8-d24 12 8 96 95 130 0.1% 0.1% 24 18-36 90 4.4 89% 91% uvq-12/10-d48 10 120 110 160 0.75% 0.05% 48 36-75 60 2.78 88.5% 90% uvq-15/7-d24 15 7 105 85 150 0.05% 0.05% 24 18-36 103 4.85 88.5% 90.3% uvq-15/7-d48 120 150 0.05% 0.02% 48 36-75 60 2.39 90% 91.5% uvq-18/5.6-d24 18 5.6 100.8 125 185 0.05% 0.075% 24 18-36 140 4.69 88% 89.5% uvq-18/6-d48 6 108 125 185 0.05% 0.075% 48 36-75 80 2.5 88.3% 90% uvq-24/4.5-d24 24 4.5 60 100 0.075% 0.15% 24 18-36 45 5.03 88% 89.5% uvq-24/4.5-d48 75 130 0.075% 0.25% 48 36-75 45 2.49 89% 90.5% uvq-48/2.5-d24 48 2.5 120 100 200 0.1% 0.2% 24 18-36 45 4.4 89% 91% uvq-48/2.5-d48 250 375 0.175% 0.2% 48 36-75 30 2.71 91% 92.3% performance specifcations and ordering guide ? mdc_uvq models.b04 page 2 of 25 uvq series low profle, isolated quarter brick 2.5C40 amp dc/dc converters technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000 www.murata-ps.com part number structure u vq 3.3 20 d48 - / - quarter-brick package output confguration u = unipolar/single nominal output voltage 1.2 to 48 volts maximum rated output current in amps b = baseplate installed blank = no baseplate baseplate pin 9, see mechanical drawings: (special order) 9 = pin 9 installed (see description on pg. 2) blank = no pin 9 alternate pin length: l1 = 0.110 (2.79mm) l2 = 0.145 (3.68mm) blank = standard pin length input voltage range: d24 = 18-36 volts (24v nominal) d48 = 36-75 volts (48v nominal) * note: not all model number combinations are available. contact murata power solutions. (datel). ?v in (1) +v in (3) opto isolation pwm controller reference & error amp input undervoltage, input overvoltage, and output overvoltage comparators * can be ordered with positive (standard) or negative (optional) polarity. remote on/off control* (2) +sense (7) ?sense (5) +v out (8) v out trim (6) ?v out (4) switch control baseplate (9) optional figure 1. simplifed schematic remote on/off control polarity: add "p" for positive polarity add "n" for negative polarity b lx 9 n - c rohs-6 compliant * typical confguration some models use a different topology mdc_uvq models.b04 page 3 of 25 uvq series low profle, isolated quarter brick 2.5C40 amp dc/dc converters technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000 www.murata-ps.com mdc_uvq models.b04 page 4 of 25 performance/functional specifcations 24v models typical @ t a = +25c under nominal line voltage, nominal output voltage, natural air convection, external caps and full-load conditions, unless noted. (1) uvq-1.5/40-d24 uvq-2.5/35-d24 uvq-3.3/30-d24 uvq-5/20-d24 uvq-12/8-d24 uvq-15/7-d24 uvq-18/5.6-d24 uvq-24/4.5-d24 uvq-48/2.5-d24 input input voltage range see ordering guide start-up threshold, (v) min. 17 17 17 17 17 17 17 17 17 undervoltage shutdown, (v) 14 16 16.25 16 16.25 16 16 overvoltage shutdown (v) none 39 none refected (back) ripple current 2 10-50 ma pk-pk, model dependent input current full load conditions see ordering guide. inrush transient, (a 2 sec) 0.5 0.5 0.05 0.5 0.1 1 1 0.05 0.05 output short circuit, (ma) 40 50 10 320 50 50 50 no load, ma 80 100 180 160 90 103 140 45 30 low line (v in = min.), (amps) 3.79 5.49 6.04 5.57 5.93 6.52 6.29 6.67 3.60 standby mode, (off, uv, ot shutdown) 1-4ma, model dependent internal input flter type l-c pi-type l-c reverse polarity protection see notes. remote on/off control 5 positive logic, "p" suffx (specifcations are max) off = ground pin to +0.8v on = open or +5v to +v in max. negative logic, "n" suffx (specifcations are max) off = open or +5v to +v in max on = ground pin to+0.8v max current 1-8 ma, model dependent uvq series low profle, isolated quarter brick 2.5C40 amp dc/dc converters technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000 www.murata-ps.com mdc_uvq models.b04 page 5 of 25 uvq-1.5/40-d24 uvq-2.5/35-d24 uvq-3.3/30-d24 uvq-5/20-d24 uvq-12/8-d24 uvq-15/7-d24 uvq-18/5.6-d24 uvq-24/4.5-d24 uvq-48/2.5-d24 output voltage output range see ordering guide. voltage output accuracy (50% load) 1.5% of v n o m 1.25% of v n o m 1% of v n o m adjustment range C20 to +10 % of v n o m . 10% of v n o m . temperature coeffcient 0.02% of v o u t range per c minimum loading no minimum load 3 amps no minimum load remote sense compensation +10%. ripple/noise see ordering guide. line/load regulation see ordering guide. effciency see ordering guide. maximum capacitive loading, low esr <0.02 max., resistive load, (f) 10,000 5000 4700 2200 current limit inception (98% of v o u t , after warmup), (amps) 45 44 36 24 10 9.5 7 5.8 3.4 short circuit protection method current limiting, hiccup autorestart. remove overload for recovery. short circuit current, (amps) 3.6 3 3 3 1.5 15 ma 3 5 2.8 short circuit duration output may be shorted continuously to ground (no damage). overvoltage protection, (via magnetic feedback) 2.3 volts 3 volts max 6.8 volts max 14.4 volts max 3.96 volts max 22 volts max 29 volts max 59 volts max isolation characteristics isolation voltage input to output, (volts min) 2000 input to baseplate 1500 baseplate to output, (volts min) 1500 1000 1500 isolation resistance 100 m? isolation capacitance, (pf) 1500 1000 2000 50 isolation safety rating basic insulation performance/functional specifcations 24v models typical @ t a = +25c under nominal line voltage, nominal output voltage, natural air convection, external caps and full-load conditions, unless noted. (1) uvq series low profle, isolated quarter brick 2.5C40 amp dc/dc converters technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000 www.murata-ps.com uvq-1.5/40-d24 uvq-2.5/35-d24 uvq-3.3/30-d24 uvq-5/20-d24 uvq-12/8-d24 uvq-15/7-d24 uvq-18/5.6-d24 uvq-24/4.5-d24 uvq-48/2.5-d24 dynamic characteristics dynamic load response (50-75-50% load step) 100 sec to 1% of fnal value 150 sec to 1.5% of fnal value 150 sec to 1.5% of fnal value 100 sec to 1.5% of fnal value 50 sec to 1% of fnal value 40 sec to 1.25% of fnal value 50 sec to 1% of fnal value 100 sec to 1% of fnal value 100 sec to 1% of fnal value start-up time v in to v o u t regulated, msec remote on/off to v o u t regulated, msec 90msec 90msec 50msec 50msec 50msec 50msec 200msec 200msec 40msec 30msec 30msec 25msec 30msec 35msec 290msec 200msec 100msec 100msec switching frequency, (khz) 380 30 500 to 650 600 360 290 30 242 240 25 290 30 250 25 environmental calculated mtbf 4 tbd operating temperature range: s ee derating curves. ?40 to +85 c (with derating, see note 15.) operating temperature, with baseplate, no derating required (c) 3 ?40 to +110 ?40 to +115 ?40 to +110 storage temperature (c) ?55 to +130 ?55 to +125 thermal protection/ shutdown +110 to 125 c, model dependent relative humidity to +85c/85%, non-condensing physical outline dimensions see mechanical specs. baseplate material aluminum pin material brass alloy pin diameter 0.04/0.062 inches (1.016/1.524 mm) weight 1.55 ounce (44 grams) 1 ounce (28 grams) electromagnetic interference (conducted and radiated) (external flter required) fcc part 15, class b, en55022 safety ul/cul 60950-1, csa c22.2 no.60950-1, iec/en 60950-1 mdc_uvq models.b04 page 6 of 25 performance/functional specifcations 24v models typical @ t a = +25c under nominal line voltage, nominal output voltage, natural air convection, external caps and full-load conditions, unless noted. (1) uvq series low profle, isolated quarter brick 2.5C40 amp dc/dc converters technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000 www.murata-ps.com mdc_uvq models.b04 page 7 of 25 performance/functional specifcations 48v models typical @ t a = +25c under nominal line voltage, nominal output voltage, natural air convection, external caps and full-load conditions, unless noted. (1) uvq-2.5/40-d48 uvq-3.3/35-d48 uvq-5/20-d48 uvq-12/10-d48 uvq-15/7-d48 uvq-18/6-d48 uvq-24/4.5-d48 uvq-48/2.5-d48 input input voltage range see ordering guide start-up threshold, min (v) 35 34.5 34 34.5 35 undervoltage shutdown, (v) 14 33.5 32 33.5 overvoltage shutdown (v) none refected (back) ripple current 10-50 ma pk-pk, model dependent input current full load conditions see ordering guide. inrush transient, (a 2 sec) 0.05 0.05 1 1 0.05 1 0.05 0.05 output short circuit, (ma) 50 10 30 50 250 50 no load, ma 100 130 80 60 30 80 45 30 low line (v in = min.), (amps) 3.15 3.56 3.07 3.72 3.21 3.35 3.30 3.60 standby mode, (off, uv, ot shutdown) 1-4ma, model dependent internal input flter type l-c pi-type l-c reverse polarity protection see notes. remote on/off control 5 positive logic, "p" suffx (specifcations are max) off = ground pin to +0.8v on = open or +5v to +v in max negative logic, "n" suffx (specifcations are max) off = open or +5v to +v in max on = ground pin to+0.8v max current 1-8 ma, model dependent uvq series low profle, isolated quarter brick 2.5C40 amp dc/dc converters technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000 www.murata-ps.com mdc_uvq models.b04 page 8 of 25 uvq-2.5/40-d48 uvq-3.3/35-d48 uvq-5/20-d48 uvq-12/10-d48 uvq-15/7-d48 uvq-18/6-d48 uvq-24/4.5-d48 uvq-48/2.5-d48 output voltage output range see ordering guide. voltage output accuracy (50% load) 1.5% of v n o m 1.25% of v n o m 1% of v n o m adjustment range C20 to +10 % of v n o m . temperature coeffcient 0.02% of v o u t range per c minimum loading no minimum load 3 amps no minimum load no minimum load remote sense compensation +10%. ripple/noise see ordering guide. line/load regulation see ordering guide. effciency see ordering guide. maximum capacitive loading, low esr <0.02 max., resistive load, (f) 10,000 4700 2200 1000 current limit inception (98% of v o u t , after warmup), (amps) 46 48 26 12.5 8.5 7 6.5 3.3 short circuit protection method current limiting, hiccup autorestart. remove overload for recovery. short circuit current, (amps) 5 0.1 1.5 3 3 3 3.5 short circuit duration output may be shorted continuously to ground (no damage). overvoltage protection, (via magnetic feedback) 3 volts max 4 volts max 6 volts max 14.4 volts max 18.5 volts max 22 volts max 29 volts max 55 volts max isolation characteristics isolation voltage input to output, (volts min) 2250 input to baseplate 1500 baseplate to output, (volts min) 1500 1500 isolation resistance 100 m? isolation capacitance, (pf) 1500 1000 50 50 1500 isolation safety rating basic insulation performance/functional specifcations 48v models typical @ t a = +25c under nominal line voltage, nominal output voltage, natural air convection, external caps and full-load conditions, unless noted. (1) uvq series low profle, isolated quarter brick 2.5C40 amp dc/dc converters technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000 www.murata-ps.com mdc_uvq models.b04 page 9 of 25 uvq-2.5/40-d48 uvq-3.3/35-d48 uvq-5/20-d48 uvq-12/10-d48 uvq-15/7-d48 uvq-18/6-d48 uvq-24/4.5-d48 uvq-48/2.5-d48 dynamic characteristics dynamic load response (50-75-50% load step) 150 sec to 1.5% of fnal value 150 sec to 1.5% of fnal value 90 sec to 2% of fnal value 50 sec to 1% of fnal value 50 sec to 1% of fnal value 50 sec to 1% of fnal value 100 sec to 1% of fnal value 75 sec to 1% of fnal value start-up time v in to v o u t regulated, msec remote on/off to v o u t regulated, msec 50msec 50msec 50msec 50msec 50msec 50msec 40msec 30msec 30msec 30msec 30msec 30msec 100msec 100msec 50msec 50msec switching frequency, (khz) 600 600 450 50 290 30 245 20 240 25 290 30 540 40 environmental calculated mtbf 4 tbd operating temperature range: s ee derating curves. ?40 to +85 c (with derating, see note 15.) operating temperature, with baseplate, no derating required (c) 3 ?40 to +110 ?40 to +115 ?40 to +110 ?40 to +110 ?40 to +120 storage temperature (c) ?55 to +125 thermal protection/ shutdown +110 to 125 c, model dependent relative humidity to +85c/85%, non-condensing physical outline dimensions see mechanical specs. baseplate material aluminum pin material brass alloy pin diameter 0.04/0.062 inches (1.016/1.524 mm) weight 1 ounce (28 grams) electromagnetic interference (conducted and radiated) (external flter required) fcc part 15, class b, en55022 safety ul/cul 60950-1, csa c22.2 no.60950-1, iec/en 60950-1 performance/functional specifcations 48v models typical @ t a = +25c under nominal line voltage, nominal output voltage, natural air convection, external caps and full-load conditions, unless noted. (1) uvq series low profle, isolated quarter brick 2.5C40 amp dc/dc converters technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000 www.murata-ps.com removal of soldered uvq's from printed circuit boards should removal of the uvq from its soldered connection be needed, thoroughly de-solder the pins using solder wicks or de-soldering tools. at no time should any prying or leverage be used to remove boards that have not been properly de-soldered frst. input source impedance uvq converters must be driven from a low ac-impedance input source. the dc/dcs performance and stability can be compromised by the use of highly inductive source impedances. the input circuit shown in figure 2 is a practical solution that can be used to minimize the effects of inductance in the input traces. for optimum performance, components should be mounted close to the dc/dc converter. i/o filtering, input ripple current, and output noise all models in the uvq series are tested/specifed for input ripple current (also called input refected ripple current) and output noise using the circuits and layout shown in figures 2 and 3. figure 2. measuring input ripple current c in v in c bu s l bu s c in = 33f , esr < 700m ? @ 100khz c bu s = 220f , esr < 100m ? @ 100khz l bu s = 12h 3 1 +input ?input current pr obe to oscilloscope + ? external input capacitors (c in in figure 2) serve primarily as energy-storage elements. they should be selected for bulk capacitance (at appropriate fre - quencies), low esr, and high rms-ripple-current ratings. the switching nature of dc/dc converters requires that dc voltage sources have low ac impedance as highly inductive source impedance can affect system stability. in figure 2, c bus and l bus simulate a typical dc voltage bus. your specifc system confgura - tion may necessitate additional considerations. input voltage 24v models 48v models continuous 0 to +36v 0 to +75v transient (100 ms) +50v +100v on/off control C0.3 v min to +13.5v max. input reverse polarity protection see fuse section output overvoltage v o u t +20% max. output current (note 7) current-limited. devices can withstand sustained short circuit without damage. storage temperature C55 to +125c lead temperature (soldering 10 sec.) +280c absolute maximums are stress ratings. exposure of devices to any of these conditions may adversely affect long-term reliability. proper operation under conditions other than those listed in the performance/functional specifca - tions table is not implied nor recommended. (1) all models are tested and specifed with 200 lfm airfow, external 1||10f ceramic/ tantalum output capacitors. external input capacitance varies according to model type. all capacitors are low esr types. these capacitors are necessary to accommodate our test equipment and may not be required to achieve specifed performance in your applications. all models are stable and regulate within spec under no-load conditions. general conditions for specifcations are +25c, v in =nominal, v o u t = nominal, full load. (2) input ripple current is tested and specifed over a 5-20mhz bandwidth. input flter - ing is c in = 33f tantalum, c b u s = 220f electrolytic, l b u s = 12h. (3) note that maximum power derating curves indicate an average current at nominal input voltage. at higher temperatures and/or lower airfow, the dc/dc converter will tolerate brief full current outputs if the total rms current over time does not exceed the derating curve. (4) mean time before failure is calculated using the telcordia (belcore) sr-332 method 1, case 3, ground fxed conditions, tpcboard = +25c, full output load, natural air convection. (5) the on/off control may be driven with external logic or by applying appropriate external voltages which are referenced to input common. the on/off control input should use either an open collector/open drain transistor or logic gate which does not exceed +13.5v. (6) short circuit shutdown begins when the output voltage degrades approximately 2% from the selected setting. (7) the outputs are not intended to sink appreciable reverse current. sinking excessive reverse current may damage the outputs. (8) output noise may be further reduced by adding an external flter. see i/o filtering and noise reduction. (9) all models are fully operational and meet published specifcations, including cold start at C40c. (10) regulation specifcations describe the deviation as the line input voltage or output load current is varied from a nominal midpoint value to either extreme. (11) overvoltage shutdown on 48v input models is not supplied in order to comply with telecom reliability requirements. these requirements attempt continued operation despite signifcant input overvoltage. (12) do not exceed maximum power specifcations when adjusting the output trim. (13) note that the converter may operate up to +110c with the baseplate installed. however, thermal self-protection occurs near +110c, and there is a temperature gradient between the hotspot and the baseplate. therefore, +100c is recom - mended to avoid thermal shutdown. (14) the converter is guaranteed to turn off at the uv shutdown voltage. (15) at full power, the package temperature of all on-board components must not exceed +128 c. part number structure mechanical specifications mdc_uvq models.b04 page 10 of 25 uvq series low profle, isolated quarter brick 2.5C40 amp dc/dc converters technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000 www.murata-ps.com figure 3. measuring output ripple/noise (pard) c1 c1 = 1f cerami c c2 = 10f t ant alum lo ad 2-3 inches (51-76mm) fr om module c2 r lo ad 7 8 copper stri p 4 5 copper stri p scope +output ?output +sense ?sense in critical applications, output ripple/noise (also referred to as periodic and random deviations or pard) can be reduced below specifed limits using flter - ing techniques, the simplest of which is the installation of additional external output capacitors. output capacitors function as true flter elements and should be selected for bulk capacitance, low esr, and appropriate frequency response. in figure 3, the two copper strips simulate real-world pcb imped - ances between the power supply and its load. scope measurements should be made using bnc connectors or the probe ground should be less than ? inch and soldered directly to the fxture. all external capacitors should have appropriate voltage ratings and be located as close to the converter as possible. temperature variations for all relevant parameters should be taken into consideration. os-con tm organic semiconductor capacitors (www.sanyo.com) can be especially effective for further reduction of ripple/noise. the most effective combination of external i/o capacitors will be a function of line voltage and source impedance, as well as particular load and layout conditions. our applications engineers can recommend potential solutions and discuss the possibility of our modifying a given devices internal fltering to meet your specifc requirements. contact our applications engineering group for additional details. start-up threshold and undervoltage shutdown under normal start-up conditions, the uvq series will not begin to regulate properly until the ramping input voltage exceeds the start-up threshold. once operating, devices will turn off when the applied voltage drops below the undervoltage shutdown point. devices will remain off as long as the undervoltage condition continues. units will automatically re-start when the applied voltage is brought back above the start-up threshold. the hysteresis built into this function avoids an indeterminate on/off condition at a single input voltage. see performance/functional specifcations table for actual limits. start-up time the v in to v out start-up time is the interval between the point at which a ramping input voltage crosses the start-up threshold voltage and the point at which the fully loaded output voltage enters and remains within its specifed 1% accuracy band. actual measured times will vary with input source imped - ance, external input capacitance, and the slew rate and fnal value of the input voltage as it appears to the converter. the on/off to v out start-up time assumes that the converter is turned off via the remote on/off control with the nominal input voltage already applied. on/off control the primary-side, remote on/off control function (pin 2) can be specifed to operate with either positive or negative polarity. positive-polarity devices ("p" suffx) are enabled when pin 2 is left open or is pulled high. positive- polarity devices are disabled when pin 2 is pulled low (0-0.8v with respect to Cinput). negative-polarity devices are off when pin 2 is high/open and on when pin 2 is pulled low. see figure 4. dynamic control of the remote on/off function is best accomplished with a mechanical relay or an open-collector/open-drain drive circuit (optically iso - lated if appropriate). the drive circuit should be able to sink appropriate current (see performance specifcations) when activated and withstand appropriate voltage when deactivated. current limiting when power demands from the output falls within the current limit inception range for the rated output current, the dc/dc converter will go into a current limiting mode. in this condition the output voltage will decrease proportionately with increases in output current, thereby maintaining a somewhat constant power dissipation. this is commonly referred to as power limiting. current limit inception is defned as the point where the full-power output voltage falls below the specifed tolerance. if the load current being drawn from the converter is signifcant enough, the unit will go into a short circuit condition. see short circuit condition. short circuit condition when a converter is in current limit mode the output voltages will drop as the output current demand increases. if the output voltage drops too low, the magnetically coupled voltage used to develop primary side voltages will also drop, thereby shutting down the pwm controller. following a time-out period of about 50 milliseconds, the pwm will restart, causing the output voltages to begin ramping to their appropriate values. if the short-circuit condition persists, another shutdown cycle will be initiated. this on/off cycling is referred to as hiccup mode. the hiccup cycling reduces the average output current, thereby preventing internal temperatures from rising to excessive levels. the uvq is capable of enduring an indefnite short circuit output condition. 6 2 % & ) . 0 5 4 % 1 5 ) 6 ! , % . 4 # ) 2 # 5 ) 4 & |