sep 12, 2003 revised to oct 26, 2006 page 1 of 8 www.power-one.com qls25 dc-dc series data sheet 25a quarter-brick applications ? distributed power architectures ? telecommunications equipment ? lan/wan applications ? data processing applications features ? rohs lead solder exemption compliant ? cost-effective single board design ? low profile ? 11 mm height ? input/output isolation: 1500vdc, basic insulation ? high efficiency - up to 90% at full load ? start-up into high capacitive load ? low conducted and radiated emi ? output overcurrent protection ? output overvoltage protection ? back drive protection ? overtemperature protection ? remote sense ? set point accuracy 1% ? remote on/off (primary referenced), positive or negative logic ? output voltage trim adjust, positive or negative ? ul 1950 recognition, csa 22.2 no. 950-95 certification, tuv iec950 description the qls25 is a new series of cost-effective, high-den sity single output dc-dc conv erters providing onboard conversion of standard telecom and datacom input voltages into isolated low voltage outputs in a through-hole mounting package. high efficiencies and a patent-pendi ng board design significantly improve thermal characteristics by evening out hot spot s and enhance product reliability. model selection model input voltage vdc input current, max adc output voltage vout, vdc output rated current i rated, adc output ripple/noise, mv p-p typical efficiency @ i rated, % qls20zg 36-75 4.8 5.0 20 150 90 qls25ze 36-75 3.3 3.3 25 100 89 qls25zd 36-75 2.5 2.5 25 100 87 this product is intended for integration into end-use equipment. all the required procedures for ce marking of end-use equipme nt should be followed.
sep 12, 2003 revised to oct 26, 2006 page 2 of 8 www.power-one.com qls25 dc-dc series data sheet 2 5a quarter-brick absolute maximum ratings stresses in excess of the absolute maximum ratings ma y cause performance degradation, adversely effect long- term reliability, and cause permanent damage to the converter. parameter conditions/description min max units input voltage continuous transient, 100ms 75 100 vdc vdc operating temperature pc board temperature -40 100 c storage temperature -40 125 c on/off control voltage referenced to -vin 50 vdc environmental and mechanical specifications all specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted. parameter conditions/descrip tion min nom max units shock halfsine wave, 3 axes 50 g sinusoidal vibration gr-63-core, section 5.4.2 1 g weight 1.2/35 oz/g water washing standard process yes mtbf per bellcore tr-nwt-000332 1,980 khrs isolation specifications all specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted. parameter conditions/descrip tion min nom max units insulation safety rating basic isolation voltage 1500 vdc isolation resistance 10 mohm isolation capacitance 1100 pf input specifications all specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted. parameter conditions/descrip tion min nom max units input voltage continuous 36 48 75 vdc turn-on input voltage ramping up 33 vdc turn-off input voltage ramping down 32 vdc turn-on time to output regulation band 100% resistive load 5 10 ms input reflected ripple current full load, 12h source inductance 60 ma p-p inrush transient vin=vin.max 0.1 a 2 s
sep 12, 2003 revised to oct 26, 2006 page 3 of 8 www.power-one.com qls25 dc-dc series data sheet 2 5a quarter-brick output specifications all specifications apply over specified input voltage, output load and temperature ra nge, unless otherwise noted. parameter conditions/descrip tion min nom max units output voltage setpoint accuracy vin=vin.nom, full load -1 1 %vout output current* see selection chart for i rated 10 100 %i rated line regulation vin.min to vin.max, i rated 0.2 %vout load regulation vin=vin.nom, 10% to 100%i rated 0.2 %vout total output voltage regulation over all input voltage, load, and temperature conditions -2 2 %vout remote sense headroom 0.5 vdc dynamic regulation peak deviation settling time 50-75% load step change to 1% error band 5 150 %vout s admissible load capacitance i rated , nom vin 20,000 f output current limit threshold** vout 0.97vout.nom 110 140 %i rated switching frequency 270 khz overvoltage protection, non latching over all input voltage and load conditions 120 140 %vout trim range i rated , vin=vnom 90 110 %vout * at iout sep 12, 2003 revised to oct 26, 2006 page 4 of 8 www.power-one.com qls25 dc-dc series data sheet 2 5a quarter-brick characteristic curves 65 70 75 80 85 90 95 0 4 8 12 16 20 output current, a efficiency, % 36v 48v 75v figure 1. qls20zg efficiency vs. output load 65 70 75 80 85 90 95 0 5 10 15 20 25 output current, a efficiency, % 36v 48v 75v figure 2. qls25ze efficiency vs. output load 65 70 75 80 85 90 95 0 5 10 15 20 25 output current, a efficiency, % 36v 48v 75v figure 3. qls25ze efficiency vs. output load 0 0.5 1 1.5 2 2.5 3 3.5 4 0 10203040506070 input voltage, vdc input current, adc figure 4. qls20zg input characteristic 0 0.5 1 1.5 2 2.5 3 3.5 0 10203040506070 input voltage, vdc input current, adc figure 5.qls25ze input characteristic 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 10203040506070 input voltage, vdc input current, adc figure 6. qls25zd input characteristic
sep 12, 2003 revised to oct 26, 2006 page 5 of 8 www.power-one.com qls25 dc-dc series data sheet 2 5a quarter-brick typical application figure 7 shows the recommended connections for the qls25 series converter. figure 7. typical application of qls25 series the qls25 series converters do not require any external components for proper operation. however, if the distribution of the input voltage to the converter contains significant inductance, the capacitor c1 may be required to enhance performance of the converter. a minimum of a 33 f electrolytic capacitor with the esr<0.7 is recommended for the qls25 series. refer to the ?inrush current control application note? on www.power-one.com for suggestions on how to limit the magnitude of the inrush current. for output decoupling we recommend to use a 10 f tantalum and a 1 f ceramic capacitors connected directly across the output pins of the converter. note, that the capacitors do not substitute the filtering required by the load. shutdown feature description the on/off pin in the qls25 series converters functions as a normal soft shutdown. it is referenced to the ?vin pin (see figure 7). with the positive logic, when the on/off pin is pulled low, the output is turned off and the unit goes into a very low input power mode. with negative logic, when the on/off pin is pulled low, the unit is turned on. an open collector switch is recommended to control the voltage between the on/off pin and the -vin pin of the converter. the on/off pin is pulled up internally, so no external voltage source is required. the user should avoid connecting a resistor between the on/off pin and the +vin pin. when the on/off pin is used to achieve remote control, the user must take care to insure that the pin reference for the control is really the -vin pin. the control signal must not be referenced ahead of emi filtering, or remotely from the unit. optically coupling the information and locating the optical coupler directly at the module will solve any of these problems. note: if the on/off pin is not used, it can be left floating (positive logic), or connected to the -vin pin (negative logic). output voltage trim the trim feature allows the user to adjust the output voltage from the nominal. this can be used to accommodate a different requirement or to do production margin testing. there are two variances available in the qls25 series. negative trim the qls25 negative trim units trim up with a resistor from the trim pin to the ?sense pin and trim down with a resistor from the trim pin to the +sense pin as shown in figure 8. the negative trim schematic is shown in figure 8. figure 8. qls25 series negative trim schematic the general equation (1) for changing the output voltage on the negative trim modules is invariant, but the constants in the equation change due to different internal values. k (1) , v v b a r trim ? =
sep 12, 2003 revised to oct 26, 2006 page 6 of 8 www.power-one.com qls25 dc-dc series data sheet 2 5a quarter-brick where a and b are constants from the table below, and v is the absolute value of the desired change in the output voltage in volts. trim up trim down model a b a b qls20zg 3.77 6.81 11.58 9.88 qls25ze 2.07 3.92 3.5 5.61 qls25zd 1.27 3.92 1.31 4.95 industry standard positive trim (suffix ?t) the -t option units trim up with a resistor from the trim pin to the +sense pin and trim down with a resistor from the trim pin to the ?sense pin as shown in the figure 9. figure 9. qls25 series positive trim schematic the equations below determine the trim resistor value required to achieve a v change in the output voltage. ? ? ? ? ? ? + ? + = % % 2 100 % 225 . 1 %) 100 ( 11 . 5 v v v v vout r up ,k ? ? ? ? ? ? ? = 2 % 100 11 . 5 v r down , k where v% is the output voltage change expressed in percents of the nominal output voltage, vout. notes: 1. when the output voltage is trimmed up, the output power from the converter must not exceed its maximum rating. the power is determined by measuring the output voltage on the output pins, and multiplying it by the output current. 2. in order to avoid creating apparent load regulation degradation, it is important that the trim resistors are connected directly to the remo te sense pins, and not to the load or to traces going to the load. 3. the qls25 series converters will trim down further than the 10% limit. in general, this is permissible. the user must confirm that the results are acceptable in the application. safety considerations the qls25 series converters feature 1500 volt dc isolation from input to output. the input to output resistance is greater than 10mohm. these converters are provided with basic insulation between input and output circuits according to all iec60950 based standards. nevertheless, if the system using the converter needs to receive safety agency approval, certain ru les must be followed in the design of the system. in particular, all of the creepage and clearance requirements of the end-use safety requirements must be observed. these documents include ul60950 - csa60950-00 and en60950, although other or additional requirements may be needed for specific applications. the qls25 series converters have no internal fuse. the external fuse must be provided to protect the system from catastrophic failure as shown in figure 7. the fuse with a rating not greater than 4a is recommended. the user can select a lower rating fuse based upon the highest inrush transient at the maximum input voltage and the maximum input current of the converter, which occurs at the minimum input voltage. both input traces and the chassis ground trace (if applicable) must be capable of conducting a current of 1.5 times the value of the fuse without opening. the fuse must not be placed in the grounded input line, if any. in order for the output of the qls25 series converter to be considered as selv (safety extra low voltage) or tnv-1, according to all iec60950 based standards, one of the following requirements must be met in the system design: ? if the voltage source feeding the module is selv or tnv-2, the output of the converter may be grounded or ungrounded. ? if the voltage source feeding the module is elv, the output of the conver ter may be considered selv only if the output is grounded per the requirements of the standard. ? if the voltage source feeding the module is a hazardous voltage secondary circuit, the voltage source feeding the module must be provided with at least basic insulation between the source to the converter and any hazardous voltages. the entire system, including the qls25 converter, must pass a dielectric withstand test for reinforced insulation. design of this type of syst ems requires expert
sep 12, 2003 revised to oct 26, 2006 page 7 of 8 www.power-one.com qls25 dc-dc series data sheet 2 5a quarter-brick engineering and understanding of the overall safety requirements and should be performed by qualified personnel. thermal considerations the qls25 series converters are designed for natural or forced convection cooling. the maximum allowable output current of the converters is determined by meeting the derating criteria for all components used in the converters. for example, the maximum semiconductor junction temperature is not allowed to exceed 120c to ensure reliable long- term operation of the converters. contact power- one for the complete list of the derating criteria. the graphs in figures 10-12 show the maximum output current of the qls25 series converters at different ambient temperatures under both natural and forced (longitudinal airflow direction, from pin 1 to pin 3) convection. for example, from figure 11, the qls25ze operating at 55c can deliver up to 18a reliably with 100lfm forced air, while up to 25a reliably with 400lfm forced air. 0 5 10 15 20 25 25 30 35 40 45 50 55 60 65 70 75 80 85 ambient temperature (c) output current (a) 0 100lfm 200lfm 300lfm 400lfm figure 10. qls20zg (5v) derating curves 0 5 10 15 20 25 25 30 35 40 45 50 55 60 65 70 75 80 85 ambient temperature (c) output current (a) 0 100lfm 200lfm 300lfm 400lfm figure 11. qls25ze (3.3v) derating curves 0 5 10 15 20 25 25 30 35 40 45 50 55 60 65 70 75 80 85 ambient temperature (c) output current (a) 0 100lfm 200lfm 300lfm 400lfm figure 12. qls25zd (2.5v) derating curves
sep 12, 2003 revised to oct 26, 2006 page 8 of 8 www.power-one.com qls25 dc-dc series data sheet 2 5a quarter-brick mechanical drawing ordering information options suffixes to add to part number positive- standard, no suffix required remote on/off negative- add ?n? suffix negative- no suffix required trim positive - add ?t? suffix 0.18?- standard, no suffix required 0.11?- add ?8? suffix pin length 0.15?- add ?9? suffix notes 1. consult factory for the complete list of available options. nuclear and medical applications - power-one products are not de signed, intended for use in, or authorized for use as critical components in life support systems, equipment used in hazardous env ironments, or nuclear control systems without the express wr itten consent of the respective divisional president of power-one, inc. technical revisions - the appearance of products, including safety agency certifications pictured on labels, may change dependi ng on the date manufactured. specifications are subject to change without notice. tolerances: .xx + .020 (.5) .xxx + .010 (.25) pin diameter + 0.002 (.05) pin function 1 -vin 2 on/off 3 +vin 4 -vout 5 -sense 6 trim 7 +sense 8 +vout
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