for technical support and more information, see inside back cover or visit www.ti.com standard application features ? 18v to 36v input v oltage range ? programmable output voltage range: 1.3v to 3.5v ? -40 to +85c ambient ? 1500 vdc isolation ? 89% efficiency ? on/off inhibit ? differential remote sense ? n+1 current sharing slts093b (revised 6/21/2002) description the pt4471 excalibur? dc/dc converter module combines state-of-the- art power conversion technology with un-paralleled flexibility. incorporating high efficiency and ultra-fast transient response, these modules provide up to 30a of output current over the program- mable voltage range of 1.3v to 3.5v. this represents a full 100w output at 3.3v. the modules include a number of inbuilt features to facilitate system integration. these include a foldback output current limit, over-temperature protection, and an inhibit on/off control. a differential remote sense is also provided to compensate for voltage drop between the converter and load. for applications requiring power supply redundancy, multiple pt4471 modules may connected for op eration in an n+1 configuration. each pt4471 connected will share the load current with other active pt4471 modules. ? over-current protection ? over-temperature protection ? over-voltage protection ? space-saving package ? solderable copper case ? safety approvals: ul 60950 csa 22.2 950 vde en60950 pending l o a d pt4471 +v sns +v out -v out -v sns 7 8-13 14-19 20 25 22 24 23 vid0 - vid4 +v in ?v in 1 2 3 inhibit c 1 + programming pins +v out +v in ?v in ?v out c o + 21 c 2 ?c o = optional 330f electrolytic capacitor ?c 1 = optional 33f, 50v electrolytic capacitor ?c 2 = optional 1f, 50v ceramic capacitor ? programming pins, vid0Cvid4, are shown configured for vo =3.3v ? for normal operation, pin 3 (inhibit) must be connected to Cvin. ? for details on additional n+1 components consult the related application note. ordering information pt4471 = 1.3 to 3.5 volts pt series suffix (pt1234 x ) case/pin order package configuration suffix code * vertical n (ekd) horizontal a (eka) smd c (ekc) * previously known as package styles 1200, 1210, and 1215. (reference the applicable package code draw- ing for the dimensions and pc board layout) pin-out information pin function 1+v in 2Cv in 3 inhibit 4 do not connect 5 do not connect 6 sync ? 7 (+)remote sense 8+v out 9+v out 10 +v out 11 +v out 12 +v out 13 +v out pin function 14 Cv out 15 Cv out 16 Cv out 17 Cv out 18 Cv out 19 Cv out 20 (C)remote sense 21 vid0 22 vid1 23 vid2 24 vid3 25 vid4 26 share ? pt4471?24v 100-w 30-a programmable isolated dc/dc converter ? pins 6 & 26 are used for n+1 configuration (see related application note). for stand-alone operation, leave open circuit. ? shaded functions indicate those pins that are referenced to primary-side potential.
for technical support and more information, see inside back cover or visit www.ti.com pt4470 series comparison output voltage configuration for functionality program range current sharing pt4471 regulator 1.3vC 3.5v n+1 with other pt4471s pt4472 regulator 1.3vC 3.5v with pt4495 boosters pt4495 pt4472 booster n/a used only with pt4472 pt4473 regulator 4.6vC5.7v n+1 with other pt4473s pt4474 regulator 4.6vC5.7v with pt4494 boosters pt4494 pt4474 booster n/a used only with pt4474 pt4475 regulator 6.5vC 17.5v n+1 with other pt4475s pt4476 regulator 6.5vC17.5v with pt4493 boosters pt4493 pt4476 booster n/a used only with pt4476 pt4471 ? 24v 100-w 30-a programmable isolated dc/dc converter programming information vid4=1 vid4=0 vid3 vid2 vid1 vid0 vout vout 1 1 1 1 2.0v 1.30v 1 1 1 0 2.1v 1.35v 1 1 0 1 2.2v 1.40v 1 1 0 0 2.3v 1.45v 1 0 1 1 2.4v 1.50v 1 0 1 0 2.5v 1.55v 1 0 0 1 2.6v 1.60v 1 0 0 0 2.7v 1.65v 0 1 1 1 2.8v 1.70v 0 1 1 0 2.9v 1.75v 0 1 0 1 3.0v 1.80v 0 1 0 0 3.1v 1.85v 0 0 1 1 3.2v 1.90v 0 0 1 0 3.3v 1.95v 0 0 0 1 3.4v 2.00v 0 0 0 0 3.5v 2.05v logic 0 = connect to (C)remote sense, pin 20 logic 1 = open circuit (no pull-up resistors) vid3 & vid4 must not be changed while unit is operating specifications (unless otherwise stated, t a =25c, v in =24v, v o =3.3v, c o =0f, and i o =i o max) pt4471 characteristic symbol conditions min typ max units output current i o over v in range 0 30 a input voltage range v in over i o range 18 24 36 vdc set point voltage tolerance v o tol 1 1.5 %v o temperature variation reg temp C40 t case +100c, i o =0 0.5 %v o line regulation reg line over v in range 0.1 1 %v o load regulation reg load over i o range 0.2 1 %v o total output voltage variation ? v o tot includes set-point, line, load, 23%v o C40 t case +100c efficiency i o =15a v o =3.3v 89 v o =2.5v 87 % v o =1.5v 81 v o ripple (pk-pk) v r 20mhz bandwidth v o > 2v 60 75 mv pp v o 2v 45 55 transient response t tr 0.1a/s load step, 50% to 75% i o max n/a s ? v tr v o over/undershoot 1 %v o 1a/s load step, 50% to 100% i o max 75 s v o over/undershoot 5 %v o current limit i lim v in =18v, ? v o = C1% 35a foldback continuous limit current share tolerance i shr tol with other pt4471 modules in n+1 10 % over-voltage protection ovp shutdown and latch off 125 %v o switching frequency ? s over v in range 270 300 350 khz under-voltage lockout uvlo 17 v inhibit (pin 3) referenced to Cv in (pin 2) input high voltage v ih 2.5 open (1) v input low voltage v il C0.5 +0.8 input low current i il C0.2 ma standby input current i in standby pins 3 & 2 connected 4 10 ma internal input capacitance c in 3 f external output capacitance c out between +v o and Cv o 0 10,000 f isolation voltage inputCoutput/inputCcase 1500 v capacitance input to output 1100 pf resistance input to output 10 m ? operating temperature range t c case temperature, over v in range -40 +115 (2) c over-temperature shutdown otp case temperature, auto reset 120 c storage temperature t s -40 +125 c reliability mtbf per bellcore tr-332 1.4 10 6 hrs 50% stress, t a =40c, ground benign mechanical shock per mil-std-883d, method 2002.3, 500 gs 1ms, half-sine, mounted to a fixture mechanical vibration mil-std-883d, method 2007.2 suffixes a, c 20 (3) gs 20-2000hz, pcb mounted weight 90 grams flammability materials meet ul 94v-0 notes: (1) the inhibit (pin 3) has an internal pull-up, which if left open circuit allows the converter to operate when input power is applied. the open-circuit is limited to 6.5v. refer to the application notes for interface considerations. (2) see safe operating area curves or contact the factory for the appropriate derating. (3) the case pins on through-hole pin configuration (suffix a) must be soldered. for more information see the applicable package outline drawing. # this specification covers only the pt4471 regulator. #
for technical support and more information, see inside back cover or visit www.ti.com note a: characteristic data has been developed from actual products tested at 25c. this data is considered typical data for the conve rter. note b: soa curves represent the conditions at which internal components are at or below the manufacturers maximum operating tempera tures efficiency vs output current ripple vs output current power dissipation vs output current typical characteristics pt4471 ? 24v 100-w 30-a programmable isolated dc/dc converter stand alone, no heatsink safe operating area, v in =24v (see note b) performance characteristics, v o =3.3v (see note a) 0 4 8 12 16 20 0 5 10 15 20 25 30 iout ( a ) pd - watts 18.0v 24.0v 36.0v v in 20 30 40 50 60 70 80 90 0 5 10 15 20 25 30 iout ( a ) ambient temperature (c) 500lfm 400lfm 300lfm 200lfm 100lfm nat conv airflow 50 60 70 80 90 100 0 5 10 15 20 25 30 iout ( a ) efficiency - % 3.3v 2.5v 1.5v v out 0 20 40 60 80 100 0 5 10 15 20 25 30 iout ( a ) ripple - mv 3.3v 2.5v 1.5v v out
for technical support and more information, see inside back cover or visit www.ti.com application notes pt4471 configuring pt4471 dc/dc converters for n+1 operation ?n+1? vs or?ing the pt4471 dc/dc converter modules may be operated with other pt4471 modules in n+1 configurations. a simple oring connection allows a number of converters to share the load current. an n+1 configuration adds redundancy by employing at least one more converter than is necessary to supply the load. this ensures that upon the loss of one converter, sufficient capacity remains to supply the load without interruption. as an example, a 45-a load configured for n+1 would require no less than three pt4471 converters. two are needed to meet the load demand, plus one additional converter to ensure redundancy. figure 1-1 shows the schematic for operating two pt4471 converters in an n+1 configuration for a 25-a load application. blocking diodes a true n+1 redundant system must also protect the output bus against fault current back-feeding a con- verter. without a blocking diode, a converter will sink current as a result of a fault at its output, or due to the loss of its input source. the blocking diodes 4 , (d 1 pt4471 pt4471 1 2 8 ? 13 20 7 remote sense (+) remote sense ( ? ) programming pins 3 c out , 330f (required) + 18 ? 13 14 ? 19 25 24 23 22 21 14 ? 19 2 626 20 626 7 remote sense (+) 21 22 23 24 25 3 programming pins d 2 , or'ing diode (required) ? v in +v in 25-a load inhibit ? v out +v out +v in ? v in +v out ? v out vid4 ? vid0 +sns ? sns share sync inhibit ? sns share sync inhibit +sns +v in ? v in +v out ? v out vid4 ? vid0 c in + c in + d 1 , or'ing diode (required) f1 f2 c out , 330f (required) + figure 1-1; connection schematic for operation in parallel/n+1 configuration & d 2 in figure 1-1), protect against reverse current flow under such conditions. notes 1. for n+1 redundancy, always use one more converter than is required to supply the load. 2. the vid pins for all converter modules must be independently set to the same voltage program code. 3. all converters connected for ?n+1? operation must be located on the same printed circuit board. a similar footprint and trace layout for each converter will facilitate current sharing. 4 a number of high-current rectifier diodes are available with a low forward voltage drop. they are specifically designed for oring applications in n+1 systems. eg. the 82cnq030, and mbrb2515. 5. as a result of excess capacity and the losses in the blocking diodes, system efficiency is reduced. 6. the interconnection of pin 6 (sync), and pin 26 (share) between all modules are required for load current sharing and operation at a common frequency.
application notes for technical support and more information, see inside back cover or visit www.ti.com operating features of the pt4470 and pt4480 series of isolated dc/dc converters under-voltage lockout an under-voltage lock-out (uvlo) inhibits the operation of the converter until the input voltage is above the uvlo threshold (see the applicable data sheet specification). below this voltage, the modules output is held off, irrespective of the state of the inhibit control (pin 3). if the inhibit control is connected to Cv in (pin 2), the module will automatically power up when the input voltage rises above the uvlo threshold. the uvlo allows the module to produce a clean transition during both power-up and power-down, even when the input voltage is rising or falling slowly. it also reduces the high start-up current during normal power-up of the converter, and minimizes the current drain from the input so urce during low-input voltage conditions. the uvlo threshold includes about 2v of hysteresis. once operational, the con verter will conform to its operating specifications when the minimum specified input voltage is reached. over-current protection to protect against load faults, the pt4470/80 series of dc/dc converters incorporate an output current limit. once the load current drawn from the module reaches the current limit threshold, any attempt by the load to draw additional current will result in a significant drop in the modules regulated output voltage. the current limit circuitry incorporates a limited amount of foldback. this has the effect of slightly reducing the output current from the module when supplying an absolute short circuit. upon removal of the load fault, the output voltage from the converter will automatically recover to its programmed regulation voltage. output over-voltage protection the pt4470/80 series of dc/dc converters incorporate circuitry that continually senses the output for an over- voltage (ov) condition. the ov threshold automatically tracks the vid output voltage program setting to a level 25% higher than that programmed at the control pins, vid0 through vid4. if the converter output voltage exceeds the ov threshold, the converter is immediately shut down and remains in a latched-off state. to resume normal operation the converter must be actively reset. this is accomplished by either cycling the status of the inhibit control (pin 3) from on to off and then back on again, or by momentarily removing the input power to the converter. for failsafe operation and redundancy, the ov protection uses circuitry that is independent of the converters internal feedback loop. over-temperature protection over-temperature protection is provided by an internal temperature sensor, which closely monitors the tempera- ture of the converters metal case. if the case temperature exceeds the specified limit (see applicable data sheet), the converter will shut down. the converter will then automatically restart when the sensed temperature drops by about 10c. when operated outside its recommended thermal derating envelope (see data sheet soa curves), the converter will typcially cycle on and off at intervals from a few seconds to one or two minutes. this is to ensure that the internal components are not permanently damaged from excessive thermal stress. primary -secondary isolation electrical isolation is provided between the input terminals (primary) and the output terminals (secondary). all con- verters are production tested to a primary-secondary withstand voltage of 1500vdc. this specification com- plies with ul60950 and en60950 and the requirements for operational isolation. operational isolation allows these converters to be configured for either a positive or negative input voltage source. the data sheet pin-out information uses shading to indicate which pins are associated with the primary. they include pins 1 through 5, inclusive. fuse recommendations if desired, an input fuse may be added to protect against the application of a reverse input voltage. thermal considerations airflow may be necessary to ensure that the module can supply the desired load current in environments with elevated ambient temperatures. the required airflow rate may be determined from the safe operating area (soa) thermal derating chart (see converter specifica- tions). the recommended direction for airflow is into the longest side of the modules metal case. see figure 1. recommended direction for airflow is into (perpendicular to) the longest side. figure 1 pt4470, pt4480 series
for technical support and more information, see inside back cover or visit www.ti.com application notes using the inhibit function on the pt4470 & pt4480 series of isolated dc/dc converters the pt4470/44480 series of dc/dc converters incor- porate an on/off inhibit function. this function may be used in applications that demand battery conservation, power-up/shutdown sequencing, and/or to coordinate power-up for active in-rush current control. the on/off feature is provided by the inhibit control, pin 3. the inhibit pin of the pt4470/4480 series of converters is an active low enable. the pin must be either connected, or actively pulled low, to Cv in (pin 2) to enable the converter output (see standard applica- tion schematic). when pins 2 & 3 are connected, the converter provides a regulated output whenever a valid source voltage 3 is applied between +v in (pin 1), and Cv in (pin 2). if pin 3 is disconnected, or allowed to become high impedance, the regulator output will be disabled. 5 table 2-1 provides details of the interface requirements for the inhibit pin. figure 2-1 shows how a discrete mosfet (q 1 ) 4 , may be referenced to Cv in and used to control the input. table 2-1 inhibit control requirements parameter min max enable (v ih ) C0.5v 0.8v disable (v il ) 2.5v (open circuit) notes: 1. the inhibit control uses Cv in (pin 2), on the primary side of the converter, as its ground reference. all voltages specified are with r espect to Cv in . 2. the internal circuitry is simple pull -up resistor. the open-circuit voltage may be as high as 6.5vdc. 3. these converters incorporate an under-voltage lockout (uvlo) function. this function automatically disables the co nverter output until there is sufficient input voltage to produce a regulated output. table 2 gives the applicable uvlo thresholds. table 2-2 uvlo thresholds 1 series uvlo threshold v in range pt4470 17.0v typical 18 C 36v pt4480 34.5v typical 36 C 75v 4. the inhibit input must be controlled with an open- collector (or open-drain) discrete transistor or mosfet. do not use a pull-up resistor. 5. when the converter output is disabled, the current drawn from the input supply is typically reduced to 4ma (10ma maximum). figure 2-1 turn-on time: with input power applied, the converter typically produces a fully regulated output voltage within 25ms after applying a low-voltage signal to the inhibit control pin. the actual turn-on time will vary with the input voltage, output load, and the total amount of capacitance connected to the output. using the circuit of figure 2-1, figure 2-2 shows the typical output voltage and input current waveforms of a pt4472 after q 1 is turned on. the turn on of q 1 correlates to the fall in v inh . the output voltage was set to 2.5v. the waveform was measured with a 48-vdc input voltage, and 15-a load current. figure 2-2 pt4470, pt4480 series 6. keep the on/off transition to less than 1ms. this prevents erratic operation of the isr, whereby the output voltage may drift un-regulated between 0v and the rated output during power-up. vout (1v/div) iin (2a/div) vinh (5v/div) horiz scale: 5ms/div pt4472 +v sns +v out -v out -v sns 7 8-13 14-19 20 21 25 22 24 23 vid0 - vid4 +v in ? v in 1 2 3 inhibit c 1 + programming pins +2.5v +v in ? v in 0v 1 =enable q 1 bss138
packaging information orderable device status (1) package type package drawing pins package qty eco plan (2) lead/ball finish msl peak temp (3) pt4471a active sip mod ule eka 26 6 tbd call ti level-1-215c-unlim PT4471C active sip mod ule ekc 26 6 tbd call ti level-3-215c-168hrs pt4471n active sip mod ule ekd 26 6 tbd call ti level-1-215c-unlim (1) the marketing status values are defined as follows: active: product device recommended for new designs. lifebuy: ti has announced that the device will be discontinued, and a lifetime-buy period is in effect. nrnd: not recommended for new designs. device is in production to support existing customers, but ti does not recommend using this part in a new design. preview: device has been announced but is not in production. samples may or may not be available. obsolete: ti has discontinued the production of the device. (2) eco plan - the planned eco-friendly classification: pb-free (rohs) or green (rohs & no sb/br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. tbd: the pb-free/green conversion plan has not been defined. pb-free (rohs): ti's terms "lead-free" or "pb-free" mean semiconductor products that are compatible with the current rohs requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. where designed to be soldered at high temperatures, ti pb-free products are suitable for use in specified lead-free processes. green (rohs & no sb/br): ti defines "green" to mean pb-free (rohs compatible), and free of bromine (br) and antimony (sb) based flame retardants (br or sb do not exceed 0.1% by weight in homogeneous material) (3) msl, peak temp. -- the moisture sensitivity level rating according to the jedec industry standard classifications, and peak solder temperature. important information and disclaimer: the information provided on this page represents ti's knowledge and belief as of the date that it is provided. ti bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. efforts are underway to better integrate information from third parties. ti has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. ti and ti suppliers consider certain information to be proprietary, and thus cas numbers and other limited information may not be available for release. in no event shall ti's liability arising out of such information exceed the total purchase price of the ti part(s) at issue in this document sold by ti to customer on an annual basis. package option addendum www.ti.com 13-may-2005 addendum-page 1
important notice texas instruments incorporated and its subsidiaries (ti) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. all products are sold subject to ti?s terms and conditions of sale supplied at the time of order acknowledgment. ti warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with ti?s standard warranty. testing and other quality control techniques are used to the extent ti deems necessary to support this warranty. except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. ti assumes no liability for applications assistance or customer product design. customers are responsible for their products and applications using ti components. to minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. ti does not warrant or represent that any license, either express or implied, is granted under any ti patent right, copyright, mask work right, or other ti intellectual property right relating to any combination, machine, or process in which ti products or services are used. information published by ti regarding third-party products or services does not constitute a license from ti to use such products or services or a warranty or endorsement thereof. use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from ti under the patents or other intellectual property of ti. reproduction of information in ti data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. reproduction of this information with alteration is an unfair and deceptive business practice. ti is not responsible or liable for such altered documentation. resale of ti products or services with statements different from or beyond the parameters stated by ti for that product or service voids all express and any implied warranties for the associated ti product or service and is an unfair and deceptive business practice. ti is not responsible or liable for any such statements. following are urls where you can obtain information on other texas instruments products and application solutions: products applications amplifiers amplifier.ti.com audio www.ti.com/audio data converters dataconverter.ti.com automotive www.ti.com/automotive dsp dsp.ti.com broadband www.ti.com/broadband interface interface.ti.com digital control www.ti.com/digitalcontrol logic logic.ti.com military www.ti.com/military power mgmt power.ti.com optical networking www.ti.com/opticalnetwork microcontrollers microcontroller.ti.com security www.ti.com/security telephony www.ti.com/telephony video & imaging www.ti.com/video wireless www.ti.com/wireless mailing address: texas instruments post office box 655303 dallas, texas 75265 copyright ? 2005, texas instruments incorporated
|
