reg1118 features l sources 800ma, sinks 400ma l 2.85v output for scsi active negation termination l 1.3v max dropout voltage at i o = 800ma l internal current limit l thermal overload protection l sot-223 surface mount package 800ma low dropout positive regulator with current source and sink capability ? 1996 burr-brown corporation pds-1352b printed in u.s.a. january, 1997 international airport industrial park ? mailing address: po box 11400, tucson, az 85734 ? street address: 6730 s. tucson blvd., tucson, az 85706 ? tel: (520) 746-1111 ? twx: 910-952-1111 internet: http://www.burr-brown.com/ ? faxline: (800) 548-6133 (us/canada only) ? cable: bbrcorp ? telex: 066-6491 ? fax: (520) 889-1510 ? immediate product info: (800) 548-6132 applications l scsi-2 and scsi-3 devices l fast-20 scsi l active negation scsi terminators l supply splitter ground generation description the reg1118-2.85 is a three-terminal voltage regula- tors capable of sourcing up to 800ma and sinking up to 400ma. the sinking capability is important in scsi applications where active negation line drivers are used. the reg1118-2.85 is useful for making a 27-line boulay terminator capable of interfacing with active negation drivers required in fast-20 scsi applications. the regulator has active current limits for both sink and source currents as well as internal thermal limiting. laser trimming assures excellent output voltage accu- racy. an npn output stage allows output stage drive current to contribute to the source load current for maximum efficiency. reg1118 is packaged in a sot-223 surface-mount package, suitable for reflow soldering techniques. reg1118 reg1118 gnd v in v out 4.7? 10? termpwr 110 w 110 w user supplied
resistor network reg1118-2.85 used to make active negation scsi terminator signal line n signal line 1 signal line 2 signal line 3 up to
27 lines 110 w 110 w sbvs005
reg1118 2 specifications at t a = 0 c to 70 c, termpwr = +5v, unless otherwise noted. reg1118-2.85 parameter conditions min typ max units output voltage no load, t a = 25 c 2.82 2.85 2.88 v all operating conditions (1) 2.79 2.85 2.91 v line regulation (2) i o = 0, v in = 4.75v to 6v 0.3 4 mv load regulation (2) i o = 0 to 800ma 2 25 mv i o = C400 to 0ma 25 60 mv dropout voltage (3) t a = 25 c i o = 100ma 0.8 1.1 v i o = 800ma 1.1 1.3 v current limit t a = 25 c positive (i sc +) (4) 800 1450 ma negative (i sc C) v out = 3.7v C750 C400 ma quiescent current i o = 0 3 7 ma ripple rejection t a = 25 c f = 120hz, v in C v out = 2v, v ripple = 0.5vp-p 56 db long-term stability t a = +125 c, 1000hr 0.2 % thermal shutdown junction temperature shutdown 150 c junction temperature reset 140 c thermal resistance specified junction temperature range 0 70 c operating junction temperature range 0 125 c storage range C55 125 c thermal resistance q jc (junction-to-case at tab) 15 c/w notes: (1) all operating conditions include the combined effects of load current, input voltage, and temperature over each parameters full specified range. (2) load and line regulation are tested at a constant junction temperature by low duty cycle testing. (3) dropout voltage is defined as the minimum input-to-output voltage that produces a 1% decrease in output voltage. (4) v out to ground through 1 w . absolute maximum ratings input voltage .......................................................................................... 7v output voltage ........................................................... C0.2v to (v+) +0.5v short-circuit duration .................................................................. indefinite operating junction temperature range ............................. 0 c to +125 c storage temperature range .......................................... C55 c to +125 c lead temperature (soldering, 10s) (1) ............................................. +300 c note: (1) see soldering methods. front view sot-223 connection diagram tab is connected
to ground v in ground v out plastic sot-223 product (1) part marking package reg1118-2.85 bb11182 sot-223 note: (1) available in tape and reel, add Ctr to model number. ordering information package information package drawing product package number (1) reg1118-2.85 sot-223 311 note: (1) for detailed drawing and dimension table, please see end of data sheet, or appendix c of burr-brown ic data book. electrostatic discharge sensitivity this integrated circuit can be damaged by esd. burr-brown recommends that all integrated circuits be handled with appropriate precautions. failure to observe proper handling and installation procedures can cause damage.
reg1118 3 load transient response 0.2
0
?.2 0.5
0
?.5 output voltage
deviation (v) load current (a) 0 25 50 75 100 125 150 200 175 250 225 time (?) sinking 400ma sourcing
800ma (ceramic) (tantalum) 10? || 0.1? (ceramic) (tantalum) 4.7? || 0.1? at t a = 25 c, termpwr = +5v, unless otherwise specified. typical performance curve quiescent current vs temperature temperature (?) 30 40 5 4 3 2 100 1020 5060708090 quiescent current (ma) dropout voltage vs temperature temperature (?) 30 40 1.3
1.2
1.1
1
0.9
0.8
0.7
0.6 100 1020 5060708090 dropout voltage (v) i out = 100ma i out = 800ma short-circuit current vs temperature temperature (?) 30 40 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 100 1020 5060708090 short-circuit current ma source sink line transient response 1
0
? 0.1
0
?.1 output voltage
deviation (v) input voltage
deviation (v) 0 0.25 0.75 1.25 0.5 1 1.5 1.75 2.25 2 2.5 time (ms) c in = 2.2?
c out = 1?
reg1118 4 applications information figure 1 shows the basic hookup diagram for the reg1118. an output capacitor is required for proper operation and to improve high frequency load regulation. a high quality capacitor should be used to assure that the esr (effective series resistance) is less than 0.5 w . a capacitor of at least 1 m f is recommended. increasing c out improves output voltage deviation, see the typical curve load transient response. it is suggested that the input be decoupled with 10 m f low esr capacitor. ambient temperature above that expected in normal opera- tion until the devices thermal shutdown is activated. if this occurs at more than 40 c above the maximum expected ambient temperature, then the t j will be less than 125 c during normal operation. soldering methods the reg1118 package is suitable for infrared reflow and vapor-phase reflow soldering techniques. the high rate of temperature change that occurs with wave soldering, or hand soldering can damage the reg1118. figure 1. basic connections. thermal considerations the reg1118 has current limit and thermal shutdown circuits that protect it from overload. the thermal shutdown activates at approximately t j = 150 c. for continuous op- eration, however, the junction temperature should not be allowed to exceed 125 c. any tendency to activate the thermal shutdown in normal use is an indication of an inadequate heat sink or excessive power dissipation. the power dissipation is equal to: p d = (v in C v out ) i out the junction temperature can be calculated by: t j = t a + p d ( q ja ) where t a is the ambient temperature, and q ja is the junction-to-ambient thermal resistance the reg1118 derives heat sinking from conduction through its copper leads, especially the large mounting tab. these must be soldered to a circuit board with a substantial amount of copper remaining (see figure 2). circuit board traces connecting to the tab and the leads should be made as large as practical. other nearby circuit traces, including those on the back side of the circuit board, help conduct heat away from the device, even though they are not electrically connected. make all nearby copper traces as wide as possible and leave only narrow gaps between traces. in addition, multiple contacts to internal power and ground planes increase heat sinking with minimal increase in circuit board area. table i shows approximate values of q ja for various circuit board and copper areas. nearby heat dissipating compo- nents, circuit board mounting conditions and ventilation can dramatically affect the actual q ja . a simple experiment will determine whether the maximum recommended junction temperature is exceeded in an actual circuit board and mounting configuration: increase the figure 2. circuit board layout example. total area: 50 x 50mm without back-side copper: ja ? 59?/w 35 x 17 mm 16 x 10 mm 16 x 10 mm q with solid back-side copper: ja ? 49?/w q topside (1) backside total pc board copper copper thermal resistance area area area junction-to-ambient 2500mm 2 2500mm 2 2500mm 2 46 c/w 2500mm 2 1250mm 2 2500mm 2 47 c/w 2500mm 2 950mm 2 2500mm 2 49 c/w 2500mm 2 2500mm 2 051 c/w 2500mm 2 1800mm 2 053 c/w 1600mm 2 600mm 2 1600mm 2 55 c/w 2500mm 2 1250mm 2 058 c/w 2500mm 2 915mm 2 059 c/w 1600mm 2 600mm 2 067 c/w 900mm 2 340mm 2 900mm 2 72 c/w 900mm 2 340mm 2 085 c/w note: (1) tab is attached to the topside copper. table i. inspec abstract number: b91007604, c91012627 kelly, e.g. thermal characteristics of surface 5wk9 w packages. the proceedings of smtcon. surface mount technology conference and exposition: competitive surface mount technology , april 3-6, 1990, atlantic city, nj, usa. abstract publisher : ic manage, 1990, chicago, il, usa. reg1118 v o v in 10? 4.7?
reg1118 5 the information provided herein is believed to be reliable; however, burr-brown assumes no responsibility for inaccuracies or omissions. burr-brown assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user's own risk. prices and specifications are subject to change without notice. no patent rights or licenses to any of the circuits described herein are implied or granted to any third party. burr-brown does not authorize or warrant any burr-brown product for use in life support devices and/or systems. figure 3. scsi active termination configuration. 4.7? 10? reg1118-2.85 110 w 110 w 110 w 110 w 10? 4.7? 1n5817 5v termpwr 2.85v 2.85v termpwr 1n5817 5v (up to 27 lines) reg1118-2.85
important notice texas instruments and its subsidiaries (ti) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. all products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those pertaining to warranty, patent infringement, and limitation of liability. ti warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with ti's standard warranty. testing and other quality control techniques are utilized to the extent ti deems necessary to support this warranty. specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. customers are responsible for their applications using ti components. in order to minimize risks associated with the customer's applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. ti assumes no liability for applications assistance or customer product design. ti does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of ti covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. ti's publication of information regarding any third party's products or services does not constitute ti's approval, warranty or endorsement thereof. copyright ? 2000, texas instruments incorporated
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