general description the ds2129 is a triple-output voltage regulator for 27-line, low-voltage-differential (lvd) scsi termination for spi-2 and spi-3 applications using lvd termination networks. the device provides reference voltages and bias currents for lvd-termination resistor pi ( ) net- works. with a pi network (475 , 121 , 475 ), the ds2129 meets the common-mode bias, differential bias, and termination-impedance requirements of spi-2 (ultra2) and spi-3 (ultra3). the device also provides a 1.3v output for diffsense signaling, and includes pro- tection features such as thermal shutdown and active current limiting. applications scsi array backplane scsi cables features ? fully compliant with spi-2 and spi-3 ? 2.7v to 5.25v operation ? differential fail-safe bias ds2129 lvd scsi 27-line regulator ______________________________________________ maxim integrated products 1 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 n.c. n.c. n.c. hs_gnd hs_gnd hs_gnd hs_gnd n.c. n.c. top view so (150 mils) termpwr reg2 reg1 gnd hs_gnd diffsense n.c. ds2129 pin configuration ordering information block diagram rev 1; 2/06 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. part* voltage (v) pin- package top mark** DS2129S 5 16 so ds2129 DS2129S+ 5 16 so ds2129 DS2129S/t&r 5 16 so ds2129 DS2129S+t&r 5 16 so ds2129 bandgap (1.25v) thermal shutdown ref125 ptat ref175 ts 1.75v reg2 reg1 diffsense 1.3v ref075 0.75v ref130 references ts ts ts termpwr gnd ds2129 + denotes lead-free package. * all devices rated for the commercial (0? to +70?) tempera- ture range. ** a ??anywhere on the topmark denotes a lead-free package.
ds2129 lvd scsi 27-line regulator 2 _____________________________________________________________________ absolute maximum ratings electrical characteristics (termpwr = 3.3v, t a = 0? to +70?, unless otherwise noted.) (note 1) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. termpwr, diffsense, reg1, reg2 ....................-0.3v, +6.0v reg1, reg2 continuous output current.......................?00ma continuous power dissipation (t a = +70?) 16-pin so (derate 13mw/ c above +70?)........................1w operating temperature range...............................0? to +70? junction temperature ......................................................+150? storage temperature range .............................-65 c to +150 c soldering temperature .......................................see ipc/jedec j-std-020a specification parameter symbol conditions min typ max units termpwr termpwr supply current i term no load 40 ma termpwr voltage v term 2.7 5.25 v v ref regulator 0.75v regulator output voltage, reg2 v 075 i out = 125ma 0.7 0.75 0.8 v 0.75v regulator source current, reg2 i src_075 v out = 0.25v -200 ma 0.75v regulator sink current, reg2 i sink_075 v out = 1.25v +200 ma 0.75v regulator source current limit i srcl_075 v out = 0v -700 ma 0.75v regulator sink current limit i sinkl_075 v out = 3.3v +700 ma 1.75v regulator output voltage, reg1 v 175 i out = 125ma 1.7 1.75 1.8 v 1.75v regulator source current, reg1 i src_175 v out = 1.25v -200 ma 1.75v regulator sink current, reg1 i sink_175 v out = 2.25v +200 ma 1.75v regulator source current limit i srcl_175 v ref = 0v -700 ma 1.75v regulator sink current limit i sinkl_175 v ref = 3.3v +700 ma diffsense output diffsense driver output voltage v dso -5ma i diffsense 50? 1.2 1.3 1.4 v diffsense driver source current i dsh v diffsense = 0v -5 -15 ma diffsense driver sink current i dsl v diffsense = 2.4v 100 200 ?
ds2129 lvd scsi 27-line regulator _____________________________________________________________________ 3 electrical characteristics (continued) (termpwr = 3.3v, t a = 0? to +70?, unless otherwise noted.) (note 1) note 1: all voltages are referenced to ground. note 2: guaranteed by design and not production tested. parameter symbol conditions min typ max units thermal shutdown thermal-shutdown threshold (note 2) for increasing temperature +150 c thermal-shutdown hysteresis (note 2) 10 c ds2129 475 1% 475 1% 475 1% 475 1% 121 1% 121 1% termpwr diffsense reg1 reg2 4.7 f 4.7 f 4.7 f termpwr 2.7v to 5.25v r1n r1p r27n r27p diffsense r2n r26p typical operating circuit
ds2129 lvd scsi 27-line regulator 4 _____________________________________________________________________ detailed description the ds2129 provides three regulated outputs. the reg1 provides a 1.75v output, and the reg2 provides a 0.75v output. both regulators can sink and source 200ma of current. these regulators are current-limited to less than 700ma. the thermal-shutdown circuit dis- ables the output buffers should the die temperature exceed +150?. with a pi network of resistors (475 , 121 , 475 ) connected to these two outputs, the ds2129 provides common-mode bias, differential bias, and common impedance and differential impedance, as required in a terminator specified in spi-2 and spi-3 standards for a scsi system. the third regulator pro- vides a 1.3v output for diffsense signaling. chip information transistor count: 3778 cmos and 80 bipolar process: bicmos substrate connected to ground thermal information thermal resistance (junction-to-ambient): ja = +77?/w thermal resistance (junction-to-case): jc = +25?/w pin description pin name function 1, 8, 9, 10, 15, 16 n.c. no connection. do not connect pins. 2 termpwr termination power. connect to scsi termpwr line and decouple with a 4.7? ceramic capacitor. 3 reg2 regulator 2, 0.75v output. decouple with a 4.7? ceramic capacitor. 4 gnd signal ground 5, 11?4 hs_gnd heat-sink ground. internally connected to the mounting pad. should be connected to ground. 6 reg1 regulator 1, 1.75v output. decouple with a 4.7? ceramic capacitor. 7 diffsense diffsense output. drives the scsi bus diffsense line.
ds2129 lvd scsi 27-line regulator maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 _____________________ 5 2006 maxim integrated products printed usa is a registered trademark of maxim integrated products, inc. package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages ) . soicn .eps package outline, .150" soic 1 1 21-0041 b rev. document control no. approval proprietary information title: top view front view max 0.010 0.069 0.019 0.157 0.010 inches 0.150 0.007 e c dim 0.014 0.004 b a1 min 0.053 a 0.19 3.80 4.00 0.25 millimeters 0.10 0.35 1.35 min 0.49 0.25 max 1.75 0.050 0.016 l 0.40 1.27 0.394 0.386 d d min dim d inches max 9.80 10.00 millimeters min max 16 ac 0.337 0.344 ab 8.75 8.55 14 0.189 0.197 aa 5.00 4.80 8 n ms012 n side view h 0.244 0.228 5.80 6.20 e 0.050 bsc 1.27 bsc c h e e b a1 a d 0 -8 l 1 variations:
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