RT9231A ds9231a-02 july 2001 www.richtek.com 1 advanced pwm and triple linear power controller general description the RT9231A is a 4-in-one power controller optimized for high-performance microprocessor and computer applications. the ic integrates a pwm controller, triple linear controller as well as monitoring and protection functions into a 28-pin sop package. the pwm controller regulates the microprocessor core voltage with a synchronous buck converter. the first linear controller supplies the computer system?s agp 1.5v or 3.3v bus power. the second linear controller provides power for the 1.5v gtl bus and the 3rd linear controller provides 1.8v power for the north/south bridge core voltage and/or cache memory circuits. the RT9231A features an intel-compatible, ttl 5-bit programmable dac that adjusts the core voltage from 2.1v to 3.5v in 0.1v increments and from 1.3v to 2.05v in 0.05v steps. the 5-bit dac has a typical 1% tolerance. the first linear controller is user- selectable for output level of 1.5v and 3.3v with 2.5% accuracy. the other two linear controllers provide fixed output voltages of 1.5v 3% and 1.8v 3%. all the three linear cont rollers drive external n- mosfet or npns bipolar for the pass transistor. the RT9231A monitors all the output voltages. a power-good signal is issued when the core voltage is within 10% of the dac setting and the other levels are above their under-voltage levels. additional build- in over-voltage protection for the core output uses the lower mosfet to prevent output voltage above 115% of the dac setting. the pwm over-current function monitors the output current using the voltage drop across the mosfet?s r ds(on) , which eliminates the need for a current sensing resistor. applications z full motherboard power regulation for computer z low-voltage distributed power supplies features z 4-in-one regulated voltages for microprocessor core, agp bus, north/south bridge and/or cache memory, gtl bus power z compatible with hip6021a z power-good output voltage monitor switching section z 5-bit dac programmable from 1.3v to 3.5v z 1% dac accuracy z fast transient response z full 0% to 100% duty cycle driver z fixed 200khz switching frequency z adaptive non-overlapping gate driver z over-current monitor uses mosfet r ds(on) z over-voltage protection uses lower mosfet linear section z fixed or user-adjustable linear regulator output voltage z mosfet and npn driving capability z ultra fast response speed z under-voltage protection z internal thermal shutdown pin configurations part number pin configurations RT9231Acs (plastic sop-28) top view 1 2 3 4 5 6 7 8 9 10 11 12 17 18 19 20 21 22 23 24 25 26 27 28 13 14 16 15 fix vid4 vid3 vid2 vid1 vid0 pgood sd vsen2 drive2 ss select fault vsen4 lgate1 vcc ugate1 phase1 pgnd ocset1 vsen1 fb1 vsen3 drive3 gnd nc vaux drive4
RT9231A www.richtek.com ds9231a-02 july 2001 2 ordering information RT9231A ? ? typical application circuit operating temperature range c: commercial standard package type s : sop-28 l1 1 h l3 3. 5 h c8 1000pf 1. 21k r2 + ss fb vsen1 pgnd lg ate phase ugate pgood ocset vcc vaux drive3 vsen3 drive4 vsen4 gnd 17 12 6 7 21 22 24 25 26 27 8 23 28 18 19 15 14 powergood c1-4 4x1000 f r12 10 c7 1 f c5-6 2x1 f q4 rfd3055 c19 1000 f c20 270 f v out3 1. 5v v out4 1. 8v gnd 5v 12v c21 0. 1 f r7 732k c17 0. 68 f q1 phb83n03lt q2 phb95n03lt r4 4. 99k c10-16 7x1000 f r13 10k v out1 1. 3 to 3.5v RT9231A f1 15a vid0 vid1 vid2 vid3 vid4 5 4 3 huf76137s3s q3 16 1 drive2 vsen2 10 11 select + + tyedet 5v 3. 3v c9 1000 f c22 1 f v out2 (3. 3v or 1. 5v) + + + c18 1000 f sd fix 9 2 rfd3055 q5
RT9231A ds9231a-02 july 2001 www.richtek.com 3 function block diagram soft-start and fault logic power-on reset(por) oscillator drive3 drive4 vsen2 select vsen1 ocset vcc pgood fault fault ss fb vid0 vid2 vid4 vcc 110% 90% 115% vid1 vid3 gate control ttl d/a contr ol (d ac ) ugate phase lg ate pgnd gnd vcc lower dr ive pwm1 pwm comp1 5v ov vsen4 1.5v or 3.6v 200a oc1 vaux vsen3 inhibit dac out error amp1 75% + vaux dacout compen -sation upper dr ive vcc 28a luv linear under- voltage 75% + 1.26v fix sd drive2 + _ + _ + _ + _ + _ + _ + _ + _ + _ + _ + _ + _
RT9231A www.richtek.com ds9231a-02 july 2001 4 absolute maximum ratings z supply voltage +15v z pgood, fault and gate voltage gnd ? 0.3v ~ v cc +0.3v z input, output or i/o voltage gnd ? 0.3v ~ 7v z ambient temperature range 0 c ~ +70 c z junction temperature range 0 c ~ +125 c z storage temperature range ? 65 c ~ +150 c z lead temperature (soldering, 10 sec.) 300 c z package thermal resistance sop-28, ja 60 c/w recommended operating conditions z supply voltage +12v 10% z ambient temperature range 0 c to 70 c z junction temperature range 0 c to 125 c caution: stresses beyond the ratings specified in ?absolute maximum ratings? may cause permanent damage to the device. this is a stress only rating and operation of t he device at these or any other conditions above those indicated in the operational sections of this specification is not implied. electrical characteristics (v cc = 12v, pgnd = 0v, t a = 25 c, unless otherw ise specified.) parameter symbol test conditions min typ max units vcc supply current nominal supply current i cc ugate, lgate, drive2, drive3, and drive4 open -- 10 -- ma power-on reset vcc rising threshold v ocset = 4.5v 7.5 -- 9.5 v vcc falling threshold v ocset = 4.5v 7 -- 9 v rising vaux threshold v ocset = 4.5v -- 2.8 -- v vaux threshold hysteresys v ocset = 4.5v -- 0.5 -- v rising v ocset threshold -- 1.25 -- v dac and band gap reference dac (vid0-vid4) input low voltage -- -- 0.8 v dac (vid0-vid4) input high voltage 2.0 -- -- v dacout voltage accuracy -1 -- 1 % band gap reference voltage v bg 1.240 1.265 1.290 v to be continued
RT9231A ds9231a-02 july 2001 www.richtek.com 5 parameter symbol test conditions min typ max units oscillator free running frequency 180 200 225 khz ramp amplitude ? v osc -- 1.9 -- v p-p linear regulators (out2, out3, and out4) vsen2 regulation voltage select < 0.8v 1.462 1.500 1.538 v vsen2 regulation voltage select > 2.0v 3.500 3.600 3.700 v vsen3 regulation voltage 1.455 1.500 1.545 v vsen4 regulation voltage 1.746 1.800 1.854 v under-voltage level (all linears) (vsen/vreg) vsen3 rising -- 75 -- % under-voltage hysteresis (all linears) (vsen/vreg) vsen3 falling -- 100 -- mv output drive current (all linears) vaux = 5v 20 40 -- ma synchronous pwm controller error amplifier dc gain -- 65 -- db pwm controller gate driver ugate source r ugate vcc = 12v vcc-v ugate = 1v -- 4 7 ? ugate sink r ugate v ugate = 1v -- 3 7 ? lgate source i lgate vcc = 12v, v lgate = 2v -- 1 -- a lgate sink r lgate v lgate = 1v -- 2 6 ? protection v out1 over-voltage trip vsen1 rising 112 115 124 % fault souring current v fault = 8v 10 14 -- ma ocset1 current source i ocset v ocset1 = 4.5v 170 200 230 a soft-start current i ss v ss = 1v -- 28 -- a power good v out1 upper threshold vsen1 rising 108 -- 112 % v out1 under voltage vsen1 rising 87 -- 95 % v out1 hysteresis (vsen1/dacout) upper/lower threshold -- 2 -- % pgood voltage low v pgood i pgood = -4ma -- -- 0.5 v
RT9231A www.richtek.com ds9231a-02 july 2001 6 functional pin description drive2 (pin 1) connect this pin to the gate of an external moseft. this pin provides the drive for the agp regulator?s pass transistor. fix (pin 2) grounding this pin bypasses the internal resistor dividers that set the voltage of the 1.5v and 1.8v linear regulators. this way, the output voltage of the two regulators can be adjusted fr om 1.3v up to the input voltage (+3.3v or +5v) by way of an external resistor divider corrected at the corresponding vsen pin. the new output voltage set by the external resistor divider can be determined using the following formula: r out v out = 1.265v x (1+ r gnd ) where r out is the resistor connected from vsen to the output of the regulator, and r gnd is the resistor connected from vsen to gr ound. left open, this pin is pulled high enabling fixed output voltage operation. vid0, vid1, vid2, vid3, vid4 (pin 7, 6, 5, 4, and 3) vid0-4 are ttl-compatible the input pins to the 5-bit dac. the state logic of these five pins program the internal voltage reference, dacout. the level of dacout sets the microprocessor core converter output voltage, as well as the corresponding pgood and ovp thresholds. table 1 specifies the dacout voltage of 32 combinations of vid levels. pgood (pin 8) pgood is an open collector output used to indicate the status of the pwm conv erter output voltage. this pin is pulled low when the synchronous regulator output is not within 10% of the dacout reference voltage, or when any of the other outputs are below their under-voltage thresholds. sd (pin 9) this pin shuts down the entire ic. a ttl-compatible, logic level high signal applied at this pin immediately disables all outputs. when re-enabled, the ic undergoes a new soft-start cycle. left open, this pin is pulled low by an internal pull-down current source, enabling operation. vsen2 (pin 10) connect this pin to the output of the agp linear regulator. the voltage at this pin is regulated to the level pre-determined by the logic-level status of the select pin. this pin is also monitored for under- voltage events. select (pin 11) this pin determines the output voltage of the agp bus switching regulator. a low ttl input sets the output voltage to 1.5v while a high input sets the output voltage to 3.6v. when the input voltage is 3.3v, drive2 continuously turn on providing a dc current path from the input(+3.3v in ) to output (v out2 ) of the agp controller. ss (pin 12) connect a capacitor from this pin to ground. this capacitor, along with an internal 28 a (v ss >1v) current source, sets the soft-start interval of the converter. fault (pin 13) this pin is low during normal operation, but it is pulled to 8v (v cc = 12v) in the event of an over-voltage or over-current condition. vsen4 (pin 14) connect this pin to the output of the 1.8v regulator. this pin is monitored for under-voltage events. drive4 (pin 15) connect this pin to the gate of an external moseft. this pin provides the drive for the 1.8v regulator?s pass transistor. vaux (pin 16) this pin provides boost current for the two linear regulator output drives in the event bipolar npn
RT9231A ds9231a-02 july 2001 www.richtek.com 7 transistors (instead of n-channel mosfets) are employed as pass elements. the voltage at this pin is monitored for power-on reset (por) purpose. gnd (pin 17) signal ground for the ic. all voltage levels are measured with respect to this pin. drive3 (pin 18) connect this pin to the gate of an external moseft. this pin provides the drive for the 1.5v regulator?s pass transistor. vsen3 (pin 19) connect this pin to the output of the 1.5v linear regulator. this pin is monitored for under-voltage events. fb (pin 21) this pin is connected to the pwm converter?s output voltage. vsen1 (pin 22) this pin is connected to the pwm converter?s output voltage. the pgood and ovp comparator circuits use the signal to report output voltage status and for over- voltage protection. ocset (pin 23) connect a resistor from this pin to the drain of the respective upper mosfet. this resistor, an internal 200 a current source, and the upper mosfet on- resistance set the converter over-current trip point. an over-current trip cycles t he soft-start function. the voltage at this pin is monitored for power-on reset (por) purpose and pulling this pin low with an open drain device will shut down the ic. pgnd (pin 24) this is the power ground of ugate. tie the synchronous pwm converter?s lower mosfet source to this pin. lgate (pin 25) connect lgate to the pwm converter?s lower mosfet gate. this pin provides the gate drive for the lower mosfet. phase (pin 26) connect the phase pin to the pwm converter?s upper mosfet source. this pin represents the gate drive return current path and is used to monitor the voltage drop across the upper mosfet for over-current protection. ugate (pin 27) connect ugate pin to the pwm converter?s upper mosfet gate. this pin provides the gate drive for the upper mosfet. vcc (pin 28) provide a 12v bias supply for the ic to this pin. this pin also provides the gate bias charge for all the mosfets controlled by the ic. the voltage at this pin monitored for power-on reset (por) purpose.
RT9231A www.richtek.com ds9231a-02 july 2001 8 table 1. vout1 voltage program pin name vid4 vid3 vid2 vid1 vid0 normal out1 voltage dacout 0 1 1 1 1 1.30 0 1 1 1 0 1.35 0 1 1 0 1 1.40 0 1 1 0 0 1.45 0 1 0 1 1 1.50 0 1 0 1 0 1.55 0 1 0 0 1 1.60 0 1 0 0 0 1.65 0 0 1 1 1 1.70 0 0 1 1 0 1.75 0 0 1 0 1 1.80 0 0 1 0 0 1.85 0 0 0 1 1 1.90 0 0 0 1 0 1.95 0 0 0 0 1 2.00 0 0 0 0 0 2.05 1 1 1 1 1 2.00 1 1 1 1 0 2.10 1 1 1 0 1 2.20 1 1 1 0 0 2.30 1 1 0 1 1 2.40 1 1 0 1 0 2.50 1 1 0 0 1 2.60 1 1 0 0 0 2.70 1 0 1 1 1 2.80 1 0 1 1 0 2.90 1 0 1 0 1 3.00 1 0 1 0 0 3.10 1 0 0 1 1 3.30 1 0 0 1 0 3.30 1 0 0 0 1 3.40 1 0 0 0 0 3.50
RT9231A ds9231a-02 july 2001 www.richtek.com 9 package information dimensions in millimeters dimensions in inches symbol min max min max a 17.704 18.110 0.697 0.713 b 7.391 7.595 0.291 0.299 c 2.362 2.642 0.093 0.104 d 0.330 0.508 0.013 0.020 f 1.194 1.346 0.047 0.053 h 0.229 0.330 0.009 0.013 i 0.102 0.305 0.004 0.012 j 10.008 10.643 0.394 0.419 m 0.381 1.270 0.015 0.050 m h b j b a c i fd
RT9231A www.richtek.com ds9231a-02 july 2001 10 richtek technology corp. headquarter 5f, no. 20, taiyuen street, chupei city hsinchu, taiwan, r.o.c. tel: (8863)5526789 fax: (8863)5526611 richtek technology corp. taipei office (marketing) 8f-1, no. 137, lane 235, paochiao road, hsintien city taipei county, taiwan, r.o.c. tel: (8862)89191466 fax: (8862)89191465 email: marketing@richtek.com
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