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microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 1 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products description the lx1673 is a highly integrated power supply controller ic featuring one pwm switching regulator stage with an additional onboard linear regulator driver. with several switching frequencies available (up to 900khz) the lx1673 can be optimized for both cost and pcb space. utilizing external compensation, a wide selection of external components can be chosen for use in any application while maintaining stable operation. the lx1673 incorporates fully programmable soft-start and power sequence capabilities. the ldo and pwm have independent enable pins. with onboard gate drivers, the switching pwm output is capable of sourcing up to 15a. the lx1673 also features an additional linear regulator controller output, which when coupled with an inexpensive mosfet is capable of supplying up to an additional 5a for i/o, memory, and other supplies surrounding today?s micro-processor designs. each regulator output voltage is programmed via a simple voltage-divider network. integrated hiccup-mode current limiting is implemented utilizing mosfet r ds(on) impedance. this enables the lx1673 to monitor maximum current limit conditions without the use of expensive current sense resistors. important: for the most current data, consult microsemi ?s website: http://www.microsemi.com key features ? two independently regulated outputs ? outputs as low as 0.8v generated from an internal 1% reference ? integrated high current mosfet drivers ? 300khz, 600khz, and 900khz high frequency operation minimizes external component requirements ? soft-start and power sequencing control ? adjustable linear regulator driver output ? no current-sense resistors applicati ons/benefits ? video card power supplies ? pc peripherals ? computer add-on cards ? 3.3v power conversion ? ddr memory termination product highlight lx1673 ldgd ldfb lddis dgnd agnd ldvcc pwgd vc1 tdrv pgnd bdrv vccl vcc vs cs eao ea- ea+ ss dis v out2 +3.3v lddis dis pwrgd v out1 +5v +12v +5v +5v +3.3v 1 2 3 4 5 678910 11 12 13 14 15 16 17 18 19 20 package order info t a ( c) switching frequency (khz) pw plastic tssop 20-pin lq plastic mlpq 20-pin -40 to 85 300 lx1673-03cpw lx1673-03clq -40 to 85 600 lx1673-06cpw lx1673-06clq -40 to 85 900 lx1673-09cpw LX1673-09CLQ l l x x 1 1 6 6 7 7 3 3
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 2 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products absolute maximum ratings supply voltage (v cc ) dc ................................................................-0.3v to 5.5v supply voltage (v cc ) transient .........................................................-0.3v to 6v driver supply voltage (v c1 , vc cl, ldvcc ) dc ..................................-0.3v to 16v driver supply voltage (v c1 ) transient............................................. -0.3v to 19v input voltage (ss/ dis ) .....................................................................-0.3v to 5.5v output drive peak current source (ho, lo).......................................1a (500ns) output drive peak current sink (ho, lo) ..........................................1a (500ns) operating temperat ure range .........................................................-40 c to 85 c maximum operating junc tion temperat ure ................................................ 150 c storage temperat ure range...........................................................-65 c to 150 c lead temperature (soldering 180 seconds) ................................................ 235 c note: exceeding these ratings could cause damage to the device. all voltages are with respect to ground. currents are positive into, negative out of specified terminal . the limitation on transient time is thermal and is due to zener diodes on the supply pins, application of maximum volta ges will increase current into that pin and increase package power dissipation.. thermal data pw plastic tssop 20-pin thermal resistance - junction to a mbient , ja 90 c/w lq plastic mlpq 20-pin thermal resistance - junction to a mbient , ja 35c/w junction temperature calculation: t j = t a + (p d x jc ). the ja numbers are guidelines for the th ermal performance of the device/pc- b oard system. all of the above assume no airflow. package pin out ldgd ldfb lddis dgnd agnd cs vs vcc vccl bdrv pgnd tdrv vc1 pwgd ldvcc eao ea- ea+ ss dis 1 6 11 16 lq p ackage (top view) n.c. ? no internal connection n/u ? not used rsvd ? do not use vc1 pwgd ldvcc ldgd ldfb lddis dgnd agnd eao cs vs vcc vccl bdrv pgnd tdrv 1 10 11 20 dis ss ea+ ea- pw p ackage (top view) p p a a c c k k a a g g e e d d a a t t a a
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 3 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products functional pin description n ame d escription ea- voltage feedback ? output voltage is connected through a resistor network to this pin for feedback to set the desired output voltage of the switching pwm output. eao error amplifier output ? sets error amplif ier gain and external compensation if used. ea+ voltage reference ? connect to the ss pin or any other ex ternal voltage. used in conjunction with ea-, and an external resistor divider, to set the desired output voltage for the pwm output. vcc ic supply voltage (nominal 5v). vccl power supply pin for low side drivers. ldfb low dropout regulator voltage feedback ? sets output voltage of external mosfet via resistor network. cs over-current limit set ? connecting a resistor between cs pin and the source of the high-side mosfet sets the current-limit threshold for the pwm output. a minimum of 1k ? must be in series with this pin. ss pwm soft-start/hiccup capacitor pin ? du ring start-up, the voltage on this pi n controls the output voltage of the switching regulator. an internal 20k ? resistor and the external capacitor set the time constant for soft-start function. the soft-start function does not initialize until the supply voltage on v cc exceeds the uvlo threshold. when an over-current condition occurs, this capacitor is used for the timing of hiccup mode protection. agnd analog ground reference. dgnd digital ground reference. ldgd low dropout regulator gate drive ? connect to gate of external n-channel mosfet for linear regulator function. pgnd mosfet driver power ground. connects to the source of the bottom n-channel mosfets of the switching regulator. tdrv high side mosfet gate driver bdrv low side mosfet gate driver vc1 high-side mosfet gate driver supply ? connect to sepa rate supply or boot strap supply to ensure proper high- side gate driver supply voltage. lddis ldo disable input ? high disables ldo output. this pin has a 100k ? pulldown resistor. vs voltage reference for short circuit current sense. this pin is also the supply pin for the current sense comparator. this pin cannot be left floating, if current limit is not used connect to vcc. pwgd power good output ? open drain output , goes high at end of soft start and no fault. pulls low if any fault condition occurs. ldvcc ldo vcc supply ? connect to voltage supply greater than supply rail for ldo mosfet drain. dis pwm disable input ?high disables the pwm output. this pin has a 80k ? pulldown resistor. p p a a c c k k a a g g e e d d a a t t a a
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 4 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products electrical characteristics unless otherwise specified, the following specificati ons apply over the operat ing ambient temperature 0 c t a 70 c except where otherwise noted and the following test conditions: v cc = 5v, v ccl = 5v, v c1 =12v, ldvcc=12v tdrv=bdrv=3000pf load. lx1673 parameter symbol test conditions min typ max units ` switching regulators v cc 4.5 5.5 v input voltage v ccl ,v c1 16 operation current i cc static and dynamic 6 ma ldo operating current i ldvcc 1 ma t a =25 c 0.792 0.8v 0.808 v reference voltage v ss 0 c t a 70 c 0.784 0.816 v line regulation note 1 -1 1 % load regulation note 1 -1 1 dead time 3000pf load 2 volt level 160 ns minimum pulse width all frequencies 150 ns maximum duty cycle lx1673-03 load = 3000 pf 85 % maximum duty cycle lx1673-06 load = 3000pf 75 % maximum duty cycle lx1673-09 load = 3000 pf 70 % ` error amplifiers input offset voltage vos common mode voltege = 1v -6.0 6.0 mv dc open loop gain 70 db unity gain bandwidth ugbw 16 mhz high output voltage v oh i source = 2ma 3.8 5.0 v low output voltage v ol i sink = 10ua 100 mv input common mode voltage range input offset voltage < 20mv 0.1 3.5 v input bias current 0 and 3.5 v common mode voltage 100 na ` current sense current sense bias current i set v cs = v vs ? 0.3v , v vs = 5v 45 50 55 a trip threshold v trip referenced to vs , v vs = 5v 260 300 340 mv current sense delay t csd 350 ns current sense comparator operating current i cs current into vs pin 2 5 ma ` output drivers ? n-channel mosfets low side driver operating current i vccl static 2.5 ma high side driver operating current i vc1 static 3 ma drive rise time, fall time t rf c l = 3000pf 50 ns high level voltage v dh i source = 20ma, v ccl = 12v 10 11 v low level voltage v dl i sink = 20ma, v ccl = 12v 0.15 0.25 v ` oscillator lx1673-03 255 300 345 lx1673-06 510 600 690 pwm switching frequency f sw lx1673-09 765 900 1035 khz ramp amplitude v ramp 1.25 v pp e e l l e e c c t t r r i i c c a a l l s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 5 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products electrical characteristics unless otherwise specified, the following specificati ons apply over the operat ing ambient temperature 0 c t a 70 c except where otherwise noted and the following test conditions: v cc = 5v, v ccl = 5v, vc1=12v, ldvcc=12v lx1673 parameter symbol test condition min typ max units ` uvlo and soft-start (ss) start-up threshold (v c1 , v ccl, ld vcc ) 3.5 4.0 4.5 v start-up threshold (v cc ) 4.0 4.25 4.5 v hysteresis v cc 0.1 v ss input resistance r ss 20 k ? ss shutdown threshold v shdn 0.1 v hiccup mode duty cycle c ss = 0.1 f 10 % ` linear regulator controller voltage referencetolerance v ldfb = .8v, c out = 330f 2 % source current i hdrv vout = 10v 30 ma sink current i ldrv vout = 0.4v 0.2 ma ` disable inputs threshold 1 v pwm disable dis internal pulldown resistance 80 k ? threshold 2.5 v ldo disable lddis internal pulldown resistance 100 k ? power good drain to source voltage i = 3ma 0.4 v leakage 0.05 ua note 1- system specification note 2 ? low duty cycle pulse testing techniques are used whic h maintain junction and case temperatures equal to the ambient temperature note 3 ? functionality over the ?40 to 85 deg c operating temper ature range is assured by design, characterization, and stati stical process control e e l l e e c c t t r r i i c c a a l l s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 6 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products block diagram cs comp + - amplifier/ compensation + - comp + - i reset r s q q v trip 20k v ref hiccup ramp oscillator uvlo l1 esr c out c in +5v v out 1 r set vcc bdrv tdrv vc1 cs ea- ss i set pwm i set +5v eao vs vccl pgnd uvlo ea+ fault temp f r s s s css 5.5v 16v 16v ss1 dis vin (5v) ldvcc pwgd figure 1 ? block diagram of pwm phase + - +5v +v v ref +12v ldgd ldfb lddis ldvcc vout 2 16v figure 2 ? ldo controller block diagram
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 7 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products application schematic lx1673 ldgd ldfb lddis dgnd agnd ldvcc pwgd vc1 tdrv pgnd bdrv vccl vcc vs cs eao ea- ea+ ss dis 1 2 3 4 5 678910 11 12 13 14 15 16 17 18 19 20 +12 +5 +5 +5 +3.3 +5 pwm vout ldo vout lddis dis pwrgd figure 3 ? schematic with bootstrap supply for pwm high side drive lx1673 ldgd ldfb lddis dgnd agnd ldvcc pwgd vc1 tdrv pgnd bdrv vccl vcc vs cs eao ea- ea+ ss dis 1 2 3 4 5 678910 11 12 13 14 15 16 17 18 19 20 +5 +5 +5 +5 pwm vout ldo vout lddis dis pwrgd pwm vout figure 4 ? schematic for 5 volt only input a a p p p p l l i i c c a a t t i i o o n n s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 8 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products theory of operation g eneral d escription the lx1673 is a voltage-mode pulse-width modulation controller integrated circuit. the internal oscillator and ramp generator frequency is fixed to 300khz, 600khz, or 900khz. the device has external compensation, for more flexibility of output current magnitude. u nder v oltage l ockout (uvlo) at power up, the lx1673 monito rs the supply voltage for vcc, vccl, ldvcc and vc1 (the re is no requirement for sequencing the supplies). before all supplies reach their under- voltage lock-out (uvlo) thresholds, the soft-start (ss) pin is held low to prevent soft-start fr om beginning, the oscillator is disabled and all mosfets are held off. there is an internal delay that will filter out transients less that 1.5usec. s oft -s tart once the supplies are above the uvlo threshold, the soft-start capacitor begins to be charged by the reference through a 20k ? internal resistor. the capacitor voltage at the ss pin rises as a simple rc circuit. the ss pin is connected to the error amplifier?s non-inverting input that controls the output voltage. the output voltage will follow the ss pin voltage if sufficient charging current is provided to the output capacitor. the simple rc soft-start allows the output to rise faster at the beginning and slower at the end of the soft-start interval. thus, the required charging current into the output capacitor is less at the end of the soft-start interval. a comparator monitors the ss pin voltage and indicates the e nd of soft-start when ss pin voltage reaches 95% of v ref . o ver -c urrent p rotection (ocp) and h iccup the lx1673 uses the r ds(on) of the upper mosfet, together with a resistor (r set ) to set the actual current limit point. the current sense comparator senses the mosfet current 350ns after the top mosfet is switched on in order to reduce inaccuracies due to ringing. a current source supplies a current (i set ), whose magnitude is 50a. the set resistor r set is selected to set the current limit for the application. r set and vs should be connected directly at the upper mosfet drain and source to get an accurate measurement across the low resistance r ds(on) . when the sensed voltage across r ds(on) plus the set resistor exceeds the 300mv, v trip threshold, the ocp comparator outputs a signal to reset the pwm latch and to start hiccup mode. the soft-start capacitor (c ss ) is discharged slowly (10 times slower than when being charged up by r ss ). when the voltage on the ss pin reaches a 0.1v threshold, hiccup finishes and the circuit soft- starts again. during hiccup both mosfets are held off. hiccup is disabled during the soft-start interval, allowing the circuit to start up with maximum current. if the rate of rise of the output voltage is too fast, the required charging current to the output capacitor may be higher than the limit-current. in this case, the peak mosfet current is regulated to the limit-current by the current-sense comparator. if the mosfet current still reaches its limit after the soft-start finishes, the hiccup is triggered again. when the output has a short circuit the hiccup circuit ensures that the average heat generation in both mosfets and the average current is much less than in normal operation,. over-current protection can also be implemented using a sense resistor, instead of using the r ds(on) of the upper mosfet, for greater set-point accuracy. o scillator f requency an internal oscillator sets th e switching frequency at 300khz, 600khz, or 900khz. a a p p p p l l i i c c a a t t i i o o n n s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 9 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products application note o utput i nductor the output inductor should be selected to meet the requirements of the output voltage ripple in steady-state operation and the inductor current slew-rate during transient. the peak-to- peak output voltage ripple is: ripple ripple i esr v = where s d l v v ? i out in f ? = ? i is the inductor ripple current, l is the output inductor value and esr is the effective series resistance of the output capacitor. ? i should typically be in the range of 20% to 40% of the maximum output current. higher inductance results in lower output voltage ripple, allowing slightly higher esr to satisfy the transient specification. higher inductance also slows the inductor current slew rate in response to the load-current step change, ? i, resulting in more output-capacitor voltage droop. when using electrolytic capacitors, the cap acitor voltage droop is usually negligible, due to the large capacitance the inductor-current rise and fall times are: () out in rise v v ? i l t ? = and out fall v ? i l t = . the inductance value ca n be calculated by s d ? i v v l out in f ? = o utput c apacitor the output capacitor is sized to meet ripple and transient performance specifications. effective series resistance (esr) is a critical parameter. when a step load current occurs, the output voltage will have a step that equals the product of the esr and the current step, ? i. in an advanced microprocessor power supply, the output capacitor is usua lly selected for esr instead of capacitance or rms current capability. a capacitor that satisfies the esr requirements usually has a larger capacitance and current capability than strictly needed. the allowed esr can be found by: ( ) ex ripple v ? i i esr < + where i ripple is the inductor ripple current, ? i is the maximum load current step change, and v ex is the allowed output voltage excursion in the transient. electrolytic capacitors can be us ed for the output capacitor, but are less stable with age than tantalum capacitors. as they age, their esr degrades, reducing the system performance and increasing the risk of failure. it is recommended that multiple parallel capacitors be used, so that, as esr increase with age, overall performance will still meet the processor?s requirements. there is frequently strong pressu re to use the least expensive components possible, however, this could lead to degraded long- term reliability, especially in the case of filter capacitors. microsemi?s demonstration boards use the cde polymer al-el (esre) filter capacitors, which are aluminum electrolytic, and have demonstrated reliability. the os-con series from sanyo generally provides the very best performance in terms of long term esr stability and general reliability, but at a substantial cost penalty. the cde polymer al-el (esre) filter series provides excellent esr performance at a reasonable cost. beware of off- brand, very low-cost filter capa citors, which have been shown to degrade in both esr and general electrolytic characteristics over time. i nput c apacitor the input capacitor and the input i nductor, if used, are to filter the pulsating current generated by the buck converter to reduce interference to other circuits connected to the same 5v rail. in addition, the input capacitor provides local de-coupling for the buck converter. the capacitor should be rated to handle the rms current requirements. the rms current is: d) d(1 i i l rms ? = where i l is the inductor current and d is the duty cycle. the maximum value occurs when d = 50%, then i rms =0.5i l . for a 5v input and output voltages in the range of 2 to 3v, the required rms current is very close to 0.5i l . s oft -s tart c apacitor the value of the soft-start capacitor determines how fast the output voltage rises and how large the inductor current is required to charge the output capacitor. the output voltage will follow the voltage at the ss pin if the required inductor current does not exceed the maximum allowable current for the inductor. a a p p p p l l i i c c a a t t i i o o n n s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 10 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products application note (continued) the ss pin voltage can be expressed as: ( ) ? ? = ref where r ss and c ss are the soft-start resistor and capacitor. the current required to charge the output capacitor during the soft start interval is. dt dvss cout iout = taking the derivative with respect to time results in ss ss c t/r e rsscss vrefcout iout ? = and at t=0 rsscss vrefcout ax im = the required inductor current for the output capacitor to follow the soft start voltage equals the required capacitor current plus the load current. the soft-start ca pacitor should be selected to provide the desired power on sequencing and insure that the overall inductor current does not exceed its maximum allowable rating. values of css equal to .1uf or greater are unlikely to result in saturation of the output induct or unless very large output capacitors are used. o ver -c urrent p rotection current limiting occurs at current level i cl when the voltage detected by the current sense comparator is greater than the current sense comparator threshold, v trip (300mv). trip set set ds(on) cl v r i r i = + so, a 50 r i mv 00 3 i r i v r ds(on) cl set ds(on) cl trip set ? = ? = example: for 10a current limit, us ing fds6670a mosfet (10m ? r ds(on) ): ? k 4 10 50 10 0.0 10 3 0. r 6 set = ? = ? note: maximum r set is 6k ? . any resistor 6k ? or greater will not allow startup since i cl will equal zero (50ua x 6k ? =300mv). at higher pwm frequencies or low duty cycles where the upper gate drive is less than 350ns wi de the 350ns delay for current limit enable may result in current pulses exceeding the desired current limit set point. if the upper mosfet on time is less than 350ns and a short circuit conditi on occurs the duty cycle will increase, since vout will be forced low. the current limit circuit will be enabled when the upper gate drive exceeds 350ns although the actual peak current limit value will be higher than calculated with the above equation. short circuit protection still exis ts due to the narrow pulse width even though the magnitude of the cu rrent pulses will be higher than the calculated value. if ocp is not desired connect bo th vsx and vcx to vcc. do not leave them floating. o utput d isable the lx1673 pwm mosfet driver outputs are shut off by pulling the disable (dis) pin above 1.2v. there is a 80k ? pulldown resistor on this input. the ldo voltage regulator has it s own disable pin (lddis) for control of this output voltage. pull ing this pin above 3 v disables the ldo. there is a 100k ? pulldown resistor on this input. p rogramming t he o utput v oltage the output voltage is sensed by the feedback pin (fb x ) which is compared to a 0.8v reference. th e output voltage can be set to any voltage above 0.8v (and lower than the input voltage) by means of a resistor divider (see figure 1). ) /r r (1 v v 2 1 ref out + = note: this equation is simplified and does not account for error amplifier input current. keep r 1 and r 2 close to 1k (order of magnitude). ddr v tt t ermination v oltage double data rate (ddr) sd ram requires a termination voltage (v tt ) in addition to the line driver supply voltage (vddq) and receiver supply voltage (vdd). v tt for ddr memory can be generated with the lx1673 by using the positive input of the pha se 2 error amplifier rf2 as a reference input from an external reference voltage v ref which is defined as one half of vddq. using v ref as the reference input will insure that all voltages are correct and track each other as specified in the jedec (eia/jesd8-9a) specification. the phase 2 output will then be equal to v ref and track the vddq supply as required. when an external reference is used the connection between the error amplifier positive input and the soft start pin is lost and soft start will not function. it is recommended that the external reference voltage have an r-c ti me constant that will be long enough to allow the output capacitor to charge slowly. see microsemi application note 17 for more details a a p p p p l l i i c c a a t t i i o o n n s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 11 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products application note considerations 1. the minimum rset resistor value is 1k ohm for the current limit sensing. if this resistor becomes shorted, it will do permanent damage to the ic. 2. a resistor has been put in seri es with the gate of the ldo pass transistor to reduce the output noise level. the resistor value can be changed to optimize the output transient response versus output noise. 3. to delay the turn on of the ldo controller output, a capacitor should be connected between the lddis pin and the +5volts. the lddis input has a 100k pull down resistor, which keeps the ldo active until this pin is pulled high. during the power up seque nce the capacitor connected to the lddis pin will keep the ldo off until this capacitor, being charge by the 100k pull down resistor, goes through the low input threshold level. 4. . if current limit is not used connect the vs and vc pins together and to vcc. do not le ave them floating. a floating vs pin will result in operation resembling a hiccup condition. a a p p p p l l i i c c a a t t i i o o n n s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 12 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products package dimensions lq 20-pin micro leadframe package (mlpq) package e a e b e2 d2 l d a3 a1 m illimeters i nches dim min max min max a 0.80 1.00 0.031 0.039 a1 0 0.05 0 0.002 a3 0.25 ref 0.010 b 0.23 0.38 0.009 0.015 d 5.00 bsc 0.197 d2 1.25 3.25 0.050 0.128 e 5.00 bsc 0.197 e2 1.25 3.25 0.050 0.128 e 0.65 bsc 0.026 l 0.35 0.75 0.014 0.030 note: dimensions do not include mold flash or protrusions; these shall not exceed 0.155m m(0.006?) on any side. lead dimension shall not include solder coverage. pw 20-pin thin small shrink outline (tssop) c 1 2 3 p d e f a g h l b m seating plane m illimeters i nches dim min max min max a 0.80 1.05 0.032 0.041 b 0.19 0.30 0.007 0.012 c 0.09 0.180 0.0035 0.0071 d 6.40 6.60 0.252 0.260 e 4.30 4.48 0.169 0.176 f 0.65 bsc 0.025 bsc g 0.05 0.15 0.002 0.005 h ? 1.10 ? 0.0433 l 0.50 0.70 0.020 0.028 m 0 8 0 8 p 6.25 6.50 0.246 0.256 *lc ? 0.10 ? 0.004 solder coverage. m m e e c c h h a a n n i i c c a a l l s s
microsemi linfinity microelectronics division 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 13 copyright ? 2000 rev 0.4, 2003-02-06 www. microsemi . com lx1673 hi g h frequenc y pwm re g ulator p reliminary d ata s heet integrated products notes product preliminary data ? information contained in this document is pre-production data, and is proprietary to linfinity. it may not be modified in any way without the express written consent of linfinity. product referred to herein is not guaranteed to achieve preliminary or production status and product specifications, configurations, and availability may change at any time. n n o o t t e e s s

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