apex microtechnology corporation ? telephone (520) 690-8600 ? fax (520) 888-3329 ? orders (520) 690-8601 ? email prodlit@apexmicrotech.com 1 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ???????????????????????????????? ?????? features ? low cost ? high voltage - 100 volts ? high output current - 20 amps ? 2kw output capability ? variable switching frequency applications ? brush motor control ? mri ? magnetic bearings ? class d switchmode amplifier description the MSA240 is a surface mount constructed pwm ampli?er that provides a cost effective solution in many industrial applica - tions. the MSA240 offers outstanding performance that rivals many much more expensive hybrid components. the MSA240 is a complete pwm ampli?er including an oscillator, comparator, error ampli?er, current limit comparators, 5v reference, a smart controller and a full bridge output circuit. the switching frequency is user programmable up to 50 khz. the MSA240 is built on a thermally conductive but electrically insulating substrate that can be mounted to a heatsink. equivalent circuit diagram 58-pin dip package style kc typical application torque motor control with the addition of a few external components the MSA240 becomes a motor torque controller. in the MSA240 the source terminal of each low side mosfet driver is brought out for current sensing via r s a and r s b. a1 is a differential ampli?er that ampli?es the difference in currents of the two half bridges. this signal is fed into the internal error ampli?er that mixes the current signal and the control signal. the result is an input signal to the MSA240 that controls the torque on the motor. external connections ????? ????? ????? ????? ???? ???? ???? ???? ????? ????? ??????? ?????? ?? ??????? ??? ??? ??? ??? ?? ? ??? ?? ????????????? ??????????? ??????? ?? ?? ?? ?? ? ? ???? ??? ????????? ? ??? ? ???? ??????? ?? ???? ??????? ??????? ?? ????????????????????? ??? ?? ???? ??? ??? ?? ???? ????? ?? ?? ??????????????????????????????????????????????? ???????????????????????????????? ?????????????????????????????? ??????????????????????????????????????? ???????????????????????????? view from component side r osc r ramp + singl e poin t gn d c3 c1 c2 ?????? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ? ?? ? ? ? ? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ? ? ? ?? ? ? ??? ????? ? ????? ?? ??? ????? ? ????? ?? ??? ??? ??????? ? ??? ?? ? ??? ??????? ??? ?????? ?????? ?????? ? ??? ??????? ????????? ?????? ??????? ?? ?? ?? ?? ?? ?? ?? ??????? ? ???? ??? ?? ?? ?? ?? ?? ?? ?? ??????? ??????? ????? ??????? ??????? ?? ?? ?? ?? ?? ??? ??? ????? ????????? ??? ????????? ????? ????? ????? ?? ? ?? ?? ?????? ?? ?? ?? ? ?? ??? ??? ????? ????? ????? ????? ?????????? ??? ? ? ? ? ? ? ????? ??? ?????? ?? ??? ? ???? ??? ?? ????????? ?? ?????? ??? ??????? ?? ? ??? ?? ? ? ??? ?? ?? ? ??? ??????? ????? ? ? ?? ?? ?? ??????? ??????? ??????? ????? ?????? ??? ?? ?????? ??? ?? ? ?? ??????? ??????? ?????? ?? ?????? ?????? ?? ?? ???? ???? ????? ?? ??????? ????? ?? ?????????? ?? ?? ?? ?? ?? ?? ?????
apex microtechnology corporation ? 5980 north shannon road ? tucson, arizona 85741 ? usa ? applications hotline: 1 (800) 546-2739 2 absolute maximum ratings specifications MSA240 specifications absolute maximum ratings parameter test conditions 1 min typ max units error amplifier offset voltage full temperature range 9 mv bias current full temperature range 500 na offset current full temperature range 150 na common mode voltage range full temperature range 0 4 v slew rate full temperature range 1 v/s open loop gain r l = 2k? 96 db unity gain bandwidth 1 mhz clock low level output voltage full temperature range .2 v high level output voltage full temperature range 4.8 v rise time 7 ns fall time 7 ns bias current, pin 22 full temperature range 0.6 a 5v reference output voltage 4.85 5.15 v load current 2 ma output total r on , both mosfets 4 i o = 20a , t j = 85c 155 m? current, continuous 20 a current, peak 100ms 30 a output mosfet body diode continuous current 20 a forward voltage i = 16a 1.3 v reverse recovery i f = 16a 250 ns power supply voltage, v s 3 60 100 v voltage, v cc 14 15 16 v current, v s , quiescent 22khz switching 4 28 ma current, v cc , quiescent 22khz switching 18 ma current, v cc , shutdown 10 ma thermal resistance, dc, junction to case full temperature range 1.2 c/w resistance, junction to air full temperature range 14 c/w temperature range, case -40 85 c/w supply voltage, vs 100v supply voltage, vcc 16v output current, peak 30a, within soa power dissipation, internal, dc 250w 3 signal input voltages 5.4v temperature, pin solder, 10s 225c. temperature, junction 2 175c. temperature range, storage -40 to 105c. operating temperature, case -40 to 85c. notes: 1. unless otherwise noted: t c =25 c, v cc = 15v, v s = 60v 2. long term operation at the maximum junction temperature will result in reduced product life. derate internal power dissipation to achieve high mtbf. 3. each of the two output transistors on at any one time can dissipate 125w. 4. maximum speci?cation guaranteed but not tested.
apex microtechnology corporation ? telephone (520) 690-8600 ? fax (520) 888-3329 ? orders (520) 690-8601 ? email prodlit@apexmicrotech.com 3 typical performance graphs MSA240 ? ?? ?? ?? ?? ??? ? ?? ?? ?? ??? ??? ?????????????? ????????????????????? ??????????????????????????????? ?? ?? ?? ??? ????????????????? ??? ???? ?? ????????????????????????? ????????????????????????? ????????????? ??? ??? ? ?? ?? ?? ?? ??? ???? ???? ???? ???? ????? ????? ????????????????????????? ????????????????????? ?????????????????????????? ??? ??? ??? ??? ??? ? ? ? ?? ?? ?? ????????????????????????????? ?????????????????? ?? ???? ????????????? ? ? ??????? ? ? ?????? ? ? ? ?? ?? ?? ? ? ? ? ? ? ??????????????????? ??????????????????????? ?????????????????? ? ? ?????? ? ? ?????? ? ?? ?? ?? ??? ? ? ?? ?? ?? ?? ????????????????? ??????????????? ????????????????????? ??? ??? ??? ??? ??? ? ?? ?? ?? ?? ??? ??????????????????????????? ??????????????? ????????????????? ????? ????? ? ?? ?? ?? ?? ?? ? ? ?? ?? ?? ?? ? ?? ?????????????????? ? ?? ???????????????????????? ???????????????????????????? ?????????????? ??? ??? ? ?? ?? ?? ?? ??? ?? ?? ?? ??? ??? ??? ? ?? ?????????????????? ????????????????????????????????? ????????????????????? ?????????????????? ????????? ? ?? ?? ?? ?? ??? ? ? ? ? ? ? ? ?????????????????? ? ? ????? ?????????? ?????????????? ? ? ???????????????????????? ? ?? ?? ?? ?? ?? ? ? ? ? ? ? ? ???????????????????????????????? ? ? ????????????????????? ? ????? ???????????????????????????? ? ? ??????? ??????????????
apex microtechnology corporation ? 5980 north shannon road ? tucson, arizona 85741 ? usa ? applications hotline: 1 (800) 546-2739 4 operating considerations MSA240 this data sheet has been carefully checked and is believed to be reliable, however, no responsibility is assumed for possible inaccuracies or omissions. all speci?cations are subject to change without notice. MSA240u rev c july 2004 ? 2004 apex microtechnology corp. general please read application note 30 pwm basics. refer also to application note 1 general operating considerations for helpful information regarding power supplies, heat sinking, mounting, soa interpretation, and speci?cation interpreta - tion. visit www.apexmicrotech.com for design tools that help automate tasks such as calculations for stability, internal power dissipation, current limit, heat sink selection, apexs complete application notes library, technical seminar workbook and evaluation kits. oscillator the MSA240 includes a user frequency programmable oscillator. the oscillator determines the switching frequency of the ampli?er. the switching frequency of the ampli?er is 1/2 the oscillator frequency. two resistor values must be chosen to properly program the switching frequency of the ampli?er. one resistor, r osc , sets the oscillator frequency. the other resistor, r ramp , sets the internal ramp amplitude. in all cases the ramp voltage will oscillate between 1.5v and 3.5v. see figure 1. if an external oscillator is applied use the equations to calculate r ramp . to program the oscillator, r osc is given by: r osc = (1.32x10 8 / f) - 2680 where f is the desired switching frequency and: r ramp = 2 x r osc use 1% resistors with 100ppm drift (rn55c type resistors, for example). maximum switching frequency is 50khz. example: if the desired switching frequency is 22khz then r osc = 3.32k and r ramp = 6.64k. choose the closest standard 1% values: r osc = 3.32k and r ramp = 6.65k. figure 1. external oscillator connections shutdown the MSA240 output stage can be turned off with a shutdown command voltage applied to pin 10 as shown in figure 2. the shutdown signal is ored with the current limit signal and simply overrides it. as long as the shutdown signal remains high the output will be off. current sensing the low side drive transistors of the MSA240 are brought out for sensing the current in each half bridge. a resistor from each sense line to pwr gnd (pin 58) develops the current sense voltage. choose r and c such that the time constant is equal to 10 periods of the selected switching frequency. the internal current limit comparators trip at 200mv. therefore, current limit occurs at i = 0.2/r sense for each half bridge. see figure 2. accurate milliohm power resistors are required and there are several sources for these listed in the accessories vendors section of the databook. figure 2. current limit with optional shutdown power supply bypassing bypass capacitors to power supply terminals +v s must be connected physically close to the pins to prevent local parasitic oscillation and overshoot. all +v s pins must be con - nected together. place an electrolytic capacitor of at least 10f per output amp required midpoint between these sets of pins. in addition place a ceramic capacitor 1f or greater directly at each set of pins for high frequency bypassing. v cc is bypassed internally. grounding and pcb layout switching ampli?ers combine millivolt level analog signals and large amplitude switching voltages and currents with fast rise times. as such grounding is crucial. use a single point ground at sig gnd (pin 26). connect signal ground pins 2 and 18 directly to the single point ground on pin 26. connect the digital return pin 23 directly to pin 26 as well. connect pwr gnd pin 58 also to pin 26. connect ac backplate pin 28 also to the single point ground at pin 26. connect the ground terminal of the v cc supply directly to pin 26 as well. make sure no current from the load return to pwr gnd ?ows in the analog signal ground. make sure that the power portion of the pcb layout does not pass over low-level analog signal traces on the opposite side of the pcb. capacitive coupling through the pcb may inject switching voltages into the analog signal path. further, make sure that the power side of the pcb layout does not come close to the analog signal side. fast rising output signal can couple through the trace-to-trace capacitance on the same side of the pcb. determining the output state the input signal is applied to +in (pin 13) and varies from 1.5 to 3.5 volts, zero to full scale. as +in varies from 1.5 to 2.5 volts the a output "high" duty cycle (relative to ground) is greater than the b output "high" duty cycle. the reverse occurs as the input signal varies from 2.5 to 3.5 volts. when +in = 2.5 volts the duty cycles of both a and b outputs are 50%. consequently, when the input voltage is 1.5v the a output is close to 100% duty cycle and the b output is close to 0% duty cycle. the reverse occurs with an input voltage of 3.5v. the output duty cycle extremes vary somewhat with switching frequency and are internally limited to approximately 5% to 95% at 10khz and 7% to 93% at 50khz. ???????? 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