set your site on vicor at www.vicorpower.com preliminary vicor corp. tel: 800-735-6200, 978-470-2900 fax: 978-475-6715 microram rev. 1.1 page 1 of 8 features ? >40db ripple attenuation from 60hz to 1mhz ? integrated or?ng diode supports n+1 redundancy ? significantly improves load transient response ? efficiency up to 98% ? user selectable performance optimization ? combined active and passive filtering ? 3-30vdc input range ? 20 and 30 ampere ratings product highlights vicor? microram output ripple attenuation module combines both active and passive filtering to achieve greater than 40db of noise attenuation from 60hz to 1mhz. the microram operates over a range of 3 to 30vdc, is available in either 20 or 30a models and is compatible with most manufacturers switching converters including vicor? 1st and 2nd generation dc-dc converters. the microram? closed loop architecture greatly improves load transient response and with dual mode control, insures precise point of load voltage regulation, the microram supports redundant and parallel operation with its integrated or?ng diode function. it is available in vicor? standard micro package (quarter brick) with a variety of terminations for through hole, socket or surface mount applications. data sheet microram tm output ripple attenuation module 4 5 shown actual size: 2.28 x 1.45 x 0.5 in 57,9 x 36,8 x 12,7 mm absolute maximum ratings thermal resistance parameter typ unit baseplate to sink; flat, greased surface 0.16 ?/watt baseplate to sink; with thermal pad (p/n 20264) 0.14 ?/watt baseplate to ambient 8.0 ?/watt baseplate to ambient; 1000 lfm 1.9 ?/watt uram 2 c 2 1 product baseplate 1 = slotted 2 = threaded 3 = thru-hole pin style* 1 = short pin 2 = long pin s = short modumate n = long modumate product grade c = ?0? to +100? t = ?0? to +100? h = ?0? to +100? m = ?5? to +100? type 2= 20a 3= 30a part numbering *pin styles s & n are compatible with the modumate interconnect system for socketing and surface mounting. patents pending parameter rating unit notes +in to ?n 30 vdc continuous +in to ?n 40 vdc 100ms load current 40 adc continuous ripple input (vp-p) 100 mv 60hzc100 khz ripple input (vp-p) 500 mv 100khz 2mhz mounting torque 4-6 (0.45-0.68) in. lbs (nm) 6 each, 4-40 screw pin soldering temperature 500 (260) ? (?) 5 sec; wave solder pin soldering temperature 750 (390) ? (?) 7 sec; wave solder storage temperature (c, t-grade) -40 to +125 c storage temperature (h-grade) -55 to +125 c storage temperature (m-grade) -65 to +125 c operating temperature (c-grade) -20 to +100 c baseplate operating temperature (t, h-grade) -40 to +100 c baseplate operating temperature (m-grade) -55 to +100 c baseplate
vicor corp. tel: 800-735-6200, 978-470-2900 fax: 978-475-6715 microram data sheet rev. 1.1 page 2 of 8 set your site on vicor at www.vicorpower.com preliminary parameter min typ max unit notes operating current range no internal current limiting. converter input must be ?am2xxx 0.02 20 a properly fused such that the ?am output current ?am3xxx 0.02 30 a does not exceed the maximum operating current rating by more than 30% under a steady state condition. operating input voltage 3.0 30 vdc continuous transient output response 50 mvp-p step load change; load current step <1a/?ec see figures 9, 12, & 15, pp. 6-7 transient output response optional capacitance c tran can be used load current step <1a/?ec 50 mvp-p to increase transient current capability; see figures (c tran = 820?) 1 & 2 on p. 3 and figures 10, 13, & 16 on pp. 6-7 v hr headroom voltage range (1) see figures 5, 6 & 7 @ 1a load 325 425 mv see table 1 for headroom setting resistor values output ripple 10 mvp-p ripple frequency 60hz to 100khz; optional capacitor input vp-p = 100mv 5 mvrms c hr = 100? required to increase low frequency attenuation as shown in figures 3a and 3b see figures 8, 11, & 14, pp. 6-7 output ripple 10 mvp-p ripple frequency 100khz to 2mhz; input vp-p = 500mv 5 mvrms see figures 8, 11, & 14, pp. 6-7 sc output voltage (2) 1.23 vdc see table 1 r sc value or?ng threshold 10 mv vin ?vout ?am bias current 60 ma power dissipation ?am2xxx v hr = 380mv@1a 7.5 w vin = 28v; iout = 20a ?am3xxx v hr = 380mv@1a 11.5 w vin = 28v; iout = 30a ram module specifications (-20? to +100? baseplate temperature) electrical characteristics electrical characteristics apply over the full operating range of input voltage, output power and baseplate temperature, unless otherwise specified. all temperatures refer to the operating temperature at the center of the baseplate. (1) headroom is the voltage difference between the +input and +output pins. r hr = (?am +out/v hr ) x 2.3k (see table 1 for example values) (2) sc resistor is required to trim the converter output up to accommodate the headroom of the ?am module when remote sense is not used. this feature can only be used when the trim reference of the converter is in the 1.21 to 1.25 volt range. (see table 1 with calculated r sc resistor values) r sc = ((?am +out)/1.23v x 1k) ?2k ram out 3.0v 5.0v 12.0v 15.0v 24.0v 28.0v v hr @ 1a 375mv 375mv 375mv 375mv 375mv 375mv r hr value (ohms) 18.4k 30.6k 73.6k 92.0k 147.2k 171.7k r sc value (ohms) 0.439k 2.07k 7.76k 10.20k 17.50k 20.76k table 1 ? hr and r sc are computed values for a 375mv case. to compute different headroom voltages, or for standard resistor values and tolerances, use notes 1 and 2.
set your site on vicor at www.vicorpower.com preliminary vicor corp. tel: 800-735-6200, 978-470-2900 fax: 978-475-6715 microram rev. 1.1 page 3 of 8 electrical characteristics (continued) application schematic drawings using vicor converters and the ram dc-dc converter ram +out v ref ?ut +in sc c tran ?n +out +s sc ? ?ut +in pc pr ?n (2) r sense 5.1 22 f c tran * * optional component r hr c hr * figure 1 ?ypical configuration using remote sensing dc-dc converter +out sc ?ut +in pc pr ?n ram +out v ref ?ut +in sc c tran ?n r sc r hr c tran * c hr * * optional component figure 2 ?ypical configuration using sc control (oppional c hr 25 f maximum in sc configuration.) functional description the microram has an internal passive filter that effectively attenuates ripple in the 50khz to 1mhz range. an active filter provides attenuation from low frequency up to the 1mhz range. the user must set the headroom voltage of the active block with the external r hr resistor to optimize performance. the microram must be connected as shown in figures 1 or 2 depending on the load sensing method. the transient load current performance can be increased by the addition of optional c tran capacitance to the c tran pin. the low frequency ripple attenuation can be increased by addition of optional c hr capacitance to the v ref pin as shown in figures 3a and 3b, on p. 5. t ransient load current is supplied by the internal c tran capacitance, plus optional external capacitance, during the time it takes the converter loop to respond to the increase in load. the microram s active loop responds in roughly one microsecond to output voltage perturbations. there are limitations to the magnitude and the rate of change of the transient current that the microram can sustain while the converter responds. see figures 8-16, on pp. 6 and 7, for examples of dynamic performance. a larger headroom voltage setting will provide increased transient performance, ripple attenuation and power dissipation while reducing overall efficiency (see figures 4a, 4b, 4c and 4d on p. 5).
vicor corp. tel: 800-735-6200, 978-470-2900 fax: 978-475-6715 microram data sheet rev. 1.1 page 4 of 8 set your site on vicor at www.vicorpower.com preliminary functional description (continued) the active loop senses the output current and reduces the headroom voltage in a linear fashion to approximate constant power dissipation of microram with increasing loads (see figures 5, 6 & 7, p. 6). the headroom setting can be reduced to decrease power dissipation where the transient requirement is low and efficient ripple attenuation is the primary performance concern. the active dynamic headroom range is limited on the low end by the initial headroom setting and the maximum expected load. if the maximum load in the application is 10 amps, for example, the 1 amp headroom can be set 75mv lower to conserve power and still have active headroom at the maximum load current of 10 amps. the high end or maximum headroom range is limited by the internal or?ng diode function. the sc or trim-up function can be used when remote sensing is not available on the source converter or is not desirable. it is specifically designed for converters with a 1.23 volt reference and a 1k ohm input impedance like v icor 2nd generation converters. in comparison to remote sensing, the sc configuration will have an error in the load voltage versus load current. it will be proportional to the output current and the resistance of the load path from the output of the microram to the load. the or?ng feature prevents current flowing from the output of the microram back through it s input terminal in a redundant system configuration in the event that a converter output fails. when the converter output supplying the microram droops below the or?d output voltage potential of the redundant system, the input of the microram is isolated from it s output. less than 50ma will flow out of the input terminal of the microram over the full range of input voltage under this condition. application notes load capacitance can affect the overall phase margin of the microram active loop as well as the phase margin of the converter loop. the distributed variables such as inductance of the load path, the capacitor type and value as well as its esr and esl also affect transient capability at the load. the following guidelines should be considered when point of load capacitance is used with the microram in order to maintain a minimum of 30 degrees of phase margin. 1) using ceramic load capacitance with <1milliohm esr and <1nh esl: (a) 20 f to 200 f requires 20nh of trace/wire load path inductance (b) 200 f to 1,000 f requires 60nh of trace/wire load path inductance 2) for the case where load capacitance is connected directly to the output of the microram, i.e. no trace inductance, and the esr is >1 milliohm: (a) 20 f to 200 f load capacitance needs an esl of >50nh (b) 200 f to 1,000 f load capacitance needs an esl of >5nh 3) adding low esr capacitance directly at the output terminals of microram is not recommended and may cause stability problems. 4) in practice the distributed board or wire inductance at a load or on a load board will be sufficient to isolate the output of the microram from any load capacitance and minimize any appreciable effect on phase margin. ram block diagram +out v ref ?ut +in sc c tran ?n passive block active block sc control
set your site on vicor at www.vicorpower.com preliminary vicor corp. tel: 800-735-6200, 978-470-2900 fax: 978-475-6715 microram rev. 1.1 page 5 of 8 ram2xxx ripple attenuation @ 28v (room temp.) -80.00 -60.00 -40.00 -20.00 0.00 20.00 10 100 1,000 10,000 100,000 1,000,000 10,000,000 freq. (hz) gain (db) 10a, 100uf vref 10a, no vref cap ripple attenuation @ 5v (room temp.) -80.00 -60.00 -40.00 -20.00 0.00 20.00 10 100 1,000 10,000 100,000 1,000,000 10,000,000 freq. (hz) gain (db) 10a, 100uf vref 10a, no vref cap figure 3a, 3b ?urves demonstrating the small signal attenuation performance as measured on a network analyzer with a typical module at (a) 28v and 10a output and (b) 5v and 10a. the low frequency attenuation can be enhanced by connecting a 100 f capacitor, c hr , to the v ref pin as shown in figures 1 and 2. figure 4a-4b ?imulated graphs demonstrating the tradeoff of attenuation versus headroom setting at 20 amps and an equivalent 100? baseplate temperature at 3v and 28v. figure 4c-4d ?icroram attenuation vs. power dissipation at 3v 20a, and 28v 20a. frequency 10hz 100hz 1.0khz 10khz 100khz 1.0mhz ... db(v(vout)) -75 -50 -25 -0 vout=3v iload=20a 100 degrees baseplate temperature rhr=28k (vheadroom=90mv) 27k (100mv) 22k (160mv) 23k (150mv) 24k (135mv) 25k (122mv) 26k (110mv) 17k (260mv) 18k (240mv) 19k (217mv) 20k (197mv) 21k (180mv) frequency 10hz 100hz 1.0khz 10khz 100khz 1.0mhz ... db(v(vout)) -75 -50 -25 -0 rhr=260k (vheadroom=90mv) 250k (100mv) 240k (110mv) 230k (122mv) 220k (135mv) 210k (150mv) 200k (160mv) 190k (180mv) 180k (197mv) 170k (217mv) 160k (240mv) 150k (260mv) vout=28v iload=20a 100 degrees baseplate temperature 17k 18k 19k 20k 21k 22k 23k 24k 25k 26k 27k rhr=28k -70 -60 -50 -40 -30 -20 -10 3.0 3.5 4.0 4.5 5.0 5.5 6.0 watts 500khz 3v 1mhz 3v 100khz 3v db 28v 20a rhr=260k 250k 240k 230k 220k 210k 200k 190k 180k 170k 160k 150k -70 -60 -50 -40 -30 -20 -10 3.0 3.5 4.0 4.5 5.0 5.5 6.0 watts db 100khz 28v 500khz 28v 1mhz 28v notes: the measurements in figures 8-16 were taken with a ?am2c21 and standard scope probes with a 20mhz bandwidth scope setting. the criteria for transient current capability was as follows: the transient load current step was incremented from 10a to the peak value indicated, then stepped b ack to 10a until the resulting output peak to peak was around 40mv.
vicor corp. tel: 800-735-6200, 978-470-2900 fax: 978-475-6715 microram data sheet rev. 1.1 page 6 of 8 set your site on vicor at www.vicorpower.com preliminary figure 7 ?eadroom vs. load current at 28v output. figure 8 ?375a28c600a and ram; input and output ripple @50% (10a) load ch1=vi; ch2=vo; vi-vo=332mv; rhr=178k ram2xxx ( ?am3xxx data not included in this rev.) figure 9 ?375a28c600a and ram; input and output dynamic response no added c tran ; 20% of 20a rating load step of 4a (10a ? 14a);r hr =178k (configured as in figs. 1 & 2) figure 10 ?375a28c600a and ram; input and output dynamic response c tran =820 f electrolytic; 32.5% of load step of 6.5a (10a ? 16.5a);r hr =178k (configured as in figs. 1 & 2) i_iload 2a 4a 6a 8a 10a 12a 14a 16a 18a 20a 1a v(vsource) v(vout) 200mv 300mv 400mv 450mv vout=28v 190k rhr=150k 160k 170k 180k 200k vheadroom figure 5 ?eadroom vs. load current at 3v output. figure 6 ?eadroom vs. load current at 15v output. i_iload 2a 4a 6a 8a 10a 12a 14a 16a 18a 20a 1a v(vsource) v(vout) 200mv 300mv 400mv 450mv vout=3v 20k rhr=16k 17k 18k 19k 21k vheadroom i_iload 2a 4a 6a 8a 10a 12a 14a 16a 18a 20a 1a v(vsource) v(vout) 200mv 300mv 400mv 450mv vout=15v 100k rhr=80k 85k 90k 95k 105k vheadroom
set your site on vicor at www.vicorpower.com preliminary vicor corp. tel: 800-735-6200, 978-470-2900 fax: 978-475-6715 microram rev. 1.1 page 7 of 8 figure 12 ?300b12c250a and ram; input and output dynamic response no added c tran ; 17.5% of 20a rating load step of 3.5a (10a ? 13.5a);r hr =80k (configured as in figs. 1 & 2) figure 11 ?375b12c250a and ram; input and output ripple @50% (10a) load ch1=vi; ch2=vo; vi-vo=305mv; r hr =80k (configured as in figs. 1 & 2) figure 13 ?300b12c250a and ram; input and output dynamic response c tran =820 f electrolytic; 30% of load step of 6a (10a ? 16a);r hr =80k (configured as in figs. 1 & 2) figure 14 ?48c5c100a and ram; input and output ripple @50% (10a) load ch1=vi; ch2=vo; vi-vo=327mv; r hr =31k (configured as in figs. 1 & 2) ram2xxx figure 15 ?48c5c100a and ram; input and output dynamic response no added c tran ; 22.5% of 20a rating load step of 4.5a (10a ? 14.5a);r hr =31k (configured as in figs. 1 & 2) figure 16 ?48c5c100a and ram; input and output dynamic response c tran =820 f electrolytic; 35% of load step of 7a (10a ? 17a);r hr =31k (configured as in figs. 1 & 2)
vicor corp. tel: 800-735-6200, 978-470-2900 fax: 978-475-6715 microram data sheet p/n 25774 rev.1.1 11/02/10m set your site on vicor at www.vicorpower.com preliminary mechanical drawings pcb mounting specifications 5 6 7 4 3 2 1 (ref) 0.080 2,03 dia. (7x) 0.21 5,2 0.27 6,9 (2x) 1.04 26,4 1.45 36,8 .275 6,99 0.800 20,32 0.525 13,34 0.400 10,16 0.12* 3,1 0.20** 5,08 0.01 0.54 13,7 0.43 10,9 pin style 2&n (long pin) 0.62 15,7 pin style 1&s (short pin) (7x) (7x) slotted (style 1) or threaded (style 2) 4-40 unc-2b (6x) or thru hole (style 3) #30 drill thru (6x) (0.1285) (all markings this surface) aluminum baseplate 12,7 0,5 0.50 0.02 * style 1 baseplate only ** style 2 & 3 baseplates *** reserved for vicor accessories not for mounting style 2 & 3 baseplates only (4x)*** 0.490 .015 12,45 0,38 (ref) in out uram 2.000 50,80 0.235 .015 5,97 0,38 (ref) 0.350 .015 8,89 0,38 (ref) full r (6x) 0.10 2,5 chamfer (ref.) (6x) 0.65 16,5 0.49 12,4 1.30 33,0 2.28 57,9 1.45 36,8 0.13 3,3 0.06 1,5 r (3x) x 45? use a 4-40 screw (6x) to rque to: 5 in-lbs 0.57 n-m 1.27 32,3 0.09 2,3 23 6 1 7 4 5 plated thru hole dia 0,08 *denotes tol = 0.003 0.133 3,38 1.734** 44,04 .400* 10,16 1.140** 28,96 0.170* 4,32 0.800* 20,32 0.525* 13,34 0.275* 6,99 2.000* 50,80 0.06 1,5 r (4x) inboard solder mount pin style 1&s 0.094 0.003 2,39 0,08 0.43 10,9 (7x) **pcb window pcb thickness 0.062 0.010 1,57 0,25 0.53 13,5 onboard solder mount pin style 2&n 0.094 0.003 2,39 0,08 pins styles style 1 & 2: tin/lead hot solder dipped style s & n: gold plated copper aluminum baseplate all markings this surface module outline unless otherwise specified, dimensions are in inches mm decimals tol. angles 0.xx ?.01 ?,25 ? 0.xxx ?.005 ?,127 uram pins no. function label 1 +in + 2 control sc 3c ext. ctran 4 ?n 5 ?ut 6 reference vref 7+out +
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