a 15 watt tc single series dc/dc converters 2401 stanwell drive concord, california 94520 ph: 925/687-4411 or 800/542-3355 fax: 925/687-3333 www.calex.com email: sales@calex.com 1 3/2001
features ! -40 to +90c case operating range standard ! dual stage output filter for low noise operation ! very low off current, 1 ma typically ! water washable design ! five year warranty description these single output dc/dc converters are designed to provide a wide range of pcb mount power solutions. the extra wide 3:1 input voltage range covers the common american and european telecom standards along with 24 volt industrial control applications. for flexibility, a trim pin is included to adjust the output voltage. use it to compensate for voltage drops in your system?s wiring or to achieve non standard voltages. use the remote on/off function to maximize battery life. the tc single series continues the calex tradition of reliable design by including transient overvoltage suppressor diode protection at the input and output terminals. also provided as standard are overcurrent protection circuits. these features assure zero failure rate operation when using the tc single series. 15 watt tc single series block diagram t r a h c n o i t c e l e s l e d o m e g n a r t u p n i c d v t u p t u o c d v t u p t u o a m n i mx a m c t 0 0 0 3 . 5 s 8 4 *0 20 60 . 50 0 0 3 c t 0 5 2 1 . 2 1 s 8 40 20 60 . 2 10 5 2 1 c t 0 0 0 1 . 5 1 s 8 40 20 60 . 5 10 0 0 1 9 5 4 1 l u : l a v o r p p a y c n e g a *
a 15 watt tc single series dc/dc converters 2401 stanwell drive concord, california 94520 ph: 925/687-4411 or 800/542-3355 fax: 925/687-3333 www.calex.com email: sales@calex.com 2 3/2001 notes * all parameters measured at tc=25c, nominal input voltage and full rated load unless otherwise noted. refer to the calex application notes for the definition of terms, measurement circuits and other information. (1) see our application note for picking the correct fuse size. (2) noise is measured per calex application notes. measurement bandwidth is 0-20 mhz. rms noise is measured over a 0.01-1 mhz bandwidth. to simulate standard pcb decoupling practices, output noise is measured with a 0.1f, ceramic capacitor located 1 inch away from the converter. (3) minimum load required for rated regulation only. dynamic response may degrade if run at less than 25% full load. (4) short term stability is specified after a 30 minute warm-up at full load, and with constant line, load and ambient conditions. (5) the transient response is specified as the time required to settle from a 50 to 75% step load change (rise time of step = 2sec) to a 1% error band. (6) dynamic response is the peak overshoot voltage during the transient response time defined in note 5. (7) the input ripple rejection is specified for dc to 120hz ripple with a modulation amplitude of 1% vin. (8) the on/off pin is open collector ttl, cmos, and relay compatible. the input to this pin is referenced to pin 2 (-input) and is protected to +75vdc. (9) case is tied to pin 3, +input. (10) the case thermal impedance is specified as the case temperature rise over ambient per package watt dissipated. (11) specifications subject to change without notice. * s r e t e m a r a p t u p n i l e d o mc t 0 0 0 3 . 5 s 8 4c t 0 5 2 1 . 2 1 s 8 4c t 0 0 0 1 . 5 1 s 8 4s t i n u e g n a r e g a t l o v n i m p y t x a m 0 . 0 2 0 . 8 4 0 . 0 6 c d v d a o l l l u f t n e r r u c t u p n i d a o l o n p y t p y t 5 9 3 2 0 8 3 4 5 7 3 4 a m y c n e i c i f f ep y t9 72 83 8% y c n e u q e r f g n i h c t i w sp y t0 2 1z h k s m 0 0 1 , e g a t l o v r e v o t u p n i m u m i x a m e g a m a d o n x a m5 7c d v r o r r e t u p t u o % 1 , e m i t n o - n r u tp y t5 0 1s m e s u f d e d n e m m o c e r ) 1 ( * s r e t e m a r a p t u p t u o l e d o mc t 0 0 0 3 . 5 s 8 4c t 0 5 2 1 . 2 1 s 8 4c t 0 0 0 1 . 5 1 s 8 4s t i n u e g a t l o v t u p t u o52 15 1c d v ) 3 ( d a o l d e t a r n i m x a m 0 0 0 0 3 0 0 5 2 1 0 0 0 0 1 a m e g n a r e g a t l o v d a o l % 0 0 1 n i m p y t x a m 0 5 9 . 4 0 0 0 . 5 0 5 0 . 5 0 0 9 . 1 1 0 0 0 . 2 1 0 0 1 . 2 1 0 0 9 . 4 1 0 0 0 . 5 1 0 0 1 . 5 1 c d v n o i t a l u g e r d a o l d a o l l l u f % 0 0 1 - 5 2 p y t x a m 5 . 0 5 7 . 0 1 . 0 2 . 0 1 . 0 2 . 0 % n o i t a l u g e r e n i l c d v x a m - n i m = n i v p y t x a m 1 . 0 5 1 . 0 1 0 . 0 1 . 0 1 0 . 0 1 . 0 % ) 4 ( y t i l i b a t s m r e t t r o h sp y t2 0 . 0 b d ) 2 ( w b z h m 0 2 - 0 , e s i o np y t5 70 60 6p - p v m e s i o n s m rp y t3 2 2 s m r v m t n e i c i f f e o c e r u t a r e p m e t p y t x a m 0 5 0 5 1 c / m p p o t n o i t c e t o r p t i u c r i c t r o h s s t u p t u o l l a r o f n o m m o c t i m i l t n e r r u c
a 15 watt tc single series dc/dc converters 2401 stanwell drive concord, california 94520 ph: 925/687-4411 or 800/542-3355 fax: 925/687-3333 www.calex.com email: sales@calex.com 3 3/2001
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n i pn o i t c n u f 1f f o / n o 2t u p n i - 3t u p n i + 4t u p t u o + 5n m c 6m i r t figure 1. recommended application circuit for tc single series mechanical tolerances unless otherwise noted: x.xx dimensions: 0.020 inches x.xxx dimensions: 0.005 inches seal around terminals is not hermetic. do not immerse units in any liquid. 15 watt tc single typical application figure 1 shows the recommended connections for the 15 watt tc singles. capacitor c1 is required for proper operation (see below). the trim and on/off pins can be safely left floating if they are not used. the input fuse should not be omitted. the fuse serves two purposes: 1) it prevents unlimited current from flowing in the case of a catastrophic system failure 2) ul regulations for telecom equipment require the use of a fuse. see calex application notes for more info on sizing the input fuse. bottom view side view * s n o i t a c i f i c e p s l a r e n e g s l e d o m l l as t i n u ) 8 ( n o i t c n u f f f o / n o l e v e l c i g o l n o n e p o n i p e v a e l r o n i m0 . 8c d v l e v e l c i g o l f f ox a m0 . 2c d v e c n a t s i s e r t u p n ip y t0 0 1s m h o k , t n e r r u c e l d i r e t r e v n o c w o l n i p f f o / n o p y t1 a 15 watt tc single series dc/dc converters 2401 stanwell drive concord, california 94520 ph: 925/687-4411 or 800/542-3355 fax: 925/687-3333 www.calex.com email: sales@calex.com 4 3/2001 solution according to the 15 watt tc single series ? reflected input ripple vs. line input ? curve at 40 vdc input and 2.25 amps output (75% of rated load), the reflected input ripple can be read as 650 ma rms. from the derating guidelines the capacitor ? s rated voltage and ripple current can be determined. capacitor voltage rating is calculated as: a capacitor selection can now be made. look only at controlled low esr types (where the esr is specified as a maximum) because these usually have the highest ripple current capability per unit volume. be careful to compare apples to apples. some manufacturers specify their capacitors at 85 c and others specify at 105 c. the manufacturers give temperature derating guidelines, so all capacitors should be normalized to your maximum ambient (plus 5 c to account for self heating) before making a selection. since the 15 watt tc single series operates at 120 khz the frequency usually does not have to be derated since most modern low esr capacitors are rated at 100 khz. one note: the temperature derating multipliers are based on the capacitor ? s expected life at 105 c. the life of a capacitor operating at a significantly lower temperature will not be greater if the ripple current in the part is increased over the 105 c rating. this means that a capacitor rated for 1 a rms current at 105 c and 2 a rms at 50 c will have the same life if used at either point while the same capacitor used at 1 a rms and 50 c will have a longer life. suggested capacitor sources suitable capacitors can be acquired from the following sources: united chemi-con sxe, rxc, rz and rza series suggested part: sxe100vb221m12.5x35ll 220f, 100v, 105 c rated esr=0.087 ohms allowable ripple=1.45 a @ 105 c nichicon pr and pf suggested part: upr2a102mph 1000f, 100v, 105 c rated esr=0.047 ohms allowable ripple=1.32 a @ 105 c sizing the input capacitor for maximum reliability the tc single series must use a capacitor of sufficient ripple handling capability connected across the input pins. the probable result of undersizing (over stressing) this capacitor is increased self heating, shortening of the capacitors and hence shortening of your systems ? life. oversizing the capacitor can have a negative effect on your product ? s cost and size, although this kind of overdesign does not result in shorter life of any components. there is no one optimum value for this capacitor. the size and capacity are dependent on the following factors: 1) expected ambient temperature and your temperature derating guidelines 2) your ripple current derating guidelines 3) the maximum load expected on the converter 4) the minimum input voltage expected on the converter 5) the statistical probability that your system will spend a significant amount of time at any worst case extreme factors 1 and 2 are determined by your system design guidelines. these can range from 50% to 100% of the manufacturer ? s rated maximum, although a usual derating factor is 70% of manufacturer ? s maximum limit. 70% derating means that if the capacitor manufacturer says their capacitor can do 1 a rms and 100 vdc you would not use the part over 700 ma rms and 70 vdc. surge voltage rating should also be evaluated against any expected voltage surges when selecting a capacitor working voltage. factors 3 and 4 realistically determine the worst case ripple current. the reflected ripple current increases with output load and increases as the input voltage decreases. so if you are running with a solid 48 vdc input and at 50% load your capacitors required ripple current rating would decrease by more than 2:1 from what would be required for operation at 20 vdc with full load (see the ? input reflected ripple ? curve). factor 5 is not easy to quantify. at calex, we can make no assumptions about a customer ? s system so we design for continuous operation at worst case extremes. example of capacitor sizing given the following conditions, select the minimum size capacitor needed to provide reliable performance: converter ......................................... 48s5.3000tc minimum input voltage .................... 40 vdc maximum input voltage ................... 52 vdc maximum load ................................ 2.25 amps maximum ambient temperature ..... 40 c your capacitor voltage derating guideline ........................... 70% of maximum specification your capacitor current derating guideline ........................... 70% of maximum specification v = 1 x maximum expected input voltage derating factor v = 1 x 52 = 74 volts or greater 0.7 i = 1 x reflected ripple current derating factor = 1 x 650 ma = 0.93 a rms or greater at 45 c 0.7 (40 c ambient + 5 c for self heating)
a 15 watt tc single series dc/dc converters 2401 stanwell drive concord, california 94520 ph: 925/687-4411 or 800/542-3355 fax: 925/687-3333 www.calex.com email: sales@calex.com 5 3/2001 !
% panasonic hfe series suggested part: ecea2afe221l 220f, 100v, 105 c rated esr=0.089 ohms allowable ripple=1.04 a @ 105 c the suggested capacitors will work for any line and load condition, however, they may be oversized for your application. low noise input filtering circuit to reduce the input reflected ripple to less than 50 ma peak to peak the circuit shown in figure 2 may be used. toroid core inductors have theoretically lower radiated noise than a rod core. use reasonable caution when selecting an inductor other than the one specified. nearly any 105 c rated capacitor can be used for the 10f / 100v part. to prevent input filter peaking the esr should be in the range of 0.5 to 2 ohms. do not use the lowest esr capacitor available for this part. this will render the filter ineffective. figure 2. low noise input filter circuit remote on/off circuit operation the remote on/off pin is best applied as follows: ! to turn the unit off, the on/off pin should be tied to the - input pin. this is best done by an open collector arrangement or contact closure. ! to turn the unit on, let the on/off pin float. ! if the remote on/off pin is not used, it may be safely left floating. there is a 100k internal pull-up resistor inside the unit to +9 volts dc. other applications of the on/off function can be found in the application note, ? understanding the remote on/off function ? . proper application of the trim pin the trim pin is used to adjust the output voltage slightly to compensate for voltage drops in the system ? s wiring. figure 3 shows the proper application of the trim pin. either a 10k trimpot or fixed resistors may be used. other applications for the trim function can be found in the calex application note: ? applying the remote sense and trim functions on dc/dc converters. ? # %&'
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%% use one resistor for either trim up or trim down. the values can range from infinity to zero ohms with zero ohms providing the most trim. temperature derating guidelines care must be taken in the application of all power devices. be sure to account for the self heating in your instrument due to the power converter and the loads. for minimum temperature gradient, the hottest components should be mounted at the bottom of your system (bottom of a vertical pcb) and the coolest components at the top of the system. this will help to even the temperature of the entire system and prevent temperature gradients. the 15 watt tc single series has a thermal impedance of 10 c per package watt dissipated. during normal operation the 15 watt tc single series can be expected to run at 80% efficiency at 48 vdc and full load. this means that the 15 watt tc single series is dissipating nearly 4 watts internally at full load. this, therefore, translates to a package temperature rise of about 40 c (10 c/watt x 4 watts dissipated). the maximum rated case temperature for the 15 watt tc series is 90 c. this means that, in the absence of other heat sources (including the load that the converter is powering) and with at least 3 inches of clearance, the 15 watt tc single series can be expected to operate at an ambient of 50 c. additional heat sinks or cooling air flow can extend the ambient temperature of operation significantly. figure 3. output trim methods
a 15 watt tc single series dc/dc converters 2401 stanwell drive concord, california 94520 ph: 925/687-4411 or 800/542-3355 fax: 925/687-3333 www.calex.com email: sales@calex.com 6 3/2001 20 25 30 35 40 45 50 55 60 line input(volts) 75 77 80 82 85 efficiency(%) efficiency vs. line input voltage 100% full load 50% full load 0 102030405060708090100 load (%) 60 65 70 75 80 85 90 efficiency (%) efficiency vs. load line = 20vdc line = 48vdc line = 60vdc 20 25 30 35 40 45 50 55 60 line input (volts) 0.20 0.40 0.60 0.80 1.00 reflected rms ripple (amps) input ripple vs. line input 100% full load 75% full load 50% full load 0 102030405060 line input (volts) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 input current (amps) input current vs. line input voltage 100% load 50% load 0 20 40 60 80 100 120 140 160 180 output load (%) 0 20 40 60 80 100 120 output voltage (%) output voltage vs. output load 10 100 1000 10000 100000 1000000 frequency (hz) .01 .1 1 output impedance (ohms) output impedance vs. frequency 48s5.3000tc 48s15.1000tc -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 case temperature (deg c) -0.5 -0.4 -0.3 -0.2 -0.1 -0.0 0.1 0.2 normalized output (%) output voltage vs case temperature typical performance (tc=25 c, vin=nom vdc, rated load, 48s12.1250tc)
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