1 dc1502af demo manual dc 1502 a description ltc 4359 hdcb 12 v /20 a ideal diode with reverse input protection demonstration circuit 1502 a showcases the lt c ? 4359 ideal diode controller with reverse input protection . the board includes two independent ltc 4359 ideal diode circuits , sharing a common ground and operating over a 4.5 v to 28 v range . l , lt, ltc, ltm, linear technology and the linear logo are registered trademarks of linear technology corporation. all other trademarks are the property of their respective owners. performance summary each channel is capable of carrying 20 a . through - hole pads are included to permit modification for even higher currents , using an off board power stage . design files for this circuit board are available at http :// www . linear . com / demo parameter conditions min typ max units input voltage limits operating dc survival 1 ms transient vin C vout 4.5 C40 C60 C60 28 90 250 v v v v output current capability 4.5 v vin 8 v vin > 8 v 10 20 a a specifications are at t a = 25 c
2 dc1502af demo manual dc 1502 a quick start procedure overview dc 1502 a features two independent ltc 4359 ideal diode circuits sharing a common ground . each channel handles up to 20 a at room temperature , with no air flow . the board is double - sided . reference designators are duplicated for the two sections of the board ; the upper section is suffixed a while the lower section is suffixed b . voltage capability and onboard clamps the voltage capability of dc 1502 a is clearly stated on the top side silkscreen and on the schematic . several factors contribute to the listed ranges . first , there are the limits of the ltc 4359 which has a specified operating range of 4 v to 80 v , and an absolute maximum rating for the in , shdn and source pins of C40 v to 100 v . second , there is the 60 v bv dss rating of mosfet q 1 that limits the vin C vout rating of the board to C60 v maximum . higher excursions are made possible by operating q 1 in avalanche , or by replacing it with a higher voltage device . third , there are the clamp diodes d 1 and d 2. clamping is necessary to rein in commutation spikes the ltc 4359 behavior is no different in this respect from ordinary rectifiers . fourth , there is the dissipation capability of r 1, a com - ponent which has been chosen for its pulse capability . it becomes the limiting factor for dc conditions when the input voltage exceeds the breakdown of d 1 or d 2. these factors combine to produce the input voltage limits table shown on the schematic and silkscreened on to the circuit board . always bear in mind the vin C vout limit of C60 v which may further restrict the survival and transient limits . current capability dc 1502 a is designed to carry 20 a per channel , provided the ltc 4359 s are enabled . in the disabled state the associ - ated q 1 mosfet is turned off , and any forward current flows through the 0.7 v body diode . this limits the current capability in the disabled state to 1 a . do not attempt to pass 20 a forward current in the disabled state , or q 1 will be destroyed . the 10 a and 20 a current limitations in the enabled state result from mosfet and board self heating , and from connector capability . circuit resistances typical r dson for the bcs 028 n 06 ns mosfet is 2.5 m , dropping 50 mv and dissipating about 1 w at 20 a . this produces a junction temperature rise of 25? c with the board lying on a bench top and deprived of air flow . the circuit traces leading to and from q 1 and the inter - face between the board and the banana jacks amounts to 500?, adding 200 mw dissipation at 20 a . the ground path measures about 350?, which contributes an additional 140 mw dissipation . the total board + mosfet dissipation for one channel driven is 1.3 w and with both channels driven , the total dissipation approaches 3 w . the ground copper loss may be eliminated by using a single power ground connection to dc 1502 a . the best banana test leads ( such as pomona model b banana plug ) are rated to only 10 a to 15 a . for this reason , and to minimize self heating , all banana connections should be doubled up and kept as short as possible . banana plugs represent a substantial loss . typical drop measured from the point where the wire exits a pomona b -12 banana plug to the shoulder of the dc 1502 a banana jack is in excess of 20 mv at 20 a , or about 1 m . if each of the eight banana jacks is used to carry 20 a , they will add over 3 w , doubling the total dissipation . if the turrets are removed , 12 awg bus wire can be installed in the vacated holes to virtually eliminate any voltage drop or dissipation associated with connections to the board . the dissipation is reduced to about 20 mw (50?) per connection . use the banana jacks for kelvin meter connections .
3 dc1502af demo manual dc 1502 a quick start procedure at 20 a even 12 awg wire has its limitations : the resistance is 1.6 m / foot ; one foot dissipates a surprising 640 mw at 20 a . some of this heat is conducted into the circuit board . another means of making connections is to attach ring terminals or copper terminal lugs to the banana jacks , using 8-32 screws . a blackburn / thomas & betts btc 1014 terminal lug , enlarged for a number eight screw with a #15 drill , accepts up to 10 awg stranded wire ; btc 0614 accepts up to 6 awg wire and needs no machining . various typical circuit resistances are summarized in the various voltage drops measured at 10 a load current table . modifying for higher current the resistance issues discussed in the previous section make obvious that modification of the demo board itself for higher current is futile . nevertheless , an off board power stage may be constructed and connected to dc 1502 a by using the source , drain and gate test pads . snub the mosfet with a 100, 10 nf series network directly across the device s drain and source terminals . do not pass load current through the dc 1502 a ground terminals . modifying for other applications pads are provided so that the board may be modified to match any of the data sheet diode applications . compo - nents used in other applications include d 3, d 5 and d 6, all located on the bottom of the board . r snub and c snub are useful for certain mosfets that exhibit parasitic stability issues , such as the fdms 86101. shutdown the ltc 4359 may be shut down by moving the shdn jumper to the off position , which pulls shdn to vss through 100 k ( r 5). shutdown reduces the quiescent cur - rent to 14 a . in the on position the shdn pin floats ; an internal 2 a pull up asserts it high , enabling the ltc 4359 . in the ext position , the shdn pin is connected through r 5 to the shdn turret . if the shdn turret is left open , the ltc 4359 is enabled . to disable , connect the shdn turret to the neighboring vss turret . shdn pin level shift circuits are shown in data sheet figure 3. because the shdn pin is high impedance , it is subject to capacitive coupling . a 10 nf noise bypass capacitor , cf , works with r 5 to keep noise out of the shdn pin . r 5 also helps protect the shdn pin against inadvertent overvoltage conditions that might arise from use of the shdn turret . it is important to note that shutting down the ltc 4359 does not interrupt the forward current path . even when the ltc 4359 is in the shutdown state and q 1 is off , q 1 s body diode is still present and will conduct forward current . do not shut down the ltc 4359 when the mosfet is carrying a forward current of more than 1 a . high dissipation will result in rapid destruction of q 1. how to operate dc 1502 a a simple demonstration of dc 1502 a s operation is as follows ( see figure 1). connect two adjustable power sup - plies , each set to 12 v . connect one to vin a and nearby gnd , the second to vin b and its associated gnd . place the shdn jumpers in the on position . join the outputs of vout a and vout b together at the input of a dc load of up to 20 a . slowly adjust one power supply up and down relative to the other while monitoring the power supply currents . the higher supply will carry the load current , with a narrow transition region where the voltages are nearly identical and the supplies droop share . if one supply is shorted , the output voltage will not collapse the other supply will carry the load . the forward characteristics of the ltc 4359 can be tested without using a high power load and using only a low volt - age 20 a supply , as shown in figure 2. first , dc 1502 a is biased with a 12 v supply . this supply provides quiescent current for the two channels , totaling less than 1 ma . second , connect the two channels in series ( vout a connected to vin b ), and connect a 20 a , current - limited low voltage (1 v ) supply to vin a and vout b .
4 dc1502af demo manual dc 1502 a turn on the 12 v bias supply first , and then turn on the 20 a supply . 20 a will flow from the input of channel a , through q 1 a , to the input of channel b , through q 1 b , and back out to the 20 a power supply . this arrangement eliminates the need for high power supplies , eliminates the need for a second high current supply and eliminates the need for a high power load , yet the forward behavior of the ltc 4359 and the board , connector and mosfet voltage drops are readily examined as though the board was fully loaded with each channel carrying 20 a . always remember that the 12 v supply must be present whenever forward current is flowing . the 20 a supply may be adjusted from zero to 20 a and the 12 v supply may be adjusted from 8.5 v to 28 v , to observe operation under any operating condition . at 10 a , the 12 v supply may be adjusted to as low as 4.5 v . when powering down , turn off the 20 a supply first and then turn off the 12 v supply . using this sequence precludes passing 20 a through the body diodes of q 1 a and q 1 b . quick start procedure various voltage drops measured at 10 a load current pat h measured voltage drop at 10 a computed resistance computed dissipation at 20 a banana tip to banana jack shoulder ( input ) 5.6 mv 560? 224 mw banana jack shoulder to source pad 0.6 mv 60? banana jack shoulder to center source lead 2.6 mv 260? 104 mw center source lead to drain lead 28.1 mv 2.81 m 1.12 w drain lead to banana jack shoulder 1.8 mv 180? 72 mw banana jack shoulder to banana lead tip ( output ) 2.8 mv 280? 112 mw source pad to drain pad 31.4 mv 3.14 m ltc 4359 in to out pins 30.5 mv 3.05 m shoulder to shoulder ( total board drop ) 32.7 mv 3.27 m 1.31 w figure 1. basic operation of dc 1502 a 12v 20a 12v 20a 12v 20a load dc1502a f01
5 dc1502af demo manual dc 1502 a quick start procedure figure 2. testing voltage drops at high current without the need for high power supplies 12v low current ( 1ma) 20a low voltage ( 1v) dc1502a f02 + ?
6 dc1502af demo manual dc 1502 a parts list item qty reference part description manufacturer / part number required circuit components 1 2 cfb , cfa cap , x 7 r , 10 nf , 100 v 20% 0805 avx , 08051 c 103 mat 2 a 2 2 coutb , couta cap , x 7 r , 47 nf , 200 v 20% 1206 avx , 12062 c 473 mat 2 a 3 0 csnubb , csnuba cap , x 7 r , 10 nf , 500 v 20% 1206, option avx , 12067 c 103 mat 2 a 4 2 d 1 b , d 1 a diode , tvs , 70 v , sma diodes inc / zetex , smat 70 a -13- f 5 2 d 2 b , d 2 a diode , tvs , 24 v , sma diodes inc / zetex , smaj 24 a -13- f 6 0 d 3 b , d 3 a , d 6 b , d 6 a diode , tvs , 70 v , sma , option diodes inc / zetex , smat 70 a -13- f 7 2 d 4 b , d 4 a diode , zener 12 v 150 mw sod -523 diodes inc / zetex , ddz 9699 t -7 8 0 d 5 b , d 5 a diode , switching , 300 v , sod -123, option diodes inc / zetex , bav 3004 w -7- f 9 8 e 1 b , e 1 a , e 4 b , e 4 a , e 6 b , e 6 a , e 8 b , e 8 a banana jack , non - insulated keystone , 575-4 10 8 e 2 b , e 2 a , e 5 b , e 5 a , e 7 b , e 7 a , e 9 b , e 9 a test point , turret , 0.094, pbf mill - max , 2501-2-00-80-00-00-07-0 11 4 e 3 b , e 3 a , e 10 b , e 10 a test point , turret , 0.061, pbf mill - max , 2308-2-00-80-00-00-07-0 12 2 jp 1 b , jp 1 a header , 2 x 3 pin , 0.079 cc samtec , tmm -103-02- l - d 13 6 mh 1 to mh 6 standoff , nylon 0.5" keystone , 8833 ( snap on ) 14 2 q 1 b , q 1 a transistor , power mosfet , n - ch 60 v , 100 a tdson -8 infineon , bsc 028 n 06 ns 15 0 rsnubb , rsnuba res , chip , 100, 1/2 w , 5%, 1210, opt nic , nrcp 25 j 101 trf 16 2 r 1 b , r 1 a res , chip , high power , 1 k , 1/2 w , 5% 1206 vishay , crcw 12061 k 00 jneahp 17 2 r 2 b , r 2 a res , chip , high power , 0, 1/2 w , 5% 1206 vishay , crcw 12060000 z 0 eahp r 2 part option 2 k , 1/2 w 5% 1206 vishay , crcw 12062 k 00 fkeahp 18 2 r 5 b , r 5 a res , chip , 100 k , 1/8 w , 5% 0805 vishay , crcw 0805100 kjnea 19 2 u 1 b , u 1 a ic , 28 v ideal diode , dfn -6 l linear technology , ltc 4359 hdcb # pbf 20 2 xjp 1 b , xjp 1 a shunt , 2 mm samtec , 2 sn - bk - g
7 dc1502af demo manual dc 1502 a information furnished by linear technology corporation is believed to be accurate and reliable . however , no responsibility is assumed for its use . linear technology corporation makes no representa - tion that the interconnection of its circuits as described herein will not infringe on existing patent rights . schematic diagram v i n a o n e x t o f f s h d n a g n d s h d n g n d v o u t a s o u r c e d r a i n v s s i n p u t v o l t a g e l i m i t s o p e r a t i n g 4 . 5 v t o 2 8 v d c s u r v i v a l 1 m s t r a n s i e n t - 4 0 v t o 9 0 v - 6 0 v t o 2 5 0 v 1 0 a 2 0 a o u t p u t c u r r e n t c a p a b i l i t y v i n m a x i m u m c o n t i n u o u s l o a d 4 . 5 v t o 8 v > 8 v s n a p - i n s t a n d o f f s o n p c b o a r d g a t e o p t i o n o p t i o n o p t i o n g a t e o p t i o n o p t i o n o n e x t o f f v i n b s h d n b g n d s h d n s o u r c e o p t i o n d r a i n g n d v o u t b v s s 1 2 v 1 2 v n o t e : l t c 4 3 5 9 h d c b t o p m a r k l f k f o p t i o n o p t i o n o p t i o n o p t i o n v i n - v o u t - 6 0 v v s s v s s r s n u b b 1 0 0 5 % 1 2 1 0 r s n u b b 1 0 0 5 % 1 2 1 0 r 5 a 1 0 0 k 0 8 0 5 r 5 a 1 0 0 k 0 8 0 5 e 4 b e 4 b m h 5 m h 5 d 3 b s m a t 7 0 a d 3 b s m a t 7 0 a 2 1 r s n u b a 1 0 0 5 % 1 2 1 0 r s n u b a 1 0 0 5 % 1 2 1 0 d 5 a b a v 3 0 0 4 w d 5 a b a v 3 0 0 4 w 2 1 r 1 a 1 k 1 2 0 6 r 1 a 1 k 1 2 0 6 r 1 b 1 k 1 2 0 6 r 1 b 1 k 1 2 0 6 e 4 a e 4 a q 1 b b s c 0 2 8 n 0 6 n s q 1 b b s c 0 2 8 n 0 6 n s 4 1 5 2 3 e 6 b e 6 b c s n u b b 1 0 n f 5 0 0 v 1 2 0 6 c s n u b b 1 0 n f 5 0 0 v 1 2 0 6 d 5 b b a v 3 0 0 4 w d 5 b b a v 3 0 0 4 w 2 1 t p 4 a t p 4 a m h 4 m h 4 c o u t b 4 7 n f 2 0 0 v 1 2 0 6 c o u t b 4 7 n f 2 0 0 v 1 2 0 6 e 3 a e 3 a e 1 a e 1 a c f a 1 0 n f 1 0 0 v 0 8 0 5 c f a 1 0 n f 1 0 0 v 0 8 0 5 m h 3 m h 3 d 2 b s m a j 2 4 a d 2 b s m a j 2 4 a 2 1 d 6 b s m a t 7 0 a d 6 b s m a t 7 0 a 2 1 m h 6 m h 6 l t c 4 3 5 9 h d c b u 1 b l t c 4 3 5 9 h d c b u 1 b s h d n 5 4 i n 3 s o u r c e 2 g a t e 1 o u t 6 v s s 7 e x p o s e d p a d t p 4 b t p 4 b d 1 b s m a t 7 0 a d 1 b s m a t 7 0 a 2 1 e 8 b e 8 b l t c 4 3 5 9 h d c b u 1 a l t c 4 3 5 9 h d c b u 1 a s h d n 5 4 i n 3 s o u r c e 2 g a t e 1 o u t 6 v s s 7 e x p o s e d p a d m h 2 m h 2 d 1 a s m a t 7 0 a d 1 a s m a t 7 0 a 2 1 r 2 a 0 o h m 1 2 0 6 1 / 2 w r 2 a 0 o h m 1 2 0 6 1 / 2 w q 1 a b s c 0 2 8 n 0 6 n s q 1 a b s c 0 2 8 n 0 6 n s 4 1 5 2 3 t p 3 b t p 3 b e 8 a e 8 a e 6 a e 6 a c f b 1 0 n f 1 0 0 v 0 8 0 5 c f b 1 0 n f 1 0 0 v 0 8 0 5 t p 2 b t p 2 b m h 1 m h 1 c s n u b a 1 0 n f 5 0 0 v 1 2 0 6 c s n u b a 1 0 n f 5 0 0 v 1 2 0 6 e 5 a e 5 a e 5 b e 5 b e 7 b e 7 b c o u t a 4 7 n f 2 0 0 v 1 2 0 6 c o u t a 4 7 n f 2 0 0 v 1 2 0 6 t p 1 a t p 1 a t p 3 a t p 3 a d 4 b d d z 9 6 9 9 t d 4 b d d z 9 6 9 9 t 1 2 e 2 a e 2 a d 6 a s m a t 7 0 a d 6 a s m a t 7 0 a 2 1 t p 2 a t p 2 a r 5 b 1 0 0 k 0 8 0 5 r 5 b 1 0 0 k 0 8 0 5 e 1 0 b e 1 0 b t p 1 b t p 1 b j p 1 a j p 1 a 1 3 5 6 4 2 r 2 b 0 o h m 1 2 0 6 1 / 2 w r 2 b 0 o h m 1 2 0 6 1 / 2 w e 2 b e 2 b e 9 b e 9 b d 3 a s m a t 7 0 a d 3 a s m a t 7 0 a 2 1 d 4 a d d z 9 6 9 9 t d 4 a d d z 9 6 9 9 t 1 2 e 9 a e 9 a e 7 a e 7 a d 2 a s m a j 2 4 a d 2 a s m a j 2 4 a 2 1 e 1 b e 1 b e 1 0 a e 1 0 a e 3 b e 3 b j p 1 b j p 1 b 1 3 5 6 4 2
8 dc1502af demo manual dc 1502 a linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax : (408) 434-0507 www.linear.com ? linear technology corporation 2012 lt 1112 ? printed in usa demonstration board important notice linear technology corporation ( lt c ) provides the enclosed product ( s ) under the following as is conditions : this demonstration board ( demo board ) kit being sold or provided by linear technology is intended for use for engineering development or evaluation purposes only and is not provided by lt c for commercial use . as such , the demo board herein may not be complete in terms of required design -, marketing -, and / or manufacturing - related protective considerations , including but not limited to product safety measures typically found in finished commercial goods . as a prototype , this product does not fall within the scope of the european union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive , or other regulations . if this evaluation kit does not meet the specifications recited in the demo board manual the kit may be returned within 30 days from the date of delivery for a full refund . the foregoing warranty is the exclusive warranty made by the seller to buyer and is in lieu of all other warranties , expressed , implied , or statutory , including any warranty of merchantability or fitness for any particular purpose . except to the extent of this indemnity , neither party shall be liable to the other for any indirect , special , incidental , or consequential damages . the user assumes all responsibility and liability for proper and safe handling of the goods . further , the user releases lt c from all claims arising from the handling or use of the goods . due to the open construction of the product , it is the user s responsibility to take any and all appropriate precautions with regard to electrostatic discharge . also be aware that the products herein may not be regulatory compliant or agency certified ( fcc , ul , ce , etc .). no license is granted under any patent right or other intellectual property whatsoeve r . lt c assumes no liability for applications assistance , customer product design , software performance , or infringement of patents or any other intellectual property rights of any kind . lt c currently services a variety of customers for products around the world , and therefore this transaction is not exclusive . please read the demo board manual prior to handling the product . persons handling this product must have electronics training and observe good laboratory practice standards . common sense is encouraged . this notice contains important safety information about temperatures and voltages . for further safety concerns , please contact a lt c applica - tion engineer . mailing address : linear technology 1630 mccarthy blvd . milpitas , ca 95035 copyright ? 2004, linear technology corporation
|
