1 description LT8606 42v , 0.35a micropower synchronous step-down regulator demonstration circuit 2564a is a 42v, 0.35a micropower synchronous step-down regulator featuring the lt ? 8606. the demo board is designed for 5v output from a 5.5v to 42v input. the wide input range allows a variety of input sources, such as automotive batteries and indus - trial supplies. the LT8606 is a compact, high efficiency, high speed synchronous monolithic step-down switch - ing regulator that consumes less than 3a of quiescent current when output is regulated at 5v . top and bottom power switches, compensation components and other necessary circuits are inside of the LT8606 to minimize external components and simplify design. the sync pin on the demo board is grounded by default for low ripple burst mode ? operation. move jp1 to pulse skipping position can change the operation mode to pulse-skipping operation. once jp1 is on spread spec - trum position, vcc is applied to the sync pin for low emi spread spectrum operation. to synchronous to an external clock, move jp1 to sync and apply the external l , lt, ltc, ltm, linear technology, the linear logo and burst mode are registered trademarks of analog devices, inc. all other trademarks are the property of their respective owners. performance summary clock to the sync turret. figure 1 shows the efficiency of the circuit. the demo board has an emi filter installed. the radiated emi performances of the board (with emi filter) are shown in figures 2 and 3. the red/green lines in figures 2 and 3 are cisp r25 class 5 peak/average limit. to use the emi filter, the input should be tied to vemi, not vin. an inductor l2, which is a 0 jumper on the board by default now, can be added in the emi filter to further reduce the conducted emission. the LT8606 data sheet gives a complete description of the part, operation and application information. the data sheet must be read in conjunction with this demo manual for dc2564a. design files for this circuit board are available at http: //www.linear.com/demo/dc2564a specifications are at t a = 25c symbol parameter conditions min typ max units v in input voltage range 5.5 42 v v out output voltage 4.8 5 5.2 v i out maximum output current 0.35 a f sw switching frequency 1.85 2 2.15 mhz efe efficiency at dc v in = 12v, i out = 0.35a 92.1 % dc2564af demo manual dc2564a
2 quick start procedure dc2564 a is easy to set up to evaluate the performance of the LT8606. refer to figure 4 for proper measurement equipment setup and follow the procedure below: note: when measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. see figure 5 for the proper scope technique. 1. set an input power supply that is capable of 42v/0.35a. then turn off the supply. 2. with power off, connect the supply to the input terminals v in and gnd. 3. turn on the power at the input. note: make sure that the input voltage never exceeds 42v. 4. check for the proper output voltage of 5v. turn off the power at the input. 5. once the proper output voltage is established, connect a variable load capable of sinking 0.35a at 5v to the output terminals v out and gnd. set the current for 0a. a. if effciency measurements are desired, an ammeter can be put in series with the output load in order to measure the dc2564as output current. b. a voltmeter can be placed across the output ter - minals in order to get an accurate output voltage measurement. 6. turn on the power at the input. note: if there is no output, temporarily disconnect the load to make sure that the load is not set too high. 7. once the proper output voltage is established again, adjust the load and/or input within the operating range and observe the output voltage regulation, ripple volt - age, effciency and other desired parameters. 8. an external clock can be added to the sync terminal when sync function is used (jp1 on the sync posi - tion). please ensure that the chosen rt sets the LT8606 switching frequency to equal or below the lowest sync frequency . see the data sheet section , synchronization . figure 1. efficiency vs load current at 2mhz switching frequency i out (a) 0 efficiency (%) 100 55 95 85 75 65 90 80 70 60 50 0.10 0.30 0.20 dn2564 f01 0.35 0.05 0.25 0.15 12v in 24v in dc2564af demo manual dc2564a
3 quick start procedure figure 2. LT8606 demo circuit emi performance in cispr25 radiated emission test, antenna polarization: vertical, peak detector (v in = 14v, v out = 5v, i out = 0.35a, 2mhz switching frequency) dc2564af demo manual dc2564a
4 quick start procedure figure 3. LT8606 demo circuit emi performance in cispr25 radiated emission test, antenna polarization: vertical, average detector (v in = 14v, v out = 5v, i out = 0.35a, 2mhz switching frequency) dc2564af demo manual dc2564a
5 quick start procedure figure 4. proper measurement equipment setup figure 5. measuring output ripple v out gnd dc2564af demo manual dc2564a
6 parts list item qty reference part description manufacturer/part number required circuit components 1 1 c2 cap., x7r, 1f, 50v, 10% 0805 murata, gr m21br71h105ka12l 2 1 c4 cap., x7r, 0.22f, 16v, 10%, 0603 murata, gr m188r71c224ka01d 3 1 c5 cap., c0g, 10pf, 25v, 5%, 0603 avx, 06033 a100 jat2a 4 1 c6 cap., x7r, 10f, 10v, 10%, 0805 murata, gr m21br71a106ke51k 5 1 c7 cap., x7r, 1f, 25v, 10%, 0603 murata, gr m188r71e105ka12d 6 1 c8 cap., x7r, 0.01f, 16v, 10%, 0603 murata, gr m188r71c103ka01d 7 1 l1 ind., 4.7h wurth electronics, 74438336047 8 1 r2 res., chip, 18.2k, 1/10w, 1%, 0603 vishay, crcw060318 k2fkea 9 1 r3 res., chip, 49.9k, 1/10w, 1%, 0603 vishay, crcw060349 k9fkea 10 2 r1, r4 res., chip, 1m, 1/ 10w, 1%, 0603 vishay, crcw06031 m00fkea 11 1 r5 res., chip, 187k, 1/10w, 1%, 0603 vishay, crcw0603187kfkea 12 1 u1 ic, regulator, m se10 linear tech., LT8606emse#pbf additional demo board circuit components 1 1 c1 cap., alum 22f 63v sun elect, 63 ce22bs 2 3 c3, c10, c11 cap., x7r, 1f, 50v, 10% 0805 murata, gr m21br71h105ka12l 3 1 c9 cap., x7r, 4.7f, 16v, 10%, 0805 murata, gr m21br71c475k73l 4 2 c12, c13 cap., x7r, 0.1f, 50v, 10%, 0603 murata, gr m188r71h104ka93d 5 1 fb1 ferrite bead 0805 tdk, mpz2012s331 at000 6 1 l2 res., chip, 0, 3/4w, 2010 vishay, crcw20100000z0ef 7 0 r6 (opt.) res., 0603 hardware: for demo board only 1 9 e1 - e9 testpoint, turret, 0.094" mill-max, 2501-2-00-80-00-00-07-0 2 1 e10 (opt.) testpoint, turret, 0.094" 3 1 jp1 double row header 2 x 4 0.079" wurth electronics, 62000821121 4 1 xjp1 shunt, 0.079" center wurth electronics, 60800213421 5 4 mh1-mh4 stand-off, nylon 0.50" tall wurth electronics, 702935000 dc2564af demo manual dc2564a
7 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 5 5 4 4 3 3 2 2 1 1 d d c c b b a a all capacitors are 0603. notes: unless otherwise specified 1. all resistors are 0603. suncon 63ce22bs (2mhz) sync spread spectrum pulse skipping burst vout vcc vcc e7 tr/ss c12 0.1f 50v r6 (opt) c5 10pf r5 187k c10 1f 50v 0805 c6 10f 10v 0805 jp1 1 2 3 5 7 4 6 8 r1 1.00m r4 1.00m e6 en/uv u1 LT8606emse vin 9 en/uv 10 sync 5 vcc 3 tr/ss 7 rt 4 fb 6 pg 8 sw 2 bst 1 gnd 1 1 + c1 22f 63v c13 0.1f 50v c7 1f c3 1f 50v 0805 e4 gnd e5 sync c11 1f 50v 0805 l1 4.7h 74438336047 e10 vin 5.5v - 42v r2 18.2k fb1 mpz2012s331at000 e2 gnd c4 0.22f l2 0 2010 e8 pg e3 vout 5v / 0.35a c8 0.01f r3 49.9k e9 gnd c2 1f 50v 0805 e1 vemi 5.5v - 42v c9 4.7f 16v 0805 dc2564af demo manual dc2564a
8 ? linear technology corporation 2017 lt 0417 ? printed in usa demonstration board important notice linear technology corporation (ltc) 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 ltc 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 ltc from all claims arising from the handling or use of the goods. due to the open construction of the product, it is the users 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 . ltc assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. ltc 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 ltc application engineer. mailing address: linear technology 1630 mccarthy blvd. milpitas, ca 95035 copyright ? 2004, linear technology corporation dc2564af demo manual dc2564a
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