1 description ltc 3111edhd 15v , 1.5a synchronous buck-boost dc/dc converter demonstration circuit 1999a is a fixed frequency syn - chronous buck-boost converter with an extended input and output range. the unique 4-switch, single inductor architecture provides low noise and seamless operation from input voltages above, below, or equal to the output voltage. the lt c ? 3111 features selectable pwm or burst mode ? operation, and an easily synchronizable oscillator. jumper jp1 is provided to enable the converter. the demo board is configured for 800khz. a jumper, jp2, is provided to select pwm , or burst mode operation. a clock signal can also be applied to jp2 if synchronization is desired. the ltc3111 operates with a 2.5v to 15v input voltage range and a v out range from 2.5v to 15v. the demon - stration board has been designed to operate with v in from 2.5v to 15v and an output current up to 1.5a. for v in < 5v, i out capability is reduced. v out is set to 5.0v. l , lt, ltc, ltm, linear technology, the linear logo and burst mode are registered trademarks of linear technology corporation. all other trademarks are the property of their respective owners. performance summary typical demo board efficiency is shown in figure 2 for several loads. the demo board has the provision to set an accurate run threshold. consult the ltc3111data sheet for more information. the transient response of the converter to a 100ma to 600ma transient at input voltages of 3.5v and 12v are presented in figures 3 and 4. the ltc3111 data sheet has detailed information about the operation, specifications, and applications of the part. the data sheet should be read in conjunction with this quick start guide. design files for this circuit board are available at http://www .linear.com/demo input voltage range 2.5v to 15v v out 5v i out 1.5a for v in > 5v specifications are at t a = 25c dc1999af demo manual dc1999a
2 quick start procedure using short twisted-pair leads for any power connections and with all loads and power supplies off, refer to figure ?1 for the proper measurement and equipment setup. the power supply should not be connected to the circuit until told to do so in the procedure below. when measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscil - loscope probe. 1. jp1, jp2 and load settings to start: jp1 (run) = off jp2 ( pwm ) = 800khz (fixed frequency) load = 0.1a/50 10w resistor 2. with power off connect the power supply as shown in figure 1. if accurate current measurements are desired (for efficiency calculations for example) then connect an ammeter in series with the supply as shown. the ammeter is not required however. 3. connect the load to vout as shown in figure 1. again, connect an ammeter if accurate current measurement or monitoring is desired. 4. turn on the power supply and slowly increase voltage until the voltage at vin is 2.5v. move jumper jp1 to on. 5. verify vout is ~5.0v. 6. v in can now be varied between 2.5v and 15.0v. v out should remain in regulation. 7. i out can also be varied from 0a to 1.5a. for v in < 5.0v, maximum i out is reduced. this reduction is due to i in increasing as v in decreases. once the input current limit is reached, v out will fall out of regulation. note: if v out drops out of regulation, check to be sure the maximum load has not been exceeded, or that v in is not below the minimum value (2.5v). figure 1. measurement setup dc1999af demo manual dc1999a
3 quick start procedure figure 2. typical efficiency as a function of input voltage and load current figure 3. typical transient load response for a 100ma to 600ma transient load v in = 3.5v figure 4. typical transient load response for a 100ma to 600ma transient load v in = 12v dc1999af demo manual dc1999a
4 parts list item qty reference part description manufacturer / part number required circuit components 1 1 c2 cap cer 47f 16v 20% x5r 1210 murata , grm32er61c476me15l 2 3 c3, c10, c12 cap cer 1f 16v 10% x5r 0603 murata , grm188r61c105ka93d 3 2 c4, c5 cap cer 0.1f 16v 10% x7r 0402 murata , grm155r71c104ka88d 4 1 c6 cap cer 22pf 50v 1% np0 0402 murata , gjm1555c1h220fb01d 5 1 c7 cap cer 1500pf 16v 10% 0402 avx , 0402yc152 kat 2a 6 1 c8 cap cer 47pf 50v 5% np0 0402 murata , grm1555c1h470jz01d 7 1 c9 cap cer 100f 16v 20% x5r 1210 taiyo yuden, emk325abj107mm-t 8 1 c11 cap cer 100pf 50v 5% np0 0402 murata , grm1555c1h101ja01d 9 1 l1 inductor, 10h coilcraft , xal5050-103m 10 1 r1 res 845k 1/16w 1% 0402 smd panasonic , erj-2rkf8453x 11 1 r2 res 158k 1/16w 1% 0402 smd panasonic , erj-2rkf1583x 12 1 r3 res 11.5k 1/16w 1% 0402 smd panasonic , erj-2rkf1152x 13 1 r4 res 41.2k 1/16w 1% 0402 smd panasonic , erj-2rkf4122x 14 1 r5 res 1.00m 1/16w 1% 0402 smd panasonic , erj-2rkf1004x 15 1 r6 res 0402 smd (dnp) 16 1 r7 res 49.9 1/16w 1% 0402 smd panasonic , erj-2rkf49r9x 17 1 u1 15v, 1.5a synchronous buck-boost dc/dc converter linear tech., ltc3111ede #pbf additional demo board circuit components 1 0 c1 ( opt ) cap, tant low esr 47f 35v 20% smd avx , tpse476m035r0200 hardware-for demo board only 1 5 e1-e5 turret, 0.09 dia mill-max, 2501-2-00-80-00-00-07-0 3 2 jp1, jp2 jmp, 3-pin 1 row 0.079cc samtec, tmm-103-02-l-s 4 2 xjp1, xjp2 shunt, 0.079" center samtec, 2sn-bk-g 5 4 stand off stand -off, nylon 0.375" tall keystone, 8832 (snap on) dc1999af demo manual dc1999a
5 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 a a b b c c d d e e 4 4 3 3 2 2 1 1 pwm 800khz burst osc sync 1. all resistors are in ohms, 0402. 2. install shunts as shown. note: unless otherwise specified run run on off tant 1210 0603 1210 0603 0603 vin > 5.0 v vin vout vcc pwm/sync vcc pwm/sync run vin run size date: ic no. rev. sheet of title: approvals pcb des. app eng. technology fax: (408)434-0507 milpitas, ca 95035 phone: (408)432-1900 1630 mccarthy blvd. ltc confidential-for customer use only customer notice linear technology has made a best effort to design a circuit that meets customer-supplied specifications; however, it remains the customer's responsibility to verify proper and reliable operation in the actual application. component substitution and printed circuit board layout may significantly affect circuit performance or reliability. contact linear technology applications engineering for assistance. this circuit is proprietary to linear technology and schematic supplied for use with linear technology parts. scale = none www.linear.com 3 demo circuit 1999a 1 1 15v, 1.5a synchronous buck-boost dc / dc converter n/a ltc3111ede nc jb 2 - 6 - 14 size date: ic no. rev. sheet of title: approvals pcb des. app eng. technology fax: (408)434-0507 milpitas, ca 95035 phone: (408)432-1900 1630 mccarthy blvd. ltc confidential-for customer use only customer notice linear technology has made a best effort to design a circuit that meets customer-supplied specifications; however, it remains the customer's responsibility to verify proper and reliable operation in the actual application. component substitution and printed circuit board layout may significantly affect circuit performance or reliability. contact linear technology applications engineering for assistance. this circuit is proprietary to linear technology and schematic supplied for use with linear technology parts. scale = none www.linear.com 3 demo circuit 1999a 1 1 15v, 1.5a synchronous buck-boost dc / dc converter n/a ltc3111ede nc jb 2 - 6 - 14 size date: ic no. rev. sheet of title: approvals pcb des. app eng. technology fax: (408)434-0507 milpitas, ca 95035 phone: (408)432-1900 1630 mccarthy blvd. ltc confidential-for customer use only customer notice linear technology has made a best effort to design a circuit that meets customer-supplied specifications; however, it remains the customer's responsibility to verify proper and reliable operation in the actual application. component substitution and printed circuit board layout may significantly affect circuit performance or reliability. contact linear technology applications engineering for assistance. this circuit is proprietary to linear technology and schematic supplied for use with linear technology parts. scale = none www.linear.com 3 demo circuit 1999a 1 1 15v, 1.5a synchronous buck-boost dc / dc converter n/a ltc3111ede nc jb 2 - 6 - 14 e5 gnd e5 gnd c10 1uf c10 1uf c7 1500pf c7 1500pf e2 vout 5.0v / 1.5a e2 vout 5.0v / 1.5a c11 100pf c11 100pf r3 11.5k r3 11.5k e3 gnd e3 gnd e4 gnd e4 gnd + c1 opt + c1 opt c5 0.1uf c5 0.1uf r5 1m 1% r5 1m 1% jp2 jp2 1 2 3 c12 1uf c12 1uf c9 100uf 16v c9 100uf 16v r1 845k 1% r1 845k 1% jp1 jp1 1 2 3 c6 22pf c6 22pf c8 47pf c8 47pf c2 47uf 16v c2 47uf 16v r4 41.2k r4 41.2k r6 dnp r6 dnp c4 0.1uf c4 0.1uf r2 158k 1% r2 158k 1% e1 vin 2.5v - 15.0v e1 vin 2.5v - 15.0v l1 10uh l1 10uh u1 ltc3111ede u1 ltc3111ede sw1 6 nc 11 bst1 7 sgnd 14 vin 5 vcc 12 pwm/sync 13 run 4 sw2 9 snsgnd 3 bst2 8 vout 10 comp 1 fb 2 gnd 15 c3 1uf c3 1uf r7 49.9 1% r7 49.9 1% dc1999af demo manual dc1999a
6 linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax : (408) 434-0507 www.linear.com ? linear technology corporation 2014 lt 0214 ? 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 whatsoever . 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 dc1999af demo manual dc1999a
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