1 description ltc 3370euh 4-channel 8a configurable buck dc/dcs demonstration circuit 2311 a is a 4- output power supply featuring the lt c ? 3370 . the ltc3370 has four current mode synchronous buck regulators which can be config- ured to share eight individual 1 a power stages to create one of eight combinations of 1a, 2a, 3 a and 4 a regulators. the dc2311a is set up as four 2 a buck regulators but can be modified to one of the other seven configurations. the input range of the ltc3370 is ideal for single cell li-ion/polymer battery applications. the buck regulators are enabled via external precision threshold enable pins to allow hardwired power up sequences. 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. p erformance s ummary boar d p hoto the ltc3370 has a default operating frequency of 2mhz but can be set between 1mhz to 3mhz using an external resistor. the ltc3370 also has a pll/mode pin which allows the internal oscillator to synchronize to an external clock from 1 mhz to 3 mhz or configure the regulators to forced continuous mode or burst mode. refer to the ltc3370 data sheet for more details on the electrical and timing specifications. design files for this circuit board are available at http://www .linear.com/demo/dc2311a. specifications are at t a = 25c input supply range (vina-h) 2.25 5.5 v vcc operating voltage 2.7 5.5 v v out1 0 to 2a 1.2 v v out2 0 to 2a, v incd > 2.5v 2.5 v v out3 0 to 2a 1.8 v v out4 0 to 2a, v ingh > 3.3v 3.3 v dc2311af demo manual dc2311a
2 t ypical a pplication ltc3370 exposed pad 2.2h v ina v inb swa swb fb1 v ing v inh swg swh fb4 v inc v ind swc swd fb2 v ine v inf swe swf fb3 3370 ta02 2.2h 511k 162k 232k 464k 22f 2.25v to 5.5v 1.2v 2a 47f 47f 22f 3.3v to 5.5v 402k rt en1 en2 en3 en4 pll/mode c1 c2 c3 v cc pgoodall temp microprocessor control 2.7v to 5.5v microprocessor control 10f 2.2h 2.2h 866k 649k 665k 309k 22f 2.5v to 5.5v 1.8v 2a 2.5v 2a 47f 47f 22f 2.25v to 5.5v 3.3v 2a c3 c2 c1 buck1 buck2 buck3 buck4 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 2 a 3a 3a 4a 3a 4a 4a 4a 2 a 1a 1a 1a 2a C C C 2 a 2a 1a 1a C 2a 1a C 2 a 2a 3a 2a 3a 2a 3a 4a 4 2a quad buck application buck efficiency vs i load dc2311af demo manual dc2311a 20 30 40 50 60 70 80 90 100 efficiency (%) load current (ma) 3370 ta01b single channel dual channel triple channel quad channel v in = 3.3v v out 1 = 1.8v f osc = 1mhz l = 3.3h burst mode operation 10 100 1000 4000 0 10
3 quick s tart p roce d ure the dc2311a is easy to set up to evaluate the performance of the ltc3370. refer to figure 1 and figure 2 for proper measurement equipment setup and follow the evaluation 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. measure the input or output voltage ripple by touching the probe tip directly across the v in or v out and gnd terminals. see figure 2 for proper scope probe technique. 1. set the jp 1 C jp4 jumpers on the dc2311a board to the on position. 2. set the jp5 jumper on the dc2311a board to the burst position. 3. set the jp6 jumper on the dc2311a board to the v cc position. 4. with power off, connect a 0 v to 6v, 50 ma power sup - ply ( ps5) to v cc input terminal and gnd with a series ammeter and a voltmeter as shown in figure 1. 5. turn on and set the ps5 to a desired input voltage between 2.7v and 5.5v. 6. with a digital volt meter, measure the voltage on the temp pin. this represents the die temperature, (v temp C 45mv)/7mv = c. 220mv = 25c 7. with power off, connect 0 v to 6v, 2 a power supplies to each input pair ( ps1-ps4), v inab , v inc /v ind , v ine / v inf , v ing /v inh and gnd with a series ammeter and a voltmeter as shown in figure 1. a single 0 v to 6v, 10a supply can be used instead to supply all v in inputs and the v cc input simultaneously. 8. turn on and set the ps1 input power supply to 5.0v and observe that v out1 regulates to 1.2v. note. make sure that the input voltage does not exceed 6 v. 9. with power off, connect a 0 a to 2 a load to v out1 and gnd with a series ammeter and a voltmeter as shown in figure 1. 10. slowly increase the load from 0 a to 2 a and observe the output voltage. the output ripple may also be observed using an oscilloscope with the probe connected as shown in figure 2. 11. set load1 to 100ma. 12. repeat steps 8 to 11 for each output using their respective power supplies and loads. each output voltage should regulate to the voltage indicated on the silkscreen of the dc2311a. 13. momentarily short v out1 to ground with a clip lead and observe that the pgoodall led, d1, on the demo board illuminates. the led shuts off when the short is removed. 14. with load1 set to 100 ma, observe the burst mode ripple on v out1 . 15. set the jp5 jumper on the dc2311a board to the forced cont position and observe the forced con - tinuous mode ripple on v out1 . 16. with an oscilloscope using two probes each set to 1v/div vertical scale and 1 s/div horizontal scale, compare the phase between swab to swcd, swef, and then swgh. observe that the switch nodes are 90, 270, and 180 out of phase respectively with swab. 17. set the jp5 jumper on the dc2311a board to the pll position. 18. set a pulse generator to output a 0 v to 5 v pulse at 2mhz, 50% duty cycle and connect it to the pll/mode terminal and gnd. 19. change the frequency of the pulse generator from 2mhz to 3 mhz and observe how the frequency of swab follows the pulse generator. 20. set load1 greater than 1.0 a. with an oscilloscope probe on swab, remove the pulse signal to the pll/ mode terminal and observe how the switch frequency settles from 3mhz back to 2mhz. 21. refer to the ltc3370 data sheet for more details on how the ltc3370 operates. 22. when done, turn off all loads and power supplies. dc2311af demo manual dc2311a
4 quick s tart p roce d ure figure 1. proper measurement equipment setup figure 2. measuring input or output ripple dc2311af demo manual dc2311a
5 m o d ifying the d c 2311 a to o ther p ower c onfigurations the ltc3370 can be configured to one of eight different power configurations as shown in table 1. to reconfigure the dc2311a to a different configuration some resistors will need to be changed, traces will need to be shorted together, and often traces will need to be cut. follow the steps below to modify the board to a desired configuration. 1. choose the desired configuration from t able 1. table 1. master slave program combinations (each letter corresponds to a v in and sw pair) program code c3c2c1 buck 1 buck 2 buck 3 buck 4 000 ab cd ef gh 001 abc d ef gh 010 abc d e fgh 011 abch d e fg 100 abc de not used fgh 101 abcd not used ef gh 110 abcd not used e fgh 111 abcd not used not used efgh 2. set the associated c bit pins high or low as per table 1 by opening and shorting the appropriate resistors. c1, c2, and c3 are set high by shorting r7, r11, and r14 respectively. c1, c2, and c3 are set low by shorting r9, r13, and r16 respectively. the c bit resistors are 0603 resistors located on the bottom of the board as shown in figure 3. figure 3. c bit resistors and optional output capacitors for v out1 and v out4 3. the dc2311a is set up with the following power stage switch nodes and v in nodes connected together; a & b, c & d, e & f, and g & h. any configuration using 1a or 3 a regulators will require one or more of the v in and switch nodes to be separated. refer to table 1 to determine which power stages are connected together and separated. cut the required v in nodes by cutting the v in traces on the bottom of the board near the v in terminals as shown in figure 4. figure 4. separate v in pairs by cutting traces at terminals dc2311af demo manual dc2311a
6 m o d ifying the d c 2311 a to o ther p ower c onfigurations 4. any switch node associated with a v in trace that was cut will also need to be cut. the swc/swd traces and swd/swf traces can be cut in between to pads near the sw pins as shown in figure 5. the swg/swh traces only need to be cut for the 4112 configuration. swh needs to be cut between the swh pin and l4 as shown in figure 6. figure 5. cut swc and swd connection near pins figure 6. cut swh trace between l4 and swh pin 5. for all combinations containing 3 a and 4 a outputs, the v in nodes of adjoining power stages will need to be connected together. connect all v in s of adjoining power stages at the v in terminals with a 22 awg wire or larger. 6. all switch nodes of adjoining power stages will need to be connected together. each power stage has a pad to solder a small bus wire , 28 awg . the switch node pads are also shown in figure 5 and figure 6. care - fully solder a bus wire as short as possible between adjoining power stages. note: for the 4112 combination switch ab will need to connect to switch c and switch h . for the 332 combina - tion switch d will need to connect to switch e. 7. the xal4020-222m inductors are rated for 5.5 a. this is less than the current limit of the 3 a or 4 a regulators. the pads for l1 and l4 as sized to accommodate a 5mm x 5 mm inductor such as the toko fdsd05xx or the coilcraft xal05xx series. change inductors l1 and/or l4 to accommodate current limit conditions if needed. 8. remove any inductors of unused regulators. note: for the 323 configuration, l 2 needs to be populated and l3 needs to be removed to utilize the regulator 2 fb network. 9. the output capacitance requirement is a minimum of 22 f for each 1 a of output current. each output has an optional 0805 capacitor on the bottom of the board. add the required amount of capacitance to c5 and/or c 29 ( shown in figure 3) for v out1 and v out4 respectively, if needed. 10. set the en jumpers of any unused regulators to the off position. dc2311af demo manual dc2311a
7 a pplication i nformation the dc2311a can be used to evaluate each of the eight configurations of the ltc3370 from 1 mhz to 3 mhz. the following efficiency graphs and transient response plots illustrate how a 1.8v, 1 a regulator performs compared to a 1.8v, 4 a regulator. please refer to the ltc3370 data sheet for more performance information for the ltc3370. 1a buck efficiency vs i load 4a buck efficiency vs i load load current (ma) 30 efficiency (%) 90 100 20 10 80 50 70 60 40 3370 g23 0 1 100 1000 10 v out = 1.8v f osc = 2mhz l = 2.2h v in = 2.25v v in = 3.3v v in = 5.5v v in = 2.25v v in = 3.3v v in = 5.5v forced continuous mode burst mode load current (ma) 30 efficiency (%) 90 100 20 10 80 50 70 60 40 3370 g33 0 1 100 1000 10 v out = 1.8v f osc = 2mhz l = 2.2h v in = 2.25v v in = 3.3v v in = 5.5v v in = 2.25v v in = 3.3v v in = 5.5v burst mode forced continuous mode 1a buck regulator, transient response ( burst mode operation) 1a buck regulator, transient response ( forced continuous mode) 50s/div v out 100mv/div ac-coupled inductor current 200ma/div 0ma 3370 g46 load step = 100ma to 700ma v in = 3.3v v out = 1.8v 50s/div v out 100mv/div ac-coupled inductor current 200ma/div 0ma 3370 g47 load step = 100ma to 700ma v in = 3.3v v out = 1.8v 4a buck regulator, transient response ( burst mode operation) 4a buck regulator, transient response ( forced continuous mode) 50s/div v out 100mv/div ac-coupled inductor current 1a/div 0ma 3370 g48 load step = 400ma to 2.8a v in = 3.3v v out = 1.8v 50s/div v out 100mv/div ac-coupled inductor current 1a/div 0ma 3370 g49 load step = 400ma to 2.8a v in = 3.3v v out = 1.8v dc2311af demo manual dc2311a
8 p arts l ist item qty reference part description manufacturer/ part number required circuit components 1 1 c1 cap, chip, x5r, 22f, 20%, 6.3v, 0805 taiyo yuden, jmk212bj226mg-t 2 9 c3, c6, c8, c10, c14, c17, c19, c23, c26 cap, chip, x5r, 10f, 20%, 6.3v, 0603 tdk, c1608x5r0j106m 3 4 c4, c11, c20, c27 cap, chip, x5r, 47f, 20%, 6.3v, 0805 taiyo yuden, jmk212bj476mg 4 4 c7, c15, c24, c29 cap, chip, npo, 10pf, 5%, 50v, 0402 avx , 04025a100 jat 2a 5 4 l1Cl4 ind, smt, 2.2h, 38m, 20%, 5.5a, 4mm 4mm coilcraft, xal4020-222mec 6 2 r2 res, chip, 232k, 1%, 1/10w, 0603 vishay, crcw0603232kfkea 7 1 r3 res, chip, 464k, 1%, 1/10w, 0603 vishay, crcw0603464kfkea 8 1 r5 res, chip,665k, 1%, 1/10w, 0603 vishay, crcw0603665kfkea 9 1 r6 res, chip, 309k, 1%, 1/10w, 0603 vishay, crcw0603309kfkea 10 1 r10 res, chip, 806k, 1%, 1/10w, 0603 vishay, crcw0603806kfkea 11 1 r12 res, chip, 649k, 1%, 1/10w, 0603 vishay, crcw0603649kfkea 12 1 r18 res, chip, 511k, 1%, 1/10w, 0603 vishay, crcw0603511kfkea 13 1 r21 res, chip,162k, 1%, 1/10w, 0603 vishay, crcw0603162kfkea 14 1 r30 res, chip,402k, 1%, 1/10w, 0603 vishay, crcw0603402kfkea 15 1 u1 4-channel 8a configurable buck dc-dcs,tssop linear tech., LTC3370EUH#pbf additional demo board circuit components 16 1 c2 cap, poscap, 100f, 20%, 6.3v, smt panasonic, 6tpg100mg 17 0 c5, c12, c21, c28 ( opt ) cap, chip, 0805 18 6 c6, c10, c14, c17, c19, c23 cap , poscap, 47f, 20%, 6.3v, smt p anasonic, 6tpc47m 19 6 c9, c13, c16, c18, c22, c25 cap, poscap, 47f, 20%, 6.3v, smt panasonic, 6tpc47m 20 1 d1 diode, led, super red diff, 0603 smd lumex, sml-lx0603 srw -tr 21 4 r1, r4, r8, r15 res, chip, 20 , 1%, 1/16w, 0402 vishay, crcw040220r0fked 22 0 r7, r11, r14 ( opt ) res, chip, 1/10w, 0603 23 3 r9, r13, r16 res, chip, 0 jumper, 1/10w, 0603 vishay, crcw06030000z0ea 24 6 r17, r20, r22, r24, r26, r28 res, chip, 1k, 5%, 1/16w, 0402 vishay, crcw04021k00jned 25 5 r19, r23, r25, r27, r29 res, chip, 1.00m, 5%, 1/16w, 0402 vishay, crcw04021m00jned hardware 26 20 e1Ce18, e27, e29 turret, 0.09 dia mill-max, 2501-2-00-80-00-00-07-0 27 10 e19Ce26, e28, e30 turret, 0.061 dia mill-max, 2308-2-00-80-00-00-07-0 28 5 jp1Cjp4, jp6 2mm to header 1 3 , 2mm samtec, tmm-103-02-l-s 29 1 jp5 2mm to header 1 4 , 2mm samtec, tmm-104-02-l-s 30 6 jp1Cjp6 shunt, 2mm samtec, 2sn-kb-g 31 4 stand-off nylon, 0.375" tall (snap-on) keystone, 8832 (snap on) dc2311af demo manual dc2311a
9 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. s chematic diagram 5 5 4 4 3 3 2 2 1 1 d d c c b b a a 2a unless noted: resistors: ohms, 0402, 1%, 1/16w capacitors: uf, 0402, 6.3v 2a 1.8v 1.2v 2a 2.5v en4 on en1 en2 offon off on en3 off pgoodall forced cont pll/mode burst designates trace to cut to change configuration pll pull-up ext pull-up pwr pwr (toko-fdsd0518-2r2) xal4020-222m vcc vcc vcc vcc vcc vcc vcc ext pwr ext pwr vcc revision history description date approved eco rev marty m. production - 2 11 - 19 - 14 revision history description date approved eco rev marty m. production - 2 11 - 19 - 14 revision history description date approved eco rev marty m. production - 2 11 - 19 - 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 2 demo circuit 2311a 1 1 n/a LTC3370EUH nc marty m. 4 - channel 8a configurable dc/dcs 11 - 19 - 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 2 demo circuit 2311a 1 1 n/a LTC3370EUH nc marty m. 4 - channel 8a configurable dc/dcs 11 - 19 - 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 2 demo circuit 2311a 1 1 n/a LTC3370EUH nc marty m. 4 - channel 8a configurable dc/dcs 11 - 19 - 14 c3 10uf 0603 jp6 c24 10pf 50v r10 806k 0603 tp1a c5 opt 0805 e8 2.25v - 5.5v vind c14 10uf 0603 e4 vout1 r3 464k 0603 e17 vout4 3.3v 2a e2 gnd c17 10uf 0603 jp4 e18 gnd e1 vcc 2.7v - 5.5v LTC3370EUH u1 gnd 33 en1 31 fb1 32 vinh 24 swe 18 vinb 4 c3 13 swf 19 vina 1 swa 2 vine 17 vcc 29 en2 10 en4 26 en3 15 swc 6 swb 3 swd 7 fb2 9 c2 12 pgoodall 14 temp 30 c1 11 swh 23 vinf 20 vinc 5 vind 8 ving 21 fb3 16 swg 22 fb4 25 rt 27 pll/mode 28 tp3a jp2 e10 2.25v - 5.5v vine + c22 47uf 6.3v 6tpc47m r5 665k 0603 r23 1m 5% r24 1k 5% r8 20 e21 pgoodall + c13 47uf 6.3v 6tpc47m r11 opt 0603 e29 gnd e11 2.25v - 5.5v vinf e12 vout3 c29 10pf 50v e19 en1 c21 opt 0805 c8 10uf 0603 e26 gnd r17 1k 5% r25 1m 5% e3 2.25v - 5.5v vinab + c18 47uf 6.3v 6tpc47m c15 10pf 50v r20 1k 5% r2 232k 0603 l4 2.2uh xal4020-222m e28 2.7v - 5.5v e13 2.25v - 5.5v ving e25 temp c1 22uf 0805 e20 en2 + c9 47uf 6.3v 6tpc47m r28 1k 5% r26 1k 5% r27 1m 5% e14 gnd r18 511k 0603 + c25 47uf 6.3v 6tpc47m r16 0 0603 r19 1m 5% e22 en3 tp4a jp3 e5 gnd e15 2.25v - 5.5v vinh + c16 47uf 6.3v 6tpc47m r9 0 0603 + c2 100uf 6.3v 6tpg100mg e23 en4 r21 162k 0603 r12 649k 0603 e16 gnd c28 opt 0805 l1 2.2uh (toko-fdsd0518-2r2) e7 vout2 c4 47uf 0805 l2 2.2uh xal4020-222m r4 20 tp2a c6 10uf 0603 e24 pll/mode r7 opt 0603 e27 gnd e30 gnd 47uf c20 0805 l3 2.2uh xal4020-222m e9 gnd tp2b 47uf c27 0805 c7 10pf 50v r1 20 d1 red tp4b tp1b r29 1m 5% c19 10uf 0603 r14 opt 0603 c23 10uf 0603 r30 402k 0603 c12 opt 0805 c11 47uf 0805 c10 10uf 0603 e6 2.25v - 5.5v vinc jp5 r13 0 0603 jp1 r15 20 c26 10uf 0603 r22 1k 5% r6 309k 0603 tp3b figure 7. dc2311a demo circuit schematic dc2311af demo manual dc2311a
10 linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax : (408) 434-0507 www.linear.com ? linear technology corporation 2015 lt 0215 ? 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 p arty 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 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 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 dc2311af demo manual dc2311a
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