1 description ltc 7860 high efficiency switching surge stopper/emi filter demonstration circuit 2239 a is a high efficiency switch- ing surge stopper and emi filter featuring the lt c ? 7860. the board operates from an input range of 3.5 v to 60 v, provides a 3.5 v to 17.2 v output at 0 a to 5 a and is output current limited. a soft-start feature controls output voltage slew rate at start-up, reducing current surge and voltage overshoot. the demonstration board has options for smaller mosfet and diode packages on the back of the board for lower output current requirements. the LTC7860 high efficiency surge stopper protects loads from high voltage transients. high efficiency compared to linear circuits permits higher currents and smaller solution sizes. during an input overvoltage event, such as a load dump in vehicles, the LTC7860 controls the gate of an external mosfet to act as a switching dc/dc regulator (protective pwm mode). this operation regulates the output voltage to a safe level, allowing the loads to oper - ate through the input over-voltage event. during normal operation ( switch-on mode), the LTC7860 turns on the external mosfet continuously, passing the input voltage through to the output with minimum power loss. p erformance s ummary in addition, the output inductor and capacitor form an l-c emi filter when in switch-on mode. an internal comparator limits the voltage across the current sense resistor and regulates the maximum output current to protect against overcurrent faults. an adjustable timer limits the time that the LTC7860 can spend in overvoltage or overcurrent regulation. when the timer expires, the external mosfet is turned off until the LTC7860 restarts after a cool down period. by strictly limiting the time in protective pwm mode when the power loss is higher, the components and thermal design can be optimized for normal operation and safely operate through high voltage input surges and/or overcurrent faults. this board is suitable for a wide range of automotive, telecom, industrial, and other applications. the LTC7860 is available in a small 12- pin thermally enhanced msop package. for other output requirements, see the LTC7860 data sheet or contact the lt c factory. design files for this circuit board are available at http://www . linear.com/demo/dc2239a l , ltc, ltm, lt, burst mode, opti-loop, over-the-top and polyphase are registered trademarks of linear technology corporation. other product names may be trademarks of the companies that manufacture the products. specifications are at t a = 25c symbol parameter conditions min typ max units v in input supply range 3.5 60 v v out output voltage 3.5 14 17.5 v i out output current range, continuous free air 0 5 a v in C v out insertion loss v in =14v, i out = 5a 245 mv f sw switching (clock) frequency during v in surge only 535 khz t pwm protective pwm mode time limit 0.85 1.06 1.24 s v out(p-p) output ripple in protective pwm mode v in = 40v, v out = 17.2v, i out = 5a (20mhz bw) 200 mv pCp approximate size component area x top component height 18 x 16 x 6 mm dc2239af demo manual dc2239a
2 quick s tart p roce d ure demonstration circuit 2239 is easy to set up to evaluate the performance of the LTC7860. refer to figure 1 for proper measurement equipment setup and follow the procedure below: note. when measuring the output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. measure the output voltage ripple by touching the probe tip and ground ring directly across the last output capacitor as shown in figure 1. 1. use an input power supply that is capable of 3.5 v to 60v. set its output to 5v. then turn off the supply. 2. with power off, connect the supply to the input terminals +v in and Cv in . a . input voltages lower than 3.5 v can keep the con - verter from turning on due to the undervoltage lockout feature of the LTC7860. b. a voltmeter with a capability of measuring at least 60 v can be placed across the input terminals in order to get an accurate input voltage measurement. 3. turn on the power at the input. note. make sure that the input voltage never exceeds 60 v. 4. check for the proper output voltage of 5 v. turn off the power at the input. 5. connect a variable load capable of sinking 5 a at 17.2 v to the output terminals + v out and C v out . set the current for 0 a. a. a voltmeter with a capability of measuring at least 18v can be placed across the output terminals 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 again established, adjust the load and/or input within the operating range up to 17v in and observe the output voltage and other desired parameters. 8. now apply an input between 18 v and 60 v and observe the output voltage and fault timer operation. 9. if desired, you may apply input transient profles in the range of 0v in to 60v in and observe the output to illustrate operation of the circuit to prevent input surges from reaching the output. dc2239af demo manual dc2239a
3 quick s tart p roce d ure figure 1. proper measurement equipment setup + ? v in v in + ? + ? i in + ? + ? v out i out load + ? figure 2. output response waveform with 14vC60vC14v input surge, (5a out ) (10v, 10v, 10ms/div) 10ms/div 10v/div 10v/div dc2239 f02 v in v out dc2239af demo manual dc2239a
4 p arts list item qty reference part description manufacturer/ part number required circuit components 1 1 cin1 cap., alum., 10f, 63v, 20%, hvh series sun electronic industries corporation, 63hvh10m 2 1 cin2 cap., 2.2f, x7r, 100v, 10%, 1210 murata grm32er72a225ka35l 3 2 cout1, cout2 cap., 10f, x7r, 50v, 10%, 1210 murata grm32er71h106ka12 4 1 c1 cap., 100pf, np0, 25v, 5%, 0603 avx 06033a101 jat 2a 5 1 c2 cap., 680pf, np0, 25v, 5%, 0603 avx 06033a681 jat 2a 6 1 c4 cap., 3.9pf, np0, 50v, 5%, 0603 avx 06035a3r9 jat 2a 7 1 c5 cap., 0.47f, x5r, 16v, 20%, 0603 avx 0603yd474 mat 2a 8 1 c6 cap., 0.1f, x5r, 16v, 20%, 0603 avx 0603yd104 mat 2a 9 1 c7 cap., 0.1f, x5r, 100v, 20%, 0805 tdk, c2012x5r2a104m125aa 10 1 c8 cap., 10pf, np0, 50v, 5%, 0603 avx 06035a100 jat 2a 11 1 c10 cap., 22f, x7r, 6.3v, 10%, 1206 murata grm31cr70j226ke19l 12 1 d2 diode, schottky, 100v, 5a, pwrdi5 diodes inc., pds5100-7 13 1 d3 diode, zener, 9.1v, 500mw, sod-123 on semi., mmsz9v1t1g 14 1 d5 diode, rectifier, 30v, 500ma, sod-123 diodes inc., b0530w-7-f 15 1 l1 ind., pwr ., shielded, 6.8h, 20%, xal6060 coilcraft xal6060-682mec 16 1 q2 xstr., mosfet p-ch, 60v, pwrpak, s0-8 vishay si7461dp-t1-ge3 17 1 r2 res., 10k, 1/10w, 1%, 0603 vishay crcw 060310k0fkea 18 1 r 3 res., 48.7k, 1/10w, 1%, 0603 visha y crcw060348k7fkea 19 1 r5 res., 1m, 1/10w, 1%, 0603 vishay, crcw06031m00fkea 20 1 r7 res., sense, 0.012, 1/2w, 1%, 2010 vishay wsl2010r0120fea 21 1 r8 res., 1, 1/10w, 1%, 0603 vishay, crcw06031r00fkea 22 1 u1 i.c., voltage reg. msop(12)-mse linear tech.corp. LTC7860emse#pbf additional demo board circuit components 1 0 cin3 cap., option, 1210 opt 2 0 cout3 cap., option, 0603 opt 3 0 c9 cap., option, d case opt 4 0 d1 diode, option, dfn3030-8 opt 5 0 d4 diode, option, sod-323 opt 6 0 q1 xstr, option power_33 opt 7 0 r1, r9, r11 res., option, 0603 opt 8 4 r4, r6, r10, r12 res., 0, 1/10w, 5%, 0603 vishay, crcw06030000z0ea hardware: for demo board only 1 4 e1, e2, e8, e9 test point, turret, 0.094" mtg. hole mill-max 2501-2-00-80-00-00-07-0 2 0 e10, e11 test pad test pad 3 1 jp1 conn., header, 1x3, 2mm samtec tmm-103-02-l-s 4 4 j3, j4, j5, j6 conn., jack, banana, non-insulated, 0.218" keystone, 575-4 5 1 xjp1 shunt, 2mm samtec 2sn-bk-g 6 4 4 corners standoff, nylon, snap-on, 0.375" keystone 8832 7 1 pcb, high voltage surge suppressor with timer demo circuit 2239a dc2239af demo manual dc2239a
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. figure 3. dc2239a demo circuit schematic s chematic diagram 5 5 4 4 3 3 2 2 1 1 d d c c b b a a note: unless otherwise specified 1. all resistors and capacitors are 0603. 3.5v-17v 5a 3.5v-60v freq freq vin vout vin vout 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 1 demo circuit 2239a thursday, march 26, 2015 11 high voltage surge suppressor with timer n/a LTC7860emse lt david b. 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 1 demo circuit 2239a thursday, march 26, 2015 11 high voltage surge suppressor with timer n/a LTC7860emse lt david b. 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 1 demo circuit 2239a thursday, march 26, 2015 11 high voltage surge suppressor with timer n/a LTC7860emse lt david b. revision history description date approved eco rev david b. production 1 1/30/15 revision history description date approved eco rev david b. production 1 1/30/15 revision history description date approved eco rev david b. production 1 1/30/15 u1 LTC7860emse u1 LTC7860emse tmr 1 freq 2 gnd 3 ss 4 vfb 5 ith 6 vfbn 7 run 8 cap 9 sense 10 vin 11 gate 12 gnd 13 c5 0.47uf c5 0.47uf r12 0 ohm r12 0 ohm q2 si7461dp q2 si7461dp c7 0.1uf 100v 0805 c7 0.1uf 100v 0805 r5 1.0m 1% r5 1.0m 1% r1 opt r1 opt gnd gnd c1 100pf 5% c1 100pf 5% d3 mmsz9v1t1g d3 mmsz9v1t1g 1 2 r7 0.012 2010 r7 0.012 2010 r8 1 r8 1 sw sw + c9 7343 opt + c9 7343 opt vout vout c10 22uf 1206 c10 22uf 1206 cout2 10uf 50v 1210 cout2 10uf 50v 1210 d4 opt d4 opt 1 2 l1 6.8uh coilcraft xal6060-682me l1 6.8uh coilcraft xal6060-682me c2 680pf c2 680pf cin3 opt 100v 1210 cin3 opt 100v 1210 (q1 opt) (q1 opt) r3 48.7k 1% r3 48.7k 1% cout1 10uf 50v 1210 cout1 10uf 50v 1210 d5 b0530w d5 b0530w r11 opt r11 opt c8 10pf 5% c8 10pf 5% r2 10.0k 1% r2 10.0k 1% gnd gnd jp1 on off shdn jp1 on off shdn 1 3 2 r4 0 ohm r4 0 ohm cout3 opt 0603 cout3 opt 0603 r10 0 ohm r10 0 ohm gate gate c6 0.1uf c6 0.1uf r9 opt r9 opt cin2 2.2uf 100v 1210 cin2 2.2uf 100v 1210 + cin1 10uf 63v + cin1 10uf 63v d2 pds5100-13 powerdi5 d2 pds5100-13 powerdi5 c4 3.9pf 5% c4 3.9pf 5% (d1 opt) (d1 opt) vin vin r6 0 ohm r6 0 ohm dc2239af demo manual dc2239a
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 0415 ? 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 dc2239af demo manual dc2239a
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