1 parameter conditions min typ max units input voltage 10 24 32 v standby current iout = 0ma, vin = 24v, vout = 5v 950 a output voltage vin = 12v to 32v, iout = 6ma to 700ma 4.75 5 5.25 v maximum output current vin = 12v vin = 24v 700 1000 ma ma output voltage ripple (peak to peak) vin = 24v, iout = 1a 90 mv switching frequency vin = 24v, iout = 1a 190 khz efficiency vin = 24v, iout = 1a 83.2 % description lt 8301 42v in micropower isolated flyback converter with 65v/1.2a switch demonstration circuit 2138b is an isolated flyback con - verter featuring the lt ? 8301. this demo circuit outputs 5v from a 10v to 32v input, with a nominal of 24v. the output current capability increases with the input voltage. the standby input current of the demo circuit is less than 950a (typical) at v in = 24v. the performance summary table summarizes the perfor - mance of the demo board at room temperature. the demo circuit can be easily modified for different applications with some pre-designed transformers. the dc2138b needs a very small minimum load (~6ma) to regulate the output voltage, thanks to the accurate current limit capability and ultralow switching frequency of LT8301 at very light load. on the board, a zener diode is placed on the output to clamp the voltage to ~5v. this zener is optional, and can be replaced with a 0.8k resistor. the LT8301 is a simple-to-use monolithic isolated flyback converter. no third winding or opto-isolator is required for l , lt, ltc, ltm, linear technology, the linear logo and burst mode are registered trademarks and thinsot is a trademark of linear technology corporation. all other trademarks are the property of their respective owners. performance summary regulation. the part sets the isolated output voltage with a single external resistor and integrates loop compensation and soft-start circuitry inside the ic. boundary mode op - eration provides a small magnetic solution with improved load regulation. low-ripple burst mode ? operation main - tains high efficiency at light loads while minimizing the output voltage ripple. a 1.2a, 65v dmos power switch is integrated along with all high-voltage circuitry and control logic into a 5-lead thinsot? package. the LT8301 data sheet gives a complete description of the part, operation and application information. the data sheet must be read in conjunction with this quick start guide for demo circuit 2138b. design files for this circuit board are available at http://www .linear.com/demo/dc2138b specifications are at t a = 25c dc2138bfa demo manual dc2138b
2 quick start procedure demo circuit 2138b is easy to set up to evaluate the performance of the LT8301. refer to figure 1 for proper equipment setup and follow the procedure below. 1. with power off, connect the input power supply to the board through vin and gnd terminals. connect the load to the terminals vout+ and voutC on the board. 2. turn on the power at the input. increase vin slowly to 10v. note. make sure that the input voltage is always within spec. to operate the board with higher input/output voltage, input capacitor, output capacitor and output diode with higher voltage ratings are needed. note. to run overload tests on the demo board at high line, additional rc snubber might be needed to make sure the voltage spike at the switching node is always less than 65v. 3. check for the proper output voltages . the output should be regulated at 5v (5%). note. the LT8301 requires very small minimum load to maintain good output voltage regulation. a zener diode is placed on the output to clamp the voltage to ~5v. this zener is optional, and can be replaced with a 0.8k resistor. 4. once the proper output voltage is established, adjust the input voltage and load current within the operating range and observe the output voltage regulation, tran - sient, ripple voltage, efficiency and other parameters. note. when measuring the input or output voltage ripples, 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 vin or vout capacitor terminals. see figure 2 for proper scope probe technique. 5. figure 5 shows the radiated emi ( vertical polarization) performance with the installation of the optional com - ponent (c9 560pf). the circuit passed the cispr 25 class 5 peak limit 5, with less than 2 percentage of efficiency drop at full load condition (0.7a, 14v in ). figure 1. proper measurement equipment setup dc2138bfa demo manual dc2138b
3 quick start procedure figure 2. proper scope probe placement for measuring input or output ripple figure 5. radiated emi vertical polarization, cispr 25 peak limit 5, 14v in , 0.7a figure 3. typical efficiency curves figure 4. typical regulation curves input or output capacitor load current (a) 0 efficiency (v) 90 80 70 85 75 65 60 0.2 0.6 dc2138a f03 1.0 0.4 0.8 v in = 12v v in = 24v v in = 32v load current (a) 0.006 v out (v) 5.25 5.15 5.10 5.05 4.85 5.20 4.95 4.90 5.00 4.80 4.75 0.206 0.606 dc2138a f04 0.406 0.806 v in = 12v v in = 24v v in = 32v frequency (mhz) 0 amplitude (dbv/m) 50 45 35 25 15 5 40 30 20 10 0 ?5 400 800 200 600 dc2138a f05 1000 300 700 100 500 900 data class 5 peak dc2138bfa demo manual dc2138b
4 parts list item qty reference part description manufacturer / part number required circuit components 1 1 c1 cap., x7r, 10f, 50v, 10%, 1210 murata , grm32er71h106ka12l 2 1 c2 cap., x5r, 100f, 6.3v, 20%, 1210 murata , grm32er60j107me20l 3 1 c4 cap., x7r, 0.01f, 50v, 10%, 0402 murata , grm155r71h103ka88d 4 1 c5 cap., x7r, 4.7f, 50v, 10%, 1210 avx , 12105c475 kat 2a 5 1 c6 cap., alum., 22f, 50v sun elect., 50ce22bs 6 1 c7 cap., x7r, 3300pf, 630v, 10%, 1206 murata , grm31br72j332kw01l 7 1 c8 cap., x7r, 0.1f, 10v, 10%, 0402 murata , grm155r71a104ka01d 8 1 d1 diode, pmeg3020eh, sod-123 nxp, pmeg3020eh 9 1 d2 diode, 5.6v, sod-523 diodes., bzt52c5v6t-7-f 10 1 d3 diode., 1n4148ws sod323 diodes., 1n4148ws-7-f 11 1 d4 diode, cmhz5250b, sod-123 central., cmhz5250b 12 1 fb1 bead, 0805 tdk, mpz2012s300a 13 1 l1 ind., 10h wurth , 744042100 14 1 r1 res., chip, 1m, 1/8w, 1% 0805 vishay , crcw08051m00fkea 15 1 r2 res., chip, 210k, 1/10w, 1% 0603 vishay , crcw0603210kfkea 16 1 r3 res., chip, 154k, 1/10w, 1% 0603 vishay , crcw0603154kfkea 17 1 r5 res., chip, 0, 1/8w, 1% 0805 vishay , crcw08050000z0ea 18 1 t1 transformer, 750313974 wurth , 750313974 19 1 u1 i.c. flyback converter, sot23-5 linear tech., LT8301es5#pbf additional demo board circuit components 1 0 r4( opt ) res., chip, 0805 2 0 c 3, c9( opt ) cap., 0603 hardware: for demo board only 1 5 e1-e5 testpoint, turret, 0.094" pbf mill-max, 2501-2-00-80-00-00-07-0 2 1 jp1 3 pin 0.079" single row header samtec, tmm103-02-l-s 3 1 xjp1 shunt, 0.079" center samtec, 2sn-bk-g dc2138bfa demo manual dc2138b
5 5 5 4 4 3 3 2 2 1 1 d d c c b b a a vin 10v - 32v note: unless otherwise specified 1. all resistors and capacitors are 0603. 5.6v 5v/0.7a,vin>12v 5v/1.0a,vin>24v gnd size date: ic no. rev. sheet of title: 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. www.linear.com 1 demo circuit 2138b tuesday, september 13, 2016 1 1 n/a LT8301es5 42vin micropower isolated flyback converter size date: ic no. rev. sheet of title: 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. www.linear.com 1 demo circuit 2138b tuesday, september 13, 2016 1 1 n/a LT8301es5 42vin micropower isolated flyback converter size date: ic no. rev. sheet of title: 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. www.linear.com 1 demo circuit 2138b tuesday, september 13, 2016 1 1 n/a LT8301es5 42vin micropower isolated flyback converter d2 bzt52c5v6t-7 1 2 c4 0.01uf 50v 0402 + c6 22uf 50ce22bs 50v r4 opt e5 en/uvlo r2 210k c7 1206 3.3nf 630v e1 r5 0 0805 d1 pmeg3020eh 1 2 r3 154k fb1 mpz2012s300a d3 1n4148ws 1 2 d4 cmhz5250b 1 2 e2 t1 wurth, 750313974 1 4 6 5 7 8 jp1 en dis 1 3 2 opt c3 opt c9 c5 1210 4.7uf 50v l1 744042100 wurth 10uh 10uf 50v c1 1210 e4 vout- r1 1m 0.1uf c8 10v 0402 100uf c2 6.3v 1210 e3 vout+ u1 LT8301es5 vin 5 en/uv 1 rfb 3 gnd 2 sw 4 sw 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 dc2138bfa demo manual dc2138b
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 1016 rev a ? 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 dc2138bfa demo manual dc2138b
|
