DEMO MANUAL DC2225A LTC3875EUJ 160A, 4-Phase, Single-Output Synchronous Buck Converter with Very Low DCR Inductors Description Demonstration circuit 2225A is a high efficiency, high density, 4-phase synchronous buck converter with a 4.5V to 14V input voltage range. It can supply up to 160A of load current with a 1.0V output. This demo board has two each LTC®3875EUJ feature-rich dual phase current mode synchronous buck controllers with very low DCR current sensing capability, on-chip drivers and remote output voltage sensing. This board is set up with 0.32mΩ DCR output inductors. The temperature compensation function offers an option for accurate current limit over a wide temperature range with DCR sensing. To shut down the converter, set the RUN pin voltage below 1V (SW1: OFF). Use JP1 jumper to select Burst Mode® operation, pulse skipping mode or forced continuous mode operation at light load. Switching frequency is preset at about 400kHz, Performance Summary PARAMETER and it can be easily modified from 250kHz to 720kHz. An on-board dynamic circuit is also available for transient test. The LTC3875 is suitable for inputs from 4.5V to 38V and outputs up to 5V. It can provide a high efficiency, high power density and versatile power solution for telecom and datacom systems, industrial and medical instruments, DC power distribution systems and computer systems. The LTC3875 is available in 40-lead 6mm × 6mm and 40-lead 5mm × 5mm QFN packages. Please see LTC3875 data sheet for more detailed information. Design files for this circuit board are available at http://www.linear.com/demo/DC2225A 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. Specifications are at TA = 25°C CONDITIONS Input Voltage Range MIN TYP 4.5 14 1.00 1.02 UNITS V Output Voltage, VOUT VIN = 4.5V to 14V, IOUT = 0A to 160A Maximum Output Current, IOUT VIN = 4.5V to 14V, VOUT = 1.0V 160 A Typical Efficiency VIN = 12V, VOUT = 1.0V, IOUT = 160A 89.3 % Peak Efficiency VIN = 12V, VOUT = 1.0V, IOUT = 100A 90.4 % 400 kHz Typical Switching Frequency 0.98 MAX V dc2225af 1 DEMO MANUAL DC2225A Quick Start Procedure Demonstration circuit 2225A is easy to set up to evaluate the performance of the LTC3875EUJ. Refer to Figure 1 for the proper measurement equipment setup and follow the procedure below: 1. With power off, connect the input power supply to VIN (4.5V to 14V) and GND (input return). 2. Connect the output load between VOUT and GND (Initial load: no load). 3. Connect the DVMs to the input and output. Set default jumper position: JP5 SW1 MODE PHASMD1 BIAS RUN CCM 90° OFF ON 5. Once the proper output voltage is established, adjust the loads within the operating range and observe the output voltage regulation, ripple voltage and other parameters. NOTE: When measuring the output or input voltage ripple, do not use the long ground lead on the oscilloscope probe. See Figure 2 for the proper scope probe technique. Short, stiff leads need to be soldered to the (+) and (–) terminals of an output capacitor. The probe’s ground ring needs to touch the (–) lead and the probe tip needs to touch the (+) lead. – JP2 + JP1 4. Turn on the input power supply and check for the proper output voltages. VOUT should be 1.0V ±2%. + 1mΩ 1mΩ + + – – 4.5V TO 14V + VIN – + – LOAD 0A TO 160A – Figure 1. Proper Measurement Equipment Setup 2 dc2225af DEMO MANUAL DC2225A Quick Start Procedure + – COUT VOUT GND Figure 2. Measuring Output Voltage Ripple Efficiency vs Load Current 95 EFFICIENCY (%) 90 85 80 75 0 20 40 60 80 100 120 140 160 OUTPUT LOAD CURRENT (A) dc2225a F03 Figure 3. Efficiency vs Load Current at VIN = 12V, VOUT = 1.0V, fSW = 400kHz Figure 4. Thermal Performance at VIN = 12V, VOUT = 1.0V, IOUT = 160A, 200LFM Forced Airflow, TA = 25°C dc2225af 3 DEMO MANUAL DC2225A Quick Start Procedure DC Load Current Sharing 50 LOAD CURRENT PER PHASE (A) 45 40 35 30 25 20 15 PHASE #1 PHASE #2 PHASE #3 PHASE #4 10 5 0 0 20 40 60 80 100 120 140 160 TOTAL LOAD CURRENT (A) dc2225a F05 Figure 5. Current Sharing vs Load Current at VIN = 12V, VOUT = 1.0V, fSW = 400kHz VOUT (20MHz BW) [20mV/DIV] Figure 6. Output Voltage Ripple at VIN = 12V, VOUT = 1.0V, IOUT = 160A, fSW = 400kHz 4 dc2225af DEMO MANUAL DC2225A Quick Start Procedure 0A TO 40A LOAD STEP VOUT MEASURED AT BNC J9 (20MHz BW) Figure 7. Transient Response at VIN = 12V, VOUT = 1.0V, IOUT = 0A ~ 40A, di/dt = 40A/µs Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER CAP., OSCON, 270µF, 16V, 20%, E12 PANASONIC, 16SVPC270M Required Circuit Components 1 4 CIN1, CIN10, CIN12, CIN13 2 16 CIN2-CIN9, CIN11, CIN14-CIN20 CAP., 22µF, X7R, 16V, 20%, 1206 Taiyo Yuden, EMK316BB7226ML-T 3 8 COUT1, COUT3, COUT7, COUT8, COUT9, COUT11, COUT21, COUT22 CAP., 100µF, X5R, 6.3V, 20%, 1206 AVX, 12066D107MAT2A 4 8 C10, C11, C20, C21, C25, C41, C46, C50 CAP., 100µF, X5R, 6.3V, 20%, 1210 AVX, 12106D107MAT2A 5 11 COUT2, COUT4, COUT5, COUT6, COUT13, COUT15, COUT16, COUT17, COUT18, COUT19, COUT20 CAP., POSCAP, 470µF, 2.5V, 7343 PANASONIC, ETPF470M5H 6 5 C2, C7, C18, C28, C48 CAP., 0.1µF, X7R, 16V, 10%, 0603 AVX, 0603YC104KAT2A 7 8 C3, C4, C16, C19, C29, C30, C42, C47 CAP., 0.22µF, X5R, 25V, 10%, 0603 AVX, 06033D224KAT2A 8 1 C8 CAP., 10nF, X7R, 25V, 10%, 0603 AVX, 06033C103K4T2A 9 1 C9 CAP., 680pF, C0G, 25V, 10%, 0603 AVX, 06033A681FAT2A 10 2 C13, C44 CAP., 1µF, X5R, 25V, 10%, 0603 MURATA, GRM188R61E105KA12D 11 2 C22, C27 CAP., 1µF, X5R, 16V, 10%, 0603 AVX, 0603YD105KAT2A 12 1 C33 CAP., 1µF, X7R, 16V, 10%, 0805 MURATA, GRM21BR71C105KA01L 13 2 C14, C45 CAP., 4.7µF, X5R, 25V, 10%, 0805 TDK, C2012X5R1E475K 14 2 C31, C35 CAP., 10µF, X5R, 16V, 10%, 1210 AVX, 1210YD106KAT2A 15 1 C34 CAP., 0.22µF, X7R, 16V, 10%, 0805 AVX, 0805YC224KAT2A 16 1 C43 CAP., 47pF, X7R, 25V, 10%, 0603 AVX, 06033C470KAT2A dc2225af 5 DEMO MANUAL DC2225A Parts List ITEM QTY REFERENCE 17 2 PART DESCRIPTION MANUFACTURER/PART NUMBER R1, R14 RES., 20k, 1/10W, 1%, 0603 NIC, NRC06F2002TRF 18 5 R4, R17, R19, R23, R61 RES., 0Ω, 1/10W, 0603 NIC, NRC06ZOTRF 19 4 R9, R10, R56, R57 RES., 2k, 1/10W, 1%, 0603 NIC, NRC06F2001TRF 20 4 R11, R34, R52, R63 RES., 3.57k, 1/10W, 1%, 0603 NIC, NRC06F3571TRF 21 4 R12, R29, R35, R62 RES., 715Ω, 1/10W, 1%, 0603 NIC, NRC06F7150TRF 22 1 R13 RES., 13.3k, 1/10W, 1%, 0603 NIC, NRC06F1332TRF 23 1 R15 RES., 1.65k, 1/10W, 1%, 0603 NIC, NRC06F1651TRF 24 2 R16, R20 RES., 10Ω, 1/10W, 1%, 0603 NIC, NRC06F10R0TRF 25 2 R18, R24 RES., 2.2Ω, 1/10W, 1%, 0603 NIC, NRC06F2R20TRF 26 3 R28, R32, R73 RES., 100k, 1/10W, 1%, 0603 NIC, NRC06F1003TRF 27 7 R37, R40, R51, R53, R55, R59, R75 RES., 10k, 1/10W, 1%, 0603 NIC, NRC06F1002TRF 28 2 R43, R44 RES., 4.99k, 1/10W, 1%, 0603 NIC, NRC06F4991TRF 29 1 R54 RES., 34.8k, 1/10W, 1%, 0603 NIC, NRC06F3482TRF 30 1 R60 RES., SENSE, 0.005Ω, 1%, 1W, 2512 PANASONIC, ERJM1WSF5M0U 31 4 D1, D2, D3, D4 DIODE, SCHOTTKY, SOD-323 CENTRAL SEMI., CMDSH-3TR 32 4 L1, L2, L3, L4 IND., 0.25µH WURTH ELEKTRONIK, 744301025 33 8 Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8 XSTR., MOSFET, DUAL N-CH INFINEON, BSG0811ND 34 2 Q20, Q21 XSTR., MOSFET, N-CH, 30V, TO-252 VISHAY, SUD50N03-09P-GE3 35 2 U1, U2 I.C., LTC3875EUJ#PBF, QFN 6mm x 6mm LINEAR TECH., LTC3875EUJ#PBF 36 1 U3 I.C., LT1763CDE#PBF, 4mm X 3mm LINEAR TECH., LT1763CDE#PBF Additional Demo Board Circuit Components 1 0 C1, C5, C6, COUT10, COUT12, COUT14, C23, C24, C26, C32, C37, C38, C39, C40 (OPT) OPTIONAL 2 0 RN1, RN2, R2, R3, RN5, R5, RN6, R6, R7, R8, R22, OPTIONAL R27, R31, R33, R36, R38, R39, R41, R42, R45, R46, R47, R48, R49, R50, R58, R64, R65, R66, R67, R68, R69, R70, R71(OPT) Hardware: For Demo Board Only 13 E1, E3-E8, E12-E14, E18-E20 TEST POINT, TURRET, .064” MTG. HOLE MILL-MAX, 2308-2-00-80-00-00-07-0 2 6 J1-J6 STUD, TESTPIN PEM, KFH-032-10 3 12 J1-J6(X2) NUT, BRASS 10-32 ANY #10-32 4 6 J1-J6 RING, LUG #10 KEYSTONE, 8205, #10 5 6 J1-J6 WASHER, TIN PLATED BRASS ANY #10 6 2 JP1, JP2 CONN., HEADER, 1X4, 2mm SAMTEC, TMM-104-02-L-S 7 1 JP5 CONN., HEADER, 1X3, 2mm SAMTEC, TMM103-02-L-S 8 1 SW1 SWITCH, SLIDE DPDT 6VDC 0.3A PCMNT C&K., JS202011CQN 1 9 2 J9, J10 CONN, BNC 5PINS CONNEX, 112404 10 3 XJP1, XJP2, XJP5 SHUNT, 2mm SAMTEC, 2SN-BK-G 6 dc2225af A B C D E5 TAVG E13 E12 C26 OPT R43 4.99k R40 10k R37 10k RN1 OPT 5 C9 680pF R3 OPT R38 OPT C23 OPT C5 OPT PLLIN R5 VOSNS1- R42 OPT 220nF R39 OPT R31 OPT C19 TCOMP2 RN2 OPT C4 SGND/PGND SNS2- SNSA2+ TK/SS2 VOSNS2- VOSNS2+ ITH2 ITH1 R8 220nF VOSNS1+ TK/SS1 3 R27 OPT 41 10 9 8 7 6 5 4 3 2 1 4 OPT JP1 MODE PS BM CCM 220nF C3 OPT TK/SS ITH E3 R22 C16 OPT 220nF C2 0.1uF TK/SS ITH RUN R6 OPT C6 OPT R41 OPT C22 1uF EXTVCC R14 20k R13 13.3k R4 0 C1 OPT R2 OPT VIN C8 10nF TCOMP1 TAVG TRSET2 TRSET1 GND EXTVCC 2 R15 1.65K 1% VO_SNS- VO_FB VO_SNS+ TRK/SS ON 5 OFF SW1 RUN 4 1 6 3 RUN 1 R7 OPT 34 TCOMP1 U1 LTC3875EUJ 38 4 C24 OPT R32 100K 1% R45 OPT 30 ENTMPB PGOOD 100K R28 OPT R17 0 PGOOD 4 C13 1uF 3 D2 CMDSH-3 C14 4.7uF 25V SW2 8 2 1 Q3 BSG0811ND INTVCC1 INTVCC1 VIN 8 2 1 Q1 BSG0811ND INTVCC1 SW1 INTVCC1 R18 2.2 CMDSH-3 D1 0.1uF C7 CLKOUT C18 0.1uF INTVCC1 BG2 SW2 TG2 R23 0 EXTVCC BG1 TG1 CLKOUT RUN 20 21 22 23 24 25 26 27 28 29 R33 SW2 TG2 BOOST2 BG2 EXTVCC INTVCC VIN BG1 BOOST1 TG1 SW1 ILIM1 R10 2K R9 2K JP2 PHASMD 60 DEG DEG DEG 1 INTVCC1 120 90 2 R1 20K 3 INTVCC1 3 SW1 8 2 1 VIN CIN2 22uF 1206 CIN4 22uF 1206 VIN VIN 5 6 7 L1 R34 3.57k 1% 0.25uH R35 715 1% 2 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. CIN6 22uF 1206 SCALE = NONE HZ JIAN L. PCB DES. APP ENG. CIN7 22uF 1206 + VOUT J3 J5 E7 E6 J2 C20 100uF 6.3V J6 VO_SNS- GND 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 E14 www.linear.com PGOOD C21 100uF 6.3V E8 GND / 160A VOUT VO_SNS+ VIN- GND C11 100uF 1.0V 6.3V J4 Fax: (408)434-0507 COUT6 470uF 2.5V 7343 VO_SNS- C10 100uF 6.3V VIN 4.5V - 14V J1 E4 VIN+ JIAN L. VIN DATE 3-20-14 APPROVED DATE: N/A SIZE 1 DEMO CIRCUIT 2225A LTC3875EUJ Wednesday, February 17, 2016 IC NO. SHEET 1 1 OF 3 REV. TECHNOLOGY LTC Confidential-For Customer Use Only TITLE: SCHEMATIC HIGH EFFICIENCY, SINGLE-OUTPUT SYNCHRONOUS BUCK CONVERTER WITH VERY LOW DRC INDUCTOR 2.5V 7343 COUT5 + VO_SNS+ CIN1 270uF 16V 470uF 2.5V 7343 + VIN + COUT4 + 470uF R20 10 470uF 2.5V 7343 R16 10 + COUT2 1 DESCRIPTION REVISION HISTORY PRODUCTION CIN9 CIN12 22uF 270uF 1206 16V 1 REV COUT8 100uF 6.3V 1206 COUT1 100uF 6.3V 1206 CIN8 22uF 1206 __ ECO COUT7 100uF 6.3V 1206 COUT3 100uF 6.3V 1206 APPROVALS DCR = 0.32m OHM 744301025 L2 0.25uH 744301025 DCR = 0.32m OHM CUSTOMER NOTICE 5 6 7 CIN5 22uF 1206 Q2 BSG0811ND R11 3.57k 1% R12 715 1% 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. 8 2 Q4 BSG0811ND 1 5 6 7 5 6 7 CIN3 22uF 1206 VIN 2 1 2 E1 2 1 40 SNSA1+ 39 SNS112 SNSD2+ 11 TRSET1 TCOMP2 SNSD1+ 37 TCOMP1 TAVG 13 TAVG TCOMP2 36 TRSET1 35 ILIM FREQ 15 TRSET2 14 TRSET2 33 32 RUN1 RUN2 16 4 4 31 PHASMD 17 MODE/PLLIN IFAST IFAST1 9 9 2 2 1 4 CLKOUT PGOOD 19 ENTMPB 18 ENTMPB 3 10 3 4 4 9 10 3 10 9 3 10 1 2 5 A B C D DEMO MANUAL DC2225A Schematic Diagram dc2225af 7 A B C TAVG C40 OPT R44 4.99k R75 10k RN6 OPT TCOMP3 TAVG TRSET4 TRSET3 R55 10k 5 C43 47pF VO_SNS- VO_FB R47 OPT R46 OPT C27 1uF EXTVCC 2 1 C32 OPT ITH VOSNS1- SGND/PGND SNS2- SNSA2+ TK/SS2 VOSNS2- VOSNS2+ ITH2 ITH1 RN5 OPT OPT C42 220nF VOSNS1+ TK/SS1 R49 OPT 220nF R50 OPT R66 OPT C29 R70 OPT 41 10 9 8 7 6 5 4 3 2 1 TCOMP4 TK/SS ITH R71 C47 OPT 220nF TK/SS 220nF C30 OPT R68 38 TCOMP3 R67 OPT 34 U2 LTC3875EUJ 4 C39 OPT R73 100K 1% 30 OPT R57 2K RUN ENTMPB BG4 SW4 TG4 R61 0 EXTVCC D3 C44 1uF 3 D4 CMDSH-3 C45 4.7uF 25V SW4 8 2 1 Q7 BSG0811ND INTVCC2 INTVCC2 VIN 8 2 1 Q5 BSG0811ND INTVCC2 SW3 R24 2.2 CMDSH-3 E20 CLKOUT INTVCC2 INTVCC2 0.1uF C48 C28 0.1uF R562K R69 OPT R19 0 BG3 TG3 PGOOD 20 21 22 23 24 25 26 27 28 29 R36 PGOOD SW2 TG2 BOOST2 BG2 EXTVCC INTVCC VIN BG1 BOOST1 TG1 SW1 ILIM2 CLKOUT RUN R64OPT 3 R65 40 SNSA1+ 39 SNS112 SNSD2+ 11 TRSET3 TCOMP4 SNSD1+ 37 TCOMP1 TAVG 13 TAVG TCOMP2 36 TRSET1 35 ILIM FREQ 15 TRSET2 14 TRSET4 33 32 RUN1 RUN2 16 SW3 4 4 31 PHASMD 17 MODE/PLLIN IFAST IFAST2 9 5 6 7 5 6 7 8 2 1 CIN11 22uF 1206 VIN VIN CIN14 22uF 1206 VIN CIN16 22uF 1206 VIN 5 6 7 OPT 2.5V 7343 + COUT10 CIN10 270uF 16V OPT 2.5V 7343 + + COUT12 CIN20 CIN13 22uF 270uF 1206 16V VIN PRODUCTION + R63 3.57k 1% 0.25uH R62 715 1% 2 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE HZ JIAN L. PCB DES. APP ENG. APPROVALS DCR = 0.32m OHM 744301025 L4 COUT11 100uF 6.3V 1206 Fax: (408)434-0507 C46 100uF 6.3V www.linear.com C25 100uF 6.3V C50 100uF 6.3V 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 COUT14 2.5V 7343 2.5V 7343 + OPT COUT13 + 470uF JIAN L. VIN DATE 3-20-14 APPROVED DATE: N/A SIZE 1 DEMO CIRCUIT 2225A LTC3875EUJ Wednesday, February 17, 2016 IC NO. SHEET 2 1 OF 3 REV. TECHNOLOGY LTC Confidential-For Customer Use Only TITLE: SCHEMATIC HIGH EFFICIENCY, SINGLE-OUTPUT SYNCHRONOUS BUCK CONVERTER WITH VERY LOW DRC INDUCTOR COUT21 100uF 6.3V 1206 VOUT COUT22 100uF 6.3V 1206 CIN19 22uF 1206 1 DESCRIPTION REVISION HISTORY C41 100uF 6.3V COUT9 100uF 6.3V 1206 CIN18 22uF 1206 1 REV L3 R29 715 1% CIN17 22uF 1206 __ ECO 0.25uH 744301025 DCR = 0.32m OHM CUSTOMER NOTICE 5 6 7 CIN15 22uF 1206 Q6 BSG0811ND R52 3.57k 1% 2 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. 8 2 Q8 BSG0811ND 1 9 D 2 4 CLKOUT PGOOD 19 ENTMPB 18 ENTMPB 3 10 1 2 3 4 4 9 10 3 10 9 3 10 1 2 8 1 5 A B C D DEMO MANUAL DC2225A Schematic Diagram dc2225af 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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. A B C 5 VOUT + COUT17 470uF 2.5V 7343 LOAD STEP CIRCUIT VIN + OFF JP5 BIAS ON C31 10uF 16V 4 COUT18 470uF 2.5V 7343 2 + VIN R51 10K OPTIONAL 5.5V BIAS 3 1 COUT15 470uF 2.5V 7343 7 8 9 10 11 12 + GND SHDN NC IN IN NC COUT16 470uF 2.5V 7343 BYP ADJ NC OUT OUT NC U3 LT1763CDE GND 13 + 1 IOUT COUT19 470uF 2.5V 7343 6 5 4 3 2 C35 10uF 16V 1210 C38 OPT 6.3V OPT R48 2512 R60 0.005 2512 R58 OPT 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. CUSTOMER NOTICE C34 0.22uF 1 C33 1uF 1 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. 1 1210 C37 OPT 6.3V EXTVCC Q21 SUD50N03-09P COUT20 470uF 2.5V 7343 J10 + R53 10K R54 34.8K 1% +5.5V 3 4 2 3 4 5 4 3 2 4 2 3 J9 R59 10K 2 SCALE = NONE HZ JIAN L. PCB DES. APP ENG. APPROVALS 1 2 VOUT Q20 SUD50N03-09P 2 3 4 5 D 5 GND IOSTEP CLK TECHNOLOGY DATE: N/A SIZE 1 DEMO CIRCUIT 2225A LTC3875EUJ Wednesday, February 17, 2016 IC NO. SHEET 3 1 OF 3 REV. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only TITLE: SCHEMATIC HIGH EFFICIENCY, SINGLE-OUTPUT SYNCHRONOUS BUCK CONVERTER WITH VERY LOW DRC INDUCTOR E19 E18 1 A B C D DEMO MANUAL DC2225A Schematic Diagram dc2225af 9 DEMO MANUAL DC2225A 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 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. 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 10 Linear Technology Corporation dc2225af LT 0316 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2016