DEMO MANUAL DC2055A LTC3875EUJ High Efficient, Single Output Synchronous Buck Converter with Very Low DCR Inductor DESCRIPTION Demonstration circuit 2055A 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 120A of load current with a 1.0V output. This demo board has two each LTC®3875EUJ feature-rich dual-phase synchronous current mode 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 can guarantee accurate current limit over a wide temperature range with DCR sensing. The LTC3875 is suitable for inputs from 4.5V to 38V and outputs up to 3.5V. It can provide a high efficiency, high power density and versatile power solution for telecom and datacom systems, industrial, medical instruments, PERFORMANCE SUMMARY PARAMETER and DC power distribution. The LTC3875 is available in a 40-lead 6mm × 6mm QFN package. To shut down the converter, set the RUN pin voltage below 1.0V (SW1 and SW2: both OFF). Use JP1 jumper to select Burst Mode® operation, pulse-skipping mode or forced continuous mode operation at light load. The switching frequency is pre-set at about 400kHz, and it can be easily modified from 250kHz to 720kHz. An onboard dynamic circuit is also available for a load transient test. Please see LTC3875 data sheet for more detailed information. Design files for this circuit board are available at http://www.linear.com/demo 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 CONDITION Input Voltage Range VALUE 4.5V to 14V Output Voltage, VOUT VIN = 4.5 to 14V, IOUT = 0A to 120A 1.0V ±2% Maximum Output Current, IOUT VIN = 4.5 to 14V, VOUT = 1.0V 120A Typical Efficiency, VOUT VIN = 12V, VOUT = 1.0 V, IOUT = 120A 87.1%, See Figure 3 Typical Switching Frequency 400kHz dc2055afa 1 DEMO MANUAL DC2055A QUICK START PROCEDURE Demonstration circuit 2055A 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-14V) and GND (input return). 2.Connect the 1.0V output load between VOUT1 and GND (Initial load: no load). 3.Connect the DVMs to the input and outputs. Set default jumper position: 2 4.Turn on the input power supply and check for the proper output voltages. VOUT1 should be 1.0V ±2%. 5.Once the proper output voltages are 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. JP1 JP2 JP3 JP4 JP5 JP6 SW1 SW2 MODE PHASMD1 ENTMPB1 ENTMPB1 BIAS PHASMD1 RUN1 RUN2 CCM 90° OFF OFF OFF 90° ON ON dc2055afa DEMO MANUAL DC2055A QUICK START PROCEDURE Figure 1. Proper Measurement Equipment Setup + VOUT COUT – GND Figure 2. Measuring Output Voltage Ripple dc2055afa 3 DEMO MANUAL DC2055A QUICK START PROCEDURE EFFICIENCY (%) 95 VIN = 12V VOUT = 1.0V fSW = 400kHz 90 85 80 0 20 40 60 80 LOAD CURRENT (A) 100 120 Figure 3. Efficiency vs Load Current Figure 4. Thermal Performance at VIN = 12V, VOUT = 1.0V, IOUT = 120A, 200LFM Forced Air Flow 35 VIN = 12V VOUT = 1.0V fSW = 400kHz CHANNEL CURRENT (A) 30 25 20 15 10 CHANNEL 1 CHANNEL 2 CHANNEL 3 CHANNEL 4 5 0 0 20 80 60 40 LOAD CURRENT (A) 100 120 Figure 5. Current Sharing vs Load Current VOUT (20MHz BW) [20mV/DIV] 0A TO 30A LOAD STEP VOUT (20MHz BW) [50mV/DIV] Figure 6. Output Voltage Ripple at VIN = 12V, VOUT = 1.0V, IOUT = 120A, fSW = 400kHz 4 Figure 7. Transient Performance at VIN = 12V, VOUT = 1.0V, IOUT = 0A to 30A, fSW = 400kHz dc2055afa DEMO MANUAL DC2055A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 2 CIN1, CIN18 CAP., OS-CON, 270µF, 16V, 20%, E12 SANYO, 16SVPC270M 2 12 COUT1, COUT3, COUT7, COUT8, COUT13, COUT15, COUT19, COUT20, C29, C30, C33, C34 CAP., X5R, 100µF, 6.3V, 20%,1210 AVX 12106D107MAT2A 3 12 COUT2, COUT4-COUT6, COUT9-COUT12, COUT14, COUT16-COUT18 CAP., OS-CON, 330µF, 2.5V, 20%, 7343 SANYO, 2R5TPE330M9 4 4 L1, L2, L3, L4 IND, 0.25µH WURTH ELECT.,744301025 5 4 Q1, Q3, Q14, Q16 OPTIMOS POWER-TRANSISTOR, PG-TDSON-8 25V INFINEON, BSC050NE2LS 6 4 Q2, Q4, Q13, Q15 OPTIMOS POWER-TRANSISTOR, PG-TDSON-8 25V INFINEON, BSC010NE2LSI 7 2 U1, U3 IC, LTC3875IUJ, QFN 6mm × 6mm LINEAR TECH., LTC3875IUJ#PBF 8 1 U2 IC, LT1763CDE, DFN 4mm × 3mm LINEAR TECH., LT1763CDE-SD AVX 1210YD106KAT2A Additional Demo Board Circuit Components 9 10 CIN2-CIN5, CIN13-CIN16, C27, C28 CAP., X5R, 10µF,16V, 10%, 1210 10 0 C1, C5, C6, CIN6-CIN12, CIN17, C23, C24, C26, C37, C48, C49, C54, C55, C58, C59, C63 CAP., OPTIONAL 11 5 C2, C7, C18, C38, C42, C43 CAP., X5R, 0.1µF, 16V, 10%, 0603 AVX 0603YD104KAT2A 12 8 C3, C4, C16, C19, C44, C46, C52, C62 CAP., X5R, 220nF, 25V, 10%, 0603 AVX 06033D224KAT2A 13 1 C8 CAP., X7R, 4.7nF, 25V, 10%, 0603 AVX 06033C472KAT2A 14 2 C9, C57 CAP., NPO, 220pF, 25V, 10%, 0603 AVX 06033A221KAT2A 15 3 C13, C22, C56 CAP., X5R, 1µF, 25V, 10%, 0603 AVX 06033D105KAT2A 16 2 C14, C60 CAP., X5R, 4.7µF, 16V, 10%, 0805 TDK C2012X5R1E475K 17 4 C31,C32,C35,C36 CAP., X5R, 0.22µF, 16V, 10%, 0805 AVX 0805YC224KAT2A 18 4 D1, D2, D3, D4 DIODE, SCHOTTKY, SOD-323 CENTRAL CMDSH-3TR 19 0 Q5, Q6, Q9-Q12, Q17, Q18 OPTIONAL 20 2 Q7, Q8 MOSFET SPEED SRS 30V 30A LFPAK RENESAS RJK0305DPB 21 2 R1, R14 RES., CHIP, 20k, 1%, 0603 NIC NRC06F2002TRF 22 0 R2, R3, R5-R8, R22, R27, R31, R33, R38, R39, R41, R42, R47, R63, R65, R68, R69, RN1-RN8, R73, R74, R75, R76, R79, R83, R84, R88, R89, R90, R91, R92, R93, R94, R96, R97 RES., OPTIONAL 23 12 R4, R17, R23, R46, R48, R51, R53, R54, R60, R61, R64, R82 RES., CHIP, 0Ω, 0603 NIC NRC06ZOTRF 24 4 R59, R66, R67, R72 RES., CHIP, 0Ω, 2512 VISHAY CRCW25120000Z0ZG 25 2 R9, R80 RES., CHIP, 3.01k, 1%, 0603 NIC NRC06F3011TRF 26 2 R10, R81 RES., CHIP, 1k, 1%, 0603 NIC NRC06F1001TRF 27 4 R11, R34, R77, R86 RES., CHIP, 3.57k, 1%, 0603 NIC NRC06F3571TRF 28 4 R12, R35, R70, R85 RES., CHIP, 715Ω, 1%, 0603 VISHAY CRCW0603715RFKEA 29 1 R13 RES., CHIP, 13.3k, 1%, 0603 VISHAY CRCW060313K3FKEA 30 8 R37, R40, R49, R52, R55, R57, R78, R101 RES., CHIP, 10k, 1%, 0603 NIC NRC06F1002TRF 31 1 R15 RES., CHIP, 2k, 1%, 0603 NIC NRC06F2001TRF 32 2 R16, R20 RES., CHIP, 10Ω, 1%, 0603 NIC NRC06F10R0TRF 33 2 R18, R62 RES., CHIP, 2.2Ω, 1%, 0603 NIC NRC06F2R20TRF dc2055afa 5 DEMO MANUAL DC2055A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER 34 4 R28, R32, R87, R99 RES., CHIP, 100k, 1%, 0603 NIC NRC06F1003TRF 35 2 R43, R44 RES., CHIP, 4.99k, 1%, 0603 NIC NRC06F4K99TRF 36 1 R50 RES., CHIP, 34.8k, 1%, 0603 VISHAY CRCW060334K8FKEA 37 2 R56, R58 RES., CHIP, 0.005Ω, 1%, 2512 VISHAY WSL25125L000FEA Hardware-For Demo Board Only 38 19 E1, E3-E8, E12-E14, E16-E19, E23, E24, E27-E29, E33 TESTPOINT, TURRET, 0.062" MILL-MAX, 2308-2-00-80-00-00-07-0 39 6 J1, J2, J3, J4, J14, J16 STUD, TESTPIN PEM KFH-032-10 40 12 J1-J4, J14, J16 (X2) NUT, BRASS 10-32 ANY #10-32 41 6 J1-J4, J14, J16 RING, LUG #10 KEYSTONE, 8205, #10 42 6 J1-J4, J14, J16 WASHER, TIN PLATED BRASS ANY #10 43 3 JP1, JP2, JP6 2MM SINGLE ROW HEADER, 4-PIN SAMTEC, TMM-104-02-L-S 44 3 JP3-JP5 HEADER 3-PIN 0.079 SINGLE ROW SAMTEC, TMM103-02-L-S 45 6 JP1-JP6 SHUNT SAMTEC, 2SN-BK-G 46 2 SW1, SW2 CONNECTOR, SUB MINIATURE SLIDE SWITCHES C&K.,JS202011CQN 47 4 J7, J8, J9, J10 CONN, BNC, 5PINS CONNEX, 112404 6 dc2055afa A B C D GND EXTVCC R15 2K 1% TRK/SS1 5 E13 E12 TAVG1 VO1_SNS- C22 1uF R43 4.99k R40 10k R37 10k 5 C2 0.1uF R3 OPT VO1_SNS+ C1 OPT R2 OPT VIN EXTVCC C9 220pF 0 R6 OPT R4 2 C26 OPT TRSET2 TRSET1 C8 4.7nF E5 OFF ON SW1 RUN1 4 1 6 3 RN5 OPT ITH1 R14 20k R13 13.3k RN1 OPT 8 TK/SS1 C23 OPT RN6 OPT 7 4 RN2 OPT R39 OPT 220nF TCOMP2 R31 OPT OPT C19 SGND/PGND SNS2- SNSA2+ TK/SS2 VOSNS2- VOSNS2+ ITH2 ITH1 VOSNS1- VOSNS1+ R8 OPT C4 220nF TK/SS1 R27 41 10 9 6 VO1_SNS- 5 4 3 2 1 220nF C3 VFB1 ITH1 TK/SS1 2 OPT R5 R1 20K R22 C16 OPT 220nF VFB1 E3 R41 OPT PLLIN R38 OPT C6 OPT C5 OPT TCOMP1 TK/SS1 RUN1 MODE JP1 PS BM CCM 1 4 R7 OPT RUN1 34 4 TCOMP1 U1 LTC3875EUJ R42 OPT TAVG1 C24 OPT R32 100K 1% TG2 INTVCC1 3 3 ON 1 2 OFF JP3 ENTMPB1 BG2 SW2 0.1uF 0 C18 20 R23 22 21 23 24 BG2 SW2 TG2 BG1 SW1 TG1 CMDSH-3 D2 2.2 25 C13 1uF CMDSH-3 D1 0.1uF C7 INTVCC1 VIN INTVCC1 BG2 SW2 TG2 BG1 SW1 TG1 Q1 BSC050NE2LS 4 4 CIN3 10uF 1210 4 R11 3.57k 1% CIN4 10uF 1210 Q3 BSC050NE2LS VIN R34 3.57k 1% Q4 BSC010NE2LSI CIN5 10uF 1210 Q2 BSC010NE2LSI CIN2 10uF 1210 CUSTOMER NOTICE 4 VIN 2 L1 2 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. VIN SCALE = NONE TECHNOLOGY 2.5V 7343 VOUT1 E14 E8 J4 J3 PGOOD1 VO1_SNS- GND VOUT1 1.0V / 90A VO1_SNS+ VIN- 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only COUT6 2.5V 7343 + 330uF COUT5 VO1_SNS- VOUT1 E7 E6 GND VIN 4.5V - 14V J2 DATE: 1 DEMO CIRCUIT 2055A LTC3875EUJ Tuesday, November 19, 2013 IC NO. SHEET 1 OF 3 2 REV. HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS BUCK CONVERTER WITH VERY LOW DCR INDUCTOR SIZE B VOUT1 + 330uF 330uF 2.5V 7343 + J1 E4 VIN+ HAORAN W. VIN DATE 11-12-13 APPROVED VO1_SNS+ CIN1 270uF 16V + COUT4 R20 10 330uF 2.5V 7343 + COUT2 COUT8 100uF 6.3V 1210 + R16 10 CIN18 270uF 16V PRODUCTION 2 1 DESCRIPTION REVISION HISTORY REV COUT1 100uF 6.3V 1210 COUT7 100uF 6.3V 1210 COUT3 100uF 6.3V 1210 __ ECO HZ HAORAN W. TITLE: SCHEMATIC APPROVALS R35 715 1% 0.25uH 744301025 DCR = 0.32m OHM L2 0.25uH 744301025 DCR = 0.32m OHM 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 PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. OPT IFAST1 R33 INTVCC1 C14 4.7uF 10V INTVCC1 R18 100K PGOOD1 R17 0 EXTVCC BG1 TG1 SW1 3.01K R9 26 27 28 29 R28 SW2 TG2 BOOST2 BG2 EXTVCC INTVCC VIN BG1 BOOST1 TG1 30 CLKOUT1 SW1 ILIM1 R10 1K PHASMD1 JP2 INTVCC1 120 90 60 DEG DEG DEG 1 4 3 2 INTVCC1 3 E1 2 1 1 2 RUN1 2 1 TRSET1 1 2 3 2 1 SNSA1+ 39 SNS1- 11 SNSD2+ 38 SNSD1+ 37 TCOMP1 12 TCOMP2 TAVG 13 TAVG1 40 2 1 15 TCOMP2 36 TRSET1 35 ILIM 16 RUN1 FREQ 17 TRSET2 14 TRSET2 32 RUN1 RUN2 33 MODE/PLLIN IFAST 31 PHASMD IFAST1 CLKOUT PGOOD 19 ENTMPB 18 ENTMPB1 5 6 7 8 1 2 3 5 6 7 8 1 2 3 5 6 7 8 1 2 3 5 6 7 8 1 2 3 5 A B C D DEMO MANUAL DC2055A SCHEMATIC DIAGRAM dc2055afa 7 A B TAVG2 R44 4.99k R101 10k R78 10k R65 OPT R64 0 C37 OPT TRSET4 TRSET3 TRK/SS2 E33 5 VO2_SNS- VO2_SNS+ C58 OPT RN7 OPT C38 0.1uF R88 OPT C57 220pF 2 1 C RN4 OPT TCOMP3 VOUT1 R63 OPT R84 OPT R83 OPT R74 OPT VFB2 ITH2 2 1 C48 OPT RN8 OPT RN3 OPT TCOMP4 TK/SS2 ITH2 ITH1 R97 C62 OPT 220nF VO1_SNS- VFB1 TK/SS1 TK/SS2 R73 OPT C55 OPT C54 OPT C63 OPT ITH1 2 1 220nF 220nF 4 R76 OPT 220nF R75 OPT R92 OPT OPT C44 SGND/PGND SNSN2 SNSPAC2 TK/SS2 VOSNS2- VOSNS2+ ITH2 ITH1 VOSNS1- VOSNS1+ R96 41 10 9 8 7 6 5 4 3 2 TK/SS1 C52 1 OPT C46 R94 OPT R91 4 40 D 2 1 39 SNSN1 C49 OPT R93 OPT TRSET3 U3 LTC3875EUJ 5 OFF ON SW2 RUN2 R99 TAVG2 100K 1% 12 SNSPAC1 38 13 TCOMP4 TAVG TAVG2 SNSPDC2 11 TCOMP3 37 SNSPDC1 36 TRSET1 35 ILIM FREQ 15 TRSET2 14 TRSET4 4 1 6 3 2 16 TCOMP2 TCOMP1 34 32 RUN1 RUN2 33 MODE/PLLIN C59 OPT TG1 SW1 ILIM2 R90 OPT 20 21 22 23 3 ON R89 OPT 3 JP4 ENTMPB2 1 OFF 2 VIN INTVCC2 BG4 SW4 TG4 C43 0.1uF R82 0 BG4 SW4 TG4 BG3 SW3 TG3 INTVCC2 VIN INTVCC2 E29 CLKOUT BG4 SW4 TG4 BG3 SW3 TG3 Q16 BSC050NE2LS 4 4 CIN13 10uF 1210 4 VIN CIN16 10uF 1210 Q14 BSC050NE2LS R86 3.57k 1% Q15 BSC010NE2LSI CIN15 10uF 1210 VIN Q13 BSC010NE2LSI R77 CIN14 3.57k 10uF 1% 1210 CUSTOMER NOTICE 4 VIN 2 L3 2 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. R83 30.1k R84 20k 10k R88 SCALE = NONE R86 TECHNOLOGY J16 J14 0 R79 0 R68 PGOOD2 RUN2 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only 931 R85 E24 E23 VO2_SNS- GND VOUT2 UP TO 30A VO2_SNS+ VO2_SNS- E28 VOUT2 E27 DATE: 1 DEMO CIRCUIT 2055A LTC3875EUJ Tuesday, November 19, 2013 IC NO. SHEET 2 OF 3 2 REV. HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS BUCK CONVERTER WITH VERY LOW DCR INDUCTOR SIZE B L4 R68 OPT COUT17 COUT18 + 330uF 2.5V 2.5V 7343 7343 VOUT2 + 330uF VOUT1 VO2_SNS+ 1.5nF 0.33uF/0.32mOHM 4.64k 744301033 C58 330uF 2.5V 7343 1 + COUT16 R79 OPT 330uF 2.5V 7343 + COUT14 COUT15 100uF 6.3V 1210 COUT20 100uF 6.3V 1210 COUT19 100uF 6.3V 1210 COUT13 100uF 6.3V 1210 HZ HAORAN W. TITLE: SCHEMATIC APPROVALS VOUT2 = 1.5V DUAL-OUTPUT CONFIG R85 715 1% 0.25uH 744301025 DCR = 0.32m OHM L4 0.25uH 744301025 DCR = 0.32m OHM R70 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 PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. OPT IFAST2 R69 INTVCC2 C60 4.7uF 10V D4 CMDSH-3 2.2 24 R62 C56 1uF CMDSH-3 D3 C42 0.1uF INTVCC2 26 100K PGOOD2 R80 3.01K R60 0 EXTVCC BG3 TG3 SW3 CLKOUT R81 1K JP6 25 R87 SW2 TG2 BOOST2 BG2 EXTVCC INTVCC VIN BG1 27 28 29 30 CLKOUT1 PHASMD2 120 90 60 DEG DEG DEG 1 4 2 INTVCC2 3 3 RUN1 BOOST1 RUN2 17 IFAST 31 PHASMD IFAST2 CLKOUT PGOOD 19 ENTMPB 18 ENTMPB2 5 6 7 8 1 2 3 5 6 7 8 1 2 3 5 6 7 8 1 2 3 5 6 7 8 8 1 2 3 5 A B C D DEMO MANUAL DC2055A SCHEMATIC DIAGRAM dc2055afa 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 0 0 R53 R54 SW3 Q17 FDMS3620S OPT SW1 Q11 FDMS3620S OPT 5 CIN17 OPT BG1 TG1 CIN9 OPT 8 1 8 BG3 8 Q9 FDMS3620S OPT TG3 1 1 8 1 VIN RUN2 TK/SS2 ITH2 VO2_SNS- VFB2 CIN6 OPT Q5 FDMS3620S OPT CIN10 OPT 0 0 0 R51 R48 R46 OPTIONAL 5mm x 6mm Dual-MOSFETs RUN1 TK/SS1 ITH1 3 D VO1_SNS- VFB1 VIN SW4 4 Q18 FDMS3620S OPT SW2 Q12 FDMS3620S OPT TAVG1 VOUT1 R59 0 R61 0 R72 0 R67 0 R66 0 3 4 8 1 8 1 BG4 TG4 CIN12 OPT BG2 TG2 CIN11 OPT TAVG2 VOUT2 8 1 CIN8 OPT 8 1 CIN7 OPT VIN 2 Q6 FDMS3620S OPT VIN 3 Q10 FDMS3620S OPT OFF JP5 BIAS ON C27 10uF 16V + + IOUT2 COUT11 330uF 7343 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. J8 C33 100uF 6.3V 1210 1 NC BYP ADJ NC OUT OUT Q7 RJK0305DPB C30 100uF 6.3V 1210 2 SCALE = NONE 6 5 4 3 C36 0.22uF TECHNOLOGY R58 0.005 2512 4 C35 0.22uF R56 0.005 2512 4 C31 0.22uF R52 10K R50 34.8K 1% J7 OPT R47 J9 E17 E16 E19 E18 GND IO2STEP_CLK VOUT2 GND IO1STEP_CLK VOUT1 EXTVCC REV. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only R57 10K 1 1 C28 10uF 16V R55 10K +5.5V 1 DATE: 1 DEMO CIRCUIT 2055A LTC3875EUJ Tuesday, November 19, 2013 IC NO. SHEET 3 OF 3 2 HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS BUCK CONVERTER WITH VERY LOW DCR INDUCTOR SIZE B 1 2 Q8 RJK0305DPB C34 100uF 6.3V 1210 C32 0.22uF GND SHDN NC IN IN NC U2 LT1763CDE HAORAN W. TITLE: SCHEMATIC HZ 1 COUT12 330uF 7343 J10 + 7 8 9 10 11 12 COUT10 C29 330uF 100uF 7343 6.3V 1210 2 APPROVALS LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. CUSTOMER NOTICE + VIN 2 R49 10K IOUT1 COUT9 330uF 7343 LOAD STEP CIRCUIT 2 VOUT2 VOUT1 LOAD STEP CIRCUIT 1 VIN OPTIONAL 5.5V BIAS 3 1 GND 13 REMOVE ZERO OHM JUMPERS FOR DUAL-OUTPUT OPERATION 2 5 4 7 4 2 5 3 6 4 7 4 7 2 7 6 3 6 5 2 5 3 6 9 9 4 7 4 9 9 9 9 2 7 6 3 6 3 6 3 6 5 2 5 4 7 4 7 5 2 5 9 9 5 4 3 2 5 4 3 2 5 3 2 1 5 3 2 1 2 3 4 5 2 3 4 5 5 A B C D DEMO MANUAL DC2055A SCHEMATIC DIAGRAM dc2055afa 9 DEMO MANUAL DC2055A 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 dc2055afa LT 0316 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2014