5 4 3 2 1 REVISION HISTORY R1 20K VIN R2 OPT __ 1 APPROVED PRODUCTION JIAN L. 1 2 4 JP2 VIN R3 OPT VIN+ 6 3 B TRSET2 TG2 C18 0.1uF D2 CMDSH-3 9 4 2 COUT1 100uF 6.3V 1206 + COUT2 470uF 2.5V 7343 + COUT4 C10 100uF 6.3V 470uF 2.5V 7343 VO_SNS+ J5 J3 VOUT C11 100uF 1.0V 6.3V J4 / 160A GND J6 Q2 BSG0811ND VO_SNS- R20 10 E8 C GND VO_SNS- VIN Q3 BSG0811ND SW2 CIN4 22uF 1206 BG2 CIN5 22uF 1206 5 6 7 2 VIN L2 8 R33 OPT R28 INTVCC1 Q4 BSG0811ND 1 2 8 R43 4.99k COUT7 100uF 6.3V 1206 0.25uH 744301025 DCR = 0.32m OHM 5 6 7 10 TAVG INTVCC1 1 R40 10k 2 1 20 100K TAVG 9 10 3 21 3 R37 10k COUT3 100uF 6.3V 1206 VIN- 8 10 TRSET1 2 SW1 C14 4.7uF 25V SW2 R32 100K 1% E7 R23 0 RUN R31 OPT 5 6 7 1 10 22 GND VOUT 9 PGOOD ENTMPB IFAST RUN2 SW2 C13 1uF J2 E6 0.25uH 744301025 DCR = 0.32m OHM VIN INTVCC1 EXTVCC 4.5V - 14V + VO_SNS+ VIN 25 23 CIN1 270uF 16V R12 715 1% R11 3.57k 1% R18 2.2 26 + 8 CMDSH-3 24 CIN9 CIN12 22uF 270uF 1206 16V L1 INTVCC1 D1 BG1 CIN8 22uF 1206 R16 10 4 220nF TG2 R17 0 19 R27 OPT 18 SGND/PGND C19 3 BOOST2 SNS2- 27 2 0.1uF TG1 28 CIN2 22uF 1206 CIN7 22uF 1206 5 6 7 1 C7 30 29 CIN3 22uF 1206 9 CLKOUT 31 32 33 RUN1 PHASMD MODE/PLLIN TRSET1 34 TCOMP1 36 35 38 SNS1- SNSA2+ 17 41 BG2 IFAST1 C22 1uF E13 10 TK/SS2 ENTMPB E12 C16 220nF EXTVCC VOSNS2- 16 R22 OPT EXTVCC VIN INTVCC FREQ 9 TG1 BG1 VOSNS2+ TRSET2 8 SW1 BOOST1 ITH2 15 7 CLKOUT SW1 ITH1 14 6 TRSET2 5 ITH TCOMP2 C9 680pF SNSD2+ R15 707 1% VOSNS1- 13 C 4 CLKOUT U1 LTC3875EUJ 12 ITH VOSNS1+ TAVG 3 C8 10nF TK/SS1 TCOMP2 2 SNSD1+ 40 1 SNSA1+ TK/SS 39 C6 OPT 11 R14 20k Q1 BSG0811ND ILIM1 ILIM 220nF TRSET1 37 220nF VO_FB VO_SNS- R10 2K 4 R7 OPT C4 CIN6 22uF 1206 VIN INTVCC1 4 OPT C3 R9 2K 3 OPT C5 OPT R13 13.3k VO_SNS+ C2 0.1uF R8 TCOMP1 R6 OPT R5 TAVG R4 0 1 VIN TK/SS E5 GND D E4 VIN J1 TRK/SS EXTVCC DATE 3-20-14 INTVCC1 120 90 4 1 C1 OPT 2 DESCRIPTION PHASMD 60 DEG DEG DEG JP1 PLLIN RUN ON 5 OFF D 2 E3 SW1 RUN REV 4 3 RUN 1 3 MODE PS BM CCM INTVCC1 E1 ECO COUT8 100uF 6.3V 1206 COUT5 + 470uF 2.5V 7343 COUT6 C20 100uF 6.3V + 470uF 2.5V 7343 C21 100uF 6.3V B R34 3.57k 1% R35 715 1% C26 OPT TCOMP1 ENTMPB C24 OPT 2 2 C23 OPT R45 OPT R42 OPT 1 RN2 OPT CUSTOMER NOTICE A 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. APPROVALS PCB DES. APP ENG. TECHNOLOGY HZ JIAN L. 4 3 2 N/A SCALE = NONE 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 SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 PGOOD PGOOD R39 OPT R41 OPT 1 RN1 OPT E14 PGOOD TCOMP2 R38 OPT DATE: IC NO. LTC3875EUJ REV. DEMO CIRCUIT 2225A Wednesday, December 09, 2015 1 1 SHEET 1 OF 3 A 5 4 3 2 1 REVISION HISTORY ECO REV __ DESCRIPTION 1 APPROVED PRODUCTION JIAN L. DATE 3-20-14 CLKOUT E20 R64OPT INTVCC2 R69 OPT RUN D D B TRSET4 20 TG4 C28 0.1uF TAVG 9 4 1 2 COUT22 100uF 6.3V 1206 470uF 2.5V 7343 + COUT12 C41 100uF 6.3V 470uF 2.5V 7343 C50 100uF 6.3V C 8 INTVCC2 VIN Q7 BSG0811ND SW4 CIN16 22uF 1206 BG4 PGOOD COUT9 100uF 6.3V 1206 + COUT10 Q6 BSG0811ND 5 6 7 1 PGOOD SW4 ENTMPB CIN15 22uF 1206 2 VIN L4 8 3 R36 OPT R75 10k Q8 BSG0811ND 1 5 6 7 2 8 R44 4.99k COUT21 100uF 6.3V 1206 0.25uH 744301025 DCR = 0.32m OHM 9 21 D4 CMDSH-3 10 TAVG R55 10k 2 SW3 C45 4.7uF 25V 10 22 5 6 7 1 10 TRSET3 R73 100K 1% 9 10 3 C44 1uF VIN + R61 0 RUN R66 OPT VIN INTVCC2 EXTVCC CIN10 270uF 16V VOUT 0.25uH 744301025 DCR = 0.32m OHM VIN 25 23 + R29 715 1% R52 3.57k 1% R24 2.2 26 24 CIN20 CIN13 22uF 270uF 1206 16V L3 INTVCC2 D3 CMDSH-3 BG3 CIN19 22uF 1206 8 4 PGOOD TG2 SW2 R19 0 28 27 0.1uF TG3 19 ENTMPB IFAST RUN2 18 220nF 17 R70 OPT ENTMPB SGND/PGND C29 3 BOOST2 SNS2- 30 29 CIN18 22uF 1206 5 6 7 2 C48 CIN14 22uF 1206 9 CLKOUT 31 32 33 RUN1 PHASMD MODE/PLLIN TRSET3 34 TCOMP3 36 38 35 ILIM TRSET1 37 SNSD1+ TCOMP1 SNS1- SNSA2+ IFAST2 41 BG2 16 C27 1uF C47 220nF TK/SS2 FREQ EXTVCC 10 EXTVCC VOSNS2- TRSET2 R71 OPT VIN INTVCC 15 9 BG1 VOSNS2+ TAVG 8 TG1 BOOST1 ITH2 TCOMP2 7 SW1 CIN11 22uF 1206 1 SW3 ITH1 14 6 13 5 ITH U2 LTC3875EUJ VOSNS1- TAVG C43 47pF VOSNS1+ Q5 BSG0811ND ILIM2 TRSET4 C 4 SNSA1+ 40 ITH SNSD2+ 3 VO_SNS- 12 2 VO_FB TK/SS1 11 1 39 220nF TCOMP4 TK/SS R57 2K CLKOUT C42 220nF TK/SS R67 OPT OPT C30 CIN17 22uF 1206 VIN INTVCC2 4 OPT R562K 4 R68 3 R65 2 1 VIN COUT11 100uF 6.3V 1206 COUT13 + 470uF 2.5V 7343 COUT14 + 470uF 2.5V 7343 C46 100uF 6.3V C25 100uF 6.3V B R63 3.57k 1% R62 715 1% C40 OPT TCOMP3 TCOMP4 R47 OPT R50 OPT C39 OPT R49 OPT RN5 OPT 1 R46 OPT 1 RN6 OPT 2 2 C32 OPT CUSTOMER NOTICE A 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. APPROVALS PCB DES. APP ENG. TECHNOLOGY HZ JIAN L. TITLE: SCHEMATIC HIGH EFFICIENCY, SINGLE-OUTPUT SYNCHRONOUS BUCK CONVERTER WITH VERY LOW DRC INDUCTOR SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 2 N/A SCALE = NONE 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only DATE: IC NO. LTC3875EUJ REV. DEMO CIRCUIT 2225A Wednesday, December 09, 2015 1 1 SHEET 2 OF 3 A 4 3 VIN VIN 12 11 10 C31 10uF 16V JP5 BIAS ON 9 R51 10K 8 7 3 D 2 1 U3 LT1763CDE OPTIONAL 5.5V BIAS 2 NC NC IN OUT IN OUT NC NC SHDN GND EXTVCC R48 OPT 3 R54 34.8K 1% 4 5 C35 10uF 16V D 6 BYP R53 10K 1 13 OFF +5.5V 1 2 ADJ GND 5 LOAD STEP CIRCUIT + COUT15 OPT 7343 + COUT16 OPT 7343 + COUT19 OPT 7343 + C38 OPT 6.3V 1210 COUT20 OPT 7343 1 C37 OPT 6.3V 1210 C33 1uF Q21 SUD50N03-09P VOUT Q20 SUD50N03-09P 1 3 1 3 J10 1 E18 C34 0.22uF 5 4 3 2 IOUT J9 C 4 2 C + COUT18 OPT 7343 2 3 4 5 + COUT17 OPT 7343 4 2 VOUT R60 0.005 2512 R58 OPT 2512 IOSTEP CLK R59 10K E19 GND B B CUSTOMER NOTICE 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 APPLICATION. COMPONENT SUBSTITUTION AND PRINTED APP ENG. CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. A TECHNOLOGY HZ JIAN L. TITLE: SCHEMATIC HIGH EFFICIENCY, SINGLE-OUTPUT SYNCHRONOUS BUCK CONVERTER WITH VERY LOW DRC INDUCTOR SIZE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 N/A SCALE = NONE 2 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only DATE: IC NO. LTC3875EUJ REV. 1 DEMO CIRCUIT 2225A Wednesday, December 09, 2015 SHEET 3 1 OF 3 A