Linear Technology LTC3875EUJ Quick setup guide

1
dc2055afa
DEMO MANUAL DC2055A
DESCRIPTION
LTC3875EUJ
High Efficient, Single Output
Synchronous Buck Converter
with Very Low DCR Inductor
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 LT C
®
3875EUJ feature-rich dual-phase synchronous
current mode buck controllers with very low DCR current
sensing capability,on-chip drivers and remote output volt-
age 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, 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.
PERFORMANCE SUMMARY
Specifications are at TA= 25°C
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
PARAMETER CONDITION VALUE
Input Voltage Range 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
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dc2055afa
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:
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, ad-
just 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
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DEMO MANUAL DC2055A
QUICK START PROCEDURE
+ –
VOUT GND
COUT
Figure 1. Proper Measurement Equipment Setup
Figure 2. Measuring Output Voltage Ripple
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DEMO MANUAL DC2055A
LOAD CURRENT (A)
0
35
30
25
20
15
10
5
060 100
20 40 80 120
CHANNEL CURRENT (A)
CHANNEL 1
CHANNEL 2
CHANNEL 3
CHANNEL 4
VIN = 12V
VOUT = 1.0V
fSW = 400kHz
LOAD CURRENT (A)
0
80
EFFICIENCY (%)
85
90
95
20 40 60 80 100 120
VIN = 12V
VOUT = 1.0V
fSW = 400kHz
QUICK START PROCEDURE
Figure 3. Efficiency vs Load Current
Figure 5. Current Sharing vs Load Current
Figure 6. Output Voltage Ripple at VIN = 12V, VOUT = 1.0V,
IOUT = 120A, fSW = 400kHz
Figure 7. Transient Performance at VIN = 12V, VOUT = 1.0V,
IOUT = 0A to 30A, fSW = 400kHz
Figure 4. Thermal Performance at VIN = 12V, VOUT = 1.0V,
IOUT = 120A, 200LFM Forced Air Flow
VOUT (20MHz BW) [20mV/DIV]
VOUT (20MHz BW) [50mV/DIV]
0A TO 30A
LOAD STEP
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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
Additional Demo Board Circuit Components
9 10 CIN2-CIN5, CIN13-CIN16, C27, C28 CAP., X5R, 10µF,16V, 10%, 1210 AVX 1210YD106KAT2A
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
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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
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DEMO MANUAL DC2055A
SCHEMATIC DIAGRAM
5
5
4
4
3
3
2
2
1
1
D D C C B B A A
60 DEG
90 DEG
120 DEG
GND VIN+
VIN-
EXTVCC
DCR = 0.32m OHM
GND
744301025
IFAST1
744301025
PLLIN
DCR = 0.32m OHM
CCMBM
PGOOD1
GND
4.5V - 14V
PS
VOUT1
TRK/SS1
VO1_SNS+
BUCK CONVERTER WITH VERY LOW DCR INDUCTOR
ON OFF
2 3 1
ENTMPB1
ON OFF
VO1_SNS-
RUN1
1.0V / 90A
RUN1
HZ
HAORAN W. 11-12-13
TG2 SW2 BG2
TRSET2
TG2
RUN1
PGOOD1
BG2
TRSET1
TK/SS1
ILIM1
TCOMP2
TG1
VO1_SNS-
TCOMP2TCOMP1
TRSET1
IFAST1
TG1
ENTMPB1
TAVG1
SW1
ITH1
BG1
SW1
VOUT1
TK/SS1
SW2
BG1
TCOMP1
TRSET2
TAVG1
VFB1
RUN1
EXTVCC
INTVCC1
VIN
INTVCC1
INTVCC1 VIN
INTVCC1
INTVCC1
VIN
INTVCC1
VIN
VIN
EXTVCC
INTVCC1
TG2 SW2 BG2
VO1_SNS-
VO1_SNS-
VOUT1
TK/SS1
VFB1
TG1
RUN1
VOUT1
ITH1
SW1
VO1_SNS+
VIN
VO1_SNS+
BG1
CLKOUT1
TAVG1
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
PRODUCTION2
__
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
PRODUCTION2
__
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
PRODUCTION2
__
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
2
Tuesday, November 19, 2013
13
HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS
HAORAN W.
B
LTC3875EUJ DEMO CIRCUIT 2055A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
2
Tuesday, November 19, 2013
13
HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS
HAORAN W.
B
LTC3875EUJ DEMO CIRCUIT 2055A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
2
Tuesday, November 19, 2013
13
HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS
HAORAN W.
B
LTC3875EUJ DEMO CIRCUIT 2055A
+
COUT2 330uF 2.5V 7343
+
COUT2 330uF 2.5V 7343
JP1MODE JP1MODE
1
2
3
4
C24 OPT C24 OPT
R3 OPT R3 OPT
R8
OPT
R8
OPT
R6
OPT
R6
OPT C2
0.1uF
C2
0.1uF
R38 OPT R38 OPT
R34 3.57k 1% R34 3.57k 1%
R20 10R20 10
J4J4
R12 715 1% R12 715 1%
D2
CMDSH-3
D2
CMDSH-3
R40 10kR40 10k
C19 220nF C19 220nF
R42 OPT R42 OPT
R5
OPT
R5
OPT
L2
0.25uH
L2
0.25uH
C7 0.1uF C7 0.1uF
C26 OPTC26 OPT
JP3JP3
Q4
BSC010NE2LSI
Q4
BSC010NE2LSI
3
1
2
4
5
6
7
8
C18
0.1uF
C18
0.1uF
E8E8
E12E12
R39 OPT R39 OPT
J1
VIN
J1
VIN
C3
220nF
C3
220nF
R17 0R17 0
R16 10R16 10
Q3 BSC050NE2LS Q3 BSC050NE2LS
3
1
2
4
5
6
7
8
C14
4.7uF
10V C14
4.7uF
10V
R28
100K
R28
100K
RN2 OPT RN2 OPT
1 2
R33 OPT R33 OPT
E14E14
SW1SW1
1
2
34
5
6
E7E7
R15 2K 1% R15 2K 1%
R32
100K
1% R32
100K
1%
C4
220nF
C4
220nF
RN6 OPT RN6 OPT
1 2
C6
OPT
C6
OPT
R23
0
R23
0
E4E4
J2J2
+
COUT5 330uF 2.5V
7343
+
COUT5 330uF 2.5V
7343
RN1 OPT RN1 OPT
1 2
COUT7 100uF
6.3V
1210
COUT7 100uF
6.3V
1210
R4 0 R4 0
E1E1
R11
3.57k
1% R11
3.57k
1%
R14 20k R14 20k
+
CIN18 270uF
16V
+
CIN18 270uF
16V
12
+
COUT6 330uF 2.5V
7343
+
COUT6 330uF 2.5V
7343
E3E3
COUT8 100uF
6.3V
1210
COUT8 100uF
6.3V
1210
R31 OPT R31 OPT
C5 OPT C5 OPT
C22 1uF C22 1uF
+
CIN1
270uF
16V
+
CIN1
270uF
16V
12
JP2PHASMD1 JP2PHASMD1
1
2
3
4
L1
0.25uH
L1
0.25uH
C9
220pF
C9
220pF
C13 1uF C13 1uF
COUT3 100uF
6.3V
1210
COUT3 100uF
6.3V
1210
R18
2.2
R18
2.2
R7
OPT
R7
OPT
E13E13
R35 715 1% R35 715 1%
Q2 BSC010NE2LSI Q2 BSC010NE2LSI
3
1
2
4
5
6
7
8
E6E6
R13
13.3k
R13
13.3k
RN5 OPT RN5 OPT
1 2
R22
OPT
R22
OPT
R9
3.01K
R9
3.01K
R1
20K
R1
20K
Q1 BSC050NE2LS Q1 BSC050NE2LS
3
1
2
4
5
6
7
8
R37 10kR37 10k
D1
CMDSH-3
D1
CMDSH-3
R27 OPT R27 OPT
CIN5 10uF 1210 CIN5 10uF 1210
CIN3 10uF 1210 CIN3 10uF 1210
C1
OPT
C1
OPT
U1
LTC3875EUJ
U1
LTC3875EUJ
TK/SS1
1
VOSNS1+
2
VOSNS1-
3
ITH1
4
ITH2
5
VOSNS2+
6
VOSNS2-
7
TK/SS2
8
SNSA2+
9
IFAST
17
ENTMPB
18
RUN2
16
BOOST2 22
BG2 23
EXTVCC 24
INTVCC 25
SNS2-
10
SNSD2+
11
TCOMP2
12
TAVG
13
TRSET2
14
FREQ
15
VIN 26
BG1 27
BOOST1 28
TG1 29
CLKOUT 31
PHASMD 32
MODE/PLLIN 33
RUN1 34
ILIM 35
TRSET1 36
TCOMP1 37
SNSD1+ 38
SNS1- 39
SGND/PGND
41
TG2 21
SW1 30
SNSA1+ 40
PGOOD
19
SW2 20
COUT1 100uF 6.3V 1210 COUT1 100uF 6.3V 1210
C23 OPT C23 OPT
R10 1K R10 1K
CIN2 10uF
1210
CIN2 10uF
1210
C8 4.7nFC8 4.7nF
C16
220nF
C16
220nF
R43 4.99kR43 4.99k
R2
OPT
R2
OPT
+
COUT4 330uF 2.5V
7343
+
COUT4 330uF 2.5V
7343
R41 OPT R41 OPT
J3J3
CIN4 10uF 1210 CIN4 10uF 1210
E5E5
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dc2055afa
DEMO MANUAL DC2055A
SCHEMATIC DIAGRAM
5
5
4
4
3
3
2
2
1
1
D D C C B B A A
60 DEG
90 DEG
120 DEG
RUN2
DCR = 0.32m OHM
744301025
IFAST2
744301025
DCR = 0.32m OHM
PGOOD2 VOUT2
VO2_SNS-
VO2_SNS+
ON
RUN2
CLKOUT
TRK/SS2
BUCK CONVERTER WITH VERY LOW DCR INDUCTOR
GND UP TO 30A
OFF
DUAL-OUTPUT
CONFIG L4 R86 R85
4.64k 931
0.33uF/0.32mOHM
744301033
ON OFF
2 3 1
ENTMPB2
C58R88
10k 1.5nF
R83 R84
30.1k 20k
R79 R68
00VOUT2 = 1.5V
HZ
TG4 SW4 BG4
TRSET4
TG4
PGOOD2
BG4
TRSET3
TK/SS2
ILIM2
VOUT1
TCOMP4
TG3
TCOMP4TCOMP3
TRSET3
IFAST2
CLKOUT
TG3
ITH2
SW3
ITH1
BG3
SW3
VOUT2SW4
BG3
TCOMP3
TRSET4
TAVG2
ENTMPB2
TAVG2
EXTVCC
INTVCC2
INTVCC2 VIN
INTVCC2
INTVCC2
VIN
INTVCC2
VIN
VIN
INTVCC2
TG4 SW4 BG4
VOUT1
TK/SS2
VFB2
TG3
RUN2
VO2_SNS-
VOUT2
VO2_SNS+
SW3
VO2_SNS+
ITH2
BG3
VO2_SNS-
ITH1
VO1_SNS-
VFB1
TK/SS1
RUN1 CLKOUT1
TAVG2
VIN
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
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2
Tuesday, November 19, 2013
23
HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS
HAORAN W.
B
LTC3875EUJ DEMO CIRCUIT 2055A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
2
Tuesday, November 19, 2013
23
HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS
HAORAN W.
B
LTC3875EUJ DEMO CIRCUIT 2055A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
2
Tuesday, November 19, 2013
23
HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS
HAORAN W.
B
LTC3875EUJ DEMO CIRCUIT 2055A
R92 OPT R92 OPT
R64 0R64 0
+
COUT18 330uF 2.5V
7343
+
COUT18 330uF 2.5V
7343
R77
3.57k
1% R77
3.57k
1%
R85 715 1% R85 715 1%
L3
0.25uH
L3
0.25uH
R89 OPTR89 OPT
E23E23
RN4 OPT RN4 OPT
1 2
E33E33
JP4JP4
Q13 BSC010NE2LSI Q13 BSC010NE2LSI
3
1
2
4
5
6
7
8
C56 1uF C56 1uF
J14J14
E27E27
C38
0.1uF
C38
0.1uF
C59 OPT C59 OPT
R93 OPT R93 OPT
R80
3.01K
R80
3.01K
R78 10kR78 10k
JP6
PHASMD2
JP6
PHASMD2
1
2
3
4
C57 220pFC57 220pF
R65
OPT
R65
OPT
COUT13 100uF
6.3V
1210
COUT13 100uF
6.3V
1210
CIN15 10uF 1210 CIN15 10uF 1210
Q16 BSC050NE2LS Q16 BSC050NE2LS
3
1
2
4
5
6
7
8
U3
LTC3875EUJ
U3
LTC3875EUJ
TK/SS1
1
VOSNS1+
2
VOSNS1-
3
ITH1
4
ITH2
5
VOSNS2+
6
VOSNS2-
7
TK/SS2
8
SNSPAC2
9
IFAST
17
ENTMPB
18
RUN2
16
BOOST2 22
BG2 23
EXTVCC 24
INTVCC 25
SNSN2
10
SNSPDC2
11
TCOMP2
12
TAVG
13
TRSET2
14
FREQ
15
VIN 26
BG1 27
BOOST1 28
TG1 29
CLKOUT 31
PHASMD
32
MODE/PLLIN 33
RUN1 34
ILIM 35
TRSET1 36
TCOMP1 37
SNSPDC1 38
SNSN1 39
SGND/PGND
41
TG2 21
SW1 30
SNSPAC1 40
PGOOD
19
SW2 20
R96 OPT R96 OPT
CIN14 10uF
1210
CIN14 10uF
1210
R90 OPT R90 OPT
R88 OPTR88 OPT
R62
2.2
R62
2.2
R81 1K R81 1K
R97
OPT
R97
OPT
D3
CMDSH-3
D3
CMDSH-3
+
COUT16 330uF 2.5V
7343
+
COUT16 330uF 2.5V
7343
CIN16 10uF 1210 CIN16 10uF 1210
CIN13 10uF 1210 CIN13 10uF 1210
C62
220nF
C62
220nF
C48 OPT C48 OPT
COUT20 100uF 6.3V 1210 COUT20 100uF 6.3V 1210
R94 OPT R94 OPT
RN7 OPT RN7 OPT
1 2
E28E28
R44 4.99kR44 4.99k R73
OPT R73 OPT
C58 OPT C58 OPT
R91
OPT
R91
OPT
+
COUT14 330uF 2.5V 7343
+
COUT14 330uF 2.5V 7343
D4
CMDSH-3
D4
CMDSH-3
R86 3.57k 1% R86 3.57k 1%
C49 OPT C49 OPT
C54 OPT C54 OPT
C37 OPTC37 OPT
R74 OPT R74 OPT
SW2SW2
1
2
34
5
6
C63 OPT C63 OPT
R101 10kR101 10k
J16J16
C52
220nF
C52
220nF
L4
0.25uH
L4
0.25uH
R70 715 1% R70 715 1%
Q15
BSC010NE2LSI
Q15
BSC010NE2LSI
3
1
2
4
5
6
7
8
R83
OPT
R83
OPT
R75 OPT R75 OPT
C44 220nF C44 220nF
C60 4.7uF 10V C60 4.7uF 10V
C42 0.1uF C42 0.1uF
R87
100K
R87
100K
R84 OPT R84 OPT
R76 OPT R76 OPT
Q14 BSC050NE2LS Q14 BSC050NE2LS
3
1
2
4
5
6
7
8
R99
100K
1% R99
100K
1%
RN8 OPT RN8 OPT
1 2
C46
220nF
C46
220nF
R60 0R60 0
C43
0.1uF
C43
0.1uF
R82 0R82 0
E24E24
COUT19 100uF
6.3V
1210
COUT19 100uF
6.3V
1210
+
COUT17 330uF 2.5V
7343
+
COUT17 330uF 2.5V
7343
R68 OPTR68 OPT
R63 OPT R63 OPT
RN3 OPT RN3 OPT
1 2
E29E29
R79 OPTR79 OPT
C55 OPT C55 OPT
COUT15 100uF
6.3V
1210
COUT15 100uF
6.3V
1210
R69 OPT R69 OPT
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9
dc2055afa
DEMO MANUAL DC2055A
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
5
5
4
4
3
3
2
2
1
1
D D C C B B A A
VOUT2
IOUT2
IO2STEP_CLK
2512
1210 1210
REMOVE ZERO OHM JUMPERS FOR DUAL-OUTPUT OPERATION
OPTIONAL 5mm x 6mm Dual-MOSFETs
OPTIONAL 5.5V BIAS
ON
OFF
BIAS
VOUT1
LOAD STEP CIRCUIT 1
IOUT1
IO1STEP_CLK
2512
1210 1210
FDMS3620S
FDMS3620S
FDMS3620S
FDMS3620S
LOAD STEP CIRCUIT 2
FDMS3620S
FDMS3620S
FDMS3620S
FDMS3620S
BUCK CONVERTER WITH VERY LOW DCR INDUCTOR
HZ
VIN
VIN EXTVCC
+5.5V
VIN
VIN
VIN
TG2 BG2
SW2
VFB1 VFB2
VO1_SNS- VO2_SNS-
ITH1 ITH2
TK/SS1 TK/SS2
RUN1 RUN2
TG1 BG1
SW1
VOUT1
VIN
VOUT2
TG4 BG4
SW4
TG3 BG3
SW3
VOUT1 VOUT2 TAVG1 TAVG2
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
2
Tuesday, November 19, 2013
33
HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS
HAORAN W.
B
LTC3875EUJ DEMO CIRCUIT 2055A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
2
Tuesday, November 19, 2013
33
HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS
HAORAN W.
B
LTC3875EUJ DEMO CIRCUIT 2055A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
2
Tuesday, November 19, 2013
33
HIGH EFFICIENCY HIGH CURRENT POLYPHASE SYNCHRONOUS
HAORAN W.
B
LTC3875EUJ DEMO CIRCUIT 2055A
Q11
OPT
Q11
OPT
4
2
3
1
5
6
7
8
9
C29 100uF 6.3V C29 100uF 6.3V
Q18 OPT Q18 OPT
4
2
3
1
5
6
7
8
9
R50 34.8K 1% R50 34.8K 1%
Q6 OPT Q6 OPT
4
2
3
1
5
6
7
8
9
R46 0R46 0
R67
0
R67
0
Q10 OPT Q10 OPT
4
2
3
1
5
6
7
8
9
+
COUT11 330uF
7343
+
COUT11 330uF
7343
J9J9
1
2
3
4
5
R53 0R53 0
C31
0.22uF
C31
0.22uF
CIN7 OPT CIN7 OPT
J7J7
1
2
3
4
5
C35
0.22uF
C35
0.22uF
C27 10uF 16V C27 10uF 16V
CIN9 OPT CIN9 OPT
+
COUT9 330uF
7343
+
COUT9 330uF
7343
CIN6 OPT CIN6 OPT
C32
0.22uF
C32
0.22uF
+
COUT12 330uF
7343
+
COUT12 330uF
7343
CIN8 OPT CIN8 OPT
J10J10
1
2
3
4
5
R54 0R54 0
CIN11 OPT CIN11 OPT
E19
GND
E19
GND
U2
LT1763CDE
U2
LT1763CDE
NC 1 NC 4
OUT 3 OUT 2
ADJ 5
BYP 6
GND
7
SHDN
8
NC
9
IN
10
IN
11
NC
12
GND
13
C28 10uF 16V C28 10uF 16V
+
COUT10 330uF
7343
+
COUT10 330uF
7343
Q8
RJK0305DPB
Q8
RJK0305DPB
1
25
3
4
R61
0
R61
0
J8J8
1
2
3
4
5
R58 0.005 R58 0.005
R72
0
R72
0
CIN12
OPT
CIN12
OPT
C36
0.22uF
C36
0.22uF
R56 0.005 R56 0.005
C34 100uF 6.3V C34 100uF 6.3V
Q12 OPT Q12 OPT
4
2
3
1
5
6
7
8
9
Q9
OPT
Q9
OPT
4
2
3
1
5
6
7
8
9
E17 GND E17 GND
CIN17 OPT CIN17 OPT
E16E16
Q17
OPT
Q17
OPT
4
2
3
1
5
6
7
8
9
E18E18
R48 0 R48 0
R52 10K R52 10K
C30 100uF 6.3V C30 100uF 6.3V
R49 10K R49 10K
Q7
RJK0305DPB
Q7
RJK0305DPB
1
25
3
4
Q5
OPT
Q5
OPT
4
2
3
1
5
6
7
8
9
JP5JP5
1
2
3
CIN10 OPT CIN10 OPT
R66
0
R66
0
R57 10K R57 10K
C33 100uF 6.3V C33 100uF 6.3V
R59
0
R59
0
R47 OPT R47 OPT
R55 10K R55 10K
R51 0R51 0
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10
dc2055afa
DEMO MANUAL DC2055A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
LT 0316 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
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