DC2055A - Demo Manual

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
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