DC2225A - Demo Manual

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
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