LINER LTC3866EUF High efficiency step-down converter with very low dcr inductor Datasheet

DEMO MANUAL DC1829A
LTC3866EUF
High Efficiency Step-Down Converter
with Very Low DCR Inductor
DESCRIPTION
Demonstration circuit 1829A is a high efficiency, high
density, synchronous buck converter with 4.5V to 14V
input voltage range. It can supply a 30A maximum load
current with a 1.5V output. This demo board utilizes the
LTC®3866EUF, a feature-rich single phase synchronous
buck controller with very low DCR current sensing capability, on-chip drivers and remote output voltage sensing. This
board is setup with 0.32mΩ DCR inductor. The temperature
compensation function guarantees accurate current limit
over a wide temperature range with DCR sensing.
To shut down the converter, set the RUN pin voltage below
1.2V (JP2: 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, and it can be easily modified from 250kHz
to 770kHz. Onboard dynamic circuit is also available for
transient test. Please see LTC3866 data sheet for more
detailed information.
The LTC3866 is suitable for operation from an input voltage
of 4.5V to 38V and output voltages up to 3.5V. It can provide
high efficiency, high power density and versatile power
solutions for telecom and datacom systems, industrial and
medical instruments, along with DC power distribution
systems and computer systems. The LTC3866 is available
in 24-pin 4mm × 4mm QFN and 24-lead FE packages.
L, LT, LTC, LTM, μModule, 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
PARAMETER
Design files for this circuit board are available at
http://www.linear.com/demo
(TA = 25°C)
CONDITION
Input Voltage Range
VALUE
4.5V to 14V
Output Voltage, VOUT
VIN = 4.5V to 14V, IOUT = 0A to 30A
1.5V ±2%
Maximum Output Current, IOUT
VIN = 4.5V to 14V, VOUT = 1.5V
30A
Typical Efficiency
VIN = 12V, VOUT = 1.5V, IOUT = 30A
90.3%
Typical Switching Frequency
400kHz
dc1829af
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DEMO MANUAL DC1829A
QUICK START PROCEDURE
Demonstration circuit 1829A is easy to set up to evaluate
the performance of the LTC3866EUF. Refer to Figure 1 for
the proper measurement equipment setup and follow the
procedure below:
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.
1. With power off, connect the input power supply to VIN
(4.5V to 14V) and GND (input return).
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.
2. Connect the 1.5V output load between VOUT and GND
(Initial load: no load).
3. Connect the DVMs to the input and outputs. Set default
jumper position: JP1: CCM; JP2: ON.
4. Turn on the input power supply and check for the proper
output voltages. VOUT should be 1.5V ±2%.
Figure 1. Proper Measurement Equipment Setup
dc1829af
2
DEMO MANUAL DC1829A
QUICK START PROCEDURE
Figure 2. Measuring Output Voltage Ripple
Efficiency Test at CCM
96
94
EFFICIENCY (%)
92
90
88
86
84
82
80
VIN = 4.5V
VIN = 12V
VIN = 14V
78
76
0
5
10
20
15
LOAD CURRENT (A)
25
30
dc1829a F03
Figure 3. Efficiency vs Load Current
Load Regulation at VIN = 12V
1.7
OUTPUT VOLTAGE (V)
1.5
1.3
1.1
0.9
0.7
0.5
0
10
20
30
LOAD CURRENT (A)
40
dc1829a F04
Figure 4. Output Voltage vs Load Current
dc1829af
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DEMO MANUAL DC1829A
QUICK START PROCEDURE
Top View
Bottom View
L
QB
QT
3866
dc1829a F05a
dc1829a F05b
Figure 5. Thermal Performance at VIN = 14V, VO = 1.5V, IO = 30A, No Forced Air, TA = 25°C
VSW
(200mV/DIV)
VP-P = 331mV
IO
(20A/DIV)
IO = 0A TO 25A
t (50μs/DIV)
dc1829a F06
Figure 6. Transient Performance at VIN = 12V, VO = 1.5V, IO = 0A ~ 25A
dc1829af
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DEMO MANUAL DC1829A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
2
CIN1, CIN2
CAP, 180μF 20% 16V
SANYO 16SVP180MX
2
2
CIN3, CIN4
CAP, 1210 10μF 20% 25V X5R
TAIYO YUDEN TMK325BJ106MM-T
3
2
COUT1, COUT2
CAP, 7343 330μF 20% 2.5V POSCAP
SANYO 2R5TPE330M9
4
4
COUT3, COUT6, C15, C16
CAP, 1210 100μF 20% 6.3V X5R
TDK C3225X5R0J107M
5
2
C19, C21
CAP, 0603 1μF 10% 25V X5R
TAIYO YUDEN TMK107BJ105MA-T
6
2
C22, C27
CAP, 0603 220nF 10% 25V X7R
TDK C1608X7R1E224K
7
2
C24, C25
CAP, 0603 0.1μF 10% 10V X5R
AVX 0603ZD104KAT
8
1
C26
CAP, 0603 1.5nF 5% 50V C0G
MURATA GRM1885C1H152JA01D
9
1
C28
CAP, 0603 220pF 10% 25V NPO
AVX 06033A221KAT2A
10
1
C31
CAP, 0805 4.7μF 20% 10V X5R
TDK C2012X5R1A475M
11
1
D2
DOIDE, CMDSH-3
CENTRAL SEMI CMDSH-3
12
1
L1
IND, 0.33μH
WURTH ELEKTRONIK M744301033
13
1
Q1
XSTR, POWER MOSFET
INFINEON BSC050NE2LS
14
1
Q3
XSTR, POWER MOSFET
INFINEON BSC010NE2LS
15
1
Q5
XSTR, SUD50N03-09P MOSFET
SILICONIX SUD50N03-09P
16
5
R9, R32, R34, R36, R44
RES, 0603 0Ω JUMPER 1/10W
VISHAY CRC06030000Z0EA
17
1
R10
RES, 0603 100k 5% 1/10W
VISHAY CRCW0603100KJNEA
18
1
R11
RES, 0603 10k 5% 1/10W
VISHAY CRCE060310K0JNEA
19
1
R12
RES, 2512 0.010Ω 5% 1W
VISHAY WSL2512R0100FEA
20
1
R27
RES, 0603 100k 1% 1/10W
VISHAY CRCW0603100KFKEA
21
1
R28
RES, 0603 1k 1% 1/10W
VISHAY CRCW06031K00FKEA
22
1
R30
RES, 0603 931Ω 1% 1/10W
YAGEO RC0603FR-07931RL
23
2
R31, R45
RES, 0603 10Ω 5% 1/10W
VISHAY CRCW060310R0JNEA
24
1
R37
RES, 0603 2.2Ω 5% 1/10W
VISHAY CRCW06032R20JNEA
25
1
R38
RES, 0603 20k 1% 1/10W
VISHAY CRCW060320K0FKEA
26
1
R39
RES, 0603 30.1k 1% 1/10W
VISHAY CRCW060330K1FKEA
27
1
R40
RES, 0603 10k 1% 1/10W
VISHAY CRCW060310K0FKEA
28
1
R42
RES, 0603 3.01k 1% 1/10W
VISHAY CRCW06033K01FKEA
29
1
R43
RES, 0603 4.64k 1% 1/10W
VISHAY CRCW06034K64FKEA
30
1
U1
IC, STEP-DOWN CONVERTER
LINEAR TECH LTC3866EUF
Additional Demo Board Circuit Components
1
0
COUT4, COUT5
CAP, 7343 330μF 20% 2.5V POSCAP OPTION
SANYO 2R5TPE330M9 OPTION
2
0
C23, C29, C32, C33, C34
CAP, 0603 OPTION
OPTION
3
0
Q2, Q4
XSTR, OPTION
OPTION
4
0
RN1
THERMISTOR, OPTION
OPTION
5
0
R1-R6, R35, R41, R47, R48
RES, 0603 OPTION
OPTION
6
0
R18
RES, 2512 OPTION
OPTION
dc1829af
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DEMO MANUAL DC1829A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Hardware/Components (For Demo Board Only)
1
13
E1, E2, E4-E8, E10-E15
TURRET
MILL-MAX 2501-2-00-80-00-00-07-0
2
1
JP1
HEADER, 4 PIN
SAMTEC TMM-104-02--L-S
3
1
JP2
HEADER, 3 PIN
SAMTEC TMM-103-02--L-S
4
2
J1, J2
JACK, BANANA
KEYSTONE 575-4
5
2
J3, J4
STUD, TEST PIN
PEM KFH-032-10
6
4
J3, J4
NUT, BRASS PL #10-32
ANY, #10-32M/S
7
2
J3, J4
RING, LUG RING #10
KEYSTONE, 8205
8
2
J3, J4
WASHER, TIN, PLATED BRASS
ANY
9
2
J5, J6
CONN, BNC, 5 PINS
CONNEX 112404
10
4
MH1, MH2, MH3, MH4
STANDOFF, SNAP ON
KEYSTONE_8833
11
2
JP1, JP2
SHUNT
SAMTEC 2SN-BK-G
dc1829af
6
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
D
E2
E1
E4
CLKOUT
GND
R9 0
C28
220pF
E12
E11
5
CLKOUT
C21
1uF
R38
20k
1%
C24
0.1uF
10V
R32 0
C23
OPT
RUN
ON
OFF
1
3
JP2
2
EXTVCC
E10
R40
10k
1%
C26
1.5nF
EXTVCC
TRK/SS
RUN
MODE/PLLIN
R6
OPT
R34 0
VOUT
R41
OPT
VOUT
R5
OPT
C29
OPT
OPT
C32
R39
30.1k
1%
R35
OPT
R2
OPT
R1
OPT
VIN
2
MODE/PLLIN
P.S. BURST CCM
1
4
JP1
3
INTVCC
6
5
4
3
2
1
R10
100k
4
OPT
OPT
12
13
14
15
16
17
18
ILIM
CLKOUT
BG
SW
TG
BOOST
INTVCC
VIN
EXTVCC
RN1
OPT
R47
OPT
OPT
R48
OPT
C34
R28
1k
1%
R42
3.01k
1%
INTVCC
R36 0
INTVCC
C19
1uF
EXTVCC
INTVCC
LTC3866EUF
U1
ITEMP
100k 1%
R27
TEMPERATURE COMPENSATION
NETWORK FOR DCR SENSING
ITEMP
220nF
R4
C27
220nF
R3
C22
SNSD+
DIFFP
DIFFN
DIFFOUT
VFB
ITH
4
SGND
25
PGOOD
24
TK/SS
23
RUN
22
FREQ
SNS-
21
8
4
4
CUSTOMER NOTICE
+
COUT5 IOUT
330uF
OPT
7343
1
C15
100uF
6.3V
1210
Q2
OPT
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
G
J6
GND
IOSTEP CLK
R31
10
TECHNOLOGY
E7
E15
VOUT
C33
OPT
COUT6 COUT3
100uF 100uF
6.3V
6.3V
1210
1210
VOUT
CIN2
180uF
16V
+
R45
10
COUT1
330uF
2.5V
7343
+
+
VOUT
GND
GND
4.5V ~ 14V
VIN
E13
VO_SNS-
VO_SNS+
E14
GND
COUT2 1.5V / 30A
330uF
2.5V
7343
J4
J3
E6
CIN1
180uF
16V
J2
VIN
JIAN L.
APPROVED
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
+
J1
E5
DATE
07/27/11
1
PROTO
VIN
REVISION HISTORY
DESCRIPTION
Monday, December 12, 2011
DATE:
1
SHEET
DEMO CIRCUIT 1829A
PCB NO.
N/A
LTC3866EUF
IC NO.
SIZE
1 OF
1
2
REV
HIGH EFFICIENCY STEP-DOWN CONVERTER
WITH VERY LOW DCR INDUCTOR
TITLE: SCHEMATIC
R11
10K
1
R43 R44
4.64k 0
1%
DCR=0.32mOHM
Q5
SUD50N03-09P
R18
OPT
2512
2
CIN3
10uF
25V
1210
L1 0.33uH
2
REV
744301033
CIN4
10uF
25V
1210
ECO
CONTRACT NO.
R12
0.010
2512
S
D
R30
931
1%
Q4
OPT
2
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
APPROVALS
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. MI
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
ENG. JIAN L.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
+
COUT4
330uF
OPT
7343
VOUT
4
Q3
BSC010NE2LS
SW
4
Q1
BSC050NE2LS
VIN
VOUT
C16
100uF
6.3V
1210
J5
INTVCC
LOAD STEP CIRCUIT
CMDSH-3
D2
C25
0.1uF
10V
VIN
C31
4.7uF
10V
0805
R37 2.2
3
5
5
2
1
7
MODE/PLLIN
SNSA+
19
ITEMP
20
PGOOD
ILIM
9
CLKOUT
10
PGND
11
5
1
2
3
5
1
2
3
1
2
3
5
1
2
3
5
4
3
2
2
3
4
5
E8
A
B
C
D
DEMO MANUAL DC1829A
SCHEMATIC DIAGRAM
dc1829af
7
DEMO MANUAL DC1829A
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
dc1829af
8
Linear Technology Corporation
LT 1211 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2011
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