Linear Technology LTC3864 Quick setup guide

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DEMO MANUAL DC1722A
DESCRIPTION
LTC3864
55V Low IQStep-Down
DC/DC Converter with
100% Duty Cycle Capability
Demonstration circuit 1722A is a high voltage, current
modeDC/DCstep-downconverterfeaturingtheLT C
®
3864.
The board operates from an input range of 3.5V to 55V,
and provides a 5V, 2A output when the input exceeds 5V.
The PMOSFET architecture allows it to operate seamlessly
up to 100% duty cycle, and function as a saturated switch
below the regulation threshold, down to 3.5VIN. It operates
at 350kHz and may be synchronized to an external clock.
A soft-start feature controls output voltage slew rate at
start-up, reducing current surge and voltage overshoot.
Burst Mode
®
operation that improves efficiency at light
loads can be enabled with a jumper. A power good output
signal is provided. The demonstration board has options
L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
PERFORMANCE SUMMARY
for larger MOSFET and diode packages on the back of the
board for higher output current requirements.
This board is suitable for a wide range of automotive,
telecom, industrial, and other applications. The LTC3864
is available in small 12-pin thermally enhanced MSOP and
DFN packages. For other output requirements, see the
LTC3864 data sheet or contact the LT C factory.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1722A
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Input Supply Range 3.5 55 V
VOUT Output Voltage 5.0 V
IOUT Output Current Range, Continuous 0 2 A
fSW Switching (Clock) Frequency 350 kHz
VOUT(P-P) Output Ripple VIN = 14V, IOUT = 2A (20MHz BW) 15 mVP–P
VREG Output Regulation Line and Load (5.5VIN to 55VIN, 0AOUT to 2AOUT) 0.23 %
POUT/PIN Efficiency (See Figure 3) VIN =14V, IOUT = 2A 84 %
Approximate Size Component Area x Top Component Height 0.6 × 0.6 × 0.14 Inches
Specifications are at TA= 25°C
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DEMO MANUAL DC1722A
QUICK START PROCEDURE
Demonstration circuit 1722 is easy to set up to evaluate
the performance of the LTC3864. Refer to Figure 1 for
proper measurement equipment setup and follow the
procedure below:
NOTE:Whenmeasuringtheoutputvoltage ripple, caremust
be taken to avoid a long ground lead on the oscilloscope
probe. Measure the output voltage ripple by touching the
probe tip and ground ring directly across the last output
capacitor as shown in Figure 1.
1. Set an input power supply that is capable of 3.5V to
55V to 6V. Then turn off the supply.
2. Withpoweroff, connect the supply to the input terminals
VIN and GND.
a. Input voltages lower than 3.5Vcan keep the converter
from turning on due to the undervoltage lockout
feature of the LTC3864.
b. If efficiency measurements are desired, an ammeter
capable of measuring 2ADC or a resistor shunt can
be put in series with the input supply in order to
measure the DC1722A’s input current.
c. A voltmeter with a capability of measuring at least
55V can be placed across the input terminals in order
to get an accurate input voltage measurement.
3. Turn on the power at the input.
NOTE: Make sure that the input voltage never exceeds 55V.
4. Check for the proper output voltage of 5V. Turn off the
power at the input.
5. Once the proper output voltage is established, connect
a variable load capable of sinking 2A at 5V to the output
terminals VOUT and GND. Set the current for 0A.
a. If efficiency measurements are desired, an ammeter
or a resistor shunt that is capable of handling 2ADC
can be put in series with the output load in order to
measure the DC1722A’s output current.
b. A voltmeter with a capability of measuring at least 5V
can be placed across the output terminals in order
to get an accurate output voltage measurement.
6. Turn on the power at the input.
NOTE: If there is no output, temporarily disconnect
the load to make sure that the load is not set too high.
7. Once the proper output voltage is again established,
adjust the load and/or input within the operating range
and observe the output voltage regulation, ripple volt-
age, efficiency and other desired parameters.
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DEMO MANUAL DC1722A
Figure 1. Proper Measurement Equipment Setup
QUICK START PROCEDURE
DC1722a F01
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DEMO MANUAL DC1722A
QUICK START PROCEDURE
Figure 2. Efficiency with Burst Mode Operation at Light Loads
Figure 3. Output Ripple at 14VIN and 2AOUT (10mV, 2µs/DIV, 20MHz)
IOUT (A)
EFFICIENCY (%)
DC1722a F02
95
90
85
80
75
70
65
60
55
0.01 1 100.1
VIN = 6V
VIN = 14V
VIN = 28V
VIN = 55V
DC1722a F03
2µs/DIV
10mV/DIV
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DEMO MANUAL DC1722A
QUICK START PROCEDURE
Figure 4. Transient Response Waveform at 14VIN and 1A - 2A - 1AOUT (1A, 50mV,100µs/DIV)
DC1722a F04
100µs/DIV
1A/DIV
50mV/DIV
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DEMO MANUAL DC1722A
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 CIN1 CAP, 10μF 20% 63V ALUM SUN ELEC. 63HEH10M
2 1 CIN2 CAP, 1210 2.2μF 10% 100V X7R MURATA GRM32ER72A225KA35L
3 2 COUT1, COUT2 CAP, 1812 100μF 20% 6.3V X5R TDK C4532X5R0J107M
4 1 COUT3 CAP, 0603 1μF 10% 6.3V X5R TAIYO YUDEN JMK107BJ105KA-T
5 1 C1 CAP, 0402 100pF 5% 25V NPO AVX 04023A101JAT2A
6 1 C2 CAP, 0402 2200pF 10% 25V X7R AVX 04023C222KAT2A
7 1 C4 CAP, 0402 47pF 5% 25V NPO AVX 04023A470JAT2A
8 1 C5 CAP, 0603 0.47μF 20% 16V X7R AVX 0603YC474MAT2A
9 1 C6 CAP, 0402 0.1μF 20% 16V X5R AVX 0402YD104MAT2A
10 1 C7 CAP, 0805 0.1μF 20% 100V X5R TDK C2012X5R2A104M
11 1 C8 CAP, 0402 220pF 5% 25V NPO AVX 04023A221JAT2A
12 1 D1 DIODE, SUPER BARRIER RECTIFIER 100V DFN3030-8 DIODES INC./ZETEX SBR3U100LP-7
13 1 L1 IND, 10μH COILCRAFT XAL5050-103ME
14 1 Q1 XSTR, FET P-CHANNEL 60V FAIRCHILD SEMI FDMC5614P
15 5 R1, R4, R6, R8, R10 RES, 0402 0Ω JUMPER VISHAY CRCW04020000Z0ED
16 1 R2 RES, 0402 10k 1% 1/16W VISHAY CRCW040210K0FKED
17 1 R3 RES, 0402 80.6k 1% 1/16W VISHAY CRCW040280K6FKED
18 1 R5 RES, 0402 422k 1% 1/16W VISHAY CRW0402422KFKED
19 1 R7 RES, 2010 0.025Ω 1% 1/2W VISHAY WSL2010R0250FEA
20 1 R9 RES, 0402 100k 5% 1/16W VISHAY CRCW0402100KJNED
21 1 U1 IC, VOLTAGE REG. MSOP(12)-MSE LINEAR TECH. LTC3864EMSE
Additional Demo Board Circuit Components
1 0 CIN3 CAP, 1210 2.2μF 10% 100V X7R OPTION MURATA GRM32ER72A225KA35L OPTION
2 0 C9 CAP, D CASE OPTION OPTION
3 0 D2 DIODE, SCHOTTKY, 5A POWERDi5 OPTION DIODES INC./ZETEXPDS5100-13 OPTION
4 0 L1 – ALTERNATE IND, 10μH TOKO B1134AS-100M
5 0 L1 – ALTERNATE IND, 10μH WURTH ELECTRONIK 744071100
6 0 Q2 XSTR, MOSFET P-CHANNEL 60V OPTION VISHAY SILICONIX Si7465DP OPTION
7 0 R11 RES, 0402 OPTION OPTION
Hardware
1 4 E1, E2, E8, E9 TURRET MILL MAX 2501-2-00-80-00-00-07-0
2 5 E3, E4, E5, E6, E7 TURRET MILL MAX 2308-2-00-80-00-00-07-0
3 1 JP1 HEADER, 3-PIN SINGLE ROW 2mm SAMTEC TMM-103-02-L-S
4 1 JP2 HEADER, 3-PIN DOUBLE ROW 2mm SAMTEC TMM-103-02-L-D
5 4 MH1, MH2, MH3, MH4 STANDOFF, SNAP ON KEYSTONE_8831
6 2 XJP1, XJP2 SHUNT, 2mm SAMTEC 2SN-BK-G
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DEMO MANUAL DC1722A
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
Q
3.3 CHANGE 04/19/16 D. B.
VIN
VOUT
VIN
VOUT
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: [phone]
Milpitas, CA 95035 Phone: [phone]
1630 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
3.3
DEMO CIRCUIT 1722A
Tuesday, April 19, 2016
11
60V, LOW I , STEP-DOWN CONTROLLER
N/A
LTC3864EMSE
RB/MI
DAVID B.
C:\DESIGN\17\1722A-3.3\1722A-3.3.DSN
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: [phone]
Milpitas, CA 95035 Phone: [phone]
1630 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
3.3
DEMO CIRCUIT 1722A
Tuesday, April 19, 2016
11
60V, LOW I , STEP-DOWN CONTROLLER
N/A
LTC3864EMSE
RB/MI
DAVID B.
C:\DESIGN\17\1722A-3.3\1722A-3.3.DSN
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: [phone]
Milpitas, CA 95035 Phone: [phone]
1630 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
3.3
DEMO CIRCUIT 1722A
Tuesday, April 19, 2016
11
60V, LOW I , STEP-DOWN CONTROLLER
N/A
LTC3864EMSE
RB/MI
DAVID B.
C:\DESIGN\17\1722A-3.3\1722A-3.3.DSN
REVISION HISTORY
DESCRIPTION DATE APPROVEDECO REV
D. B.PROD3 04/17/12
REVISION HISTORY
DESCRIPTION DATE APPROVEDECO REV
D. B.PROD3 04/17/12
REVISION HISTORY
DESCRIPTION DATE APPROVEDECO REV
D. B.PROD3 04/17/12
R7
0.025
2010
E5
VOUT
5V / 2A
COUT3 1uF 6.3V
0603
Q1
FDMC5614P
E6
GND
C7
0.1uF
100V
0805
E7
PGOOD
C2 2200pF
R6
0 Ohm
R10 0 Ohm
R8
0 Ohm E9
E4
TRACK
C6
0.1uF
+
CIN1 10uF
63V
JP2
BURST CLKIN
SKIP
MODE
1 3
2 4 6 5
E8
E3
CLKIN
COUT1 100uF
6.3V
1812
Q2
Si7465DP (OPT)
C4
47pF
5%
R11
(OPT)
D2
PDS5100-13
(OPT)
PowerDi5
CIN2
2.2uF 100V 1210
R5
422K 1%
R2
10.0K 1%
C1 100pF 5%
E1
VIN
5V - 55V
(3.5V Min)
R4 0 Ohm
CIN3
2.2uF 100V 1210
(OPT)
R9
100k
JP1
ON
OFF
SHDN
1 3 2
R3
80.6K 1%
D1
SBR3U100LP-7
C8 220pF
5%
C5
0.47uF
0603
U1
LTC3864EMSE
PLL/MODE
1
FREQ
2
GND
3
SS
4
VFB
5
ITH
6PGOOD 7
RUN 8
CAP 9
SENSE 10
VIN 11
GATE 12
GND
13
E2
GND
L1
10uH
COILCRAFT
XAL5050-103ME COUT2
100uF
6.3V
1812
+
C9
(OPT)
"D" Case
R1
0 Ohm
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DEMO MANUAL DC1722A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2013
LT 0516 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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