Analog Devices Linear DC2681A-A Quick setup guide

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dc2681aaf
DEMO MANUAL DC2681A-A
DESCRIPTION
LTM4645
25A DC/DC Step-Down
µModule Regulator
Demonstration circuit DC2681A-A features the
LT M ®4645EY, a 25A high efficiency, switch mode step-
down power µModule®regulator. The input voltage
range is from 6V to 15V. To use DC2681A-A for input
voltage range from 4.7V to 6V, connect INTVCC to SVIN
(change R22 from OPT to 0Ω), DRVCC to VIN (change
R21 from 0Ω to OPT, R28 from OPT to 0Ω). The output
voltage range is 0.6V to 1.8V. Derating is necessary for
certain VIN, VOUT, frequency and thermal conditions. The
DC2681A-A offers the TRK/SS pin allowing the user to
program output tracking or soft-start period. The board
operates in continuous conduction mode in heavy load
conditions. For high efficiency at low load currents, the
MODE_PLLIN jumper selects pulse-skipping mode for
noise sensitive applications or burst mode operation in
L, LT, LTC, LTM, µModule, Linear Technology and the Linear logo are registered trademarks of
Analog Devices, Inc. All other trademarks are the property of their respective owners.
BOARD PHOTO
less noise sensitive applications. The MODE_PLLIN pin
also allows the LTM4645 to synchronize to an external
clock signal (between 400kHz and 800kHz). DC2681A-A
has the option of choosing both internal and external
compensation circuit for LTM4645. Tying the PHASMD
pin to different voltage generates certain phase differ-
ence between MODE_PLLIN and CLKOUT. The LTM4645
data sheet must be read in conjunction with this demo
manual prior to working on or modifying demo circuit
DC2681A-A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2681A-A

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dc2681aaf
DEMO MANUAL DC2681A-A
QUICK START PROCEDURE
Demonstration circuit DC2681A-A is an easy way to evalu-
ate the performance of the LTM4645EY. Please refer to
Figure 1 for proper measurement equipment setup and
follow the procedure below:
1. Place jumpers in the following positions for a typical
application:
MODE RUN
CCM ON
2. With power off, connect the input power supply, load
and meters as shown in Figure 1. Preset the load to 0A
and VIN supply to 12V.
3. Turn on the power supply at the input. The output volt-
age should be 1.0V ± 1.0% (0.99V to 1.01V).
4. Vary the input voltage from 6V to 15V and adjust the
load current from 0A-25A. Observe the output voltage
regulation, ripple voltage, efficiency, and other param-
eters.
5. (Optional) For optional load transient test, apply an
adjustable pulse signal between IOSTEP_CLK and GND
test points. The pulse amplitude sets the load step cur-
rent amplitude. Keep the pulse width short (<1ms) and
pulse duty cycle low (<5%) to limit the thermal stress
on the load transient circuit.
6. (Optional) LTM4645 can be synchronized to an external
clock signal. Place the JP1 jumper on EXT_CLK and
apply a clock signal (0V to 5V, square wave) on the
MODE_PLLIN test point.
PERFORMANCE SUMMARY
PARAMETER CONDITIONS/NOTES VALUE
Input Voltage Range 6V to 15V
Output Voltages 1.0V ± 1.0%
Maximum Continuous Output Current Derating is Necessary for Certain Operating
Conditions. See Data Sheet for Details
25ADC
Operating Frequency 600kHz
Efficiency VIN = 12V, VOUT = 1.0V, IOUT = 25A 84.6% Figure 2
Load Transient VOUT(P-P) VIN = 12V, VOUT = 1.0V, ISTEP = 0A to 12.5A 128mV Figure 3

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dc2681aaf
DEMO MANUAL DC2681A-A
QUICK START PROCEDURE
Figure 1. Measurement Setup of DC2681A-A
+
–
+
–
+
–
+
–
LOADVIN
dc2681aaf F01

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dc2681aaf
DEMO MANUAL DC2681A-A
QUICK START PROCEDURE
70.00
72.00
74.00
76.00
78.00
80.00
82.00
84.00
86.00
88.00
90.00
EFFICIENCY (%)
0.00 5.00 10.00 15.00 20.00 25.00
OUTPUT CURRENT (A)
1.8 VOUT
1.5 VOUT
1.2 VOUT
1.0 VOUT
0.8 VOUT
dc2681aaf F02
VOUT: 50mV/DIV
IOUT_STEP: 10A/DIV
dc2681aaf F03
Figure 2. Measured Efficiency at VIN = 12.0V, fSW = 600kHz, CCM
Figure 3. Measured Load Transient
12VIN, 600kHz Efficiency Sweeps

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dc2681aaf
DEMO MANUAL DC2681A-A
QUICK START PROCEDURE
Figure 4. Thermal Image of LTM4645
VIN = 12V, VOUT = 1.0V, ILOAD = 25A
Ambient Temperature = 25.0°C, No Forced Air Flow

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dc2681aaf
DEMO MANUAL DC2681A-A
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 CIN1 CAP., ALUM., 150µF, 35V, 20%, HVH SUN ELECTRONIC INDUSTRIES CORP., 35HVH150MT
2 3 CIN3, CIN4 CAP., 22µF, X5R, 25V, 20%,1210 MURATA, GRM32ER61E226ME15L
3 3 COUT1, COUT2, COUT4 CAP., 100µF, X5R, 6.3V, 20%, 1210 MURATA,GRM32ER60J107ME20L
4 2 COUT7, COUT8 CAP., POSCAP, 330µF, 2V, D2E PANASONIC, 2TPF330M6
5 1 C2 CAP., 4.7µF, X5R, 10V, 10%, 0603 AVX, 0603ZD475KAT2A
6 1 C3 CAP., 0.1µF, X7R, 16V, 10%, 0603 AVX, 0603YC104KAT2A
7 1 C5 CAP., 120pF, X7R, 50V,10%, 0603 YAGEO, CC0603KRX7R9BB121
8 1 C8 CAP., 1µF, X7R, 50V,10%, 0805 MURATA, GRM21BR71H105KA12L
9 1 C11 CAP., 1µF, X7R, 50V,10%, 0603 TAIYO YUDEN, UMK107AB7105KA-T
10 1 Q1 XSTR., MOSFET, N-CH, 40V, TO-252 VISHAY, SUD50N04-8M8P-4GE3
11 2 R3, R19 RES., 10k, 1/10W, 1%, 0603 VISHAY, CRCW060310K0FKEA
12 1 R4 RES., 100k, 1/10W, 1%, 0603 VISHAY, CRCW0603100KFKEA
13 1 R9 RES., 47.5k, 1/10W, 1%, 0603 VISHAY, CRCW060347K5FKEA
14 2 R14, R16 RES., 10Ω, 1/10W, 5%, 0603 VISHAY, CRCW060310R0JNEA
15 1 R15 RES., 90.9k, 1/10W, 1%, 0603 VISHAY, CRCW060390K9FKEA
16 1 R20 RES., SENSE, 0.01Ω, 1/2W, 1%, 2010 VISHAY, WSL2010R0100FEA
17 1 R25 RES., 2.2Ω, 1/10W, 5%, 0603 VISHAY, CRCW06032R2JNEA
18 1 R26 RES., 50k, 1/10W, 1%, 0603 VISHAY, CRCW060350K0FKEA
19 1 U1 IC, LTM4645EY#PBF BGA77-15×9-5.01 LINEAR TECH., LTM4645EY#PBF
Additional Demo Board Circuit Components
1 0 CIN2 CAP., OPTION, 1206 MURATA, GRM31CR6YA106KA12L
2 0 CIN5, COUT3, COUT5, COUT6,
COUT9, COUT10
CAP., OPTION, 1210 OPT
3 0 COUT11, COUT12 CAP., OPTION, D3L OPT
4 0 C4, C6, C7, C9 CAP., OPTION, 0603 OPT
5 6 R1, R6, R13, R18, R21, R27 RES., 0Ω, 1/10W, 0603 VISHAY, CRCW06030000Z0EA
6 0 R8, R10, R11, R17, R22, R23,
R24, R28
RES., OPTION, 0603 OPT
Hardware: For Demo Board Only
1 18 E1-E18 TESTPOINT, TURRET, .062" MILL-MAX, 2308-2-00-80-00-00-07-0
2 1 JP1 CONN., HEADER, 2×4, 2mm SULLINS, NRPN042PAEN-RC
3 1 JP2 CONN., HEADER, 1×3, 2mm SULLINS, NRPN031PAEN-RC
4 2 J1,J3 CONN., BANANA JACK KEYSTONE, 575-4
5 2 J2,J4 STUD, TESTPIN PEM, KFH-032-10
6 4 J2,J4 (×2) NUT, BRASS 10-32 ANY, #10-32M/S BR PL
7 2 J2,J4 RING, LUG #10 KEYSTONE, 8205
8 2 J2,J4 WASHER, TIN PLATED BRASS ANY, #10 EXT BZ TN
9 2 J5,J6 CONN, BNC, 5 PINS CONNEX, 112404
10 2 XJP1, XJP2 SHUNT, 2mm SAMTEC, 2SN-BK-G
11 4 MTGS. at 4 CORNERS STAND-OFF, NYLON, SNAP-ON, 0.50" TALL KEYSTONE, 8833 (SNAP ON)

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dc2681aaf
DEMO MANUAL DC2681A-A
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
35V
6V - 15V
*
DYNAMIC LOAD CIRCUIT
DO NOT EXCEED 5% DUTY CYCLE!
1.0V
OFF
ON
2V
2TPF330M6
VOUT
GND
NOTE: UNLESS OTHERWISE SPECIFIED 1. ALL CAPACITORS AND RESISTORS ARE 0603.
MODULE REGULATOR
m
LTM4647EY
*
LTM4645EY 25 LTM4647EY 30
-A -B
*
ASSY AMPIC
AMP
VIN
VOUT
VOUT
VIN
INTVCC
INTVCCINTVCC
INTVCC VIN
INTVCC
INTVCC
VIN
SVIN
SVIN
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
YL
PRODUCTION
1 02-27-17
__
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
YL
PRODUCTION
1 02-27-17
__
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
YL
PRODUCTION
1 02-27-17
__
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
1
Monday, February 27, 2017
11
SINGLE-OUTPUT, HIGH EFFICIENCY STEP-DOWN
LT
YL
B
LTM4645EY / LTM4647EY
DEMO CIRCUIT 2681A(A,B)
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
1
Monday, February 27, 2017
11
SINGLE-OUTPUT, HIGH EFFICIENCY STEP-DOWN
LT
YL
B
LTM4645EY / LTM4647EY
DEMO CIRCUIT 2681A(A,B)
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
1
Monday, February 27, 2017
11
SINGLE-OUTPUT, HIGH EFFICIENCY STEP-DOWN
LT
YL
B
LTM4645EY / LTM4647EY
DEMO CIRCUIT 2681A(A,B)
E10
VIN
E15
GND
J2
C5 120pF
COUT3 OPT 1210
E4
INTVCC
JP2
RUN
1 3 2
+
COUT12
R25 2.2
E3
DRVCC
C11
1uF
R24 OPT
R1
0
CIN2 OPT 1206
E13
GND_SNS
COUT2 100uF 1210
R4 100k
E7
PGOOD
R8
OPT
E16
SVIN
R27
0
J1
VIN
E6
HIZB
R28 OPT
C7 OPT
E8
COMP
P1
R6
0
COUT4 100uF 1210
J5
VOUT
1
2
3
4
5
E14
IOSTEP_CLK
COUT10
OPT 1210
C6
OPT
R14
10
E9
MODE/PLLIN
R16
10
R22 OPT
R18
0
E2
CLKOUT
R3
10k
Q1
SUD50N04-8M8P
2
1
3
4
E12 VOUT_SNS
R15 90.9k
C4
OPT
E17
TEMP-
J3
GND
E5
TRK/SS
C9
OPT
R13
0
J4
R26 49.9k
E18
TEMP+
COUT9
OPT 1210
E1
RUN
+
CIN1 150uF
JP1
EXT_CLK PS
CCM
MODE
BM
1 3
2 4 65
7 8
R20
0.01
2010
R9 47.5K
COUT5 OPT 1210
R11 OPT
COUT6 OPT 1210
CIN4 22uF 1210
+
COUT7 330uF
COUT1 100uF 1210
CIN5 OPT 1210
R19 10K
R21 0
R17 OPT
CIN3 22uF 1210
C3
0.1uF
C2 4.7uF 10V
+
COUT11 OPT
C8
1uF
0805
U1
LTM4645EY
VOUT J1
GND
A5
GND
A7
PWM
B4
TEST1
B6
GND
D1
TEST2 D5
RUN A6
HIZB E5
CLKOUT B5
FB
E6
PHASMD C7
COMPb
H7
COMPa
H6
VOSNS- G5
VOSNS+ G6
INTVCC C6
DRVCC C5
SW F3
VIN
B1 VIN A3 VIN A2 VIN A1
GND
C3
VIN
C2 VIN C1
GND
B3
VIN
B2
SGND
E7
TEST3
F7
GND
D2
GND
D3
GND
D4
GND
A4
SVIN
D6
TEMP-
E1 GND
E2 GND
E3
TEMP+
F1
GND
F2
GND
F4
GND
F6
GND
G1
GND
G2
GND
G3
GND
G4
GND
H1
GND
H2
GND
H3
GND
H4
GND
H5
GND
J5
GND
J7
GND
J6
GND
K5
GND
K7
GND
K6
GND
C4
GND
E4
VOUT J3 VOUT J2 VOUT J4 VOUT K1 VOUT K2 VOUT K3 VOUT K4 VOUT L1 VOUT L2 VOUT L3 VOUT L4 VOUT L5 VOUT L6 VOUT L7
MODE/PLLIN B7
FREQ D7
PGOOD G7
TRACK/SS F5
R10 OPT
+
COUT8
J6
IOSTEP
1
2
3
4
5
P2
R23 OPT
E11
GND
VOSNS+
RUN
VOSNS-
TEMP- TEMP+

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dc2681aaf
DEMO MANUAL DC2681A-A
 LINEAR TECHNOLOGY CORPORATION 2017
LT 0517 • PRINTED IN USA
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