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dc2005af
DEMO MANUAL DC2005A
DESCRIPTION
LTC3624EDD
High Efficiency Synchronous Step-Down
Regulator with Ultralow Quiescent Current
Demonstration circuit DC2005A is a synchronous step-
down regulator using an LT C
®
3624 monolithic buck
regulator. The DC2005A operates from an input voltage
range of 2.7V to 17V and provides an adjustable output
voltage range from 1.2V to 5V (VOUT < VIN) at 2A of output
current. A user-selectable mode input is provided to allow
the user to trade off ripple noise for light load efficiency.
Burst Mode
®
operation provides the highest efficiency at
light load, while pulse-skipping mode provides the lowest
voltage ripple. The MODE pin can also be used to sync the
switching frequency to an external clock.
The switching frequency is fixed at 1MHz or 2.25MHz
with a ±40% synchronizing range. The regulator features
ultralow quiescent current and high efficiency over a wide
VOUT range.
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.
The DC2005A uses very low profile surface mount com-
ponents and all ceramic output capacitors. The compact
8-lead DFN (3mm × 3mm) package makes the LTC3624 an
excellent choice for battery-powered equipment, general
purpose step-down power supply, and emergency radio
applications.
It is recommended to read the data sheet and demo manual
of the LTC3624 prior using or making any changes to
DC2005A.
Design files for this circuit board are available at
http://www.linear.com/demo
PERFORMANCE SUMMARY
Specifications are at TA = 25°C
PARAMETER CONDITIONS VALUE
Input Voltage Range 2.7V to 17V
Onboard User Selectable Output Voltages VIN = 2.7V to 17V, IOUT = 2A (VOUT ≤ VIN) 1.2V, 1.8V, 2.5V, 3.3V and 5V
Default Mode Setting JP2 Burst Mode Operation (BM)
Default Switching Frequency 1MHz
Default Output Voltage, VOUT VIN = 12V, VOUT = 5V, IOUT = 0A to 2A 5V ±2%
Maximum Continuous Output Current, IOUT 2A
Output Voltage Ripples (Peak-to-Peak) VIN = 12V, VOUT = 5V, IOUT = 2A 9.4mV (See Figure 5)
Load Transient Response VIN = 12V, VOUT = 5V, IOUT = 1A to 2A See Figure 6
Thermal Image VIN = 12V, VOUT = 5V, IOUT = 2A, 1MHz See Figure 7
Efficiency VIN = 12V, VOUT = 5V, IOUT = 2A, BM, 1MHz 90.4% (See Figure 3 )
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dc2005af
DEMO MANUAL DC2005A
QUICK START PROCEDURE
Demonstration circuit DC2005A is easy to set up to evaluate
the performance of the LTC3624. Please refer to Figure1
for proper measurement equipment setup and follow the
procedure below:
1. Place jumpers in the following positions for a typical
5V output application:
Table 1. Typical 5V Output Voltage Jumper Selection
JP1 JP2 JP7
RUN MODE/SYNC VOUT
ON BM 5.0V
2. With power off, connect the input power supply at VIN
(E1) and GND (E2).
3. Connect the load between VOUT (E8) and GND (E9).
Preset the load to 0A.
4. Connect the DMMs to the input and output to monitor
the input voltage and output voltage.
5. Turn on the power supply at the input. The RUN pin
jumper should be at ON position. Measure and make
sure the input supply voltage is 12V. The output voltage
should be 5V ±2%.
6. Once the input and output voltages are properly es-
tablished adjust the loads within the operating range
(0A to 2A max) and observe the output voltage regula-
tion, output ripple voltage, switch node waveform and
other parameters. Refer to Figure 2 for proper input/
output voltage ripple measurement.
7. To select other output voltages, use the on board user
selectable output voltage jumpers. Shutting down
LTC3624 by placing RUN pin jumper (JP1) to the OFF
position or turn off the input power supply. Refer to the
following table (Table 2) for the output voltage selection
and repeat steps 2 to 6:
Table 2. Output Voltage Jumper Selection
JP3 JP4 JP5 JP6 JP7 JP8
1.2V 1.8V 2.5V 3.3V 5V *User Select
* Note: If JP8 is selected, R6 needs to be calculated and inserted to
obtain the desired output voltage.
Note 1: To measure the input/output voltage ripple prop-
erly, 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.
Note 2: The DC2005A can also be used to evalu-
ate LTC3624-2 (2.25MHz) by simply changing U1 to
LTC3624-2 and L1 to 1.5µH (Coilcraft XAL4020-152ME).
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dc2005af
DEMO MANUAL DC2005A
QUICK START PROCEDURE
Figure 1. Proper Equipment Measurement Setup
Figure 2. Scope Probe Placements for Measuring Input or Output Ripple
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dc2005af
DEMO MANUAL DC2005A
QUICK START PROCEDURE
LOAD CURRENT (A)
60
EFFICIENCY (%)
70
80
90
100
0.01 1 2
50
0.1
1.2VOUT
1.8VOUT
2.5VOUT
3.3VOUT
5.0VOUT
VIN = 12V
IOUT = 0A TO 2A
fSW = 1MHz
LOAD CURRENT (A)
0
EFFICIENCY (%)
70
80
2
60
50 0.5 11.5
100
90
1.2VOUT
1.8VOUT
2.5VOUT
3.3VOUT
5.0VOUT
VIN = 12V
IOUT = 0A TO 2A
fSW = 1MHz
VOUT
20mV/DIV
VSW
10V/DIV
20MHz BW LIMIT
VIN = 12V
VOUT = 5V
IOUT = 2A
fSW = 1MHz
1µs/DIV
VOUT
200mV/DIV
IOUT
1A/DIV
VP-P = 250mV
1A TO 2A
VIN = 12V
VOUT = 5V
IOUT = 1A
100µs/DIV
Figure 3. Measured Efficiency in Burst Mode Operation (BM) Figure 4. Measured Efficiency in Forced Continuous Mode (FCM)
Figure 5. Measured Output Voltage Ripple
Figure 6. Load Transient Response
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dc2005af
DEMO MANUAL DC2005A
QUICK START PROCEDURE
NO FORCED AIRFLOW
TA = 24°C
VIN = 12V
VOUT = 5V
IOUT = 2A
fSW = 1MHz
Figure 7. Thermal Performance
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dc2005af
DEMO MANUAL DC2005A
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 CFF CAP, 0402 15pF 5% 50V NPO AVX 04025A150JAT2A
2 1 CIN CAP, 47µF 20% 20V 33mΩ PANASONIC OSCON 20SVPA47M
3 2 C2,C3 CAP, 1206 22µF10% 25V X5R MURATA GRM31CR61E226KE15L
4 1 C4 CAP, 1206 47µF 20% 6.3V X5R TAIYO YUDEN JMK316BJ476ML-T
5 1 C8 CAP, 0603 2.2µF 10% 10V X5R MURATA GRM188R61A225KE34P
6 1 L1 IND, 3.3µH COILCRAFT XAL4030-332ME
7 2 R1, RSET RES, 0402 619k 1% 1/16W VISHAY CRCW0402619KFKED
8 1 R2 RES, 0402 309k 1% 1/16W VISHAY CRCW0402309KFKED
9 1 R3 RES, 0402 196k 1% 1/16W VISHAY CRCW0402196KFKEA
10 1 R4 RES, 0402 137k 1% 1/16W VISHAY CRCW0402137KFKED
11 1 R5 RES, 0402 84.5k 1% 1/16W VISHAY CRCW040284K5FKED
12 2 R7, R12 RES, 0402 0Ω JUMPER VISHAY CRCW04020000Z0ED
13 1 R11 RES, 0402 1MΩ 5% 1/16W VISHAY CRCW04021M00JNED
14 1 U1 IC, MONOLITHIC SYNCHRONOUS BUCK REGULATOR LINEAR TECH LTC3624EDD
Additional Demo Board Circuit Components
1 0 C5 CAP, 1206 22µF 20% 6.3V X5R OPTION TAIYO YUDEN EMK316BJ226ML-T OPTION
2 0 C6 CAP, 1210 OPTION OPTION
3 0 C7 CAP, 0402 OPTION OPTION
4 0 R6, R8 RES, 0402 OPTION OPTION
5 0 R9, R10 RES, 0402 1MΩ 5% 1/16W OPTION VISHAY CRCW04021M00JNED OPTION
Hardware
1 10 E1, E2, E3, E4, E5, E6, E7, E8,
E9, E10
TURRET MILL-MAX 2501-2-00-80-00-00-07-0
2 1 JP1 HEADER, 3-PIN, 2mm SAMTEC TMM-103-02-L-S
3 1 JP2 HEADER, 4-PIN, 2mm SAMTEC TMM-104-02-L-S
4 6 JP3, JP4, JP5, JP6, JP7, JP8 HEADER, 2-PIN, 2mm SAMTEC TMM 102-02-L-S
5 4 MH1, MH2, MH3, MH4 STANDOFF, SNAP ON KEYSTONE_8833
6 3 JP1, JP2, JP3 SHUNT, 2mm SAMTEC 2SN-BK-G
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dc2005af
DEMO MANUAL DC2005A
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
[1]
CIN IS AN OPTIONAL CAPACITOR. IT IS INSERTED
ON THE DC2005A TO DAMPEN THE (POSSIBLE)
RINGING VOLTAGE DUE TO THE LONG INPUT LEADS.
ON A NORMAL, TYPICAL PCB, WITH SHORT TRACES,
THE CAPACITOR IS NOT NEEDED.
NOTES:
[2]
FOR FCM OPERATION, STUFF R9 AND
R10 WITH 1MEG OHM RESISTOR.
[2]
[2]
[2]
VOUT
INTVCC
INTVCC
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
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
2
Tuesday, January 07, 2014
11
MONOLITHIC SYNCHRONOUS BUCK REGULATOR
MI
G LE
N/A
LTC3624EDD
DEMO CIRCUIT 2005A
WITH ULTRA-LOW QUIESCENT CURRENT
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
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
2
Tuesday, January 07, 2014
11
MONOLITHIC SYNCHRONOUS BUCK REGULATOR
MI
G LE
N/A
LTC3624EDD
DEMO CIRCUIT 2005A
WITH ULTRA-LOW QUIESCENT CURRENT
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
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
2
Tuesday, January 07, 2014
11
MONOLITHIC SYNCHRONOUS BUCK REGULATOR
MI
G LE
N/A
LTC3624EDD
DEMO CIRCUIT 2005A
WITH ULTRA-LOW QUIESCENT CURRENT
JP8
USER SELECT
JP8
USER SELECT
15pF
CFF
15pF
CFF
R7
0
R7
0
E6
PGOOD
E6
PGOOD
47uF
C4
6.3V
1206
47uF
C4
6.3V
1206
E8
VOUT
2A
E8
VOUT
2A
C7
OPT
C7
OPT
JP1
ON
OFF
RUN
JP1
ON
OFF
RUN
1
3
2
R5
84.5K
1%
R5
84.5K
1%
JP4
1.8V
JP4
1.8V
U1
LTC3624EDD (1MHz)
U1
LTC3624EDD (1MHz)
VIN
2
RUN
3
INTVCC
6
MODE/SYNC
7
PGOOD 4
FB 5
SW 1
8
GND
9
GND
R3
196k
1%
R3
196k
1%
JP7
5.0V
JP7
5.0V
C8
2.2uF
10V
0603
C8
2.2uF
10V
0603
22uF
C3
25V
1206
22uF
C3
25V
1206
E10
GND
E10
GND
C6
OPT
1210
C6
OPT
1210
E2
GND
E2
GND
RSET
619k
1%
RSET
619k
1%
E3
INTVCC
E3
INTVCC
R1
619k
1%
R1
619k
1%
R11
1M
R11
1M
OPT
C5
1206
OPT
C5
1206
R10
OPT
R10
OPT
E7
RUN
E7
RUN
L1
3.3uH
L1
3.3uH
R2
309k
1%
R2
309k
1%
E5
GND
E5
GND
E9
GND
E9
GND
E1
VIN
2.7V - 17V
E1
VIN
2.7V - 17V
R4
137k
1%
R4
137k
1%
22uF
C2
25V
1206
22uF
C2
25V
1206
JP3
1.2V
JP3
1.2V
JP2
BM
FCM / SYNC
MODE
PS
JP2
BM
FCM / SYNC
MODE
PS
1
3
2
4
+
CIN
47uF
20V
[1]
+
CIN
47uF
20V
[1]
E4
SYNC
E4
SYNC
R8
OPT
R8
OPT R6
OPT
R6
OPT
R12
0
R12
0
JP5
2.5V
JP5
2.5V
JP6
3.3V
JP6
3.3V
R9
OPT
R9
OPT
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dc2005af
DEMO MANUAL DC2005A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2014
LT 0114 • 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
