DC2005A - Demo Manual

DEMO MANUAL DC2005A
LTC3624EDD
High Efficiency Synchronous Step-Down
Regulator with Ultralow Quiescent Current
DESCRIPTION
Demonstration circuit DC2005A is a synchronous stepdown regulator using an LTC®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.
PERFORMANCE SUMMARY
PARAMETER
The DC2005A uses very low profile surface mount components 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
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
VALUE
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
Default Output Voltage, VOUT
1MHz
VIN = 12V, VOUT = 5V, IOUT = 0A to 2A
5V ±2%
2A
Maximum Continuous Output Current, IOUT
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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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%.
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 properly, 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 evaluate LTC3624‑2 (2.25MHz) by simply changing U1 to
LTC3624‑2 and L1 to 1.5µH (Coilcraft XAL4020-152ME).
6.Once the input and output voltages are properly established adjust the loads within the operating range
(0A to 2A max) and observe the output voltage regulation, output ripple voltage, switch node waveform and
other parameters. Refer to Figure 2 for proper input/
output voltage ripple measurement.
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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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DEMO MANUAL DC2005A
100
100
90
90
EFFICIENCY (%)
EFFICIENCY (%)
QUICK START PROCEDURE
80
70
60
VIN = 12V
IOUT = 0A TO 2A
fSW = 1MHz
50
0.01
0.1
LOAD CURRENT (A)
1.2VOUT
1.8VOUT
2.5VOUT
3.3VOUT
5.0VOUT
1
80
VIN = 12V
IOUT = 0A TO 2A
fSW = 1MHz
1.2VOUT
1.8VOUT
2.5VOUT
3.3VOUT
5.0VOUT
70
60
50
2
0.5
0
1
1.5
2
LOAD CURRENT (A)
Figure 3. Measured Efficiency in Burst Mode Operation (BM)
Figure 4. Measured Efficiency in Forced Continuous Mode (FCM)
20MHz BW LIMIT
VOUT
20mV/DIV
VSW
10V/DIV
VIN = 12V
VOUT = 5V
IOUT = 2A
fSW = 1MHz
1µs/DIV
Figure 5. Measured Output Voltage Ripple
VP-P = 250mV
VOUT
200mV/DIV
IOUT
1A/DIV
1A TO 2A
VIN = 12V
VOUT = 5V
IOUT = 1A
100µs/DIV
Figure 6. Load Transient Response
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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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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
1
10
E1, E2, E3, E4, E5, E6, E7, E8, TURRET
E9, E10
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
Hardware
MILL-MAX 2501-2-00-80-00-00-07-0
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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
E6
E5
E4
E3
E7
E2
[2]
[1]
[2]
PS
OFF
ON
JP2
MODE
BM
FCM / SYNC
INTVCC
47uF
20V
+ CIN [1]
4
3
2
1
JP1
RUN
3
2
1
[2]
[2]
R9
OPT
R8
OPT
C2
22uF
25V
1206
R10
OPT
R11
1M
INTVCC
R7
0
6
7
C8
2.2uF
10V
0603
C7
OPT
3
C3
22uF
25V
1206
2
5
FOR FCM OPERATION, STUFF R9 AND
R10 WITH 1MEG OHM RESISTOR.
4
MODE/SYNC
INTVCC
RUN
VIN
PGOOD
FB
SW
4
5
1
3
JP3
1.2V
VOUT
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
JP5
2.5V
R2
309k
1%
APPROVALS
JP4
1.8V
R1
619k
1%
3.3uH
L1
SCALE = NONE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
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
APP ENG. G LE
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
CUSTOMER NOTICE
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:
PGOOD
GND
SYNC
INTVCC
RUN
GND
E1
VIN
2.7V - 17V
U1
LTC3624EDD (1MHz)
GND
9
4
GND
8
5
R4
137k
1%
C4
47uF
6.3V
1206
C5
OPT
1206
1
GND
GND
VOUT
2A
E10
E9
C6
OPT
1210
E8
IC NO.
2
1
SHEET 1
LTC3624EDD
DEMO CIRCUIT 2005A
DATE: Tuesday, January 07, 2014
N/A
SIZE
2
REV.
OF 1
MONOLITHIC SYNCHRONOUS BUCK REGULATOR
WITH ULTRA-LOW QUIESCENT CURRENT
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
JP8
USER SELECT
R6
OPT
CFF
15pF
TECHNOLOGY
JP7
5.0V
R5
84.5K
1%
RSET
619k
1%
R12
0
TITLE: SCHEMATIC
JP6
3.3V
R3
196k
1%
2
A
B
C
D
DEMO MANUAL DC2005A
SCHEMATIC DIAGRAM
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DEMO MANUAL DC2005A
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
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8
Linear Technology Corporation
LT 0114 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
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