DC1852A - Demo Manual

DEMO MANUAL DC1852A
LTC3536
1A, Low Noise, Wide VIN
Buck-Boost DC/DC Converter
DESCRIPTION
Demonstration circuit 1852A is a combined step-up and
step-down DC/DC converter, using the LTC3536 monolithic
synchronous buck-boost regulator. The DC1852A has
wide input voltage range of 1.8V to 5.5V and is capable of
delivering up to 1A of output current. The output voltage
of the DC1852A can be set as low as 1.8V and can go as
high as 5.5V. DC1852A supports two operation modes:
fixed-frequency pulse-width modulation (PWM) and
Burst Mode® operation. Fixed-frequency mode of operation maximizes the output current, reduces output voltage
ripple, and yields a low noise switching spectrum. Burst
Mode operation employs a variable frequency switching
algorithm that minimizes the no-load input quiescent current and improves efficiency at light loads.
PERFORMANCE SUMMARY
PARAMETER
The DC1852A consumes less than 28μA of quiescent current during Burst Mode operation, and during shutdown,
it consumes less than 1μA. The DC1852A has a standard
operating frequency of 1MHz, but can be adjusted to
frequencies as high as 2MHz. If Pin 1 (RT) is tied to VIN,
the default switching frequency is 1.2MHz. Because of
the high switching frequency of the DC1852A, small, low
profile surface mount components are used in the circuit.
These features, plus the LTC3536’s small 12-lead MSOP
package, make the DC1852A a perfect match for batterypowered, handheld applications.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, μModule, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
(TA = 25°C)
CONDITIONS
VALUE
Minimum Input Voltage
1.8V
Maximum Input Voltage
5.5V
Output Voltage VOUT Regulation
VIN = 1.8V to 5.5V
3.3V ±2%
Maximum Continuous Output Current
Fixed Frequency Mode
1A
Preset Operating Frequency
R6 = 100kΩ
1MHz
Efficiency
VIN = 5V, VOUT = 3.3V, IOUT = 1A
95%
Typical Output Ripple VOUT
VIN = 5V, IOUT = 1A (20MHz BW)
<15mVP-P
Burst Mode Operation
VIN = 5V, VOUT = 3.3V
VIN = 2.5V, VOUT = 3.3V
<0.15A
<0.1A
External Clock Sync. Frequency Range
300kHz to 2MHz
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DEMO MANUAL DC1852A
QUICK START PROCEDURE
Demonstration circuit 1852A is easy to set up to evaluate
the performance of the LTC3536. For proper measurement
equipment configuration, set up the circuit according to
the diagram in Figure 1. Before proceeding to test, insert
shunts into JP1 FIXED FREQ and JP2 OFF positions, which
connects the RUN pin to ground (GND), and thus, shut
down the circuit.
2. Turn on the circuit by inserting the shunt in header
JP2 into the ON position. The output voltage should be
regulating. Measure VOUT– it should measure 3.3V ±1%
(Do not apply more than the rated maximum voltage
of 5.5V to the board or the part may be damaged).
NOTE: When measuring the input or output voltage ripple,
care must be taken to avoid a long ground lead on the
oscilloscope probe. Measure the input or output voltage
ripple by touching the probe tip directly across the VIN or
VOUT and GND terminals. See Figure 2 for proper scope
probe technique.
4. Vary the input voltage from 1.8V to 5.5V, the available
output current depends on the input voltage, see
LTC3536 data sheet for details.
1. With the DC1852 set up according to the proper measurement and equipment in Figure 1, apply 5V at VIN.
Measure VOUT; it should read 0V. If desired, one can
measure the shutdown supply current at this point.
The supply current will be approximately 3μA, or less,
in shutdown.
3. Vary the converter load, which should not exceed 1A
at VIN 5V.
5. Set output current to zero and move jumper JP2 into
Burst Mode position and measure VOUT– it should
register 3.3V ±1%.
6. Vary the input voltage from 1.8V to 5.5V, the available
output current depends on the input voltage. Load in
Burst Mode should no exceed 0.15A at VIN 5V and 0.1A
at 2.5V, see LTC3536 data sheet for details.
+
+
Figure 1. Proper Measurement Equipment Setup
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DEMO MANUAL DC1852A
QUICK START PROCEDURE
GND
VIN
Figure 2. Measuring Input or output Ripple
100
100
ILOAD = 200mA
95
90
80
85
ILOAD = 1A
80
EFFICIENCY (%)
EFFICIENCY (%)
90
75
70
70
60
50
40
65
30
60
20
55
10
50
1.5
2.0
2.5
3.0 3.5 4.0 4.5
INPUT VOLTAGE (V)
5.0
5.5
0
0.001
dc1852a F03
Figure 3. Efficiency vs Input Voltage
VIN = 1.8V
VIN = 2.5V
VIN = 5.5V
VIN = 1.8V BURST
VIN = 2.5V BURST
VIN = 5.5V BURST
0.01
0.1
LOAD CURRENT (A)
1
dc1852a F04
Figure 4. Efficiency vs Input Voltage for Fixed Frequency
and Burst Mode Operation
Figure 5. Output Noise, VIN 4.5V, IO 1A
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DEMO MANUAL DC1852A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
C1
CAP CER 10μF 10V X5R 10% 0805
MURATA, GRM21BR61A106KE19L
2
2
C2, C4
CAP CER 1μF 10V X7R 20% 0603
AVX, 06036C105MAT2A
3
1
C3
CAP CER 22μF 6.3V X5R 10% 1206
AVX, 12066D226KAT2A
4
1
C5
CAP CER 47pF 50V C0G 5% 0402
TDK, C1005C0G1H470J
5
1
C7
CAP CER 220pF 50V C0G 5% 0402
MURATA, GRM1555C1H221JA01D
6
1
L1
INDUCTOR, 4.7μH
COILCRAFT XFL4020-472MEC
7
3
R1, R7, R8
RES 1mΩ 1/16W 1% 0402 SMD
VISHAY, CRCW04021M00FK
8
1
R2
RES 220k 1/16W 1% 0402 SMD
VISHAY, CRCW0402220KFKED
9
1
R3
RES 6.49k 1/16W 1% 0402 SMD
VISHAY, CRCW04026K49FKED
10
1
R4
RES 49.9k 1/16W 1% 0402 SMD
VISHAY, CRCW040249K9FKED
11
1
R6
RES 100k 1/16W 1% 0402 SMD
VISHAY, CRCW0402100KFKED
12
1
U1
BUCK-BOOST CONVERTER
LINEAR TECHNOLOGY, LTC3536EMSE
Additional Demo Board Circuit Components
1
0
C6
CAP POSCAP 47μF 10V
SANYO, 10TPB47MC, OPT
2
0
C8
CAP C0G 0402
OPT
3
0
R5
RES 0402
OPT
1
4
MH1-MH4
STAND-OFF, NYLON (SNAP ON), 0.375" TALL
KEYSTONE, 8832
2
6
E1, E2, E3, E4, E5, E6
TURRET, 0.09 DIA
MILL-MAX, 2501-2-00-80-00-00-07-0
3
2
JP2, JP1
HEADERS, 3 PINS, 2mm CTRs
SAMTEC, TMM-103-02-L-S
4
2
XJP1, XJP2
SHUNT, 2mm CTRs
SAMTEC, 2SN-BK-G
5
1
FAB, PRINTED CIRCUIT BOARD
DEMO CIRCUIT 1797A-2
Hardware
dc1852af
4
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
E2
JP2
RUN
JP1
MODE
VIN
VIN
1
2
3
VIN
1
2
3
+
C6
OPT
R7
1 Meg
R8
1 Meg
C1
10uF
10V
0805
5
2. INSTALL SHUNTS AS SHOWN.
1. ALL RESISTORS AND CAPACITORS ARE 0402.
NOTE: UNLESS OTHERWISE SPECIFIED
OFF
ON
FIXED FREQ
BURST MODE
GND
SYNC
GND
E1
VIN
1.8V - 5.5V
OPT
100k
4
R5
R6
C2
1uF
10V
0603
4
2
1
3
9
8
4
SGND
RT
MODE/SYNC
VIN
VIN
SW1
U1
LTC3536EMSE
5
10
12
11
7
6
49.9K
R4
CUSTOMER NOTICE
PGND
SHDN
VC
FB
VOUT
SW2
3
C8
OPT
220pF
C7
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
2
R2
220K
1%
R1
1 Meg
1%
2
SCALE = NONE
DATE:
N/A
SIZE
TECHNOLOGY
C9
OPT
1206
1
C4
1uF
10V
0603
E4
E3
GND
06-27-11
IC NO.
DATE
06-27-11
VOUT
3.3V / 1A
VICTOR K.
APPROVED
1
LTC3536EMSE
DEMO CIRCUIT 1852A
SHEET
1
OF
1
1
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
1ST PROTOTYPE
DESCRIPTION
REVISION HISTORY
1A, LOW NOISE, BUCK-BOOST REGULATOR
VICTOR K. TITLE: SCHEMATIC
APP ENG.
C3
22uF
6.3V
1206
1
REV
LT
__
ECO
PCB DES.
APPROVALS
R3
6.49K
C5
47pF
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.
L1
XFL4020 - 472
4.7uH
PGND
13
5
A
B
C
D
DEMO MANUAL DC1852A
SCHEMATIC DIAGRAM
dc1852af
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DEMO MANUAL DC1852A
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
dc1852af
6
Linear Technology Corporation
LT 0711 • 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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