DC1797A - Demo Manual

DEMO MANUAL DC1797A
LTC3536
1A, Low Noise, Wide VIN
Buck-Boost DC/DC Converter
Description
Demonstration circuit 1797A is a combined step-up and
step-down DC/DC converter using the LTC®3536 monolithic
synchronous buck-boost regulator. The DC1797A 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 DC1797A can be set as low as 1.8V and can go
as high as 5.5V. The DC1797A supports two operational
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.
The DC1797A consumes less than 28µA of quiescent current during Burst Mode operation, and during shutdown,
it consumes less than 1µA. The DC1797A 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 DC1797A, small, low
profile surface mount components are used in the circuit.
These features, plus the LTC3536 availability in a small
10-lead DFN package, make the DC1797A a perfect match
for battery-powered, hand-held applications.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, µModule, 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.
PERFORMANCE SUMMARY
PARAMETER
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
External Clock Sync. Frequency Range
300kHz to 2MHz
Efficiency
VIN = 5V, VOUT = 3.3V, IOUT = 0.2A
95%
Typical Output Ripple VOUT
VIN = 5V, IOUT = 1A (20MHz Bandwidth)
< 15mVP-P
Burst Mode Operation
VIN = 5V, VOUT = 3.3V
VIN = 2.5V, VOUT = 3.3V
< 0.15A
< 0.1A
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DEMO MANUAL DC1797A
quick start procedure
Demonstration circuit 1797A 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 frequency and JP2 off positions,
which connects the RUN pin to ground (GND), and thus,
shutdown the circuit.
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.
1.With the DC1797 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.
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 ±%
(Do not apply more than the rated maximum voltage of
5.5V to the board or the part may be damaged).
3.Vary the converter load, which should not exceed 1A
at VIN 5.0V.
4.Vary the input voltage from 1.8V to 5.5V, the available
output current depends on the input voltage, see the
LTC3536 data sheet for details.
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 operation should no exceed 0.15A at VIN
5.0V and 0.1A at 2.5V, see the LTC3536 data sheet for
details.
Figure 1. Proper Measurement Equipment Setup
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DEMO MANUAL DC1797A
Quick Start Procedure
GND
VIN
100
100
95
90
90
80
85
70
EFFICIENCY (%)
EFFICIENCY (%)
Figure 2. Measuring Input or Output Ripple
80
75
70
65
60
60
50
40
FIXED FREQUENCY MODE
30
20
ILOAD = 200mA
ILOAD = 1A
55
50
1.5
Burst Mode
OPERATION
2
2.5
3 3.5 4 4.5
INPUT VOLTAGE (V)
5
5.5
0
0.001
DC1797A F03
Figure 3. Efficiency vs Input Voltage
VIN = 5.5V
VIN = 2.5V
VIN = 1.8V
10
0.01
0.1
LOAD CURRENT (A)
1
DC1797A F04
Figure 4. Efficiency vs Input Voltage for Fixed
Frequency and Burst Mode Operation
14mVP-P
DC1797A F05
Figure 5. Output Noise, VIN = 4.5V, IOUT = 1A
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DEMO MANUAL DC1797A
parts list
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER, PART NUMBER
Required Circuit Components
1
1
C1
Capacitor Ceramic 10µF 10V X5R 10% 0805
Murata, GRM21BR61A106KE19L
2
2
C2, C4
Capacitor Ceramic 1.0µF 10V X7R 20% 0603
AVX, 06036C105MAT2A
3
1
C3
Capacitor Ceramic 22µF 6.3V X5R 10% 1206
AVX, 12066D226KAT2A
4
1
C5
Capacitor Ceramic 47PF 50V C0G 5% 0402
TDK, C1005C0G1H470J
5
1
C7
Capacitor Ceramic 220PF 50V C0G 5% 0402
Murata, GRM1555C1H221JA01D
6
1
L1
Inductor, 4.7µH
Coilcraft XFL4020-472MEC
7
3
R1, R7, R8
Resistor 1.00MΩ 1/16W 1% 0402 SMD
Vishay, CRCW04021M00FK
8
1
R2
Resistor 220kΩ 1/16W 1% 0402 SMD
Vishay, CRCW0402220KFKED
9
1
R3
Resistor 6.49kΩ 1/16W 1% 0402 SMD
Vishay, CRCW04026K49FKED
10
1
R4
Resistor 49.9kΩ 1/16W 1% 0402 SMD
Vishay, CRCW040249K9FKED
11
1
R6
Resistor 100kΩ 1/16W 1% 0402 SMD
Vishay, CRCW0402100KFKED
12
1
U1
Buck-Boost Converter
Linear Technology, LTC3536EDD
Additional Demo Board Circuit Components
1
0
C6
Capacitor, POSCAP 47µF 10V
Sanyo, 10TPB47MC, Optional
2
0
C8
Capacitor C0G 0402
Optional
3
0
R5
Resistor, 0402
Optional
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 Diameter
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
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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
VIN
+
C6
OPT
VIN
R8
1 Meg
OFF
ON
JP2
RUN
C1
10uF
10V
VIN
1
2
3
5
2. INSTALL SHUNTS AS SHOWN.
1. ALL RESISTORS ARE 0402 AND CAPACITORS ARE 0603.
NOTE: UNLESS OTHERWISE SPECIFIED
MODE
1
BURST MODE
2
3
FIXED FREQ
JP1
GND
SYNC
GND
E2
E1
VIN
1.8V - 5.5V
R7
1 Meg
4
C2
1uF
10V
4
R6
100k
R5
OPT
LTC3536EDD
2 SGND
1 RT
SW2 5
49.9K
R4
CUSTOMER NOTICE
SHDN 8
VC 10
FB 9
VOUT 6
C8
OPT
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
2
R3
6.49K
C5
47pF
R2
220K
1%
2
DATE:
N/A
SIZE
04-11-11
IC NO.
E4
GND
DATE
04-11-11
VOUT
3.3V / 1A
1
SHEET 1
1A LOW NOISE, WIDE VIN
BUCK-BOOST DC / DC CONVERTER
LTC3536EDD
DEMO CIRCUIT 1797A
TECHNOLOGY
C4
1uF
10V
E3
VICTOR K.
APPROVED
OF
1
2
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
C3
22uF
6.3V
DESCRIPTION
PRODUCTION FAB
2
1
REVISION HISTORY
REV
R1
1 Meg
1%
__
ECO
VICTOR K. TITLE: SCHEMATIC
SCALE = NONE
APP ENG.
NC
APPROVALS
PCB DES.
220pF
C7
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.
3 MODE/SYNC
7 VIN
4 SW1
U1
3
L1
XFL4020 - 472
4.7uH
PGND
11
5
A
B
C
D
DEMO MANUAL DC1797A
Schematic Diagram
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DEMO MANUAL DC1797A
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
dc1797af
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Linear Technology Corporation
LT 0611 • 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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