DC1781A - Demo Manual

DEMO MANUAL DC1781A
LT3507A
Triple Monolithic Step-Down
Regulator with LDO
DESCRIPTION
Demo circuit 1781A is a Triple Monolithic Step-Down Regulator with LDO featuring the LT3507A. The demo circuit
is designed for 1.8V, 3.3V, 5.0V and 2.5V outputs from a
7V to 36V input. The current capability of each channel
is 2.7A, 1.5A, 1.8A and 0.3A respectively. Independent
input voltage, feedback, soft-start and power good pins
for each channel simplify complex power supply tracking/
sequencing requirements.
All three converters are either synchronized to a common
external clock input or single-resistor programmable from
250kHz to 2.5MHz using internal oscillator. At all frequencies, a 180° phase shift between VOUT1 and the other two
outputs is maintained, reducing input voltage ripple and
PERFORMANCE SUMMARY
PARAMETER
component size. Programmable frequency allows for optimization between efficiency and external component size.
Each output can be independently disabled using its own
soft-start pin, or by using the SD terminal the entire part
can be placed in a low quiescent current shutdown mode.
The LT3507A data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demo circuit 1781A.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, 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
Minimum Input Voltage
VALUE
7V
Maximum Input Voltage
36V
Output Voltage VOUT1
VIN = 7~36V
1.80V ±3%
Output Voltage VOUT2
VIN = 7~36V
3.33V ±3%
Output Voltage VOUT3
VIN = 7~36V
5.0V ±3%
Output Voltage VOUT4
VIN = 7~36V
2.52V ±3%
Switching Frequency
450kHz ±10%
Maximum Output Current IOUT1
VIN = 7~36V
2.7A
Maximum Output Current IOUT2
VIN = 7~36V
1.5A
Maximum Output Current IOUT3
VIN = 7~36V
1.8A
Maximum Output Current IOUT4
VIN = 7~36V
0.3A
Voltage Ripple VOUT1
VIN = 12V, IOUT1 = 2.7A
<20mV
Voltage Ripple VOUT2
VIN = 12V, IOUT2 = 1.5A
<20mV
Voltage Ripple VOUT3
VIN = 12V, IOUT3 = 1.8A
<20mV
Voltage Ripple VOUT4
VIN = 12V, IOUT4 = 0.3A
<10mV
dc1781af
1
DEMO MANUAL DC1781A
QUICK START PROCEDURE
Demo circuit 1781A is easy to set up to evaluate the
performance of the LT3507A. Refer to Figure 2 for proper
measurement equipment setup and follow the procedure
below:
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 3 for
proper scope probe technique.
1. With power off, connect the input power supply to VIN
and GND.
2. Turn on the power at the input.
NOTE. Make sure that the input voltage does not exceed 36V.
3. Check for the proper output voltages.
NOTE. If there is no output, temporarily disconnect
the load to make sure that the load is not set too high.
4. Once the proper output voltages are established, adjust
the load within the operating range and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
100
90
EFFICIENCY (%)
80
70
60
50
40
30
20
VOUT1 = 1.8V
VOUT1 = 3.3V
VOUT1 = 5.0V
10
0
0.3
0.6
0.9
1.2 1.5 1.8 2.1
LOAD CURRENT (A)
2.4
2.7
DC1781A F01
Figure 1. DC1781A Buck Channel Efficiency at VIN = 12V, f = 450kHz
dc1781af
2
DEMO MANUAL DC1781A
QUICK START PROCEDURE
Figure 2. DC1781A Proper Equipment Setup
GND
VIN
Figure 3. Measuring Input or Output Ripple
dc1781af
3
DEMO MANUAL DC1781A
QUICK START PROCEDURE
SYNC FUNCTION
EMI FILTER
Install a 10k R20 resistor if the board is synchronized from
an external signal generator.
Install EMI filters on the backside of the DC1781A, however, a trace cut is required for the insertion of the option
circuit. See Figure 4 for the cut line.
Figure 4. Cut Line for the EMI Filter Installation
dc1781af
4
DEMO MANUAL DC1781A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
3
CIN1, CIN2, CIN3
CAP., X7R, 2.2μF, 50V, 10%, 1210
TDK, C3225X7R1H225K
2
1
C1
CAP., X7R, 0.47μF, 25V, 10%, 0603
MURATA, GRM188R71E474KA12D
3
2
C2, C9
CAP., X7R, 0.22μF, 25V, 10%, 0603
TDK, C1608X7R1E224K
4
2
C3, C10
CAP., X5R, 47μF, 10V, 20%, 1206
TAIYO YUDEN, LMK316BJ476ML-T
5
1
C4
CAP., X5R, 22μF, 6.3V, 20%, 1206
TAIYO YUDEN, JMK316BJ226ML
6
3
C5, C6, C11
CAP., X7R, 680pF, 50V, 10%, 0402
AVX, 04025C681KAT
7
4
C7, C8, C13, C20
CAP., X5R, 0.1μF, 10V, 10%, 0402
AVX, 0402ZD104KAT
8
1
C12
CAP., X5R, 2.2μF, 6.3V, 20%, 0603
TAIYO YUDEN, JMK107BJ225MA
9
3
C15, C17, C19
CAP., NPO, 47pF, 50V, 5%, 0402
AVX, 04025A470JAT
10
1
D4
DIODE, SCHOTTKY, B340A, SMA-DIODE
DIODES INC., B340A
11
2
D5, D6
DIODE, SCHOTTKY, B240A, SMA-DIODE
DIODES INC., B240A
12
3
D7, D8, D9
DIODE, SCHOTTKY, CMDSH-4E, SOD323
CENTRAL SEMI., CMDSH-4E
13
1
L1
IND., 4.7μH
NIC, NPIM74C4R7MTRF
14
1
L2
IND., 8.2μH
NIC, NPIM74C8R2MTRF
15
1
L3
IND., 10μH
NIC, NPIM74C100MTRF
16
1
Q1
XTOR, NPN, 50V LOW SATURATION, MLP322
ZETEX, ZXTCM322TA
17
5
R1, R2, R3, R15, R22
RES., CHIP, 100k, 1/16W, 1%, 0402
YAGEO, RC0402FR-07100KL
18
1
R4
RES., CHIP, 12.4k, 1/16W, 1%, 0402
VISHAY, CRCW040212K4FKEA
19
1
R5
RES., CHIP, 31.6k, 1/16W, 1% 0402
VISHAY, CRCW040231K6FKEA
20
3
R6, R7, R11
RES., CHIP, 20k, 1/16W, 1% 0402
VISHAY, CRCW040220K0FKEA
21
3
R8, R9, R23
RES., CHIP, 10k, 1/16W, 1% 0402
YAGEO, RC0402FR-0710KL
22
1
R10
RES., CHIP, 53.6k, 1/16W, 1% 0402
VISHAY, CRCW040253K6FKEA
23
1
R12
RES., CHIP, 10.2k, 1/16W, 1% 0402
NIC, NRC04F1022TRF
24
1
R13
RES., CHIP, 1.07k, 1/16W, 1% 0402
YAGEO, RC0402FR-071K07L
25
1
R14
RES., CHIP, 49.9k, 1/16W, 1% 0402
VISHAY, CRCW040249K9FKEA
26
1
R16
RES., CHIP, 499, 1/16W, 1% 0402
AAC, CR05-4990FM
27
1
R17
RES., CHIP, 18.2k, 1/16W, 1% 0402
VISHAY, CRCW040218K2FKEA
28
1
R18
RES., CHIP, 3.32k, 1/16W, 1% 0402
VISHAY, CRCW04023K32FKEA
29
1
R19
RES., CHIP, 107k, 1/16W, 1% 0402
AAC, CR05-1073FM
30
1
U1
I.C., LT3507EUHF, QFN38UHF
LINEAR TECH., LT3507EUHF
dc1781af
5
DEMO MANUAL DC1781A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Additional Demo Board Circuit Components
1
1
CIN4
CAP., ELECTROLYTIC, 22μF, 50V
SANYO, 50CE22LX
2
0
C14, C16, C18, C28
CAP., 0402
OPT
3
0
C21
CAP., X7R, 0.01μF, 50V, 10%, 0603
OPT
4
0
C22
CAP., X7R, 2.2μF, 50V, 10%, 1210
OPT
5
0
C23
CAP., ELECTROLYTIC, 22μF 50V
OPT
6
4
C24-C27
CAP., X5R, 1μF, 10V, 10%, 0603
MURATA, GRM188R61A105K
7
0
C29
CAP., 1206
OPT
8
0
D1, D2, D3
DIODE, SCHOTTKY, CMDSH-4E, SOD323
OPT
9
0
FB1
BEAD, 1206
OPT TAIYO YUDEN, FB MJ3216HS800
10
0
L4
IND., 22μH,
OPT
11
0
R20
RES., CHIP, 0402
OPT
12
0
R21
RES., CHIP, 0603
OPT
VISHAY, IHLP4040DZER220-M01
Hardware-For Demo Board Only:
1
10
E1, E2, E6-E9, E12-E15
TP, TURRET, 0.094"
MILL-MAX, 2501-2-00-80-00-00-07-0
2
9
E3, E4, E5, E10, E11, E16-E19
TP, TURRET, 0.064"
MILL-MAX, 2308-2-00-44
dc1781af
6
DEMO MANUAL DC1781A
SCHEMATIC DIAGRAM
dc1781af
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.
7
DEMO MANUAL DC1781A
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
dc1781af
8
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
Similar pages