Linear Technology LT3507A Demo Manual

Download

Page 1

DESCRIPTION

DEMO MANUAL DC1781A

LT3507A

Triple Monolithic Step-Down

Regulator with LDO

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

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.

input voltage, feedback, soft-start and power good pins for each channel simplify complex power supply tracking/ sequencing requirements.

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

All three converters are either synchronized to a common

guide for demo circuit 1781A.

external clock input or single-resistor programmable from 250kHz to 2.5MHz using internal oscillator. At all frequencies, a 180° phase shift between V

and the other two

OUT1

outputs is maintained, reducing input voltage ripple and

PERFORMANCE SUMMARY

PARAMETER CONDITIONS VALUE

Minimum Input Voltage 7V

Maximum Input Voltage 36V

Output Voltage V

Switching Frequency 450kHz ±10%

Maximum Output Current I

Voltage Ripple V

OUT1

OUT2

OUT3

OUT4

OUT1

OUT2

OUT3

OUT4

OUT1

OUT2

OUT3

OUT4

(TA = 25°C)

= 7~36V 1.80V ±3%

VIN = 7~36V 3.33V ±3%

VIN = 7~36V 5.0V ±3%

VIN = 7~36V 2.52V ±3%

VIN = 7~36V 2.7A

VIN = 7~36V 1.5A

VIN = 7~36V 1.8A

VIN = 7~36V 0.3A

VIN = 12V, I

= 2.7A <20mV

OUT1

= 1.5A <20mV

OUT2

= 1.8A <20mV

OUT3

= 0.3A <10mV

OUT4

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.

dc1781af

Page 2

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 V

or V

and GND terminals. See Figure 3 for

OUT

proper scope probe technique.

1. With power off, connect the input power supply to V

and GND.

100

EFFICIENCY (%)

0.3

0.6 1.8 2.1 2.4 2.70.9 1.2 LOAD CURRENT (A)

Figure 1. DC1781A Buck Channel Efficiency at VIN = 12V, f = 450kHz

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.

= 1.8V

OUT1

= 3.3V

OUT1

= 5.0V

OUT1

1.5

DC1781A F01

dc1781af

Page 3

QUICK START PROCEDURE

DEMO MANUAL DC1781A

Figure 2. DC1781A Proper Equipment Setup

Figure 3. Measuring Input or Output Ripple

GND

dc1781af

Page 4

DEMO MANUAL DC1781A

QUICK START PROCEDURE

SYNC FUNCTION

Install a 10k R20 resistor if the board is synchronized from an external signal generator.

EMI FILTER

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

Page 5

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

Page 6

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 VISHAY, IHLP4040DZER220-M01

11 0 R20 RES., CHIP, 0402 OPT

12 0 R21 RES., CHIP, 0603 OPT

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

Page 7

SCHEMATIC DIAGRAM

DEMO MANUAL DC1781A

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.

dc1781af

Page 8

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

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com

dc1781af

LT 0711 • PRINTED IN USA