DC1749B - ANALOG DEVICES - Datasheet.Live

dc1749bfa

DEMO MANUAL DC1749B

Description

LT8610

42V, 2.5A Micropower Synchronous

Step-Down Regulator

Demonstration circuit 1749B is a 42V, 2.5A micropower

synchronous step-down regulator featuring the LT

8610.

The LT8610 is a compact, high efficiency, high speed

synchronous monolithic step-down switching regulator

that consumes only 2.5µA of quiescent current when

output is regulated at 5V. Top and bottom power switches,

compensation components and other necessary circuits

are inside of the LT8610 to minimize external components

and simplify design.

The SYNC pin on the demo board is grounded by default

for low ripple Burst Mode

operation. To synchronous to

an external clock, move JP1 to SYNC and apply the external

clock to the SYNC turret. Once JP1 is on SYNC position,

a DC voltage of higher than 2V or INTVCC can be applied L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks

of Linear Technology Corporation. All other trademarks are the property of their respective

owners.

to the SYNC turret for pulse-skipping operation. Figure 1

shows the efficiency of the circuit at 12V input.

The demo board has an EMI filter installed. The EMI per-

formance of the board is shown on Figure 2. The limit in

Figure 2 is EN55022 class B, average. It shows the circuit

passes the test with a wide margin.

The LT8610 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 1749B.

Design files for this circuit board are available at

http://www.linear.com/demo/DC1749B

Figure 1. LT8610 12VIN to 5VOUT Efficiency at 2MHz

Switching Frequency

Figure 2. LT8610 Demo Circuit EMI Performance,

Switching Frequency = 2MHz

LOAD CURRENT (A)

EFFICIENCY (%)

100

0.5 1

dc1749b F01

21.5 2.5 START 150kHz

RES BW (CISPR) 9kHz

–10

MKR1 2.003MHz

21.69 dBµV

10 dB/DIV

dc1749b F02

VBW 62kHz STOP 30MHz

SWEEP 717ms (6637 PTS)

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DEMO MANUAL DC1749B

Quick start proceDure

Demonstration circuit 1749B is easy to set up to evalu-

ate the performance of the LT8610. Refer to Figure 3 and

Figure 4 for proper measurement equipment setup and

follow the procedure below:

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

and GND.

2. With power off, connect the load VOUT and GND.

3. Check JP1 setting

4. Turn on the power at the input.

5. Carefully evaluate other design parameters as needed.

Figure 3. Proper Measurement Equipment Setup

DC1749b F03

performance summary

Specifications are at TA = 25°C

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

VIN Input Supply Range 5.5 42 V

VOUT Output Voltage 4.8 5 5.2 V

IOUT Maximum Output Current 2.5 A

FSW Switching Frequency 1.85 2 2.15 MHz

EFE Efficiency at DC IOUT = 1A 92 %

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DEMO MANUAL DC1749B

Quick start proceDure

Figure 4. Measure Output Ripple

DC1749b F04

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DEMO MANUAL DC1749B

parts List

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

Required Circuit Components

1 1 C2 CAP, X7R, 4.7µF, 50V, 10%, 1206 MURATA, GRM31CR71H475KA12L

2 1 C4 CAP, X7R, 0.22µF, 16V, 10%, 0603 AVX, 0603YC224KAT2A

3 1 C5 CAP, C0G, 10pF, 25V, 10%, 0402 AVX, 04023A100KAT2A

4 1 C6 CAP, X7R, 47µF, 10V, 10%, 1210 MURATA, GRM32ER71A476KE20L

5 1 C7 CAP, X7R, 1µF, 25V, 10%, 0603 MURATA, GRM188R71E105KA12D

6 1 C8 CAP, X7R, 0.1µF, 16V, 10%, 0402 MURATA, GRM155R71C104KA88D

7 1 L1 IND, 2.2UH COILCRAFT, XAL5030-222MEC

8 1 R2 RES, CHIP, 18.2k, 1/10W, 1%, 0603 VISHAY, CRCW060318K2FKED

9 1 R3 RES, CHIP, 49.9k, 1/16W, 1%, 0402 VISHAY, CRCW040249K9FKED

10 2 R1, R4 RES, CHIP, 1M, 1/16W, 1%, 0402 VISHAY, CRCW04021M00FKED

11 1 R5 RES, CHIP, 243k, 1/16W, 1%, 0402 VISHAY, CRCW0402243KFKED

12 1 U1 IC, LT8610EMSE, MSE16 LINEAR TECHNOLOGY CORPORATION, LT8610EMSE

Additional Demo Board Circuit Components

1 1 C1 CAP, ALUM, 22µF, 63V SUN ELECT, 63CE22BS

2 2 C3, C10 CAP, X7R, 4.7µF, 50V, 10%, 1206 MURATA, GRM31CR71H475KA12L

3 1 C9 CAP, X7R, 4.7µF, 16V, 10%, 0805 MURATA, GRM21BR71C475K73L

4 1 C11 CAP, X7R, 1µF, 50V, 10%, 0805 TDK, C2012X7R1H105K

5 2 C12, C13 CAP, X7R, 0.1µF, 50V, 10%, 0402 TDK, C1005X7R1H104K

61 FB1 FERRITE BEAD, 0805 TDK, MPZ2012S221A

71 L2 IND 4.7UH VISHAY, IHLP2020BZ-ER4R7M01

8 0 R6 RES, OPT, 0402 OPT

Hardware: For Demo Board Only

1 9 E1 TO E9 TESTPOINT, TURRET, 0.094" MILL-MAX, 2501-2-00-80-00-00-07-0

2 1 JP1 HEADER 1X3 079 SAMTEC, TMM-103-02-L-S

3 1 XJP1 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G

4 4 MH1 TO MH4 STAND-OFF, NYLON 0.50" TALL KEYSTONE, 8833 (SNAP ON)

dc1749bfa

DEMO MANUAL DC1749B

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 representa-

tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

schematic Diagram

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DEMO MANUAL DC1749B

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

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

 LINEAR TECHNOLOGY CORPORATION 2012

LT 1113 REV A • PRINTED IN USA

DEMONSTRATION BOARD IMPORTANT NOTICE

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This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT

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measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union

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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

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