Linear Technology DC2012A Demo Manual

Description

DEMO MANUAL DC2012A

LT8610AB

42V, 3.5A Micropower Synchronous

Step-Down Regulator

Demonstration circuit 2012A is a 42V, 3.5A micro­power synchronous

®

8610AB. The LT8610AB is a compact, high efficiency,

LT

step-down regulator featuring the

high speed synchronous monolithic step-down switching
regulator that consumes only 2.5µA of quiescent current
when output is regulated at 5V. The efficiency of the circuit
is greater than 90% at light load up to 1.5A. This is a 10%
improvement over competing parts. Top and bottom power
switches, compensation components and other necessary
circuits are inside of the LT8610AB 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 INTV

can be applied

CC

to the SYNC turret for pulse-skipping operation. Figure 1
shows the efficiency of the circuit at 12V input.

Figure 2 shows the thermal performance of the circuit.
When running at input voltage greater than 30V, 3.5A
output current and 2MHz switching frequency, the tem

­perature rise will be significant. Either reducing the input
voltage, the output current or the switching frequency will
bring the temperature down to acceptable level without
external cooling.

The demo board has an EMI filter installed. The board
and the IC are designed to minimize conducted and radi

­ated EMI. The conducted EMI performance of the board
is shown on Figure 3. The limit in Figure 3 is EN55022
class B, average. It shows the circuit passes the test with
a wide margin.

The LT8610AB 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 DC2012A.

Design files for this circuit board are available at

http://www.linear.com/demo/DC2012A

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.

performance summary

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

* Input Supply Range 5.5 42 V

V

IN

V

OUT

I

OUT

f

SW

EFE Efficiency at DC I

* Refer to Figure 2 to determine the maximum input voltage. If IC temperature exceeds target, reduce input voltage, output current or switching
frequency.

Output Voltage 4.8 5 5.2 V

Maximum Output Current 3.5 A

Switching Frequency 1.85 2 2.15 MHz

Specifications are at TA = 25°C

= 1A 91 %

OUT

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1

DEMO MANUAL DC2012A

DC2012A F03

Quick start proceDure

DC2012A is easy to set up to evaluate the performance of
the LT8610AB. Refer to Figure 4 and Figure 5 for proper
measurement equipment setup and follow the procedure
below:

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

IN

and GND.

100

95

90

85

80

75

EFFICIENCY (%)

70

65

60

0 0.01 1 100.1

LOAD CURRENT (A)

DC2012A F01

2. With power off, connect the load V

and GND.

OUT

3. Check JP1 setting

4. Turn on the power at the input.

5. Carefully evaluate other design parameters as needed.

140

120

100

80

60

40

CASE TEMPERATURE RISE (°C)

20

2MHz, 2.5A

0

6 11 21 3616 3126

2MHz, 3.5A

VIN (V)

700kHz, 3.5A

DC2012A F02

Figure 1. LT8610AB 12VIN to 5V
2MHz Switching Frequency

Figure 3. LT8610AB Demo Circuit Conducted EMI Performance

Efficiency at

OUT

70

60

50

40

30

20

dBµV

10

0

–10

–20

–30

START 150kHz
RES BW 9kHz

Figure 2. LT8610AB Case Temperature Rise.
V

= 5V, TA = 25°C

OUT

EN55022 CLASS B

VBW 62kHz STOP 30MHz

2

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Quick start proceDure

DEMO MANUAL DC2012A

Figure 4. Proper Measurement Equipment Setup

Figure 5. Measure Output Ripple

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3

DEMO MANUAL DC2012A

parts List

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

Required Circuit Components

1 1 C2 CAP., X7R, 2.2µF, 50V, 10%, 1206 MURATA, GCJ31CR71H225KA12L

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

3 1 C5 CAP., C0G, 10pF, 25V, 10%, 0402 AVX, 04023A100K AT2A

4 2 C6, C14 CAP., X7R, 47µF, 10V, 10%, 1210 MURATA, GRM32ER71A476KE15L

5 1 C7 CAP., X7R, 1.0µF, 25V, 10%, 0603 MURATA, GRM188R71E105KA12D

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

7 1 L1 IND., 2.2µH COILCRAFT, XAL5030-222MEC

8 1 R2 RES., CHIP, 18.2k, 1/10W, 1% 0603 VISHAY, CRCW060318K2FKEA

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, LT8610ABEMSE#PBF MSE16 LINEAR TECH, LT8610ABEMSE#PBF

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, 1.0µF, 16V, 10%, 0805 AVX, 0805YC105K AT2A

4 1 C11, C12 CAP., X7R, 0.1µF, 50V, 10%, 0402 TDK, C1005X7R1H104K

5 2 C13 CAP., X7R, 0.1µF, 50V, 10%, 0603 MURATA, GCJ188R71H104KA

6 1 FB1 FERRITE BEAD 0805 TDK, MPZ2012S101

7 1 L2 IND., 4.7µH VISHAY, IHLP2020BZ-ER4R7M01

8 0 R6 RES., O PT, 0402 OPT

Hardware: For Demo Board Only

1 9 E1-E9 TESTPOINT, TURRET, .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, .079" CENTER SAMTEC, 2SN-BK-G

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

AT

12D

4

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DEMO MANUAL DC2012A

5

4

3

2

1

schematic Diagram

VOUT

VOUT

5V / 3.5A

5V / 3.5A

VOUT

L1

L1

2.2uH

2.2uH

C4

0.22uF

0603

16VC40.22uF

0603

16V

GNDE4GND

E3

E3

C9

1uF

0805

16VC91uF

0805

16V

C6

47uF

10V

1210C647uF

10V

1210

C14

47uF

10V

1210

C14

47uF

10V

1210

XAL5030-222MEC

XAL5030-222MEC

PG

E4

R3

49.9kR349.9k

R4

1MegR41Meg

R5

C5

243kR5243k

E8PGE8

1

10pFC510pF

2

SYNCE5SYNC

E5

11SW10SW9

SYNC

SYNC

14

16

15

FB

PG

SW

BIAS

GND

17

3

4

5

132

GND

GND

JP1

JP1

8

R2

R2

18.2k

0603

18.2k

0603

(2MHz)

C8

0.1uFC80.1uF

C7

1uF

0603

25VC71uF

0603

25V

E7

GNDE9GND

E9

TR/SSE7TR/SS

ALL CAPACITORS ARE 0402.

NOTES: UNLESS OTHERWISE SPECIFIED

REFER TO THE DEMO MANUAL FOR VIN RANGE.

1. ALL RESISTORS ARE 0402.

*

12

L2

4.7uHL24.7uH

FB1FB1

BST

U1

U1

LT8610ABEMSE

LT8610ABEMSE

VIN5VIN6EN/UV4SYNC1INTVCC13TR/SS2RT3PGND7GND

R6

OPTR6OPT

R11MR1

1M

50V

50V

0603

0603

C13

0.1uF

C13

0.1uF

50V

50V

C2

2.2uF

1206C22.2uF

1206

SUNCON

63CE22BS

C1

22uF

63V+C1

22uF

63V

+

50V

50V

C10

4.7uF

1206

C10

4.7uF

1206

50V

50V

C3

4.7uF

1206C34.7uF

1206

50V

50V

C12

0.1uF

C12

0.1uF

50V

50V

C11

0.1uF

C11

0.1uF

E1

E1

E2

E6

EN/UVE6EN/UV

*

GNDE2GND

VIN

VIN

5.5V - 42V

5.5V - 42V

D D

C C

B B

A A

dc2012af

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.

5

DEMO MANUAL DC2012A

DEMONSTRATION BOARD IMPORTANT NOTICE

Linear Technology Corporation (LT C) 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 LT C 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 LT C 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. LT C assumes no liability for applications assistance,

customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.

LT C 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 LT C applica­tion engineer.

Mailing Address:

Linear Technology

1630 McCarthy Blvd.

Milpitas, CA 95035

Copyright © 2004, Linear Technology Corporation

Linear Technology Corporation

6

1630 McCarthy Blvd., Milpitas, CA 95035-7417

[phone] ● FAX: [phone] ● www.linear.com

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LT 1113 • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 2013