DC2139A - ANALOG DEVICES - Datasheet.Directory

dc2139af

DEMO MANUAL DC2139A

Description

LT8610A

42V, 3.5A Micropower

Synchronous Step-Down Regulator

Demonstration circuit 2139A is a 42V, 3.5A micropower

synchronous step-down regulator featuring the LT

8610A.

The LT8610A 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 and is unloaded. The 2139A uses two

input ceramic capacitors in series to improve reliability in

case of an input capacitor short failure. Top and bottom

power switches, compensation components and other

necessary circuits are inside of the LT8610A 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 synchronize 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

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

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

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 radiated

EMI. The radiated EMI performances of the board are

shown in Figure 3 to Figure 5. The limits on those figures

are CISPR25, Class 5 peak limits. The circuit passes the

test with a wide margin.

The LT8610A 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 2139A.

Design files for this circuit board are available at

http://www.linear.com/demo

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 3.5 A

FSW Switching Frequency 1.85 2 2.15 MHz

EFE Efficiency at DC IOUT = 1A 92 %

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

dc2139af

DEMO MANUAL DC2139A

Quick start proceDure

Demonstration circuit 2139A is easy to set up to evaluate

the performance of the LT8610A. Refer to Figure 6 and

Figure 7 for proper measurement equipment setup and

follow the procedure below:

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

and GND. When evaluating EMI performance, input

power supply should be connected between VEMI 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 1. LT8610A 12VIN to 5VOUT Efficiency at 2MHz

Switching Frequency

Figure 2. LT8610A Case Temperature Rise, VOUT = 5V, TA = 25°C

LOAD CURRENT (A)

EFFICIENCY (%)

100

60 21 3

DC2139a F01

INPUT VOLTAGE (V)

CASE TEMPERATURE RISE (°C)

140

120

100

02416 32

DC2139a F02

362012 28

TA = 25°C

fSW = 2MHz

ILOAD = 3.5A

fSW = 2MHz

ILOAD = 2.5A

fSW = 1MHz

ILOAD = 3.5A

dc2139af

DEMO MANUAL DC2139A

Quick start proceDure

Figure 3. 30MHz to 1GHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2.5A

Antenna Polarization: Horizontal; Switching Frequency: 2MHz.

Figure 4. 30MHz to 1GHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2.5A

Antenna Polarization: Vertical; Switching Frequency: 2MHz.

dc2139af

DEMO MANUAL DC2139A

Figure 5. 150kHz to 30MHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2.5A

Antenna Polarization: Vertical; Switching Frequency: 2MHz.

(In the frequency range between 150kHz and 30MHz, only vertical polarization is required)

Quick start proceDure

dc2139af

DEMO MANUAL DC2139A

Figure 6. Proper Measurement Equipment Setup

Figure 7. Measure Output Ripple

Quick start proceDure

dc2139af

DEMO MANUAL DC2139A

parts List

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

Required Circuit Components

1 2 C2, C19 CAP, X7R, 4.7µF, 50V, 10%, 1206 MURATA, GRM31CR71H475KA12L

2 2 C4, C8 CAP, X7R, 0.1µF, 16V, 10%, 0402 MURATA, GRM155R71C104KA88D

3 1 C5 CAP, C0G, 4.7pF, 25V, ±0.1pF, 0402 MURATA, GRM1555C1E4R7BZ01D

4 1 C6 CAP, X7R, 47µF, 10V, 10%, 1210 MURATA, GRM32ER71A476KE15L

5 1 C7 CAP, X5R, 1µF, 10V, 10%, 0402 MURATA, GRM155R61A105K

6 1 L1 IND, 2.2UH COILCRAFT, XAL5030-222MEC

7 2 R1, R4 RES, CHIP, 1M, 1/16W, 1% 0402 NIC, NRC04F1004TRF

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

11 1 U1 IC, LT8610AEMSE MSE16 LINEAR TECHNOLOGY CORPORATION, LT8610AEMSE#PBF

Additional Demo Board Circuit Components

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

2 4 C3, C10, C18, C20 CAP, X7R, 4.7µF, 50V, 10%, 1206 MURATA, GRM31CR71H475KA12L

3 1 C9 CAP, X7R, 1µF, 16V, 10%, 0805 AVX, 0805YC105KAT2A

4 6 C11, C12, C13,

C15, C16, C17

CAP, X7R, 0.1µF, 50V, 10%, 0402 TDK, C1005X7R1H104K

5 1 FB1 FERRITE BEAD 0805 TDK, MPZ2012S101AT

6 1 L2 IND 4.7UH VISHAY, IHLP2020BZ-ER4R7M01

7 0 R6 RES, OPT, 0402 OPT

Hardware: For Demo Board Only

1 10 E1 TO E10 TESTPOINT, TURRET, 0.094" pbf MILL-MAX, 2501-2-00-80-00-00-07-0

2 1 JP1 3 PIN 0.079 SINGLE ROW HEADER SAMTEC, TMM103-02-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)

dc2139af

DEMO MANUAL DC2139A

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

D D

C C

B B

A A

ALL CAPACITORS ARE 0402.

NOTES: UNLESS OTHERWISE SPECIFIED

1. ALL RESISTORS ARE 0402.

SUNCON

63CE22BS

(2MHz)

REFER TO THE DEMO MANUAL FOR VIN RANGE.

VOUT

OPT

C15

0.1uF

50V

C15

0.1uF

50V

243k

GND E2

GND

EN/UV

4.7uF

50V

1206

4.7uF

50V

1206

LT8610AEMSE

VIN

EN/UV

SYNC

INTVCC

TR/SS

GND

FB 16

PG 15

BIAS 14

SW 11

SW 10

SW 9

BST 12

GND

C12

0.1uF

50V

C12

0.1uF

50V

E10

VIN

5.5V - 42V E10

VIN

5.5V - 42V

C17

0.1uF

50V

C17

0.1uF

50V

JP1

GND

SYNC

JP1

GND

SYNC

C18

4.7uF

50V

1206

C18

4.7uF

50V

1206

1uF

10V

1uF

10V

SYNC

C11

0.1uF

50V

C11

0.1uF

50V

2.2uH

XAL5030-222MEC

2.2uH

XAL5030-222MEC

18.2k

0603

18.2k

0603

C19

4.7uF

50V

1206

C19

4.7uF

50V

1206

FB1FB1

TR/SS

1uF

0805

16V

1uF

0805

16V

1Meg

0.1uF

4.7uH

4.7pF

C20

4.7uF

50V

1206

C20

4.7uF

50V

1206

C16

0.1uF

50V

C16

0.1uF

50V

47uF

10V

1210

47uF

10V

1210

4.7uF

50V

1206

4.7uF

50V

1206

E8 PG

22uF

63V

22uF

63V

49.9k

E4 GND

C10

4.7uF

50V

1206

C10

4.7uF

50V

1206

C13

0.1uF

50V

C13

0.1uF

50V

0.1uF

10V

0.1uF

10V

VOUT

5V / 3.5A

VOUT

5V / 3.5A

VEMI

5.5V - 42V E1

VEMI

5.5V - 42V

dc2139af

DEMO MANUAL DC2139A

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

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

 LINEAR TECHNOLOGY CORPORATION 2014

LT 0614 • PRINTED IN USA

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

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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

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agency certified (FCC, UL, CE, etc.).

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This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LT C applica-

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