Linear technology Dc1934a Quick setup guide

dc1934af

DEMO MANUAL DC1934A

DESCRIPTION

LTM8053

40V, 3.5A Step-Down

μModule Regulator

Demonstration circuit 1934A is a 40V, 3.5A step-down

μModule

regulator featuring the LT M

8053. The demo

board is designed for 5V output from a 5.6V to 40V input.

The wide input range allows a variety of input sources,

such as automotive batteries and industrial supplies. The

user adjustable features of the LTM8053 such as output

voltage, switching frequency, soft-start, and power good

can be changed on DC1934A simply by modifying the

appropriate resistors and/or capacitors. Two or more

LTM8053s can be paralleled to share load current equally.

The LTM8053 can be programmed to different operation

modes. The SYNC pin on the demo board is grounded

(JP1 at BURST position) by default for low ripple Burst

Mode

operation. Pulse-skipping mode, spread spectrum

mode, or synchronization mode can be selected respec-

tively by moving JP1 shunt to NON-BURST position and

adding different signals to SYNC terminal. See Quick Start

Procedure section for more details.

L, LT, LTC, LTM, Linear Technology, the Linear logo, μModule and Burst Mode are registered

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

respective owners.

BOARD PHOTO

Figure 1 shows the efficiency of the circuit under different

input voltagesin BurstMode operation.The ratedmaximum

load current is 3.5A, while derating is necessary for certain

input voltage and thermal conditions. Figure 2 shows the

LTM8053 derating curve on DC1934A demo board. The

demo board has an optional EMI filter. To achieve high

EMI/EMC performance, the input EMI filter is required and

the input voltage should be applied at VIN_EMI terminal.

The LTM8053 data sheet gives a complete description of

the part, operation and application information. The data

sheet must be read in conjunction with this demo manual

for demo circuit 1934A.

Design files for this circuit board are available at

http://www.linear.com/demo/DC1934A

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DEMO MANUAL DC1934A

Figure1. LTM8053 Demo Circuit DC1934A Efficiency

vs Load Current (fSW = 1MHz, VOUT = 5V, Burst

ModeOperation)

PERFORMANCE SUMMARY

Specifications are at TA= 25°C

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

VIN* Input Supply Range 5.6 40 V

VOUT Output Voltage 4.85 5 5.15 V

IOUT** Maximum Output Current 3.5 A

fSW Switching Frequency VIN = 12V, IOUT = 3.5A 1 MHz

EFE Efficiency at DC VIN = 12V, IOUT = 2A 93.5 %

*When VIN voltage is low, the LTM8053 may skip switching cycles.

**Derating is necessary for certain VIN and thermal conditions.

Figure2. LTM8053 Demo Circuit DC1934A Maximum

Load Current Derating

VIN = 12V

VIN = 24V

LOAD CURRENT (A)

0.001

0.01

0.1

EFFICIENCY (%)

DC1934A F01

0 LFM

12V

24V

36V

AMBIENT TEMPERATURE (°C)

100

125

MAXIMUM LOAD CURRENT (A)

DC1934A F02

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DEMO MANUAL DC1934A

QUICK START PROCEDURE

Demonstration circuit 1934A is easy to set up to evalu-

ate the performance of the LTM8053. Refer to Figure 3

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 4 for

the proper scope technique.

1. Place JP1 on BURST position.

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

and GND. If the input EMI filter is desired, install the

filter and connect the input power supply to VIN_EMI

and GND.

3. With power off, connect the load from VOUT to GND.

4. Turn on the power at the input.

NOTE. Make sure that the input voltage does not ex-

ceed40V.

5. Check for the proper output voltage (VOUT = 5V).

NOTE. If there is no output, temporarily disconnect the

load to make sure that the load is not set too high or

is shorted.

6. Once the proper output voltage is established, adjust

the load within the operating ranges and observe the

output voltage regulation, ripple voltage, efficiency and

other parameters.

7. JP1 is placed on BURST position by default, for the low

ripple Burst Mode operation. When JP1 is placed on

NON-BURST position, LTM8053 can operate in pulse-

skipping mode, spread spectrum mode, or synchroni-

zation mode respectively, based on the different SYNC

terminal inputs. If SYNC terminal is floating, LTM8053

is in pulse-skipping mode. If an external clock is driv-

ing the SYNC terminal, LTM8053 is in synchronization

mode. Please make sure that RT should be chose to set

the LTM8053 switching frequency equal to or below the

lowest SYNC frequency. If a 2.9V to 4.2V DC voltage

is tied to the SYNC terminal, LTM8053 is in spread

spectrum mode. This DC voltage can also be added

through a voltage divider (R7 and R8) from the output.

The recommended divider bottom resistor (R8) is 200k.

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DEMO MANUAL DC1934A

Figure3. Proper Measurement Equipment Setup

QUICK START PROCEDURE

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DEMO MANUAL DC1934A

QUICK START PROCEDURE

Figure4. Measuring Output Ripple

OUT

GND

Figure5. DC1934A Output Noise Spectrum, VIN = 12V, VOUT = 5V, IO= 3.5A

DC1934A F05

INTENSITY (dBm)

–20

–80

–100

–120

–60

–40

FREQUENCY (MHz)

0 4.5

0.5 1.0 1.5 2.52.0 3.0 3.5 4.0 5.0

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DEMO MANUAL DC1934A

PARTS LIST

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

Required Circuit Components

1 1 C1 CAP., X7R, 0.1μF, 25V, 10% 0603 MURATA, GRM188R71E104KA01D

2 1 C4 CAP., X7R, 4.7μF, 50V, 10% 1206 MURATA, GRM31CR71H475KA12L

3 1 C5 CAP., X5R, 100μF, 6.3V, 20% 1206 MURATA, GRM31CR60J107ME39L

4 1 C6 CAP., X5R, 4.7μF, 6.3V, 10% 0603 MURATA, GRM188R60J475KE19D

5 1 R1 RES., CHIP, 41.2k, 1/10W,1% 0603 VISHAY, CRCW060341K2FKEA

6 2 R3, R5 RES., CHIP, 100k, 1/10W, 1% 0603 VISHAY, CRCW0603100KFKEA

7 1 R4 RES., CHIP, 60.4k, 1/10W, 1% 0603 VISHAY, CRCW060360K4FKEA

8 1 U1 IC., BGA, 48L, 9X6.25X3.23MM LINEAR TECH., LTM8053EY#PBF

Additional Demo Board Circuit Components

1 0 C2, C9, C11 (OPT) CAP., 0603

2 1 C3 CAP., ALUM 22μF, 63V SUN ELECT., 63CE22BS

3 0 C7 (OPT) CAP., X7R, 10μF, 50V, 10% 1210 MURATA, GRM32ER71H106KA12L

4 0 C10 (OPT) CAP., X7R, 0.1μF, 50V, 10% 0402 TDK, C1005X7R1H104K050BB

5 0 L1 (OPT) INDUCTOR, 1.2μH WURTH ELEKTRONIK, 74437324012

6 1 R2 RES., CHIP, 0Ω, 1/10W, 0603 VISHAY, CRCW06030000Z0EA

7 0 R6, R7, R8 (OPT) RES., 0603

Hardware/Components (for Demo Board Only)

1 10 E1-E6, E8-E11 TESTPOINT, TURRET, 0.094" PBF MILL-MAX, 2501-2-00-80-00-00-07-0

2 0 E7 OPT

3 1 JP1 HEADER 3-PIN 0.079" SINGLE ROW WURTH ELEKTRONIK, 62000311121

4 1 XJP1 SHUNT, 0.079" CENTER WURTH ELEKTRONIK, 60800213421

5 4 MH1-MH4 STAND-OFF, NYLON 19.1mm WURTH ELEKTRONIK, 702937000

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DEMO MANUAL DC1934A

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.