LM5030EVAL National Semiconductor, LM5030EVAL Datasheet

LM5030EVAL

Manufacturer Part Number

LM5030EVAL

Description

EVALUATION BOARD FOR LM5030

Manufacturer

National Semiconductor

Series

PowerWise®r

Datasheets

1.LM5030SDNOPB.pdf (12 pages)

2.LM5030EVAL.pdf (11 pages)

Specifications of LM5030EVAL

Main Purpose

DC/DC, Step Down

Outputs And Type

1, Isolated

Voltage - Output

3.3V

Current - Output

10A

Voltage - Input

36 ~ 75V

Regulator Topology

Buck

Board Type

Fully Populated

Utilized Ic / Part

LM5030

Lead Free Status / RoHS Status

Not applicable / Not applicable

Power - Output

Frequency - Switching

Other names

*LM5030EVAL

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LM5030 Evaluation Board

Introduction

The LM5030EVAL evaluation board provides the design en-

gineer with a fully functional push-pull power converter using

the LM5030 PWM controller. The performance of the board

is as follows:

• Input range: 36V to 75V

• Output voltage: 3.3V

• Output current: 0 to 10A

• Measured efficiency: 82% (at 48V in, 10A Load Current)

• Board size: 2.4 x 2.4 x 0.5 inches

• Load regulation: ± 1.0% (1 - 10A)

• Line regulation: ± 0.15% (36 - 75V)

• Shutdown input

• Synchronizing input

The printed circuit board consists of 2 layers of 2 ounce

copper on FR4 material, with a total thickness of 0.062

inches. The board is designed for continuous operation at

rated load.

Theory Of Operation

Referring to Figure 7, the LM5030 controller (U1) alternately

drives two N channel MOSFETs, which feed the two halves

of the power transformer’s primary (T1). The transformer’s

secondary is rectified, and filtered with an LC filter (L2,

C3-5), to provide the output voltage. The feedback path

starts with the LM3411 precision regulator driver (U3) which

senses the output voltage, compares it to its internal refer-

ence, and drives an optocoupler (U2) based on the error

voltage. The optocoupler provides isolation in the feedback

path, and its open collector output drives the COMP pin on

the LM5030, which controls the pulse width to the MOS-

FETs. The lower the voltage at the COMP pin, the smaller

the MOSFET duty cycle.

Current in the main transformer’s primary is monitored at the

LM5030’s CS pin via a current sense transformer (T2). The

voltage at the CS pin is used for current mode PWM control

and current limit protection.

AN200892

National Semiconductor

Application Note 1305

Dennis Morgan

January 2004

The output inductor (L2) not only smoothes the output volt-

age waveform, but also generates an auxiliary voltage (by

means of its secondary winding) to power the Vcc pin on the

LM5030. This feature reduces power dissipation within the

IC, thereby increasing reliability.

A Synchronizing input pad (SYNC) is provided on the board

to synchronize the circuit’s operating frequency to an exter-

nal source. A Shutdown input pad (SD) permits shutting

down the circuit’s operation from an external switch to

ground.

Board Layout and Probing

The pictorial in Figure 1 shows the placement of the signifi-

cant components which may be probed in evaluating the

circuit’s operation. The following should be kept in mind

when using scope or meter probes:

1. The board has two circuit grounds - one associated with

2. The main current carrying components (L1, T1, T2, Q1,

3. Use care when probing the primary side at maximum

4. At maximum load current (10A), the wire size, and

5. The input voltage conector is J1.

the input power, and one associated with the output

power. The grounds are capacitively coupled (C6), but

are DC isolated.

Q2, D1 and L2) will be hot to the touch at maximum load

current. USE CAUTION. If operating at maximum load

current for extended periods, the use of a fan to provide

forced air flow is recommended.

input voltage. 75 volts is enough to produce shocks and

sparks.

length, used to connect the board’s output to the load

becomes important. Ensure there is not a significant

voltage drop in the wires. Note that two connectors are

provided at the output - one for the +3.3V output (J2

Out), and one for the Ground connection (J3 IGND). It is

advisable to make good use of this feature to ensure a

low loss connection.

www.national.com

Related parts for LM5030EVAL

LM5030EVAL Summary of contents

Page 1

... LM5030 Evaluation Board Introduction The LM5030EVAL evaluation board provides the design en- gineer with a fully functional push-pull power converter using the LM5030 PWM controller. The performance of the board is as follows: • Input range: 36V to 75V • Output voltage: 3.3V • Output current 10A • ...

Page 2

Board Layout and Probing Board Connections/Start-Up The input connection to the board from a power supply is made to connector J1. The power supply must be capable of supplying not only the current during normal operation, but also the inrush ...

Page 3

Performance (Continued) current, the output will be regulated to within the input voltage is varied over its range (36 - 75V). The power conversion efficiency is shown in Figure 3. Waveforms If the circuit ...

Page 4

FIGURE 3. Efficiency vs Load Current and V 4 20089203 IN ...

Page 5

OUT 36V 1.0A 2.2µS 5.3µS 266.7 48V 10A 1.9µS 5.5µS 270.3 75V 1.0A 1.2µS 6.2µS 270 10.5V 36V 72V 90V 10V 11.5V 48V 96V 130V 18V 10.5V 75V 150V ...

Page 6

FIGURE 6. Average Voltage at the CS pin vs Input Current www.national.com FIGURE 5. V Voltage vs Load Current CC 20089206 6 20089205 ...

Page 7

7 www.national.com ...

Page 8

... Q1, 2 SUD19N20-90 J1-3 651-1727010 Note 1: Data sheets for L1, L2, and T1 are available from Coilcraft at http://www.coi1craft.com/prod_pwr.cfm. Select “Magnetics for National Semiconductor 100V Push-Pull Current Mode PWM Controller, LM5030”. Note 2: Data sheet for T2 is available from Pulse Engineering at http://www.pulseeng.com/default.cfm. www.national.com ...

Page 9

PCB Layout Diagrams FIGURE 8. Bottom Layer (viewed from top) 9 20089208 www.national.com ...

Page 10

PCB Layout Diagrams www.national.com (Continued) FIGURE 9. Top Silk Screen 10 20089209 ...

Page 11

... BANNED SUBSTANCE COMPLIANCE National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2. ...

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