LM22677EVAL/NOPB National Semiconductor, LM22677EVAL/NOPB Datasheet

LM22677EVAL/NOPB

Manufacturer Part Number

LM22677EVAL/NOPB

Description

BOARD EVALUATION FOR LM22677

Manufacturer

National Semiconductor

Series

SIMPLE SWITCHER®r

Datasheets

1.LM22677TJE-ADJNOPB.pdf (16 pages)

2.LM22677EVALNOPB.pdf (6 pages)

Specifications of LM22677EVAL/NOPB

Main Purpose

DC/DC, Step Down

Outputs And Type

1, Non-Isolated

Voltage - Output

3.3V

Current - Output

Voltage - Input

4.5 ~ 42V

Regulator Topology

Buck

Frequency - Switching

500kHz

Board Type

Fully Populated

Utilized Ic / Part

LM22677

Lead Free Status / RoHS Status

Not applicable / Not applicable

Power - Output

Other names

*LM22677EVAL
LM22677EVAL

Current page: 1 of 6
Download datasheet (648Kb)

LM22677 Evaluation Board

Introduction

The LM22677 evaluation board is designed to demonstrate

the capabilities of the LM22677 switching regulator. The

LM22677 evaluation board schematic shown in

configured to provide an output voltage of 3.3V up to 5A load

current with an input voltage range of 4.5V to 42V. Due to the

low R

mum duty-cycle limitations, the minimum input voltage of 4.5V

will only provide a 3.3V output voltage for load currents up to

500 mA. At 5.5V input voltage 3A of output current is possible

while maintaining 3.3V of output voltage. For load currents

higher than 3A, an input voltage of 6.5V or higher is required.

The typical operating frequency is 500 kHz. The evaluation

board is designed to operate at ambient temperatures up to

30°C.

DS(ON)

of the integrated N-channel MOSFET and maxi-

300780

FIGURE 1. Evaluation Board Schematic

Figure 1

National Semiconductor

Application Note 1892

Frederik Dostal , Ricardo Capetillo

March 15, 2010

The performance of the evaluation board is as follows:

Input Range: 4.5V to 42V

Output Voltage: 3.3V

Output Current Range: 0A to 5A

Frequency of Operation: 500 kHz

Board Size: 2.25 X 2 inches (57 mm x 50.5 mm)

Package: TO-263 THIN

At low input voltages between 4.5V and 6V, a minimum load

of approximately 5 mA may be required to reach a regulated

3.3V output voltage. See the LM22677 datasheet for more

details.

To aid in the design and evaluation of DC/DC buck converter

solutions based on the LM22677 switching regulator, the

evaluation board can be re-configured for different output

voltages.

The evaluation board is designed to highlight applications

with a small solution size. This implies that there will be a

tradeoff with the area of heat dissipation available. If this eval-

uation board is operated continuously at a full 5A load, it will

get hot. For higher output voltages than the pre-adjusted

3.3V, the total output power as well as the total power con-

version losses will increase. It is recommended to use a fan

or other source of air flow when evaluating the board at full

5A load or at output voltages greater than 3.3V. Typical eval-

uation board performance and characteristics curves are

shown in

layout.

Test points are provided to enable easy connection and mon-

itoring of critical signals. When performing over load or short

circuit tests, refer to the current limit section of the LM22677

datasheet to determine if the circuit is in safe operating mode.

For more information about device function and electrical

characteristics, refer to the LM22677 datasheet.

Figure 2

through

Figure

Figure 6

30078001

shows the PCB

www.national.com

Related parts for LM22677EVAL/NOPB

LM22677EVAL/NOPB Summary of contents

Page 1

... For load currents higher than 3A, an input voltage of 6.5V or higher is required. The typical operating frequency is 500 kHz. The evaluation board is designed to operate at ambient temperatures up to 30°C. © 2010 National Semiconductor Corporation National Semiconductor Application Note 1892 Frederik Dostal , Ricardo Capetillo March 15, 2010 The performance of the evaluation board is as follows: Input Range: 4 ...

Page 2

... Output capacitor C5 is not populated but space is provided to add a second output capacitor. This second output capacitor may be used to further reduce output voltage ripple. Supplier TDK C4532X7R1H685M Panasonic TDK C1608X7R1H103K Panasonic - Central Semiconductor Wurth Coilcraft MSS1278-472MLD - CRCW0603976RFKEA - CRCW06031K54FKEA - National Semiconductor 2 Part Number EEEFK1J220XP EEFUE0J181R CMSH5-60 74477004 LM22677TJ-ADJ ...

Page 3

Performance Characteristics Unless otherwise specified 12V FIGURE 2. Start-Up Waveforms (Load Resistor = 0.66Ω) FIGURE 3. Operation 25°C. A 30078002 30078005 FIGURE 5. Overall Loop Gain and Phase (I 3 30078003 FIGURE 4. ...

Page 4

PCB Layout Diagram www.national.com FIGURE 6. Top Layer FIGURE 7. Bottom Layer 4 30078006 30078007 ...

Page 5

5 www.national.com ...

Page 6

... For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock and Timing www.national.com/timing Data Converters www.national.com/adc Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www ...

Related keywords

lm22670
lm22680
lm22671
lm22679
lm22677
lm22673
lm22672
LM22677EVAL/NOPB datasheet
LM22677EVAL/NOPB data sheet
LM22677EVAL/NOPB pdf datasheet
LM22677EVAL/NOPB component
LM22677EVAL/NOPB part
LM22677EVAL/NOPB distributor
LM22677EVAL/NOPB RoHS
LM22677EVAL/NOPB datasheet download