LM2576WU Micrel Inc, LM2576WU Datasheet

LM2576WU

Manufacturer Part Number

LM2576WU

Description

IC REG BUCK 3A ADJ TO-263-5

Manufacturer

Micrel Inc

Type

Step-Down (Buck)r

Datasheet

1.LM2576WU_TR.pdf (9 pages)

Specifications of LM2576WU

Internal Switch(s)

Yes

Synchronous Rectifier

Number Of Outputs

Voltage - Output

1.23 ~ 37 V

Current - Output

Frequency - Switching

42kHz ~ 63kHz

Voltage - Input

4 ~ 40 V

Operating Temperature

-40°C ~ 85°C

Mounting Type

Surface Mount

Package / Case

D²Pak, TO-263 (5 leads + tab)

Lead Free Status / RoHS Status

Lead free / RoHS Compliant

Power - Output

Available stocks

Company

Part Number

Manufacturer

Quantity

Price

Company:

Meier Automation Equipment Co., Limited

Part Number:

LM2576WU

Manufacturer:

MICREL/麦瑞

Quantity:

20 000

Current page: 1 of 9
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LM2576

General Description

The LM2576 series of monolithic integrated circuits provide

all the active functions for a step-down (buck) switching

regulator. Fixed versions are available with a 3.3V, 5V, or 12V

fixed output. Adjustable versions have an output voltage

range from 1.23V to 37V. Both versions are capable of driving

a 3A load with excellent line and load regulation.

These regulators are simple to use because they require a

minimum number of external components and include internal

frequency compensation and a fixed-frequency oscillator.

The LM2576 series offers a high efficiency replacement for

popular three-terminal adjustable linear regulators. It

substantially reduces the size of the heat sink, and in many

cases no heat sink is required.

A standard series of inductors available from several different

manufacturers are ideal for use with the LM2576 series. This

feature greatly simplifies the design of switch-mode power

supplies.

The feedback voltage is guaranteed to 2% tolerance for

adjustable versions, and the output voltage is guaranteed to

output load conditions. The oscillator frequency is guaranteed

to 10%. External shutdown is included, featuring less than

200 A standby current. The output switch includes cycle-by-

cycle current limiting and thermal shutdown for full protection

under fault conditions.

Typical Applications

August 2005

3% for fixed versions, within specified input voltages and

Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

Unregulated

Note: Pin numbers are for TO-220 Package

DC Input

7V–40V

100µF

Fixed Regulator in Typical Application

Gnd

LM2575-5.0

On/Off

Output

1N5822

Feedback

330µH

330µF

OUT

Regulated

+5V, 1A

Output

Unregulated

Note: Pin numbers are for TO-220 Package

Features

• 3.3V, 5V, 12V, and adjustable output versions

• Voltage over specified line and load conditions:

• Guaranteed 3A output current

• Wide input voltage range:

• Wide output voltage range

• Requires only 4 external components

• 52kHz fixed frequency internal oscillator

• Low power standby mode I

• 80% efficiency (adjustable version typically > 80%)

• Uses readily available standard inductors

• Thermal shutdown and current limit protection

• 100% electrical thermal limit burn-in

Applications

• Simple high-efficiency step-down (buck) regulator

• Efficient pre-regulator for linear regulators

• On-card switching regulators

• Positive to negative converter (inverting Buck-Boost)

• Isolated Flyback Converter using minimum number of

• Negative Boost Converter

DC Input

7V–40V

100µF

external components

Adjustable Regulator in Fixed Output Application

OUT

Fixed version: 3% max. output voltage

Adjustable version: 2% max. feedback voltage

4V to 40V

1.23V to 37V

= 1.23 1 +

52kHz Simple 3A Buck Regulator

Gnd

(

LM2575

On/Off

)

LM2576

Output

1N5822

Feedback

330µH

typically < 200 A

330µF

OUT

M9999-082605-B

Regulated

+5V, 1A

Output

R2 3.09k

R1 1k

Micrel, Inc.

Related parts for LM2576WU

LM2576WU Summary of contents

Page 1

LM2576 General Description The LM2576 series of monolithic integrated circuits provide all the active functions for a step-down (buck) switching regulator. Fixed versions are available with a 3.3V, 5V, or 12V fixed output. Adjustable versions have an output voltage range ...

Page 2

... Range † LM2576WT* † – +85 C † LM2576-3.3WT † – +85 C † † LM2576-5.0WT – +85 C † † LM2576-12WT – +85 C LM2576WU* – +85 C LM2576-3.3WU – +85 C LM2576-5.0WU – +85 C LM2576-12WU – +85 C GND 5- ON/OFF 4- FEEDBACK 3- GROUND 2- OUTPUT Temperature Package TO-220-5 ...

Page 3

LM2576 Absolute Maximum Ratings Maximum Supply Voltage ON/OFF Pin Input Voltage Output Voltage to Ground (Steady State) Power Dissipation Storage Temperature Range Minimum ESD Rating C = 100pF 1.5k FB Pin Lead Temperature (soldering, 10 sec.) Maximum Junction ...

Page 4

LM2576 Electrical Characteristics (continued) Symbol Parameter Conditions DEVICE PARAMETERS, ADJUSTABLE REGULATOR I Feedback Bias Current V B DEVICE PARAMETERS, FIXED and ADJUSTABLE REGULATORS f Oscillator Frequency O V Saturation Voltage I SAT DC Max Duty Cycle (ON) (Note 5) I ...

Page 5

LM2576 Electrical Characteristics (continued) Symbol Parameter Conditions ON/OFF CONTROL, FIXED and ADJUSTABLE REGULATORS Test Circuit Figure 1 V ON/OFF Pin Logic Input Level /OFF Pin Logic ON /OFF Pin = 5V (OFF) IH ...

Page 6

LM2576 Typical Performance Characteristics (continued) Supply Current 20 Measured at Ground Pin 25˚ OUT = LOAD INPUT VOLTAGE ...

Page 7

LM2576 Typical Performance Characteristics Output Voltage Change Output Current August 2005 (Circuit of Figure 1 ) Load Transient Response +100mV 0 -100mV 100 µS/div. Switching Waveforms 50V ...

Page 8

LM2576 Test Circuits and Layout Guidelines +V IN LM2575 40V 100 µF + UNREGULATED GND 3 DC INPUT LM2575-5 40V 100 µF + UNREGULATED GND 3 DC INPUT C IN ...

Page 9

... DIM. = INCH MICREL INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA + 1 (408) 944-0800 TEL This information furnished by Micrel in this data sheet is believed to be accurate and reliable. However no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. ...

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