LM2574BN Micrel Inc, LM2574BN Datasheet

LM2574BN

Manufacturer Part Number

LM2574BN

Description

IC REGULATOR BUCK 0.5A 8-DIP

Manufacturer

Micrel Inc

Type

Step-Down (Buck)r

Datasheet

1.LM2574-5.0YN.pdf (8 pages)

Specifications of LM2574BN

Internal Switch(s)

Yes

Synchronous Rectifier

Number Of Outputs

Voltage - Output

1.23 ~ 37 V

Current - Output

500mA

Frequency - Switching

52kHz

Voltage - Input

4.75 ~ 40 V

Operating Temperature

-40°C ~ 85°C

Mounting Type

Through Hole

Package / Case

8-DIP (0.300", 7.62mm)

Lead Free Status / RoHS Status

Contains lead / RoHS non-compliant

Power - Output

Available stocks

Company

Part Number

Manufacturer

Quantity

Price

Company:

Bonase Electronics (HK) Co., Limited

Part Number:

LM2574BN

Manufacturer:

MicrelInc

Quantity:

2 000

Current page: 1 of 8
Download datasheet (188Kb)

General Description

The LM2574 family is a series of easy to use ﬁxed and ad-

justable switching voltage regulators. The LM2574 contains

all of the active circuitry necessary to construct a stepdown

(buck) switching regulator and requires a minimum of external

components.

The LM2574 is available in 3.3V and 5V ﬁxed output ver-

sions, or an adjustable version with an output voltage range

of 1.23V to 37V. Output voltage is guaranteed to ±4% for

speciﬁed input and load conditions.

The LM2574 can supply 0.5A while maintaining excellent

line and load regulation. The output switch includes cycle-

by-cycle current limiting, as well as thermal shutdown for full

protection under fault conditions.

An external shutdown connection selects operating or standby

modes. Standby current is less than 200µA.

Heat sinks are generally unnecessary due the regulator’s

high efﬁciency. Adequate heat transfer is usually provided

by soldering all package pins to a printed circuit board.

The LM2574 includes internal frequency compensation and

an internal 52kHz ﬁxed frequency oscillator guaranteed to

±10% of the frequency.

Circuits constructed around the LM2574 use a standard

series of inductors which are available from several different

manufacturers.

All support documentation can be found on Micrel’s web site

at www.micrel.com.

Typical Application

July 2005

LM2574

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

U N R E G U L A T E D

40V MAX

DC IN

22µF

Figure 1. Fixed Output Regulator Circuit

PWR

GND

LM2574

GND

SIG

OUT

OFF

ON/

Features

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

• Adjustable version output 1.23V to 37V ±4% max. over

• Guaranteed 0.5A output current

• Wide input voltage, up to 40V

• Thermal shutdown and current limit protection

• Requires only 4 external components.

• Shutdown capability (standby mode)

• Low power standby mode < 200µA Typical

• High-efﬁciency

• 52kHz ﬁxed frequency internal oscillator

• Uses standard inductors

Applications

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

• Efﬁcient pre-regulator for linear regulators

• On-card switching regulators

• Positive to negative converter (buck-boost)

line and load conditions.

11DQ05

330µH

52kHz Simple 0.5A Buck Regulator

REGULATED

O U T P U T

0.5A

220µF

OU T

LM2574

M9999-072805

Micrel, Inc.

Related parts for LM2574BN

LM2574BN Summary of contents

Page 1

LM2574 General Description The LM2574 family is a series of easy to use ﬁxed and ad- justable switching voltage regulators. The LM2574 contains all of the active circuitry necessary to construct a stepdown (buck) switching regulator and requires a minimum ...

Page 2

... LM2574 Ordering Information Part Number Standard Pb-Free LM2574BN LM2574YN LM2574-3.3BN LM2574-3.3YN LM2574-5.0BN LM2574-5.0YN Pin Conﬁguration PWR GND 4 M9999-072805 Junction Temp. Range Package –40ºC to +85ºC 8-pin Plastic DIP –40ºC to +85ºC 8-pin Plastic DIP –40ºC to +85ºC ...

Page 3

LM2574 Absolute Maximum Ratings Maximum Supply Voltage LM2574 ...................................................................... 45V OFF Pin Input Voltage ................................ –0.3V ≤ V ≤ V Output Voltage to Ground (Steady State) ...................... –1V Power Dissipation ..................................... Internally Limited Storage Temperature Range (T ) ............. –65°C ...

Page 4

LM2574 Electrical Characteristics Symbol Parameter Device Parameters, Adjustable Regulator I Feedback Bias Current B Device Parameters, Fixed and Adjustable Regulators f Oscillator Frequency o V Saturation Voltage SAT DC Max Duty Cycle (ON) I Current Limit CL I Output Leakage ...

Page 5

LM2574 Typical Characteristics (Circuit of Figure 1) Supply Current 20 Measured at Ground Pin 25˚ OUT = 0. ...

Page 6

LM2574 Typical Performance Characteristics (continued) Feedback Voltage -10 -15 -20 -25 -75 -50 - TEM PER ATU ˚ Adjustable ...

Page 7

LM2574 Block Diagrams INTERNAL REGULATOR F EED - 4 BACK FIXED GAIN 3.1k + COM PARAT OR 1. 1.23V BAND-GAP 52 kHz RESET REFERENCE OSCILLATOR SHUTDOWN Note: ...

Page 8

... LM2574 Package Information 0.018 (0.57) 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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