LM2574 - SIMPLE SWITCHER 0.5A Step-Down Voltage Regulator

LM2574

SIMPLE SWITCHER 0.5A Step-Down Voltage Regulator

Overview

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Reliability

Obsolete

Features

• 3.3V, 5V, 12V, 15V, and adjustable output versions

• Adjustable version output voltage range, 1.23V to 37V (57V for HV version) ±4% max over line and load conditions

• Guaranteed 0.5A output current

• Wide input voltage range, 40V, up to 60V for HV version

• Requires only 4 external components

• 52 kHz fixed frequency internal oscillator

• TTL shutdown capability, low power standby mode

• High efficiency

• Uses readily available standard inductors

• Thermal shutdown and current limit protection

Description
The LM2574 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving a 0.5A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, 15V, and an adjustable output version.

Requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation and a fixed-frequency oscillator.

The LM2574 series offers a high-efficiency replacement for popular three-terminal linear regulators. Because of its high efficiency, the copper traces on the printed circuit board are normally the only heat sinking needed.

A standard series of inductors optimized for use with the LM2574 are available from several different manufacturers. This feature greatly simplifies the design of switch-mode power supplies.

Other features include a guaranteed ±4% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency. External shutdown is included, featuring 50 µA (typical) standby current. The output switch includes cycle-by-cycle current limiting, as well as thermal shutdown for full protection under fault conditions.

Applications

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

• Efficient pre-regulator for linear regulators

• On-card switching regulators

• Positive to negative converter (Buck-Boost)

LM2574HV

4.75 <= V in Lower
V
<= V in Upper
V
<= 40.00

V out 1.24 <= V <= 37.00

I out A <= 0.50

Ambient Temperature °C <= 100

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Also Recommended

LM25007▲ Better Transient Response , Wider Switching Frequency Range

LM25574▲ 42V Vin, .5A Iout, Selectable Switching Frequency

LM2594▲ 150Khz, Smaller Inductor

LM2671▲ 260 - 400 Khz, Sync Frequency

LM2694▲ Better Transient Response , Wider Switching Frequency Range

LM2736▲ 750mA, SOT23, 500Khz - 3Mhz FSW

LM5007▲ 0.5A, 80V Vin, 50Khz - 800Khz FSW

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LM2574

Also Recommended

LM25007▲	Better Transient Response , Wider Switching Frequency Range
LM25574▲	42V Vin, .5A Iout, Selectable Switching Frequency
LM2594▲	150Khz, Smaller Inductor
LM2671▲	260 - 400 Khz, Sync Frequency
LM2694▲	Better Transient Response , Wider Switching Frequency Range
LM2736▲	750mA, SOT23, 500Khz - 3Mhz FSW
LM5007▲	0.5A, 80V Vin, 50Khz - 800Khz FSW

Typical Application click for larger image

Block Diagram click for larger image

Typical Performance *click for larger image

Paramaters / Values	LM2574	LM25007	LM25574	LM2594	LM2671	LM2694	LM2736	LM5007
Output Current	500 mA	500 mA	500 mA	500 mA	500 mA	600 mA	750 mA	500 mA
Input Min Voltage	4 Volt	9 Volt	6 Volt	4.5, 7, 4.75, 15 Volt	6.5 Volt	8 Volt	3 Volt	9 Volt
Input Max Voltage	40 Volt	42 Volt	42 Volt	40 Volt	40 Volt	30 Volt	18 Volt	75 Volt
Output Min	3.3, 1.23, 12, 5 Volt	2.5 Volt	1.23 Volt	3.3, 1.23, 12, 5 Volt	1.23 Volt	2.5 Volt	1.25 Volt	2.5 Volt
Output Max	3.3, 37, 12, 5 Volt	37 Volt	40 Volt	3.3, 37, 12, 5 Volt	37 Volt	24 Volt	16 Volt	73 Volt
Frequency Min	52 kHz	50 kHz	50 kHz	150 kHz	260 kHz	50 kHz	1600, 550 kHz	50 kHz
Frequency Max	52 kHz	800 kHz	1000 kHz	150 kHz	260 kHz	1000 kHz	1600, 550 kHz	800 kHz
Efficiency (peak)	77, 88, 72 %	93 %	91 %	88, 80, 82 %	90 %	93 %	90 %	93 %
On/Off Pin	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Error Flag	No	No	No	No	No	No	No	No
SoftStart	No	No	Yes	No	Yes	Yes	Yes	No
Sync Pin	No	No	Yes	No	Yes	No	No	No
Inverting	Yes	Yes	Yes	Yes		Yes	No	Yes
Flyback	No	No	No	No	No	No	No	No
RegType	Switching Regulator	Switching Regulator	Switching Regulator	Switching Regulator	Switching Regulator	Switching Regulator	Switching Regulator	Switching Regulator
Temperature Min	-40 deg C	-40 deg C	-40 deg C	-40 deg C	-40 deg C	-40 deg C	-40 deg C	-40 deg C
Temperature Max	125 deg C	125 deg C	125 deg C	125 deg C	125 deg C	125 deg C	125 deg C	125 deg C
Adjustable Output	Yes, No	Yes	Yes	Yes, No	Yes	Yes	Yes	Yes
Adj Switch Frequency	No	Yes	Yes	No	No	Yes	No	Yes
PWM Mode	Voltage	Constant on-time	Current	Voltage	Voltage with Vin Feedforward	Constant on-time	Current	Constant on-time
Topology	Buck	Buck	Buck	Buck	Buck	Buck	Buck	Buck
Special Features	SIMPLE SWITCHER regulator	Internal startup regulator for Vin>9V, internal 42V/07A N-FET, Pull Ron pin to ground for shutdown	1.5% feedback voltage accuracy, emulated current mode	SIMPLE SWITCHER regulator	Internal Type 3 compensation, 1.5% output voltage accuracy, SIMPLE SWITCHER regulator	No compensation required, ultra-fast transient response	OVP, internal compensation	Internal startup regulator for Vin>9V, internal 80V/0.7A N-FET, Pull Ron pin to ground for shutdown
Step-Down	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Multiple Output Capability	No	No	No	No	No	No	No	No
Output Power	Undefined Watt	Undefined Watt	Undefined Watt	Undefined Watt	Undefined Watt	Undefined Watt		Undefined Watt
Output Voltage	3.3, Undefined, 12, 5 Volt	Undefined Volt	Undefined Volt	3.3, Undefined, 12, 5 Volt	Undefined Volt	Undefined Volt	Undefined Volt	Undefined Volt
Output Range	5V, 12V, 1.23V to 37V, 3.3V	2.5V to 37V	1.23V to 37V	5V, 12V, 1.23V to 37V, 3.3V	1.23V to 37V	2.5V to 24V	1.25V to 13V	2.5V to 73V
Switching Frequency	52 kHz	800 kHz	1000 kHz	150 kHz	260 kHz	1000 kHz	1600, 550 kHz	800 kHz
Regulator Family	SIMPLE SWITCHER	Undefined	SIMPLE SWITCHER	SIMPLE SWITCHER	SIMPLE SWITCHER	Undefined	Undefined	Undefined
Synchronous Rectification	No	No	No	No	No	No	No	No

Datasheet
Title Size Date Other
Language

LM2574/LM2574HV SIMPLE SWITCHER 0.5A Step-Down Voltage Regulator 639
Kbytes 30-Jun-99 日本語

Featured Application Notes
Title Size Date Other
Language

AN-1061: Application Note 1061 Power Conversion in Line-Powered Equipment 162
Kbytes 1-Oct-02 日本語

More Application Notes
Title Size Date Other
Language

AN-1229: Application Note 1229 SIMPLE SWITCHER PCB Layout Guidelines 229
Kbytes 1-May-04 日本語
 中文

AN-777: Application Note 777 LM2577 Three Output, Isolated Flyback Regulator 112
Kbytes 26-Sep-02

AN-776: Application Note 776 20 Watt Simple Switcher Forward Converter 459
Kbytes 26-Sep-02

AN-946: Application Note 946 High-Efficiency 3A Battery Chargers Use LM2576 Regulators 109
Kbytes 3-Oct-02 日本語

Part Number(s)
(NSID)

Top View

Availability

Current Reported Stock

Budgetary Pricing

Standard Pack Size

LM2574M-12/NOPB
LM2574M-12

RoHS

SOIC WIDE

Full production
Lead Time: 12 weeks

Distributor	Region	Qty
ARROW	Worldwide	2700
AVNET-EM	Worldwide	40
DIGIKEY	Worldwide	0
NEWARK	Americas	179

$0.96 each at 1K+ pcs

rail
of
50

LM2574M-3.3/NOPB
LM2574M-3.3

RoHS

SOIC WIDE

Full production
Lead Time: 8 weeks

Distributor	Region	Qty
ARROW	Worldwide	149
DIGIKEY	Worldwide	208
FUTURE	Worldwide	1100
NEWARK	Americas	159

$0.96 each at 1K+ pcs

rail
of
50

LM2574M-5.0/NOPB
LM2574M-5.0

RoHS

SOIC WIDE

Full production
Lead Time: 12 weeks

Distributor	Region	Qty
ARROW	Worldwide	1450
AVNET-EM	Worldwide	622
DIGIKEY	Worldwide	1097
FARNELL	Europe and Asia	1532
FUTURE	Worldwide	1100
KEIKONG	Asia Pacific	525
NEWARK	Americas	287
RS COMPONENTS	Worldwide	224
TAYLOR	Americas	2100

$0.96 each at 1K+ pcs

rail
of
50

LM2574M-ADJ/NOPB
LM2574M-ADJ

RoHS

SOIC WIDE

Full production
Lead Time: 12 weeks

Distributor	Region	Qty
AVNET-EM	Worldwide	43
DIGIKEY	Worldwide	0
FARNELL	Europe and Asia	1458
FUTURE	Worldwide	1100
KEIKONG	Asia Pacific	1850
NEWARK	Americas	324

$0.96 each at 1K+ pcs

rail
of
50

LM2574MX-12/NOPB

RoHS

SOIC WIDE

Full production
Lead Time: 16 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	0

$0.96 each at 1K+ pcs

reel
of
1000

LM2574MX-3.3/NOPB
LM2574MX-3.3

RoHS

SOIC WIDE

Full production
Lead Time: 6 weeks

Distributor	Region	Qty
DIGIKEY	Worldwide	0
FUTURE	Worldwide	275
KEIKONG	Asia Pacific	1000
TECHMOSA	Asia Pacific	5000

$0.96 each at 1K+ pcs

reel
of
1000

LM2574MX-5.0/NOPB
LM2574MX-5.0

RoHS

SOIC WIDE

Full production
Lead Time: 6 weeks

Distributor	Region	Qty
ARROW	Worldwide	638
AVNET-EM	Worldwide	1000
DIGIKEY	Worldwide	0
FUTURE	Worldwide	1100
KEIKONG	Asia Pacific	28000
TAYLOR	Americas	2000

$0.96 each at 1K+ pcs

reel
of
1000

LM2574MX-ADJ/NOPB
LM2574MX-ADJ

RoHS

SOIC WIDE

Full production
Lead Time: 12 weeks

Distributor	Region	Qty
ARROW	Worldwide	860
DIGIKEY	Worldwide	1000
FUTURE	Worldwide	1100

$0.96 each at 1K+ pcs

reel
of
1000

LM2574N-12/NOPB
LM2574N-12

RoHS

MDIP

Full production
Lead Time: 12 weeks

Distributor	Region	Qty
AVNET-EM	Worldwide	230
DIGIKEY	Worldwide	132
FUTURE	Worldwide	1100
NEWARK	Americas	253
RS COMPONENTS	Worldwide	287
TAYLOR	Americas	655

$0.99 each at 1K+ pcs

rail
of
40

LM2574N-3.3/NOPB
LM2574N-3.3

RoHS

MDIP

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	0
FUTURE		Worldwide	480

$0.99 each at 1K+ pcs

rail
of
40

LM2574N-5.0/NOPB
LM2574N-5.0

RoHS

MDIP

Full production
Lead Time: 16 weeks

Distributor	Region	Qty
ARROW	Worldwide	3240
AVNET-EM	Worldwide	10409
DIGIKEY	Worldwide	232
FARNELL	Europe and Asia	2273
FUTURE	Worldwide	1100
NEWARK	Americas	309
RS COMPONENTS	Worldwide	556
TAYLOR	Americas	2059

$0.99 each at 1K+ pcs

rail
of
40

LM2574N-ADJ/NOPB
LM2574N-ADJ

RoHS

MDIP

Full production
Lead Time: 14 weeks

Distributor	Region	Qty
AVNET-EM	Worldwide	400
DIGIKEY	Worldwide	374
FARNELL	Europe and Asia	1304
FUTURE	Worldwide	1100
KEIKONG	Asia Pacific	20370
NEWARK	Americas	276
RS COMPONENTS	Worldwide	348
RSL MICRO	Asia Pacific	800
TAYLOR	Americas	2130

$0.99 each at 1K+ pcs

rail
of
40

Obsolete Versions

Obsolete Part Alternate Part or Supplier Source Last Time Buy Date

LM2574-5.0 MDA
NONE
NATIONAL SEMICONDUCTOR
03 Dec 2008

LM2574-5.0 MWA
LM5574 MWC
NATIONAL SEMICONDUCTOR
03 Dec 2008

LM2574HV-12 MWC
LM5574 MWC
NAITONAL SEMICONDUCTOR
03 Dec 2008

LM2574HV-15 MWC
LM5574 MWC
NATIONAL SEMICONDUCTOR
03 Dec 2008

LM2574HV-5 MDC
LM5574 MDC
NATIONAL SEMICONDUCTOR
03 Dec 2008

LM2574HV-5 MWC
LM5574 MWC
NATIONAL SEMICONDUCTOR
03 Dec 2008

LM2574HV3.3 MDC
LM5574 MDC
NATIONAL SEMICONDUCTOR
03 Dec 2008

LM2574HV3.3 MWC
LM5574 MWC
NATIONAL SEMICONDUCTOR
03 Dec 2008

LM2574HVN-3.3
LM2574HVN-5.0
NATIONAL SEMICONDUCTOR
01 Dec 2009

LM2574M-15
LM2574M-ADJ
NATIONAL SEMICONDUCTOR
16 Nov 2008

LM2574MX-15
LM2574M-ADJ
NATIONAL SEMICONDUCTOR
16 Nov 2008

LM2574N-15
LM2574N-ADJ
NATIONAL SEMICONDUCTOR
16 Nov 2008

Part Number(s) (NSID)	Type	Pins	MSL Rating	Peak Reflow	RoHS	CAD Symbols	Models	Package Marking Format
LM2574M-12/NOPB LM2574M-12	SOIC WIDE	14	3 2A	260 220	RoHS	N/A	N/A	NSUZXYTTE# LM2574M -12 P+
LM2574M-3.3/NOPB LM2574M-3.3	SOIC WIDE	14	3 2A	260 220	RoHS	N/A	N/A	NSUZXYTTE# LM2574M -3.3 P+
LM2574M-5.0/NOPB LM2574M-5.0	SOIC WIDE	14	3 2A	260 220	RoHS	N/A	N/A	NSUZXYTTE# LM2574M -5.0 P+
LM2574M-ADJ/NOPB LM2574M-ADJ	SOIC WIDE	14	3 2A	260 220	RoHS	N/A	N/A	NSUZXYTTE# LM2574M -ADJ P+
LM2574MX-12/NOPB	SOIC WIDE	14	3	260	RoHS	N/A	N/A	NSUZXYTTE# LM2574M -12 P+
LM2574MX-3.3/NOPB LM2574MX-3.3	SOIC WIDE	14	4 2A	260 220	RoHS	N/A	N/A	NSUZXYTTE# LM2574M -3.3 P+
LM2574MX-5.0/NOPB LM2574MX-5.0	SOIC WIDE	14	3 2A	260 220	RoHS	N/A	N/A	NSUZXYTTE# LM2574M -5.0 P+
LM2574MX-ADJ/NOPB LM2574MX-ADJ	SOIC WIDE	14	3 2A	260 220	RoHS	N/A	N/A	NSUZXYTTE# LM2574M -ADJ P+
LM2574N-12/NOPB LM2574N-12	MDIP	8	1 1	NA NA	RoHS	N/A	N/A	NSUZXYTTE# LM2574N -12 P+
LM2574N-3.3/NOPB LM2574N-3.3	MDIP	8	1 1	NA NA	RoHS	N/A	N/A	NSUZXYTTE# LM2574N -3.3 P+
LM2574N-5.0/NOPB LM2574N-5.0	MDIP	8	1 1	NA NA	RoHS	N/A	N/A	NSUZXYTTE# LM2574N -5.0 P+
LM2574N-ADJ/NOPB LM2574N-ADJ	MDIP	8	1 1	NA NA	RoHS	N/A	N/A	NSUZXYTTE# LM2574N -ADJ P+

Design Tools
Title Size Date

SimpleSwitcher® DC-DC Converters Design Software

Reliability Metrics

Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)

LM2574M-12 SLM 0 44046 0 0 3532500 1 1002356520

LM2574M-15 SLM 0 44046 0 0 3532500 1 1002356520

LM2574M-3.3 SLM 0 44046 0 0 3532500 1 1002356520

LM2574M-5.0 SLM 0 44046 0 0 3532500 1 1002356520

LM2574M-ADJ SLM 0 44046 0 0 3532500 1 1002356520

LM2574MX-12 SLM 0 44046 0 0 3532500 1 1002356520

LM2574MX-15 SLM 0 44046 0 0 3532500 1 1002356520

LM2574MX-3.3 SLM 0 44046 0 0 3532500 1 1002356520

LM2574MX-5.0 SLM 0 44046 0 0 3532500 1 1002356520

LM2574MX-ADJ SLM 0 44046 0 0 3532500 1 1002356520

LM2574N-12 SLM 0 44046 0 0 3532500 1 1002356520

LM2574N-15 SLM 0 44046 0 0 3532500 1 1002356520

LM2574N-3.3 SLM 0 44046 0 0 3532500 1 1002356520

LM2574N-5.0 SLM 0 44046 0 0 3532500 1 1002356520

LM2574N-ADJ SLM 0 44046 0 0 3532500 1 1002356520

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.

[Information as of 22-Nov-2009]