IC, STEP-DOWN REGULATOR, SOIC-14

LM2574HVM-5.0

Manufacturer Part NumberLM2574HVM-5.0
DescriptionIC, STEP-DOWN REGULATOR, SOIC-14
ManufacturerNational Semiconductor
LM2574HVM-5.0 datasheet
 


Specifications of LM2574HVM-5.0

Primary Input Voltage12VNo. Of Outputs1
Output Voltage5VOutput Current500mA
No. Of Pins14Operating Temperature Range-40°C To +125°C
Supply Voltage Range4V To 60VTermination TypeSMD
Lead Free Status / RoHS StatusContains lead / RoHS non-compliant  
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LM2574/LM2574HV
SIMPLE SWITCHER
General 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 out-
put voltage within specified input voltages and output load
±
conditions, and
10% on the oscillator frequency. External
shutdown is included, featuring 50 µA (typical) standby cur-
rent. The output switch includes cycle-by-cycle current limit-
ing, as well as thermal shutdown for full protection under
fault conditions.
Typical Application
(Fixed Output Voltage Versions)
Note: Pin numbers are for 8-pin DIP package.
Patent Pending
SIMPLE SWITCHER
is a trademark of National Semiconductor Corporation
© 1999 National Semiconductor Corporation
DS011394
0.5A Step-Down Voltage Regulator
Features
n 3.3V, 5V, 12V, 15V, and adjustable output versions
n Adjustable version output voltage range, 1.23V to 37V
(57V for HV version)
conditions
n Guaranteed 0.5A output current
n Wide input voltage range, 40V, up to 60V for HV version
n Requires only 4 external components
n 52 kHz fixed frequency internal oscillator
n TTL shutdown capability, low power standby mode
n High efficiency
n Uses readily available standard inductors
n Thermal shutdown and current limit protection
Applications
n Simple high-efficiency step-down (buck) regulator
n Efficient pre-regulator for linear regulators
n On-card switching regulators
n Positive to negative converter (Buck-Boost)
June 1999
±
4% max over line and load
DS011394-1
www.national.com

LM2574HVM-5.0 Summary of contents

  • Page 1

    ... Typical Application (Fixed Output Voltage Versions) Note: Pin numbers are for 8-pin DIP package. Patent Pending SIMPLE SWITCHER ™ trademark of National Semiconductor Corporation © 1999 National Semiconductor Corporation DS011394 0.5A Step-Down Voltage Regulator ™ Features n 3.3V, 5V, 12V, 15V, and adjustable output versions n Adjustable version output voltage range, 1 ...

  • Page 2

    ... Top View Order Number LM2574-3.3HVN, LM2574HVN-5.0, LM2574HVN-12, LM2574HVN-15, LM2574HVN-ADJ, LM2574N-3.3, LM2574N-5.0, LM2574N-12, LM2574N-15 or LM2574N-ADJ See NS Package Number N08A www.national.com 14-Lead Wide Surface Mount (WM) DS011394-3 Top View Order Number LM2574HVM-3.3, LM2574HVM-5.0, LM2574HVM-12, LM2574HVM-15, LM2574HVM-ADJ, LM2574M-3.3 LM2574M-5.0, LM2574M-12, LM2574M-15 or LM2574M-ADJ See NS Package Number M14B 2 ...

  • Page 3

    ... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Maximum Supply Voltage LM2574 LM2574HV ON /OFF Pin Input Voltage Output Voltage to Ground (Steady State) Minimum ESD Rating (C = 100 pF 1 Storage Temperature Range LM2574-3 ...

  • Page 4

    LM2574-12, LM2574HV-12 Electrical Characteristics Specifications with standard type face are for T ture Range. Symbol Parameter SYSTEM PARAMETERS (Note 3) Test Circuit Figure 2 = 25V Output Voltage V OUT IN V Output Voltage 15V OUT LM2574 V ...

  • Page 5

    LM2574-ADJ, LM2574HV-ADJ Electrical Characteristics Specifications with standard type face are for T ture Range. Unless otherwise specified, V Symbol Parameter SYSTEM PARAMETERS (Note 3) Test Circuit Figure 2 V Feedback Voltage LM2574 V Programmed for 5V. ...

  • Page 6

    All Output Voltage Versions Electrical Characteristics Specifications with standard type face are for T ture Range. Unless otherwise specified 30V for the 15V version. I and V IN LOAD Symbol Parameter ON /OFF CONTROL Test Circuit Figure 2 ...

  • Page 7

    Typical Performance Characteristics Current Limit DS011394-30 Oscillator Frequency DS011394-33 Minimum Operating Voltage DS011394-36 (Circuit of Figure 2 ) (Continued) Supply Current DS011394-31 Switch Saturation Voltage DS011394-34 Supply Current vs Duty Cycle DS011394-37 7 Standby Quiescent Current DS011394-32 Efficiency DS011394-35 Feedback ...

  • Page 8

    Typical Performance Characteristics Feedback Pin Current DS011394-39 Continuous Mode Switching Waveforms = 5V, 500 mA Load Current 330 µH V OUT Notes: A: Output Pin Voltage, 10V/div B: Inductor Current, 0.2 A/div C: Output Ripple Voltage, 20 mV/div, ...

  • Page 9

    Block Diagram 3.3V 1.7k 5V 3.1k 12V 8.84k 15V 11.3k For Adj. Version R1 = Open Note: Pin numbers are for the 8-pin DIP package. FIGURE ...

  • Page 10

    Test Circuit and Layout Guidelines C — 22 µF, 75V IN Aluminum Electrolytic C — 220 µF, 25V OUT Aluminum Electrolytic D1 — Schottky, 11DQ06 L1 — 330 µH, 52627 (for 5V in, 3.3V out, use 100 µH, RL-1284-100) R1 ...

  • Page 11

    Test Circuit and Layout Guidelines (Continued) Inductor Pulse Eng. Renco Value (Note 1) (Note µH RL-1284-68-43 100 µH * RL-1284-100-43 150 µH 52625 RL-1284-150-43 220 µH 52626 RL-1284-220-43 330 µH 52627 RL-1284-330-43 470 µH 52628 RL-1284-470-43 680 ...

  • Page 12

    LM2574 Series Buck Regulator Design Procedure PROCEDURE (Fixed Output Voltage Versions) Given: = Regulated Output Voltage (3.3V, 5V, 12V, or 15V) V OUT (Max) = Maximum Input Voltage V IN (Max) = Maximum Load Current I LOAD 1. Inductor Selection ...

  • Page 13

    LM2574 Series Buck Regulator Design Procedure INDUCTOR VALUE SELECTION GUIDES (For Continuous Mode Operation) FIGURE 4. LM2574HV-3.3 Inductor Selection Guide FIGURE 5. LM2574HV-5.0 Inductor Selection Guide (Continued) DS011394-26 FIGURE 6. LM2574HV-12 Inductor Selection Guide DS011394-13 FIGURE 7. LM2574HV-15 Inductor Selection ...

  • Page 14

    LM2574 Series Buck Regulator Design Procedure FIGURE 8. LM2574HV-ADJ Inductor Selection Guide PROCEDURE (Adjustable Output Voltage Versions) Given: = Regulated Output Voltage V OUT (Max) = Maximum Input Voltage V IN (Max) = Maximum Load Current I LOAD F = ...

  • Page 15

    LM2574 Series Buck Regulator Design Procedure PROCEDURE (Adjustable Output Voltage Versions) 3. Output Capacitor Selection (C ) OUT A. The value of the output capacitor together with the inductor defines the dominate pole-pair of the switching regulator loop. For stable ...

  • Page 16

    LM2574 Series Buck Regulator Design Procedure Application Hints INPUT CAPACITOR ( maintain stability, the regulator input pin must be by- passed with at least a 22 µF electrolytic capacitor. The ca- pacitor’s leads must be kept short, ...

  • Page 17

    Application Hints (Continued) INDUCTOR RIPPLE CURRENT When the switcher is operating in the continuous mode, the inductor current waveform ranges from a triangular to a saw- tooth type of waveform (depending on the input voltage). For a given input voltage ...

  • Page 18

    Application Hints (Continued) pacitor and the amplitude of the inductor ripple current ( I ). See the section on inductor ripple current in Applica- IND tion Hints. The lower capacitor values (100 µF- 330 µF) will allow typi- cally 50 ...

  • Page 19

    Application Hints (Continued) The data sheet thermal resistance curves and the thermal model in Switchers Made Simple software (version 3.3) can estimate the maximum junction temperature based on operating conditions. ln addition, the junction temperature can be estimated in actual ...

  • Page 20

    Additional Applications Note: Pin numbers are for 8-pin DIP package. FIGURE 12. Negative Boost Because of the boosting function of this type of regulator, the switch current is relatively high, especially at low input volt- ages. Output load current limitations ...

  • Page 21

    Additional Applications (Continued) Note: Pin numbers are for 8-pin DIP package. FIGURE 16. 1.2V to 55V Adjustable 500 mA Power Supply with Low Output Ripple Definition of Terms BUCK REGULATOR A switching regulator topology in which a higher voltage is ...

  • Page 22

    Definition of Terms (Continued) INDUCTOR SATURATION The condition which exists when an inductor cannot hold any more magnetic flux. When an inductor saturates, the induc- tor appears less inductive and the resistive component domi- nates. Inductor current is then limited ...

  • Page 23

    ... Physical Dimensions inches (millimeters) unless otherwise noted Order Number LM2574M-3.3, LM2574HVM-3.3, LM2574M-5.0, LM2574HVM-5.0, LM2574M-12, LM2574HVM-12, LM2574M-15, LM2574HVM-15, LM2574M-ADJ or LM2574HVM-ADJ 14-Lead Wide Surface Mount (WM) NS Package Number M14B 23 www.national.com ...

  • Page 24

    ... Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Order Number LM2574M-3.3, LM2574HVM-3.3, LM2574HVN-5.0, LM2574HVN-12, LM2574HVN-15, LM2574HVN-ADJ, LM2574N-5.0, LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION ...