Table of Contents
Advertisement
Quick Links
LM1575/LM2575/LM2575HV
SIMPLE SWITCHER
General Description
The LM2575 series of regulators are monolithic integrated
circuits that provide all the active functions for a step-down
(buck) switching regulator, capable of driving a 1A load with
excellent line and load regulation. These devices are avail-
able 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 LM2575 series offers a high-efficiency replacement for
popular three-terminal linear regulators. It substantially re-
duces the size of the heat sink, and in many cases no heat
sink is required.
A standard series of inductors optimized for use with the
LM2575 are available from several different manufacturers.
This feature greatly simplifies the design of switch-mode
power supplies.
Other features include a guaranteed
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
Versions)
Note: Pin numbers are for the TO-220 package.
SIMPLE SWITCHER
®
is a registered trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation
1A Step-Down Voltage Regulator
®
±
4% tolerance on out-
(Fixed Output Voltage
DS011475
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)
line and load conditions
n Guaranteed 1A 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
+
n P
Product Enhancement tested
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)
August 2004
±
4% max over
01147501
www.national.com
Advertisement
Table of Contents
Subscribe to Our Youtube Channel
Summary of Contents for National Semiconductor LM1575 Series
-
Page 1: General Description
Typical Application (Fixed Output Voltage Versions) 01147501 Note: Pin numbers are for the TO-220 package. SIMPLE SWITCHER ® is a registered trademark of National Semiconductor Corporation. © 2004 National Semiconductor Corporation DS011475 www.national.com... -
Page 2: Block Diagram And Typical Application
Block Diagram and Typical Application 01147502 3.3V, R2 = 1.7k 5V, R2 = 3.1k 12V, R2 = 8.84k 15V, R2 = 11.3k For ADJ. Version R1 = Open, R2 = 0Ω Note: Pin numbers are for the TO-220 package. FIGURE 1. Connection Diagrams (XX indicates output voltage option. -
Page 3: Ordering Information
Connection Diagrams (XX indicates output voltage option. See Ordering Information table for complete part number.) (Continued) 16–Lead DIP (N or J) 24-Lead Surface Mount (M) 01147525 *No Internal Connection Top View 01147526 LM2575N-XX or LM2575HVN-XX *No Internal Connection See NS Package Number N16A Top View LM1575J-XX-QML LM2575M-XX or LM2575HVM-XX... - Page 4 Ordering Information (Continued) Package Standard High Temperature Type Package Voltage Rating Voltage Rating Range Number (40V) (60V) −40˚C ≤ T ≤ +125˚C 16-Pin Molded N16A LM2575N-5.0 LM2575HVN-5.0 LM2575N-12 LM2575HVN-12 LM2575N-15 LM2575HVN-15 LM2575N-ADJ LM2575HVN-ADJ 24-Pin M24B LM2575M-5.0 LM2575HVM-5.0 Surface Mount LM2575M-12 LM2575HVM-12 LM2575M-15 LM2575HVM-15...
-
Page 5: Absolute Maximum Ratings
(Note 1) Minimum ESD Rating (C = 100 pF, R = 1.5 kΩ) 2 kV If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Lead Temperature Distributors for availability and specifications. (Soldering, 10 sec.) 260˚C Maximum Supply Voltage... - Page 6 LM1575-5.0, LM2575-5.0, LM2575HV-5.0 Electrical Characteristics (Continued) Specifications with standard type face are for T = 25˚C, and those with boldface type apply over full Operating Tempera- ture Range. Symbol Parameter Conditions LM1575-5.0 LM2575-5.0 Units (Limits) LM2575HV-5.0 Limit Limit (Note 2) (Note 3) η...
-
Page 7: All Output Voltage Versions Electrical Characteristics
LM1575-ADJ, LM2575-ADJ, LM2575HV-ADJ Electrical Characteristics Specifications with standard type face are for T = 25˚C, and those with boldface type apply over full Operating Temperature Range. Symbol Parameter Conditions LM1575-ADJ LM2575-ADJ Units (Limits) LM2575HV-ADJ Limit Limit (Note 2) (Note 3) SYSTEM PARAMETERS (Note 4) Test Circuit Figure 2 Feedback Voltage = 12V, I... - Page 8 All Output Voltage Versions Electrical Characteristics (Continued) Specifications with standard type face are for T = 25˚C, and those with boldface type apply over full Operating Tempera- ture Range. Unless otherwise specified, V = 12V for the 3.3V, 5V, and Adjustable version, V = 25V for the 12V version, and V = 30V for the 15V version.
-
Page 9: Typical Performance Characteristics
Typical Performance Characteristics (Circuit of Figure 2) Normalized Output Voltage Line Regulation 01147532 01147533 Dropout Voltage Current Limit 01147534 01147535 Standby Quiescent Current Quiescent Current 01147536 01147537 www.national.com... - Page 10 Typical Performance Characteristics (Circuit of Figure 2) (Continued) Switch Saturation Oscillator Frequency Voltage 01147539 01147538 Efficiency Minimum Operating Voltage 01147541 01147540 Quiescent Current Feedback Voltage vs Duty Cycle vs Duty Cycle 01147542 01147543 www.national.com...
-
Page 11: Test Circuit And Layout Guidelines
Typical Performance Characteristics (Circuit of Figure 2) (Continued) Maximum Power Dissipation Feedback Pin Current (TO-263) (See (Note 12)) 01147528 01147505 Switching Waveforms Load Transient Response 01147506 = 5V 01147507 A: Output Pin Voltage, 10V/div B: Output Pin Current, 1A/div C: Inductor Current, 0.5A/div D: Output Ripple Voltage, 20 mV/div, AC-Coupled Horizontal Time Base: 5 µs/div... - Page 12 Test Circuit and Layout Guidelines (Continued) Fixed Output Voltage Versions 01147508 — 100 µF, 75V, Aluminum Electrolytic — 330 µF, 25V, Aluminum Electrolytic D1 — Schottky, 11DQ06 L1 — 330 µH, PE-52627 (for 5V in, 3.3V out, use 100 µH, PE-92108) Adjustable Output Voltage Version 01147509 where V...
-
Page 13: Lm2575 Series Buck Regulator Design Procedure
LM2575 Series Buck Regulator Design Procedure PROCEDURE (Fixed Output Voltage Versions) EXAMPLE (Fixed Output Voltage Versions) Given: V = Regulated Output Voltage (3.3V, 5V, 12V, or Given: V = 5V V (Max) = 20V I (Max) = 0.8A LOAD 15V) V (Max) = Maximum Input Voltage I (Max) = LOAD... -
Page 14: Inductor Value Selection Guides
Inductor Value Selection Guides (For Continuous Mode Operation) 01147512 01147510 FIGURE 5. LM2575(HV)-12 FIGURE 3. LM2575(HV)-3.3 01147513 01147511 FIGURE 6. LM2575(HV)-15 FIGURE 4. LM2575(HV)-5.0 01147514 FIGURE 7. LM2575(HV)-ADJ www.national.com... - Page 15 Inductor Value Selection Guides (For Continuous Mode Operation) (Continued) PROCEDURE (Adjustable Output Voltage Versions) EXAMPLE (Adjustable Output Voltage Versions) Given: V = Regulated Output Voltage V (Max) = Given: V = 10V V (Max) = 25V I (Max) = 1A F = LOAD Maximum Input Voltage I (Max) = Maximum Load...
- Page 16 To further simplify the buck regulator design procedure, National Semiconductor is making available computer design software to be used with the Simple Switcher line of switching regulators. Switchers Made Simple (version 3.3) is available on a (3 ⁄...
- Page 17 Inductor Value Selection Guides (For Continuous Mode Operation) (Continued) Schottky Fast Recovery 20V 1N5817 1N5820 MBR120P MBR320 SR102 SR302 30V 1N5818 1N5821 MBR130P MBR330 The following The following diodes are all diodes are all 11DQ03 31DQ03 rated to 100V rated to 100V SR103 SR303 40V 1N5819...
-
Page 18: Application Hints
pletely contained within the core, it generates more electro- Application Hints magnetic interference (EMI). This EMI can cause problems in sensitive circuits, or can give incorrect scope readings INPUT CAPACITOR (C because of induced voltages in the scope probe. To maintain stability, the regulator input pin must be by- The inductors listed in the selection chart include ferrite pot passed with at least a 47 µF electrolytic capacitor. - Page 19 Application Hints high-level TTL or CMOS signal. The ON /OFF pin can be (Continued) safely pulled up to +V without a resistor in series with it. Tantalum capacitors can have a very low ESR, and should The ON /OFF pin should not be left open. be carefully evaluated if it is the only output capacitor.
-
Page 20: Additional Applications
Application Hints the available output current. Also, the start-up input current (Continued) of the buck-boost converter is higher than the standard Since the lead frame is solid copper, heat from the die is buck-mode regulator, and this may overload an input power readily conducted through the leads to the printed circuit source with a current limit less than 1.5A. -
Page 21: Undervoltage Lockout
Additional Applications (Continued) 01147517 Note: Complete circuit not shown. 01147516 Note: Pin numbers are for the TO-220 package. Typical Load Current 200 mA for V = −5.2V FIGURE 12. Undervoltage Lockout for Buck Circuit 500 mA for V = −7V Note: Pin numbers are for TO-220 package. -
Page 22: Definition Of Terms
Additional Applications (Continued) 01147520 Note: Pin numbers are for the TO-220 package. FIGURE 15. 1.2V to 55V Adjustable 1A Power Supply with Low Output Ripple Definition of Terms BUCK REGULATOR A switching regulator topology in which a higher voltage is 01147521 converted to a lower voltage. -
Page 23: Continuous/Discontinuous Mode Operation
Definition of Terms nates. Inductor current is then limited only by the DC resis- (Continued) tance of the wire and the available source current. CONTINUOUS/DISCONTINUOUS MODE OPERATION OPERATING VOLT MICROSECOND CONSTANT (E • T Relates to the inductor current. In the continuous mode, the The product (in VoIt •... -
Page 24: Physical Dimensions
Physical Dimensions inches (millimeters) unless otherwise noted 16-Lead Ceramic Dual-in-Line (J) Order Number LM1575J-3.3/883, LM1575J-5.0/883, LM1575J-12/883, LM1575J-15/883, or LM1575J-ADJ/883 NS Package Number J16A 14-Lead Wide Surface Mount (WM) Order Number LM2575M-5.0, LM2575HVM-5.0, LM2575M-12, LM2575HVM-12, LM2575M-15, LM2575HVM-15, LM2575M-ADJ or LM2575HVM-ADJ NS Package Number M24B www.national.com... - Page 25 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 16-Lead Molded DIP (N) Order Number LM2575N-5.0, LM2575HVN-5.0, LM2575N-12, LM2575HVN-12, LM2575N-15, LM2575HVN-15, LM2575N-ADJ or LM2575HVN-ADJ NS Package Number N16A 5-Lead TO-220 (T) Order Number LM2575T-3.3, LM2575HVT-3.3, LM2575T-5.0, LM2575HVT-5.0, LM2575T-12, LM2575HVT-12, LM2575T-15, LM2575HVT-15, LM2575T-ADJ or LM2575HVT-ADJ NS Package Number T05A www.national.com...
- Page 26 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) TO-263, Molded, 5-Lead Surface Mount Order Number LM2575S-3.3, LM2575HVS-3.3, LM2575S-5.0, LM2575HVS-5.0, LM2575S-12, LM2575HVS-12, LM2575S-15, LM2575HVS-15, LM2575S-ADJ or LM2575HVS-ADJ NS Package Number TS5B www.national.com...
-
Page 27: Life Support Policy
BANNED SUBSTANCE COMPLIANCE National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2.
Need help?
Do you have a question about the LM1575 Series and is the answer not in the manual?
Questions and answers