LM2598SX-5.0/NOPB National Semiconductor, LM2598SX-5.0/NOPB Datasheet
LM2598SX-5.0/NOPB
Specifications of LM2598SX-5.0/NOPB
*LM2598SX-5.0/NOPB
LM2598SX-5.0
Related parts for LM2598SX-5.0/NOPB
LM2598SX-5.0/NOPB Summary of contents
Page 1
... Patent Number 5,382,918. SIMPLE SWITCHER ® and Switchers Made Simple ® are registered trademarks of National Semiconductor Corporation. © 2001 National Semiconductor Corporation Power Converter 150 kHz ® ternal shutdown is included, featuring typically 85 µA standby current. Self protection features include a two stage current limit for the output switch and an over temperature shutdown for complete protection under fault conditions ...
Page 2
Connection Diagrams and Order Information Bent and Staggered Leads, Through Hole Package 7-Lead TO-220 (T) Order Number LM2598T-3.3, LM2598T-5.0, LM2598T-12 or LM2598T-ADJ See NS Package Number TA07B www.national.com Surface Mount Package 7-Lead TO-263 (S) DS012593-50 Order Number LM2598S-3.3, LM2598S-5.0, LM2598S-12 ...
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 ( SD/SS Pin Input Voltage (Note 2) Delay Pin Voltage (Note 2) Flag Pin Voltage Feedback Pin Voltage Output Voltage to Ground ...
Page 4
LM2598-ADJ Electrical Characteristics Specifications with standard type face are for T ture Range. Symbol Parameter SYSTEM PARAMETERS (Note 6) Test Circuit Figure 1 V Feedback Voltage 4. OUT Efficiency V IN All Output Voltage Versions Electrical Characteristics Specifications ...
Page 5
All Output Voltage Versions Electrical Characteristics Specifications with standard type face are for T ture Range. Unless otherwise specified, V sion 200 mA LOAD Symbol Parameter SHUTDOWN/SOFT-START CONTROL Test Circuit of Figure 1 I Shutdown Current SD I ...
Page 6
Typical Performance Characteristics Normalized Output Voltage DS012593-2 Switch Saturation Voltage DS012593-15 Operating Quiescent Current DS012593-4 www.national.com (Circuit of Figure 1 ) Line Regulation DS012593-3 Switch Current Limit DS012593-16 Shutdown Quiescent Current DS012593-5 6 Efficiency DS012593-14 Dropout Voltage DS012593-17 Minimum Operating ...
Page 7
Typical Performance Characteristics Feedback Pin Bias Current DS012593-49 Soft-start DS012593-9 Soft-start Response DS012593-12 (Circuit of Figure 1 ) (Continued) Flag Saturation Voltage DS012593-7 Shutdown/Soft-start Current DS012593-10 Shutdown/Soft-start Threshold Voltage 7 Switching Frequency DS012593-8 Delay Pin Current DS012593-11 DS012593-13 www.national.com ...
Page 8
Typical Performance Characteristics Continuous Mode Switching Waveforms V = 20V 5V OUT LOAD µ 120 µF, C ESR = 100 m OUT OUT A: Output Pin Voltage, 10V/div. B: ...
Page 9
Test Circuit and Layout Guidelines Component Values shown are for V = 15V OUT 120 µF, 50V, Aluminum Electrolytic Nichicon “PL Series” 120 µF, 35V Aluminum Electrolytic, Nichicon “PL Series” 3A, 40V Schottky Rectifier, 1N5822 68 µH, L30 ...
Page 10
Test Circuit and Layout Guidelines (Continued any switching regulator, layout is very important. Rap- idly switching currents associated with wiring inductance can generate voltage transients which can cause problems. For minimal inductance and ground loops, the wires indicated ...
Page 11
LM2598 Series Buck Regulator Design Procedure (Fixed Output) PROCEDURE (Fixed Output Voltage Version simplify the capacitor selection procedure, refer to the quick design component selection table shown in Figure 2 . This table contains different input voltages, output ...
Page 12
LM2598 Series Buck Regulator Design Procedure (Fixed Output) PROCEDURE (Fixed Output Voltage Version) 4. Input Capacitor ( low ESR aluminum or tantalum bypass capacitor is needed between the input pin and ground to prevent large voltage transients ...
Page 13
LM2598 Series Buck Regulator Design Procedure (Adjustable Output) PROCEDURE (Adjustable Output Voltage Version) Given Regulated Output Voltage OUT V (max) = Maximum Input Voltage IN I (max) = Maximum Load Current LOAD F = Switching Frequency (Fixed at ...
Page 14
LM2598 Series Buck Regulator Design Procedure (Adjustable Output) (Continued) PROCEDURE (Adjustable Output Voltage Version simplify the capacitor selection procedure, refer to the quick design table shown in Figure 3 . This table contains different output voltages, and lists ...
Page 15
LM2598 Series Buck Regulator Design Procedure (Adjustable Output) (Continued) PROCEDURE (Adjustable Output Voltage Version) 6. Input Capacitor ( low ESR aluminum or tantalum bypass capacitor is needed between the input pin and ground to prevent large voltage ...
Page 16
LM2598 Series Buck Regulator Design Procedure INDUCTOR VALUE SELECTION GUIDES (For Continuous Mode Operation) FIGURE 4. LM2598-3.3 FIGURE 5. LM2598-5.0 www.national.com DS012593-25 DS012593-26 16 DS012593-27 FIGURE 6. LM2598-12 DS012593-28 FIGURE 7. LM2598-ADJ ...
Page 17
LM2598 Series Buck Regulator Design Procedure Inductance Current (µH) (A) Through Hole L4 68 0.32 67143940 L5 47 0.37 67148310 L6 33 0.44 67148320 L9 220 0.32 67143960 L10 150 0.39 67143970 L11 100 0.48 67143980 L12 68 0.58 67143990 ...
Page 18
LM2598 Series Buck Regulator Design Procedure Coilcraft Inc. Coilcraft Inc., Europe Pulse Engineering Inc. Pulse Engineering Inc., Europe Renco Electronics Inc. Schott Corp. Nichicon Corp. Panasonic AVX Corp. Sprague/Vishay FIGURE 10. Capacitor Manufacturers Phone Numbers VR 1A Diodes Surface Mount ...
Page 19
Block Diagram Application Information PIN FUNCTIONS +V (Pin 2) — This is the positive input supply for the IC IN switching regulator. A suitable input bypass capacitor must be present at this pin to minimize voltage transients and to supply ...
Page 20
Application Information the narrow pulses and ramp controlled manner. This is a very useful feature in some switcher topologies that require large startup currents (such as the inverting configu- ration) which can load down the input power ...
Page 21
Application Information DELAY CAPACITOR C — Provides delay for the error flag output. See the DELAY upper curve in Figure 13 , and also refer to timing diagrams in Figure capacitor on this pin provides a time ...
Page 22
Application Information FIGURE 16. RMS Current Ratings for Low ESR Electrolytic Capacitors (Typical) FIGURE 17. Capacitor ESR vs Capacitor Voltage Rating (Typical Low ESR Electrolytic Capacitor) The consequences of operating an electrolytic capacitor above the RMS current rating is a ...
Page 23
Application Information teristic may cause instability or EMI problems. Ultra-fast recovery diodes typically have reverse recovery times less. Rectifiers such as the 1N5400 series are much too slow and should not be used. FIGURE 18. Capacitor ...
Page 24
Application Information DISCONTINUOUS MODE OPERATION The selection guide chooses inductor values suitable for continuous mode operation, but for low current applications and/or high input voltages, a discontinuous mode design may be a better choice. It would use an inductor that ...
Page 25
Application Information In a switching regulator design, knowing the value of the peak-to-peak inductor ripple current ( I determining a number of other circuit parameters. Param- eters such as, peak inductor or peak switch current, mini- mum load current before ...
Page 26
Application Information Circuit Data for Temperature Rise Curve TO-220 Package (T) Capacitors Through hole electrolytic Inductor Through hole, Schott, 68 µH Diode Through hole, 3A 40V, Schottky PC board 3 square inches single sided 2 oz. copper (0.0028") FIGURE 22. ...
Page 27
Application Information FIGURE 24. Output Voltage, Input Current, Error Flag Signal, at Start-Up, WITH Soft-start FIGURE 26. Typical Circuit Using Shutdown /Soft-start and Error Flag Features FIGURE 27. Inverting −5V Regulator With Shutdown and Soft-start (Continued) DS012593-40 FIGURE 25. Output ...
Page 28
Application Information lNVERTING REGULATOR The circuit in Figure 27 converts a positive input voltage to a negative output voltage with a common ground. The circuit operates by bootstrapping the regulators ground pin to the negative output voltage, then grounding the ...
Page 29
Application Information FIGURE 31. Undervoltage Lockout With Hysteresis for an Inverting Regulator NEGATIVE VOLTAGE CHARGE PUMP Occasionally a low current negative voltage is needed for biasing parts of a circuit. A simple method of generating a negative voltage using a ...
Page 30
Application Information TYPICAL THROUGH HOLE PC BOARD LAYOUT, FIXED OUTPUT (1X SIZE), DOUBLE SIDED, THROUGH HOLE C — 150 µF/50V Aluminum Electrolytic, Panasonic “HFQ series” — 120 µF/25V Aluminum Electrolytic, Panasonic “HFQ series” OUT D1 — 3A, 40V ...
Page 31
Application Information TYPICAL THROUGH HOLE PC BOARD LAYOUT, ADJUSTABLE OUTPUT (1X SIZE), DOUBLE SIDED, C — 150 µF/50V, Aluminum Electrolytic, Panasonic “HFQ series” — 120 µF/25V Aluminum Electrolytic, Panasonic “HFQ series” OUT D1 — 3A, 40V Schottky Rectifier, ...
Page 32
Physical Dimensions www.national.com inches (millimeters) unless otherwise noted 7-Lead TO-220 (T) Order Number LM2598T-3.3, LM2598T-5.0, LM2598T-12 or LM2598T-ADJ NS Package Number TA07B 32 ...
Page 33
... 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. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant ...