National Semiconductor LM1575 Series Manual Download

Page: 17 / 27

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

diodes are all

rated to 100V

11DF1

MUR110

HER102

The following

diodes are all

rated to 100V

31DF1

MURD310

HER302

11DQ03

31DQ03

SR103

SR303

40V

1N5819

IN5822

MBR140P

MBR340

11DQ04

31DQ04

SR104

SR304

50V

MBR150

MBR350

11DQ05

31DQ05

SR105

SR305

60V

MBR160

MBR360

11DQ06

31DQ06

SR106

SR306

FIGURE 8. Diode Selection Guide

Inductor

Schott

Pulse Eng.

Renco

Code

Value

(Note 15)

(Note 16)

(Note 17)

L100

100 µH

67127000

PE-92108

RL2444

L150

150 µH

67127010

PE-53113

RL1954

L220

220 µH

67127020

PE-52626

RL1953

L330

330 µH

67127030

PE-52627

RL1952

L470

470 µH

67127040

PE-53114

RL1951

L680

680 µH

67127050

PE-52629

RL1950

H150

150 µH

67127060

PE-53115

RL2445

H220

220 µH

67127070

PE-53116

RL2446

H330

330 µH

67127080

PE-53117

RL2447

H470

470 µH

67127090

PE-53118

RL1961

H680

680 µH

67127100

PE-53119

RL1960

H1000

1000 µH

67127110

PE-53120

RL1959

H1500

1500 µH

67127120

PE-53121

RL1958

H2200

2200 µH

67127130

PE-53122

RL2448

Note 15:

Schott Corp., (612) 475-1173, 1000 Parkers Lake Rd., Wayzata, MN 55391.

Note 16:

Pulse Engineering, (619) 674-8100, P.O. Box 12236, San Diego, CA 92112.

Note 17:

Renco Electronics Inc., (516) 586-5566, 60 Jeffryn Blvd. East, Deer Park, NY 11729.

FIGURE 9. Inductor Selection by Manufacturer’s Part Number

LM1575/LM2575/LM2575HV

www.national.com

Summary of Contents for LM1575 Series

Page 1: ...d 10 on the oscillator frequency External shutdown is included featuring 50 A typical standby cur rent The output switch includes cycle by cycle current limit ing as well as thermal shutdown for full...

Page 2: ...red Leads 5 Lead TO 220 T 01147522 Top View LM2575T XX or LM2575HVT XX See NS Package Number T05A 01147523 Top View 01147524 Side View LM2575T XX Flow LB03 or LM2575HVT XX Flow LB03 See NS Package Num...

Page 3: ...Side View LM2575S XX or LM2575HVS XX See NS Package Number TS5B Ordering Information Package NSC Standard High Temperature Type Package Voltage Rating Voltage Rating Range Number 40V 60V 5 Lead TO 22...

Page 4: ...LM2575HVN ADJ 24 Pin M24B LM2575M 5 0 LM2575HVM 5 0 Surface Mount LM2575M 12 LM2575HVM 12 LM2575M 15 LM2575HVM 15 LM2575M ADJ LM2575HVM ADJ 5 Lead TO 263 TS5B LM2575S 3 3 LM2575HVS 3 3 Surface Mount L...

Page 5: ...UT Output Voltage VIN 12V ILOAD 0 2A 3 3 V Circuit of Figure 2 3 267 3 234 V Min 3 333 3 366 V Max VOUT Output Voltage 4 75V VIN 40V 0 2A ILOAD 1A 3 3 V LM1575 LM2575 Circuit of Figure 2 3 200 3 168 3...

Page 6: ...4 11 52 11 52 11 40 V Min Circuit of Figure 2 12 36 12 48 12 48 12 60 V Max VOUT Output Voltage 0 2A ILOAD 1A 12 V LM2575HV 15V VIN 60V 11 64 11 52 11 52 11 40 V Min Circuit of Figure 2 12 42 12 54 12...

Page 7: ...rical Characteristics Specifications with standard type face are for TJ 25 C and those with boldface type apply over full Operating Tempera ture Range Unless otherwise specified VIN 12V for the 3 3V 5...

Page 8: ...tor input and output capacitors can affect switching regulator system performance When the LM1575 LM2575 is used as shown in the Figure 2 test circuit system performance will be as shown in system par...

Page 9: ...s Circuit of Figure 2 Normalized Output Voltage Line Regulation 01147532 01147533 Dropout Voltage Current Limit 01147534 01147535 Quiescent Current Standby Quiescent Current 01147536 01147537 LM1575 L...

Page 10: ...Continued Oscillator Frequency Switch Saturation Voltage 01147538 01147539 Efficiency Minimum Operating Voltage 01147540 01147541 Quiescent Current vs Duty Cycle Feedback Voltage vs Duty Cycle 011475...

Page 11: ...Layout Guidelines As in any switching regulator layout is very important Rap idly switching currents associated with wiring inductance generate voltage transients which can cause problems For minimal...

Page 12: ...tic COUT 330 F 25V Aluminum Electrolytic D1 Schottky 11DQ06 L1 330 H PE 52627 for 5V in 3 3V out use 100 H PE 92108 Adjustable Output Voltage Version 01147509 where VREF 1 23V R1 between 1k and 5k R1...

Page 13: ...the dominate pole pair of the switching regulator loop For stable operation and an acceptable output ripple voltage approximately 1 of the output voltage a value between 100 F and 470 F is recommended...

Page 14: ...For Continuous Mode Operation 01147510 FIGURE 3 LM2575 HV 3 3 01147511 FIGURE 4 LM2575 HV 5 0 01147512 FIGURE 5 LM2575 HV 12 01147513 FIGURE 6 LM2575 HV 15 01147514 FIGURE 7 LM2575 HV ADJ LM1575 LM25...

Page 15: ...Inductor Value 470 H Choose from AIE part 430 0634 Pulse Engineering part PE 53118 or Renco part RL 1961 3 Output Capacitor Selection COUT A The value of the output capacitor together with the induct...

Page 16: ...Capacitor CIN A 100 F aluminum electrolytic capacitor located near the input and ground pins provides sufficient bypassing To further simplify the buck regulator design procedure National Semiconducto...

Page 17: ...E 92108 RL2444 L150 150 H 67127010 PE 53113 RL1954 L220 220 H 67127020 PE 52626 RL1953 L330 330 H 67127030 PE 52627 RL1952 L470 470 H 67127040 PE 53114 RL1951 L680 680 H 67127050 PE 52629 RL1950 H150...

Page 18: ...eadings because of induced voltages in the scope probe The inductors listed in the selection chart include ferrite pot core construction for AIE powdered iron toroid for Pulse Engineering and ferrite...

Page 19: ...ON OFF pin should be grounded or driven with a low level TTL voltage typically below 1 6V To put the regulator into standby mode drive this pin with a high level TTL or CMOS signal The ON OFF pin can...

Page 20: ...sing a delayed turn on or an undervoltage lockout circuit described in the next section would allow the input voltage to rise to a high enough level before the switcher would be allowed to turn on Bec...

Page 21: ...cessively large RC time constants can cause problems with input voltages that are high in 60 Hz or 120 Hz ripple by coupling the ripple into the ON OFF pin ADJUSTABLE OUTPUT LOW RIPPLE POWER SUPPLY A...

Page 22: ...less than 0 15 EQUIVALENT SERIES INDUCTANCE ESL The pure inductance component of a capacitor see Figure 16 The amount of inductance is determined to a large extent on the capacitor s construction In a...

Page 23: ...y more magnetic flux When an inductor saturates the induc tor appears less inductive and the resistive component domi nates Inductor current is then limited only by the DC resis tance of the wire and...

Page 24: ...5J 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...

Page 25: ...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 LM25...

Page 26: ...oted 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 Packa...

Page 27: ...easonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness BANNED SUBSTANCE COMPLIANCE National Semiconductor certifies that the products and...

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