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LM3524DMNOPB Datasheet

Download or read online National Semiconductor LM3524DMNOPB Voltage Mode PWM Controller, Regulating Pulse Width Modulator pdf datasheet.



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LM2524D/LM3524D
Regulating Pulse Width Modulator
General Description
The LM3524D family is an improved version of the industry
standard LM3524. It has improved specifications and addi-
tional features yet is pin for pin compatible with existing 3524
families. New features reduce the need for additional exter-
nal circuitry often required in the original version.
±
The LM3524D has a
1% precision 5V reference. The cur-
rent carrying capability of the output drive transistors has
been raised to 200 mA while reducing V
CEsat
V
breakdown to 60V. The common mode voltage range of
CE
the error-amp has been raised to 5.5V to eliminate the need
for a resistive divider from the 5V reference.
In the LM3524D the circuit bias line has been isolated from
the shut-down pin. This prevents the oscillator pulse ampli-
tude and frequency from being disturbed by shut-down. Also
at high frequencies ( 300 kHz) the max. duty cycle per out-
put has been improved to 44% compared to 35% max. duty
cycle in other 3524s.
In addition, the LM3524D can now be synchronized exter-
nally, through pin 3. Also a latch has been added to insure
Block Diagram
© 1999 National Semiconductor Corporation
DS008650
one pulse per period even in noisy environments. The
LM3524D includes double pulse suppression logic that in-
sures when a shut-down condition is removed the state of
the T-flip-flop will change only after the first clock pulse has
arrived. This feature prevents the same output from being
pulsed twice in a row, thus reducing the possibility of core
saturation in push-pull designs.
Features
and increasing
n Fully interchangeable with standard LM3524 family
±
1% precision 5V reference with thermal shut-down
n
n Output current to 200 mA DC
n 60V output capability
n Wide common mode input range for error-amp
n One pulse per period (noise suppression)
n Improved max. duty cycle at high frequencies
n Double pulse suppression
n Synchronize through pin 3
June 1999
DS008650-1
www.national.com

Summary of Contents

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... In addition, the LM3524D can now be synchronized exter- nally, through pin 3. Also a latch has been added to insure Block Diagram © 1999 National Semiconductor Corporation DS008650 one pulse per period even in noisy environments. The LM3524D includes double pulse suppression logic that in- ...

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... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Collector Supply Voltage (LM2524D) (LM3524D) Output Current DC (each) Oscillator Charging Current (Pin 7) Electrical Characteristics (Note 1) Symbol Parameter REFERENCE SECTION ...

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Electrical Characteristics (Note 1) Symbol Parameter ERROR-AMP SECTION Current 2.5V I Input Offset Current I Compensation V V COSI IN(I) IN(NI) Current (Sink) I Compensation V V COSO IN(NI) IN(I) Current (Source ...

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Electrical Characteristics (Note 1) Symbol Parameter OUTPUT SECTION (EACH OUTPUT) 60V I Collector Leakage V CES CE 55V Current 40V Saturation I CESAT E 200 mA Voltage I ...

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Typical Performance Characteristics Output Transistor Saturation Voltage DS008650-31 Standby Current vs Voltage DS008650-34 Test Circuit (Continued) Output Transistor Emitter Voltage DS008650-32 Standby Current vs Temperature DS008650-35 5 Reference Transistor Peak Output Current DS008650-33 Current Limit Sense Voltage DS008650-36 DS008650-4 www.national.com ...

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Functional Description INTERNAL VOLTAGE REGULATOR The LM3524D has an on-chip 5V, 50 mA, short circuit pro- tected voltage regulator. This voltage regulator provides a supply for all internal circuitry of the device and can be used as an external reference. ...

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Functional Description (Continued) applied to pin 9 which will override the error amplifier and force a particular duty cycle to the outputs. An example of this could be a non-regulating motor speed control where a variable voltage was applied to ...

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Typical Applications FIGURE 7. Positive Regulator, Step-Up Basic Configuration (I FIGURE 8. Positive Regulator, Step-Up Boosted Current Configuration www.national.com DS008650- mA) IN(MAX) DS008650-12 8 ...

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Typical Applications (Continued) FIGURE 9. Positive Regulator, Step-Down Basic Configuration (I FIGURE 10. Positive Regulator, Step-Down Boosted Current Configuration DS008650- mA) IN(MAX) DS008650-14 9 www.national.com ...

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Typical Applications (Continued) FIGURE 11. Boosted Current Polarity Inverter BASIC SWITCHING REGULATOR THEORY AND APPLICATIONS The basic circuit of a step-down switching regulator circuit is shown in Figure 12 , along with a practical circuit design us- ing the LM3524D ...

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Typical Applications (Continued) FIGURE 13. Relation of Switch Timing to Inductor Current in Step-Down Regulator I Neglecting and settling I SAT where T Total Period The above shows the relation ...

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Typical Applications (Continued) FIGURE 14. Inductor Current Slope in Step-Down Regulator A complete step-down switching regulator schematic, using the LM3524D, is illustrated in Figure 15 . Transistors Q1 and Q2 have been added to boost the output to 1A. The ...

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Typical Applications (Continued) Parameter Output Voltage Switching Frequency Short Circuit Current Limit Load Regulation Line Regulation Efficiency Output Ripple FIGURE 16. 5V, 1 Amp Switching Regulator, Foil Side FIGURE 17. Stuffing Diagram, Component Side TABLE 1. Conditions Typical Characteristics ...

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Typical Applications (Continued) THE STEP-UP SWITCHING REGULATOR Figure 18 shows the basic circuit for a step-up switching regulator. In this circuit Q1 is used as a switch to alternately apply V across inductor L1. During the time and ...

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Typical Applications (Continued) In calculating the output capacitor C it can be seen that C o supplies I during t . The voltage change time will be some V or the output ripple of ...

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Typical Applications (Continued) > turns No. 24 wire on Ferroxcube No. K300502 Toroid core. FIGURE 20. 15V, 0.5A Step-Up Switching Regulator DS008650-26 FIGURE 21. Replacing R3/R4 Divider in Figure 20 with Reference Circuit Improves Line Regulation www.national.com ...

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Connection Diagram Order Number LM2524DN or LM3524DN DS008650-2 Top View See NS Package Number N16E Order Number LM3524DM See NS Package Number M16A 17 www.national.com ...

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Physical Dimensions inches (millimeters) unless otherwise noted www.national.com Molded Surface-Mount Package (M) Order Number LM3524DM NS Package Number M16A 18 ...

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... NATIONALS 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 ...

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