LM3524DN National Semiconductor, LM3524DN Datasheet

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LM3524DN

Manufacturer Part Number
LM3524DN
Description
ENHANCED PWM CONTROLLER, 3524, DIP
Manufacturer
National Semiconductor
Datasheet

Specifications of LM3524DN

Frequency
350kHz
Power Dissipation Pd
1W
Digital Ic Case Style
DIP
No. Of Pins
16
Operating Temperature Range
0°C To +125°C
Svhc
No SVHC (15-Dec-2010)
Operating Temperature Max
125°C
Base Number
3524
Controller Type
PWM
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

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0
© 2005 National Semiconductor Corporation
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
rent carrying capability of the output drive transistors has
been raised to 200 mA while reducing V
V
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
output 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
Connection Diagram
CE
breakdown to 60V. The common mode voltage range of
±
1% precision 5V reference. The cur-
CEsat
DS008650
Order Number LM2524DN or LM3524DN
See NS Package Number M16A
See NS Package Number N16E
and increasing
Order Number LM3524DM
Top View
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
n Fully interchangeable with standard LM3524 family
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
±
1% precision 5V reference with thermal shut-down
00865002
www.national.com
March 2005

LM3524DN Summary of contents

Page 1

... 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 00865002 Top View Order Number LM2524DN or LM3524DN See NS Package Number N16E Order Number LM3524DM See NS Package Number M16A DS008650 March 2005 www.national.com ...

Page 2

Block Diagram www.national.com 2 00865001 ...

Page 3

... 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 ...

Page 4

Electrical Characteristics (Note 1) Symbol Parameter Sawtooth Valley R = 5.6k Voltage ERROR-AMP SECTION V Input Offset Voltage I Input Bias Current I Input Offset Current I Compensation V ...

Page 5

Electrical Characteristics (Note 1) Symbol Parameter TC-V Sense Voltage T.C. sense Common Mode Voltage Range V − SHUT DOWN SECTION V High Input V SD (Pin 2) Voltage 150 mV I High Input I SD (pin 10) Current ...

Page 6

Typical Performance Characteristics Switching Transistor Peak Output Current vs Temperature Maximum & Minimum Duty Cycle Threshold Voltage Output Transistor Emitter Voltage www.national.com Maximum Average Power Dissipation (N, M Packages) 00865028 00865030 Reference Transistor Peak Output Current 00865032 6 00865029 Output ...

Page 7

Typical Performance Characteristics Standby Current vs Voltage Current Limit Sense Voltage Test Circuit (Continued) 00865034 00865036 7 Standby Current vs Temperature 00865035 00865004 www.national.com ...

Page 8

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. ...

Page 9

Functional Description The output of the amplifier, or input to the pulse width modu- lator, can be overridden easily as its output impedance MΩ). For this reason a DC voltage can be very high (Z O applied ...

Page 10

Typical Applications FIGURE 7. Positive Regulator, Step-Up Basic Configuration (I FIGURE 8. Positive Regulator, Step-Up Boosted Current Configuration www.national.com 00865011 = 80 mA) IN(MAX) 00865012 10 ...

Page 11

Typical Applications (Continued) FIGURE 9. Positive Regulator, Step-Down Basic Configuration (I 00865013 = 80 mA) IN(MAX) 11 www.national.com ...

Page 12

Typical Applications FIGURE 10. Positive Regulator, Step-Down Boosted Current Configuration www.national.com (Continued) FIGURE 11. Boosted Current Polarity Inverter 12 00865014 00865015 ...

Page 13

Typical Applications (Continued) 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 using the LM3524D in Figure 15. FIGURE 12. Basic Step-Down Switching ...

Page 14

Typical Applications where Henrys f is switching frequency in Hz Also, see LM1578 data sheet for graphical methods of in- ductor selection. CALCULATING OUTPUT FILTER CAPACITOR C Figure 13 shows L1’s current with respect to Q1’s t ...

Page 15

Typical Applications (Continued) *Mounted to Staver Heatsink No. V5- BD344 Q2 = 2N5023 > turns No. 22 wire on Ferroxcube No. K300502 Torroid core. FIGURE 15. 5V, 1 Amp Step-Down Switching Regulator 15 00865020 www.national.com ...

Page 16

Typical Applications 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 www.national.com (Continued) TABLE 1. Conditions V = 10V ...

Page 17

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 ...

Page 18

Typical Applications This equation shows that the input, or inductor, current is larger than the output current by the factor ( Since this factor is the same as the relation between can also be ...

Page 19

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 = ∆V or the output ripple of ...

Page 20

Typical Applications > turns No. 24 wire on Ferroxcube No. K300502 Toroid core. FIGURE 21. Replacing R3/R4 Divider in Figure 20 with Reference Circuit Improves Line Regulation FIGURE 22. Polarity Inverter Provides Auxiliary −15V Unregulated Output from ...

Page 21

Physical Dimensions inches (millimeters) unless otherwise noted Molded Surface-Mount Package (M) Order Number LM3524DM NS Package Number M16A 21 www.national.com ...

Page 22

... Deutsch Tel: +49 (0) 69 9508 6208 English www.national.com Français Tel: +33 ( 8790 Molded Dual-In-Line Package (N) Order Number LM2524DN or LM3524DN NS Package Number N16E 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system affect its safety or effectiveness ...

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