LM3478MM/NOPB National Semiconductor, LM3478MM/NOPB Datasheet
LM3478MM/NOPB
Specifications of LM3478MM/NOPB
LM3478MMTR
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LM3478MM/NOPB Summary of contents
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... Adjustable clock frequency ■ ±2.5% (over temperature) internal reference ■ 10µA shutdown current (over temperature) Typical Application Circuit © 2011 National Semiconductor Corporation LM3478/LM3478Q Features ■ LM3478Q is AEC-Q100 qualified and manufactured on an Automotive Grade Flow ■ 8-lead Mini-SO8 (MSOP-8) package ■ ...
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Connection Diagram Package Marking and Ordering Information Order Number Package Type LM3478MM MSOP-8 LM3478MMX LM3478QMM MSOP-8 LM3478QMMX * Automotive Grade (Q) product incorporates enhanced manufacturing and support processes for the automotive market, including defect detection methodologies. Reliability qualification is compliant ...
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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. Input Voltage FB Pin Voltage FA/SD Pin Voltage Peak Driver Output Current (<10µs) Power Dissipation Storage Temperature Range Junction Temperature ESD Susceptibilty ...
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Symbol Parameter V Internal Compensation Ramp SL Voltage V ratio SENSE V Output Over-voltage OVP Protection (with respect to feedback voltage) (Note V Output Over-Voltage OVP(HYS) Protection Hysteresis(Note Gm Error Ampifier Transconductance A Error Amplifier Voltage ...
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Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device is intended to be functional. For guaranteed specifications and test conditions, see the Electrical Characteristics. ...
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Typical Performance Characteristics I vs Input Voltage (Shutdown (Switching) Supply IN Frequency vs Temperature www.national.com Unless otherwise specified Input Voltage (Non-Switching) Supply 10135503 Switching Frequency vs R 10135535 Drive Voltage vs Input Voltage ...
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Current Sense Threshold vs Input Voltage Efficiency vs Load Current (3.3V In and 12V Out) Efficiency vs Load Current (9V In and 12V Out) COMP Pin Voltage vs Load Current 10135545 Efficiency vs Load Current (5V In and 12V Out) ...
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Error Amplifier Gain COMP Pin Source Current vs Temperature Compensation Ramp vs Compensation Resistor www.national.com Error Amplifier Phase 10135555 Short Circuit Sense Voltage vs Input Voltage 10135536 Shutdown Threshold Hysteresis vs Temperature 10135551 8 10135556 10135557 10135546 ...
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Duty Cycle vs Current Sense Voltage 10135594 9 www.national.com ...
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Functional Block Diagram Functional Description The LM3478 uses a fixed frequency, Pulse Width Modulated (PWM) current mode control architecture. The block diagram above shows the basic functionality typical application circuit, the peak current through the external MOSFET is ...
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Hence, the output voltage overshoot here can also trigger ...
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Sub-harmonic Oscillation can be easily understood as a ge- ometric problem. If the control signal does not have slope, the slope representing the inductor current ramps up until the control signal is reached and then slopes down again. If the ...
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FIGURE 6. Frequency Adjust FIGURE 7. Shutdown Operation in Frequency Adjust Mode SHORT-CIRCUIT PROTECTION When the voltage across the sense resistor measured on the Isen pin exceeds 343 mV, short circuit current limit protection gets activated. A comparator inside the ...
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A. First Cycle Operation B. Second Cycle of Operation POWER INDUCTOR SELECTION The inductor is one of the two energy storage elements in a boost converter. Figure 9 shows how the inductor current varies during a switching cycle. The current ...
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FIGURE 9. Inductor Current and Diode Current 15 10135524 www.national.com ...
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PROGRAMMING THE OUTPUT VOLTAGE The output voltage can be programmed using a resistor di- vider between the output and the FB pin. The resistors are selected such that the voltage at the FB pin is 1.26V. Pick R (the resistor ...
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This changes the equation for current limit (or R The R and R values may have to be calculated iteratively SEN SL in order to achieve both the desired current limit and stable operation. In some designs R can also ...
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OUTPUT CAPACITOR SELECTION The output capacitor in a boost converter provides all the out- put current when the inductor is charging result it sees very large ripple currents. The output capacitor should be ca- pable of handling the ...
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POWER MOSFET SELECTION boost converter, parameters governing the selection of the MOSFET are the minimum threshold voltage the on-resistance the total gate charge, Q (MIN) DS(ON) reverse transfer capacitance and the ...
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I must be lower than the maximum current rating set by L1PK the current sense resistor. The value of L1 can be increased above the minimum rec- ommended to reduce input ripple and output ripple. However, once D is less ...
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Other Application Circuit FIGURE 14. Typical Flyback Circuit 21 10135543 www.national.com ...
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Physical Dimensions www.national.com inches (millimeters) unless otherwise noted 22 ...
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Notes 23 www.national.com ...
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