LM3485MM/NOPB National Semiconductor, LM3485MM/NOPB Datasheet
LM3485MM/NOPB
Specifications of LM3485MM/NOPB
LM3485MMTR
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LM3485MM/NOPB Summary of contents
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... DS(ON) sense resistor. The cycle-by-cycle current limit can be adjust- ed with a single resistor, ensuring safe operation over a range of output currents. Typical Application Circuit Connection Diagram © 2009 National Semiconductor Corporation LM3485 Features ■ Easy to use control methodology ■ No control loop compensation required ■ ...
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Package Marking and Ordering Information Order Number Package Type LM3485MM LM3485MMX Pin Descriptions Pin Name Pin Number ISENSE GND NC FB ADJ PWR GND PGATE VIN www.national.com Package Marking MSOP-8 S29B S29B Description 1 The current sense input pin. This ...
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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. VIN Voltage PGATE Voltage FB Voltage ISENSE Voltage ADJ Voltage Maximum Junction Temp. Power Dissipation Electrical Characteristics Specifications in Standard type face are for T Range (T = − ...
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Note 1: Absolute maximum ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions for which the device is intended to be functional, but device parameter specifications may not be guaranteed. For guaranteed specifications and ...
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Current Limit ADJ Current vs Temperature PGATE Voltage vs Input Voltage Minimum ON Time vs. Temperature Current Limit One Shot OFF Time vs. Temperature 20034602 Typical V 20034603 Operating ON Time vs Output Load Current 20034612 5 20034604 vs Time ...
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Operating ON Time vs Output Load Current (V = 12V) IN Efficiency vs Load Current (V = 3.3V 22µH) OUT Start Up www.national.com Efficiency vs Load Current (V 20034640 Efficiency vs Load Current (V 20034618 Continuous Mode Operation ...
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Discontinuous Mode Operation (V = 12V 50mA 22µH) IN OUT OUT Output Ripple Voltage vs Input Voltage (V = 3.3V 1A 80mΩ, C OUT OUT OUT(ESR) Feed-Forward Capacitor (Cff) ...
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Block Diagram Functional Description OVERVIEW The LM3485 is buck (step-down) DC-DC controller that uses a hysteretic control scheme. The comparator is designed with approximately 10mV of hysteresis. In response to the voltage at the FB pin, the gate drive (PGATE ...
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FIGURE 1. Hysteretic Window The minimum output voltage ripple (V OUT_PP lated in the same way OUT_PP HYST For example, with V set to 3.3V, V OUT OUT_PP V = ...
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A value of 100pF to 1nF is recommended in most applications. Higher values can be used to create a soft-start function (See Start Up section). The current limit comparator has approximately 100ns of blanking time. ...
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Design Information Hysteretic control is a simple control scheme. However the operating frequency and other performance characteristics highly depend on external conditions and components. If ei- ther the inductance, output capacitance, ESR, V changed, there will be a change in ...
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The off state voltage across the catch diode is approximately equal to the input voltage. The peak reverse voltage rating must be greater than input voltage. In nearly all cases a Schottky diode is recommended. In low output voltage appli- ...
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FIGURE 6. Typical PCB Layout Schematic (3.3V output) 20034642 Top Layer 13 20034628 20034644 Bottom Layer www.national.com ...
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C1: C 22µF/35V EEJL1VD226R (Panasonic) IN C2: C 100µF/6.3V 6TPC100M (Sanyo) OUT C3: C 1nF Ceramic Chip Capacitor ADJ C4: C 100pF Ceramic Chip Capacitor FF D1: 1A/40V MBRS140T3 (On Semiconductor) L1: 22µH :QH66SN220M01L (Murata) Q1: FDC5614P (Fairchild) R1: 33KΩ ...
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Physical Dimensions inches (millimeters) unless otherwise noted 8 Lead Plastic MSOP-8 NS package Number MUA08A 15 www.national.com ...
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