lm27953tlx National Semiconductor Corporation, lm27953tlx Datasheet
lm27953tlx
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lm27953tlx Summary of contents
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... Voltage boost is achieved with a high- efficiency 3/2x-gain charge pump. The LM27953 is available in National’s chip-scale 18-bump micro SMD package. Typical Application Circuit © 2004 National Semiconductor Corporation Features n Drives 4 Individual Common-Anode LEDs with up to 20mA each for a Main Display Backlight n Independent Resistor-Programmable Current Setting ...
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... SET C7 NC Operational States Ordering Information Order Information LM27953TL LM27953TLX www.national.com 18-Bump Thin Micro SMD Package, Large Bump NS Package Number TLA18 Input voltage. Input range: 2.7V to 5.5V. Power Ground Charge pump output. Approximately 1.5xV Flying capacitor connections. LED Outputs - Group A Signal P : Tie pins externally to PWR P OUT Enable for Charge Pump and LEDs (current outputs) ...
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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. V pin voltage IN EN pin voltages I Pin Voltages Dx Continuous Power Dissipation (Note 3) Junction Temperature (T ...
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Electrical Characteristics Limits in standard typeface are for T less otherwise specified 3.6V Symbol Parameter t Start-up Time START 1.5x/1x Charge pump gain cross-over: Gain = 1.5 when V is below IN threshold. Gain = 1 ...
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Typical Performance Characteristics 8.35kΩ and C IN SET LED Current (D1, D2,D3, D4) vs. Input Voltage Quiescent Current vs. Input Voltage, Unless otherwise specified 1µF. ...
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Typical Performance Characteristics R = 8.35kΩ and C SET POUT Charge Pump Output Voltage vs. Output Current Input Current vs. Input Voltage www.national.com Unless otherwise specified 1µF. (Continued) Charge ...
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Typical Performance Characteristics R = 8.35kΩ and C SET POUT Charge Pump Switching Frequency vs. Input Voltage Diode Current (Dx) vs. PWM Duty Cycle (EN) Input Voltage (Top) and Output Voltage ...
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Block Diagram Circuit Description OVERVIEW The LM27953 is primarily intended for Lithium-Ion battery driven white-LED drive applications, and is well suited to drive white LEDs that are used for backlighting small-format displays. The part has four matched constant-current out- puts, ...
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Circuit Description (Continued) When the voltage on the EN pin is low ( shutdown mode. All internal circuitry is OFF and the part consumes very little supply current when the LM27953 is shutdown. When the voltage on the EN pin ...
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Circuit Description (Continued) outputs rise at the rate of the reference voltage ramp. Due to the soft-start circuitry, turn-on time of the LM27953 is ap- proximately 350µs (typ.). THERMAL PROTECTION Internal thermal protection circuitry disables the LM27953 when the junction ...
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Physical Dimensions inches (millimeters) unless otherwise noted TLA18EHA: 18-Bump Thin Micro SMD, Large Bump National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time ...