A4402_1 ALLEGRO [Allegro MicroSystems], A4402_1 Datasheet
A4402_1
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A4402_1 Summary of contents
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Features and Benefits ▪ 2 MHz switching frequency ▪ Adjustable soft start timer ▪ Watchdog input ▪ Power-on reset output ▪ Adjustable 2% buck regulator ▪ Adjustable 2% linear regulator ▪ Enable input ▪ supply voltage ...
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A4402 Selection Guide Part Number A4402ELPTR-T 4000 pieces per 13-in. reel Absolute Maximum Ratings Characteristic VIN1 Pin VIN2 Pin LX Pin ISEN Pin ENB Pin VO2 Pin WDI Pin TON Pin FB1 and FB2 Pins NPOR Ambient Operating Temperature Junction ...
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A4402 C TSET TSET 0.15 μF WDI C POR POR 0.33 μF ENB kΩ NPOR WDI 4.7 kΩ Constant On-Time Buck Converter with Integrated Linear Regulator Functional Block Diagram V REF Soft Start Boot Ramp Generator Charge ...
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A4402 ELECTRICAL CHARACTERISTICS Characteristics Symbol Input Voltage Supply 1 Input Voltage Supply 2 Supply Quiescent Current ENB Logic Input Voltage ENB Hysteresis V ENB Logic Input Current Linear Regulator Output Voltage Range Feedback Voltage V Undervoltage Lockout O2 V Threshold ...
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A4402 ELECTRICAL CHARACTERISTICS Characteristics Symbol Protection Circuitry NPOR Output Voltage V NPOR Leakage Current NPOR Reset V NPORRESET Thermal Shutdown Threshold Thermal Shutdown Hysteresis T Timing Circuitry TSET Current, Watchdog Mode I TSETWDI TSET Valley Voltage, Watchdog Mode TSET Reset ...
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A4402 Power-Up and Power-Down Timing Diagrams Using ENB ENB VIN1 LIN NPOR Using VIN1 VIN1 LIN NPOR VPOR VCTSET Constant On-Time Buck Converter with Integrated Linear Regulator t ss UVLO Rising UVLO Falling t ...
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A4402 ENB VO2 NPOR WDI V TSET Constant On-Time Buck Converter with Integrated Linear Regulator Watchdog Timing Diagram UVLO Rising t por t wait V reset t por t wait V trip Allegro MicroSystems, Inc. 115 ...
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A4402 Basic Operation The A4402 contains a fixed on-time, adjust- able voltage buck switching regulator with valley sensing current mode control, and an adjustable linear regulator designed to run off the buck regulator output. The constant on-time converter maintains a ...
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A4402 TSET The TSET pin serves a dual function by controlling the timing for both the soft start ramp and the WDI input. The current sourced from the TSET pin is dependant on the state of NPOR. There are two ...
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A4402 The valley current must be calculated so that, at the worst-case ripple, the converter can still supply the required current to the load. Further information on how to calculate the ripple current is included in the Application Information section. ...
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A4402 Switcher On-Time and Switching Frequency In order for the switcher to maintain regulation, the energy that is transferred to the inductor during the on-time must be transferred to the capacitor during the off-time. Because of this relationship, the load ...
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A4402 Worst-case ripple current occurs at maximum supply voltage. After calculating the duty cycle, DC, for this condition, the ripple current can be calculated. First to calculate DC × SENSE DC = ...
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A4402 The ground from each of the components should be very close to each other and be connected on the same surface as the com- ponents. Internal ground planes should not be used for the star ground connection, as vias ...
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A4402 Power Terminals GND GND V IN1 BOOT GND V IN2 VO2 GND Constant On-Time Buck Converter with Integrated Linear Regulator Pin Circuit Diagrams V IN1 TON GND VIN1 54 V GND Logic ...
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A4402 5.00 ±0. 3.00 16X 0.10 C +0.05 0.65 0.25 –0.06 Copyright ©2008-2009, Allegro MicroSystems, Inc. The products described here are manufactured under one or more U.S. patents or U.S. patents pending. Allegro MicroSystems, Inc. ...