2A 150KHz 40V Buck DC to DC Converter

The XL1509-5.0E1 is a fixed frequency PWM buck step-down DC-DC converter capable of driving a load with high efficiency, low ripple, and excellent line and load regulation. It is manufactured by XLSEMI and belongs to the XL1509 product family, a series of fixed-output and adjustable-output step-down switching regulator ICs designed to simplify the design of compact, efficient DC power conversion stages in a wide range of embedded, industrial, and consumer electronics applications. The "5.0" designation in the part number specifies that this variant produces a fixed regulated output voltage of five volts, making it directly suited to powering five-volt logic, microcontrollers, sensors, communication modules, and other standard digital subsystems from higher-voltage DC rails without requiring a linear regulator and its inherent power dissipation penalty. Unikeyic Electronics The XL1509 requires a minimum number of external components, making it simple to use, and includes internal frequency compensation and a fixed-frequency oscillator. The PWM control circuit is able to adjust the duty ratio linearly from zero to one hundred percent. This internal compensation architecture removes the burden of control loop design from the system engineer, which is a common point of complexity in discrete buck converter designs, and allows the device to be implemented with a straightforward application circuit consisting of an input capacitor, an output inductor, a freewheeling Schottky diode, and an output capacitor, without requiring additional feedback network components in the fixed-output version. Unikeyic Electronics The device operates across a wide input voltage range, accepting input rails ranging from just above the output voltage all the way up to the high end of the input range, making it compatible with a variety of common source voltages including twelve-volt, twenty-four-volt, and other industrial bus rails frequently encountered in embedded and industrial power system designs. This wide input range also makes it suitable for battery-powered applications where the supply voltage varies considerably across the battery discharge cycle, as the converter maintains a regulated output throughout the input voltage window. The fixed switching frequency is set internally at a value that represents a practical tradeoff between external component size and switching loss, allowing the use of standard commodity inductors and electrolytic or ceramic output capacitors without requiring unusually large or small values. An enable function and an overcurrent protection function are built inside. When a secondary current limit condition occurs, the operating frequency is reduced to a lower switching frequency, which limits the energy delivered per cycle and prevents damage to the power switch and external components during sustained overload events. This dual-level current protection approach provides both instantaneous peak current limiting and sustained overload protection, improving the robustness of designs built around the device in applications where load transients or fault conditions may cause temporary overcurrent conditions. Unikeyic Electronics The device is housed in a standard eight-pin small-outline integrated circuit surface-mount package, making it compatible with automated pick-and-place and reflow soldering assembly processes and suitable for compact power supply layouts on densely populated PCBs.

Spec Sheet Identification

Part Number: XL1509-5.0E1 Device Family: XL1509 Buck DC-DC Converter Series Manufacturer: XLSEMI

Part Number Decode

XL1509: Base device family 5.0: Fixed output voltage — five volts E1: Tape-and-reel packaging variant

Functional Classification

Device Type: Fixed-frequency PWM step-down buck DC-DC converter IC Topology: Non-synchronous buck converter with internal power switch Output Configuration: Single output, fixed voltage Regulation Method: Fixed-frequency PWM with internal compensation

Electrical Characteristics

Input Voltage Range: Wide input range, compatible with common industrial and consumer DC bus voltages Output Voltage: Fixed regulated output at five volts Output Current: Continuous rated current class suitable for moderate embedded system loads Switching Frequency: Fixed internal oscillator, mid-frequency class Duty Cycle Range: Adjustable from zero to maximum, internally controlled Minimum Dropout Voltage: Low dropout class Output Ripple: Low ripple characteristic with appropriate external filter components

Control & Protection Features

Enable Function: Built-in enable control input for power sequencing and shutdown Overcurrent Protection: Integrated primary current limit with frequency fold-back secondary protection Internal Compensation: Built-in frequency compensation, no external compensation network required Feedback: Internal reference for fixed output voltage regulation

External Components Required

Input Capacitor: Required for input decoupling Output Inductor: Required, standard commodity value Freewheeling Diode: External Schottky diode required Output Capacitor: Required for output filtering

Environmental & Qualification

Operating Temperature Range: Industrial range, below zero to elevated ambient RoHS Compliance: Yes, Halogen-Free

Package

Package Type: SOIC-8 (SOP-8) Mounting Method: Surface mount technology (SMT)

Packaging Format

Supply Format: Tape-and-reel Reel Quantity: Standard production reel quantity

Available Variants in XL1509 Family

XL1509-3.3E1: Fixed output at regulated lower voltage XL1509-5.0E1: Fixed output at five volts (this device) XL1509-12E1: Fixed output at twelve volts XL1509-ADJE1: Adjustable output version

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