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Switching regulators have largely replaced linear regulators in many applications because they provide higher efficiency, better thermal management, and greater flexibility in output voltage design. This article will discuss the XL6009 regulator’s basic operation, pinout details, functional block diagram, specifications, features, application circuits, comparisons with other regulators, etc.
The XL6009 is a high-frequency DC-DC switching regulator designed to efficiently convert one DC voltage level to another. Unlike linear regulators that dissipate excess voltage as heat, the XL6009 uses pulse-width modulation (PWM) and an internal N-channel MOSFET to switch power rapidly. This switching method allows it to achieve higher efficiency and better thermal performance.
It operates over a wide input voltage range (typically around 3.5 V to 32 V) and supports adjustable output voltages depending on the external circuit configuration. With a fixed switching frequency of about 400 kHz and current-mode control architecture, it maintains stable regulation across varying load and supply conditions. The device is commonly configured in boost, SEPIC, flyback, or inverting topologies, offering flexible power design options in compact systems.
If you are interested in purchasing the XL6009, feel free to contact us for pricing and availability.
| Pin Number | Pin Name | Type | Description |
| 1 | GND | Ground | Ground reference of the regulator. Connect to system ground. |
| 2 | EN | Input | Enable control pin. High level turns ON the regulator; low level shuts it down. |
| 3 | SW | Output | Switching node. Connects to inductor and diode. This pin carries high-frequency switching current. |
| 4 | VIN | Input | Input supply voltage. Connect to the power source. |
| 5 | FB | Input | Feedback pin. Used to set the output voltage via an external resistor divider. |
| Tab (Metal Tab) | SW | Output | Internally connected to the SW pin. Used for heat dissipation and switching connection. |
• XL6019
• MT3608
• MC34063
• LM2577
• TPS61029
• SE3608
• ME2188
The XL6009 functional block diagram shows how the internal circuits work together to regulate and boost voltage. The input voltage (VIN) first powers an internal 2.5V regulator and a 1.25V reference source. The 1.25V reference is compared with the feedback (FB) voltage through the error amplifier (EA). This comparison determines whether the output voltage needs to increase or decrease.
The error signal then goes to the comparator (COMP), where it is combined with slope compensation and the 400 kHz oscillator signal. These signals control the RS latch, which sets the switching timing. The driver block then turns the internal NDMOS power switch ON and OFF at high frequency, sending energy through the SW pin to the external inductor and diode.
Protection circuits improve reliability. UVLO (Under-Voltage Lockout) prevents operation when VIN is too low. OVP (Over-Voltage Protection), OCP (Over-Current Protection), and Thermal Shutdown protect the IC from abnormal conditions. Soft-Start gradually increases the output voltage during startup to reduce inrush current and stress.
| Parameter | Value |
| Input Voltage (Vin) | -0.3 to 36 V |
| Feedback Pin Voltage (VFB) | -0.3 to Vin V |
| EN Pin Voltage (VEN) | -0.3 to Vin V |
| Output Switch Pin Voltage (VSW) | -0.3 to 60 V |
| Power Dissipation (PD) | Internally limited |
| Thermal Resistance (RJA, TO263-5L) | 30 °C/W |
| Operating Junction Temperature (TJ) | -40 to 125 °C |
| Storage Temperature (TSTG) | -65 to 150 °C |
| Lead Temperature (Soldering, 10 sec) | 260 °C |
| ESD (HBM) | >2000 V |
| Parameter | Value |
| Feedback Voltage (VFB) | 1.213 – 1.287 V (Typ. 1.25 V) |
| Efficiency | 92% (Typ.) |
| Input Operating Voltage (Vin) | 5 – 32 V |
| Shutdown Supply Current (ISTBY) | 70 – 100 µA |
| Quiescent Supply Current (Iq) | 2.5 – 5 mA |
| Oscillator Frequency (Fosc) | 320 – 480 kHz (Typ. 400 kHz) |
| Switch Current Limit (IL) | 4 A |
| Output Power NMOS RDS(on) | 110 – 120 mΩ |
| EN Pin Threshold (High) | 1.4 V |
| EN Pin Threshold (Low) | 0.8 V |
| EN Pin Input Leakage Current | 3 – 10 µA |
| Maximum Duty Cycle (Dmax) | 90% |
• Wide 5V to 32V Input Voltage Range - Supports a broad input range, making it suitable for battery-powered and adapter-based systems.
• Positive or Negative Output Voltage Programming - Allows flexible configuration for boost or inverting applications using a single feedback pin.
• Current Mode Control - Provides fast transient response and simplifies stability compensation.
• 1.25V Adjustable Reference - Uses an internal 1.25V reference to accurately set the output voltage.
• Fixed 400kHz Switching Frequency - Enables smaller external components and improved efficiency.
• Maximum 4A Switching Current - Supports high current applications with strong internal switching capability.
• SW Pin Built-in Over Voltage Protection - Protects the device from excessive voltage conditions at the switching node.
• Excellent Line and Load Regulation - Maintains stable output voltage under varying input and load conditions.
• EN Pin TTL Shutdown Capability - Allows easy on/off control using logic-level signals.
• Internal Optimized Power MOSFET - Integrates a low RDS(on) NMOS to improve efficiency and reduce external parts.
• High Efficiency Up to 94% - Minimizes power loss and heat generation during operation.
• Built-in Frequency Compensation - Ensures stable operation without complex external compensation networks.
• Built-in Soft-Start Function - Gradually increases output voltage during startup to reduce inrush current.
• Built-in Thermal Shutdown Function - Automatically disables the device when temperature exceeds safe limits.
• Built-in Current Limit Function - Protects the regulator from overcurrent damage.
• Available in TO263-5L Package - Designed in a surface-mount package suitable for better heat dissipation.
The first diagram shows the XL6009 configured as a boost converter. In this circuit, the input voltage (12V–16V) is applied to the VIN pin, and the internal switch at the SW pin drives the external inductor (33µH). When the internal NMOS switch turns ON, current flows through the inductor and energy is stored in its magnetic field. When the switch turns OFF, the stored energy is released through the Schottky diode (1N5824) to the output capacitor, raising the output voltage to 18.5V. The output voltage is set by the resistor divider network (R1 and R2) connected to the FB pin, following the formula VOUT = 1.25 × (1 + R2/R1). The input and output capacitors reduce ripple and stabilize the voltage, while the EN pin allows the converter to be turned ON or OFF.
The second diagram shows the XL6009 configured as a SEPIC buck-boost converter. This topology allows the output voltage (12V) to be either higher or lower than the input voltage (10V–30V). Two inductors (L1A and L1B) and a coupling capacitor (CDC) are used to transfer energy from input to output. When the internal switch turns ON, energy is stored in both inductors. When the switch turns OFF, the energy is delivered through the diode (1N5825) to the output capacitor. The feedback resistors (R1 and R2) again set the output voltage using the same 1.25V reference formula. This configuration provides more flexibility than a simple boost converter because it can regulate the output even when the input voltage varies above or below the desired output.
• DC-DC Boost Converter Circuits
• Buck-Boost Converter Systems
• SEPIC Converter Designs
• Battery-Powered Devices
• Portable Power Banks
• Automotive Power Systems
• LED Driver Circuits
• Industrial Power Supplies
• Solar Power Systems
• LCD and Display Power Modules
• Embedded System Power Regulation
• DIY Electronics Projects
| Feature | XL6009 | LM2577 | MT3608 | TPS61029 |
| Topology | Boost / Buck-Boost / SEPIC | Boost | Boost | Boost |
| Input Voltage Range | 5V – 32V | 3.5V – 40V | 2V – 24V | 0.9V – 5.5V |
| Switching Frequency | 400 kHz | 52 kHz | 1.2 MHz | 1 MHz (typ.) |
| Max Switch Current | 4A | 3A | 2A | ~2A (internal switch) |
| Output Voltage | Adjustable | Adjustable | Adjustable | Adjustable |
| Efficiency | Up to 94% | Up to ~85% | Up to 93% | Up to 95% |
| Internal MOSFET | Yes | Yes | Yes | Yes |
| Protection Features | OVP, OCP, Thermal | Current Limit, Thermal | OCP, Thermal | OCP, OVP, Thermal |
| Package Type | TO263-5L | TO220 / TO263 | SOT23-6 | WSON / QFN |
| Typical Application | High-power boost | General boost | Compact boost | Low-voltage boost |
| Symbol | Min (mm) | Max (mm) | Min (inch) | Max (inch) |
| A | 4.440 | 4.650 | 0.175 | 0.183 |
| B | 0.710 | 0.970 | 0.028 | 0.038 |
| C | 0.360 | 0.640 | 0.014 | 0.025 |
| C2 | 1.255 | 1.285 | 0.049 | 0.051 |
| D | 8.390 | 8.890 | 0.330 | 0.350 |
| E | 9.960 | 10.360 | 0.392 | 0.408 |
| e | 1.550 | 1.850 | 0.061 | 0.073 |
| F | 6.360 | 7.360 | 0.250 | 0.290 |
| L | 13.950 | 14.750 | 0.549 | 0.581 |
| L2 | 1.120 | 1.420 | 0.044 | 0.056 |
XLSEMI has strong capabilities in designing and manufacturing high-frequency switching power management ICs such as the XL6009. The company integrates optimized high-voltage MOSFET technology with current-mode PWM control architecture to support wide input voltage ranges up to 36V. XLSEMI also demonstrates expertise in power semiconductor process technology, TO263-5L package engineering, and thermal performance optimization. In addition, the manufacturer supports mass production, quality assurance testing, and reliable DC-DC converter solutions.
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