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Texas Instruments LM5009SDCX
- Part No.:
- LM5009SDCX
- Manufacturer:
- Texas Instruments
- Package:
- 8-WDFN Exposed Pad
- Datasheet:
-
LM5009SDCX.pdf
- Description:
- IC REG BUCK ADJ 150MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:2,833
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Product details
Overview
LM5009SDCX from Texas Instruments is a wide-input, non-synchronous buck switching regulator with integrated 100-V N-channel MOSFET, delivering up to 150 mA output current across 9.5 V to 95 V input range, featuring 2.5-V ±2% feedback reference over –40°C to +125°C and no external loop compensation required. It enables compact, high-efficiency bias supplies in telecom, industrial, and LED driver applications.
For engineers reviewing the LM5009SDCX datasheet, LM5009SDCX pinout, LM5009SDCX application, or LM5009SDCX equivalent, key selection criteria include its VIN-referenced on-time control architecture, intelligent current limit with VOUT-dependent off-time, thermal shutdown at 165°C, and dual-package availability (VSSOP-8/WSON-8) for thermal optimization.
Technical Context
The LM5009SDCX implements a constant-frequency buck topology using an on-time inversely proportional to VIN, eliminating need for external compensation while enabling ultra-fast transient response. Its control scheme operates in both continuous and discontinuous conduction modes, with frequency stability maintained via VIN feedforward and minimum off-time timer (300 ns).
It integrates a high-voltage startup regulator (7.0 V ±0.4 V, 9.5 mA current-limited), gate drive UVLO (4.5 V threshold), and dual protection comparators: regulation comparator (2.5 V trip) and overvoltage comparator (2.875 V trip). Current limiting uses forced off-time inversely proportional to FB voltage, ensuring short-circuit robustness without foldback.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 9.5 V to 95 V - supports rectified AC mains, 48-V telecom, and 42-V automotive bus without pre-regulation |
| Output Current | 150 mA - sufficient for biasing gate drivers, microcontrollers, and isolated controllers in high-side power stages |
| Feedback Reference | 2.5 V ±2% from –40°C to +125°C - enables precise output setting from 2.5 V to 85 V using resistor divider |
| Switch RDS(on) | 2.0 Ω (typ) - low conduction loss with integrated 100-V N-MOSFET, reducing BOM count vs discrete solutions |
| Current Limit Threshold | 0.31 A (typ) - protects against overload and short-circuit with intelligent off-time scaling based on FB voltage |
| Thermal Shutdown | 165°C with 25°C hysteresis - prevents catastrophic failure during sustained overload or poor heatsinking |
| Startup Regulator | 7.0 V ±0.4 V, 9.5 mA - powers internal circuitry directly from VIN up to 95 V, eliminating need for auxiliary supply |
Pinout & Package
LM5009SDCX is available in thermally enhanced 8-pin WSON package (4.00 mm × 4.00 mm, exposed pad) optimized for high-voltage, high-temperature operation. The exposed pad must be soldered to PCB ground plane for thermal performance (RθJB = 20.1°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Switching Output | Drives external inductor and recirculating diode; connects to BST capacitor; handles 100-V peak swing |
| BST | Bootstrap Supply | Charged from VCC via internal diode; supplies floating gate drive for N-MOSFET; requires 0.022-µF ceramic cap to SW |
| RCL | Current Limit Off-Time Set | Resistor-to-ground sets off-time duration inversely proportional to FB voltage - ensures safe short-circuit recovery |
| FB | Feedback Input | Connects to resistor divider; 2.5-V reference enables output programming; <1 nA bias current minimizes divider error |
| RTN | Ground Reference | Common return for all internal circuits; must be low-impedance connection to system ground |
| RON/SD | On-Time Set / Shutdown | Resistor-to-VIN sets on-time; pulled low disables regulator - enables remote enable/disable without additional logic |
| VCC | Internal Regulator Output | 7.0-V regulated supply for gate drive and control; shuts down if externally biased >8 V - reduces dissipation at high VIN |
| VIN | Main Input | Accepts 9.5–95 V DC; withstands 100-V transients; powers startup regulator and provides on-time reference |
Key Features
| Feature | Design Value |
|---|---|
| No external compensation required | On-time control architecture eliminates need for compensation network - reduces design time and component count |
| VIN feedforward frequency stability | Operating frequency remains stable across input and load variations - simplifies EMI filtering and magnetics selection |
| Intelligent current limit | Off-time scales with FB voltage - provides fast short-circuit protection while minimizing foldback during mild overloads |
| Integrated high-voltage startup regulator | Self-biases from VIN up to 95 V - removes need for external bias supply or charge pump in high-input applications |
| Thermal shutdown with hysteresis | 165°C trip with 25°C hysteresis - ensures reliable recovery after overheating without oscillation or latch-up |
Applications
| Heat Sink Eliminator | 48-V Telecom Bias Supply |
|---|---|
Use Scenario: Replacing linear regulators (e.g., 78Lxx) in space-constrained industrial controls where heat sink mounting is impractical. IC Role / Device Role / Timing Role: Non-synchronous buck controller providing fixed 5-V or 3.3-V bias rail from 24-V or 36-V rectified input. Use Value: Achieves >85% efficiency at 100 mA, reducing junction temperature rise by >40°C versus linear solution - eliminates need for mechanical heat sinking. | Use Scenario: Generating isolated controller bias in 48-V telecom power systems with strict size and reliability requirements. IC Role / Device Role / Timing Role: Primary-side buck regulator powering gate drivers and PWM controllers in flyback or forward converters. Use Value: Withstands 100-V transients and operates continuously at 95-V DC input - ensures uptime in harsh telecom environments without derating. |
| LED Constant-Current Driver | Non-Isolated AC Mains Supply |
Use Scenario: Driving strings of high-brightness LEDs from unregulated 12-V to 48-V industrial bus with analog dimming capability. IC Role / Device Role / Timing Role: Buck controller configured as constant-current source using FB pin sensing across sense resistor. Use Value: 2.5-V reference tolerance (±2%) and <1 nA FB bias current enable ±3% LED current accuracy - meets Class II lighting standards. | Use Scenario: Powering auxiliary circuits in non-isolated AC-DC supplies derived from rectified 120/230-VAC mains. IC Role / Device Role / Timing Role: High-voltage buck stage stepping down rectified DC (e.g., ~170 V or ~325 V) to 12-V or 15-V intermediate rail. Use Value: 95-V operating range and 100-V transient rating allow direct use after bridge rectifier - avoids bulky pre-regulator stage and improves system efficiency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5009MMX | VSSOP-8 package (3.00 mm × 3.00 mm); higher RθJA (157.7°C/W) vs WSON-8 (42.8°C/W) | Better suited for low-power, space-constrained layouts where thermal load is moderate | Select LM5009MMX when board area is critical and ambient temperature remains below 60°C |
| LM5163HWRX | Synchronous 0.5-A buck; lower quiescent current (15 µA); integrated high-side/low-side FETs | Higher efficiency at light loads; supports wider duty cycle range; requires different layout and compensation | Choose LM5163HWRX for new designs needing >90% efficiency at 10–100 mA or reduced solution size |
Compared with LM5009SDCX, LM5009MMX offers identical electrical functionality in a smaller footprint but inferior thermal performance, while LM5163HWRX delivers higher current and synchronous operation at the cost of increased complexity and different design rules - making LM5009SDCX optimal for ruggedized, high-input, medium-current bias applications where simplicity and transient robustness are prioritized.
Availability
LM5009SDCX is available at Aetrix Electronics and suitable for 48-V telecom bias supplies, industrial LED drivers, and non-isolated AC mains auxiliary power requiring stable component supply across extended temperature and high-voltage stress conditions.
Supply support for LM5009SDCX includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in high-reliability power conversion ICs.
The LM5009 product line delivers wide-input, high-voltage buck regulators targeting industrial, telecom, and automotive subsystems where input transients, thermal constraints, and design simplicity are critical - enabling robust, minimal-component bias solutions.
FAQ
What is the maximum input voltage rating for LM5009SDCX?
The LM5009SDCX has an absolute maximum input voltage rating of 100 V, with recommended operating range from 9.5 V to 95 V. This allows safe operation in 48-V telecom systems with 100-V surge immunity and rectified 230-VAC applications where peak DC voltage reaches ~325 V - only with appropriate external clamping or pre-regulation. The device's internal 100-V N-MOSFET and startup regulator are designed for this extended range.
Does LM5009SDCX require external compensation components?
No, LM5009SDCX does not require external compensation components. Its constant-on-time control architecture, with on-time inversely proportional to VIN, inherently stabilizes the control loop across line and load variations. This eliminates the need for compensation capacitors or resistors - reducing bill-of-materials count, PCB area, and design validation effort while delivering ultra-fast transient response.
How does the current limit protection work in LM5009SDCX?
The LM5009SDCX implements intelligent current limit protection using a forced off-time generator whose duration is inversely proportional to FB voltage. When switch current exceeds 0.31 A, the on-time pulse terminates immediately and an off-time timer activates. At FB = 0 V (e.g., output short), off-time is fixed at 35 µs; at higher FB voltages (e.g., overload), off-time decreases - minimizing foldback and enabling faster recovery. This scheme ensures robust short-circuit protection without external sensing components.
Can LM5009SDCX operate without an external bootstrap capacitor?
No, LM5009SDCX cannot operate without an external bootstrap capacitor. A 0.022-µF ceramic capacitor is required between BST and SW pins to provide gate drive voltage for the internal N-channel MOSFET. During each off-time, the capacitor recharges from VCC through an internal diode. Omitting this capacitor causes gate drive failure, resulting in no switching action and potential thermal damage - the datasheet explicitly mandates this component for functional operation.
What is the purpose of the RON/SD pin on LM5009SDCX?
The RON/SD pin on LM5009SDCX serves dual functions: it sets the switch on-time via a resistor to VIN (RON), and acts as a remote shutdown input. Pulling RON/SD to ground disables the regulator, reducing shutdown current to 76–150 µA. The pin's rising threshold is 0.4–1.05 V, allowing direct interface with microcontroller GPIOs or optocouplers. This dual role simplifies system-level enable control while maintaining precise frequency programming without additional pins.
LM5009SDCX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-WDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 9.5V
- Voltage - Input (Max):
- 95V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 85V
- Current - Output:
- 150mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-WSON (4x4)
LM5009SDCX FAQ
1.How can I place an order for LM5009SDCX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5009SDCX on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM5009SDCX reliable?
The price and inventory of LM5009SDCX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5009SDCX is usually 5 days.
3.What payment methods are accepted for LM5009SDCX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5009SDCX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5009SDCX?
LM5009SDCX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5009SDCX order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM5009SDCX?
For technical support, including LM5009SDCX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5009SDCX requirements.
6.How does Aetrix verify that LM5009SDCX is sourced from the original manufacturer or authorized distributors?
All LM5009SDCX products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM5009SDCX meets industry standards.
7.What is the process for return or replacement of LM5009SDCX?
All LM5009SDCX units undergo pre-shipment inspection (PSI). If there is an issue with LM5009SDCX, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM5009SDCX part is unused and in its original packaging.
Return procedure for LM5009SDCX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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