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Texas Instruments LM25018SD/NOPB
- Part No.:
- LM25018SD/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-WDFN Exposed Pad
- Datasheet:
-
LM25018SD/NOPB.pdf
- Description:
- IC REG BUCK ADJ 325MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:923
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Product details
Overview
LM25018SD/NOPB from Texas Instruments is a 48-V, 325-mA synchronous buck/Fly-Buck™ regulator with integrated high-side and low-side N-channel MOSFETs, constant on-time (COT) control, 7.5–48 V input range, and 1.225 V ±2% feedback reference. It enables isolated bias supplies in telecom systems and industrial power rails without external Schottky diodes.
For engineers reviewing the LM25018SD/NOPB datasheet, LM25018SD/NOPB pinout, LM25018SD/NOPB application, or LM25018SD/NOPB equivalent, key selection criteria include its COT architecture eliminating loop compensation, programmable on-time via RON, intelligent peak current limit (575 mA typ), thermal shutdown (165°C), and dual-package availability (WSON-8 and SO PowerPAD-8).
Technical Context
The LM25018SD/NOPB implements a constant on-time control scheme where on-time is inversely proportional to VIN and set by an external RON resistor, enabling near-constant switching frequency across 7.5–48 V input. Its internal 7.6-V VCC regulator powers gate drivers and logic, with UVLO hysteresis programmable via external resistors on the UVLO pin.
It integrates both high-side and low-side N-MOSFETs (RDS(ON) = 0.8 Ω / 0.45 Ω typ), uses FB voltage (1.225 V reference) to trigger on-time, and features forced off-time protection that scales with VFB and VIN for intelligent short-circuit response - no diode emulation, operating in continuous conduction mode at all loads.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 7.5 V to 48 V - supports wide industrial and telecom input rails without pre-regulation |
| Output Current | 325 mA - maximum continuous load capability with integrated switches |
| Feedback Reference | 1.225 V ±2% - sets output voltage accuracy and stability via external resistor divider |
| Switching Control | Constant On-Time (COT) - eliminates need for external compensation network |
| Peak Current Limit | 575 mA typical - provides overload protection with adaptive off-time scaling |
| Thermal Shutdown | 165°C with 20°C hysteresis - prevents catastrophic failure during sustained overtemperature |
| Operating Junction Temp | –40°C to +125°C - rated for harsh industrial environments |
Pinout & Package
LM25018SD/NOPB is packaged in an 8-pin WSON (4.00 mm × 4.00 mm) with exposed thermal pad, optimized for compact, high-power-density layouts and enhanced thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RTN (Pin 1) | Ground reference | Primary GND connection; exposed pad must be soldered to PCB ground plane for thermal and electrical integrity |
| VIN (Pin 2) | Main input supply | Accepts 7.5–48 V; powers internal VCC regulator and high-voltage circuitry |
| UVLO (Pin 3) | Undervoltage lockout input | Programmable startup threshold (1.225 V) and hysteresis via external resistor divider |
| RON (Pin 4) | On-time programming | Resistor from VIN sets minimum on-time (e.g., 100 ns min at 48 V) and thus switching frequency |
| FB (Pin 5) | Feedback input | Compares output voltage (via resistor divider) to 1.225 V reference to regulate VOUT |
| VCC (Pin 6) | Bias supply output | Internally regulated 7.6 V output powering gate drivers and logic; requires 1-μF decoupling |
| BST (Pin 7) | Bootstrap capacitor node | Connects to SW via 0.01-μF ceramic capacitor to enable high-side N-MOSFET gate drive |
| SW (Pin 8) | Power switching node | Drives external inductor; connects to BST capacitor and output filter; handles full switching waveform |
Key Features
| Feature | Design Value |
|---|---|
| No external Schottky diode required | Synchronous rectification with integrated low-side N-MOSFET eliminates conduction loss and heat sink needs |
| No loop compensation needed | COT architecture ensures stable regulation across line/load without external RC networks or op-amps |
| Ultra-fast transient response | On-time triggered directly by FB voltage drop enables sub-microsecond recovery from load steps |
| Adjustable undervoltage lockout | Independent programming of UVLO threshold and hysteresis via two-resistor divider on UVLO pin |
| Fly-Buck™ topology support | Integrated synchronous switch and COT control enable isolated auxiliary outputs without optocouplers or extra controllers |
Applications
| Industrial Power Rails | Telecom Isolated Bias |
|---|---|
Use Scenario: Regulating 48-V backplane to 5-V/3.3-V logic rails in PLCs and motor drives. IC Role / Device Role / Timing Role: Primary synchronous buck controller delivering up to 325 mA with integrated switches and COT stability. Use Value: Eliminates external MOSFETs and compensation components, reducing BOM count and layout area while maintaining tight regulation under dynamic load. | Use Scenario: Generating isolated ±12-V bias for RS-485 transceivers or gate drivers in telecom base stations. IC Role / Device Role / Timing Role: Fly-Buck™ converter core using SW and BST pins to drive coupled inductor, delivering galvanically isolated output without optocoupler feedback. Use Value: Achieves isolation with single IC and one magnetics component, avoiding secondary-side regulation complexity and cost of isolated DC-DC modules. |
| Smart Meter Auxiliary Supply | Industrial Sensor Node Power |
Use Scenario: Deriving 3.3-V supply from 24-V or 48-V utility meter main rail for microcontroller and RF transceiver. IC Role / Device Role / Timing Role: High-input-voltage buck regulator with remote shutdown (via UVLO pin) enabling low-power sleep modes. Use Value: Supports energy harvesting-compatible shutdown current (≤225 µA) and operates reliably across wide temperature (–40°C to +125°C) and input ranges. | Use Scenario: Powering low-power analog front-ends and ADCs in distributed industrial sensors connected to 24-V field buses. IC Role / Device Role / Timing Role: Precision-regulated local supply with 2% reference tolerance and minimal output ripple via RC-filtered FB network. Use Value: Ensures measurement accuracy by minimizing noise coupling into sensitive analog circuits through stable, low-noise 1.225-V reference tracking. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QDRCRQ1 | Automotive-grade (AEC-Q100), 100-V input, 300-mA output, adjustable frequency (100 kHz–2.2 MHz) | Requires external compensation; higher VIN rating but lower IOUT and no Fly-Buck™ support | Choose for automotive safety-critical systems needing extended input range and qualification; not drop-in for LM25018SD/NOPB |
| TPS54240DGQR | 42-V input, 2-A output, current-mode control, integrated compensation, 2.5-V to 42-V operation | Higher current, larger package (MSOP-10), requires compensation network and external high-side FET | Choose when >325 mA output or tighter current-mode transient response is required; adds design complexity vs. COT simplicity |
Compared with LM25018SD/NOPB, LM5164QDRCRQ1 offers automotive qualification and wider input range but lacks Fly-Buck™ capability and requires compensation, while TPS54240DGQR delivers higher current but increases BOM count and layout size due to external FET and compensation components.
Availability
LM25018SD/NOPB is available at Aetrix Electronics and suitable for industrial equipment, smart power meters, and telecommunication systems requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM25018SD/NOPB 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.
LM25018SD/NOPB belongs to TI's high-voltage DC-DC regulator product line, designed specifically for efficient, compact, and robust power conversion in 24-V and 48-V industrial and telecom infrastructure applications.
FAQ
What is the recommended minimum on-time for LM25018SD/NOPB and how is it set?
The LM25018SD/NOPB requires a minimum on-time of 100 ns at maximum input voltage (48 V) for stable operation. This is set by selecting the RON resistor between VIN and the RON pin using the equation TON = (10−10 × RON) / VIN. For example, at 48 V, RON = 100 kΩ yields ~250 ns on-time. The LM25018SD/NOPB datasheet specifies this constraint to ensure reliable bootstrap capacitor recharge and proper COT timing accuracy.
Does LM25018SD/NOPB support Fly-Buck™ operation out of the box?
Yes, LM25018SD/NOPB natively supports Fly-Buck™ topology without additional ICs. Its integrated synchronous switch, constant on-time control, and ability to drive a coupled inductor from the SW and BST pins enable isolated auxiliary outputs. The LM25018SD/NOPB datasheet includes dedicated Fly-Buck™ application schematics and design guidelines, confirming direct implementation capability for isolated bias generation.
What is the purpose of the UVLO pin on LM25018SD/NOPB and how is it configured?
The UVLO pin on LM25018SD/NOPB enables programmable input undervoltage lockout with independent threshold and hysteresis. A resistor divider from VIN to RTN sets the rising threshold (1.225 V), while an internal 20-μA current source creates hysteresis when enabled. Pulling UVLO below 0.66 V places LM25018SD/NOPB in low-current shutdown mode. This allows precise startup control and brownout protection tailored to system-level input requirements.
Can LM25018SD/NOPB operate without an external bootstrap capacitor?
No, LM25018SD/NOPB requires an external 0.01-μF ceramic capacitor between BST and SW pins. This capacitor supplies gate drive voltage for the high-side N-MOSFET during on-time. The internal VCC regulator charges it via an internal diode when SW is low. Omitting this capacitor prevents high-side switching, causing LM25018SD/NOPB to fail to regulate. The LM25018SD/NOPB datasheet mandates this component for functional operation.
How does the current limit protection work in LM25018SD/NOPB?
LM25018SD/NOPB implements intelligent peak current limiting: if inductor current exceeds 575 mA (typ), the on-time terminates immediately and a non-resettable off-time timer activates. This off-time scales inversely with FB voltage and linearly with VIN - e.g., 16 μs at FB = 0 V and VIN = 48 V (short-circuit), but shorter for partial overloads. This minimizes foldback and improves recovery, and is fully documented in the LM25018SD/NOPB electrical characteristics table and Section 7.3.6.
LM25018SD/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-WDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 7.5V
- Voltage - Input (Max):
- 48V
- Voltage - Output (Min/Fixed):
- 1.225V
- Voltage - Output (Max):
- 40V
- Current - Output:
- 325mA
- Frequency - Switching:
- Up to 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-WSON (4x4)
LM25018SD/NOPB FAQ
1.How can I place an order for LM25018SD/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25018SD/NOPB 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 LM25018SD/NOPB reliable?
The price and inventory of LM25018SD/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25018SD/NOPB is usually 5 days.
3.What payment methods are accepted for LM25018SD/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM25018SD/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM25018SD/NOPB?
LM25018SD/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25018SD/NOPB 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 LM25018SD/NOPB?
For technical support, including LM25018SD/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25018SD/NOPB requirements.
6.How does Aetrix verify that LM25018SD/NOPB is sourced from the original manufacturer or authorized distributors?
All LM25018SD/NOPB 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 LM25018SD/NOPB meets industry standards.
7.What is the process for return or replacement of LM25018SD/NOPB?
All LM25018SD/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM25018SD/NOPB, 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 LM25018SD/NOPB part is unused and in its original packaging.
Return procedure for LM25018SD/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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