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Texas Instruments LM5018SDX/NOPB
- Part No.:
- LM5018SDX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-WDFN Exposed Pad
- Datasheet:
-
LM5018SDX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 300MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:4,020
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Product details
Overview
LM5018SDX/NOPB from Texas Instruments is a 100-V, 300-mA synchronous buck/Fly-Buck™ regulator with integrated high-side and low-side N-channel MOSFETs, constant-on-time (COT) control, 1.225-V precision feedback reference, and adjustable switching frequency up to 1 MHz - used in isolated bias supplies for telecom power systems.
For engineers reviewing the LM5018SDX/NOPB datasheet, LM5018SDX/NOPB pinout, LM5018SDX/NOPB application, or LM5018SDX/NOPB equivalent, key selection criteria include input voltage range (7.5–100 V), integrated dual-MOSFET topology, no loop compensation requirement, thermal shutdown at 165°C, and WSON-8 package compatibility with Fly-Buck™ transformer-coupled isolation.
Technical Context
The LM5018SDX/NOPB implements constant-on-time (COT) control with on-time inversely proportional to VIN via external RON resistor, enabling near-constant frequency across 7.5–100 V input and eliminating need for loop compensation. Its intelligent peak current limit (575 mA typ) uses FB-voltage-dependent off-time to reduce foldback during partial overloads.
It integrates a 7.6-V internal VCC regulator powered from VIN, a bootstrap gate driver (BST/SW), and dual-level UVLO (0.66 V shutdown / 1.225 V enable) programmable via external divider. The synchronous rectifier maintains continuous conduction mode (CCM) even at light loads without diode emulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 7.5 V to 100 V - supports direct connection to 48-V telecom buses and automotive battery rails without pre-regulation. |
| Output Current | 300 mA - maximum continuous load current delivered by integrated high-side (0.8–1.8 Ω RDS(ON)) and low-side (0.45–1 Ω RDS(ON)) MOSFETs. |
| Feedback Reference | 1.225 V ±2% - sets output voltage via external resistor divider (VOUT = 1.225 × (1 + RFB2/RFB1)), enabling adjustable outputs down to 1.225 V. |
| Switching Frequency | Adjustable up to 1 MHz - set by RON and VIN per TON = (10⁻¹⁰ × RON)/VIN; minimum off-time fixed at 144 ns for bootstrap recharge. |
| Thermal Shutdown | 165°C with 20°C hysteresis - disables switch and VCC regulator until junction cools to ~145°C, preventing catastrophic failure under overload. |
| UVLO Threshold | Programmable 0.66 V (shutdown) and 1.225 V (enable) - allows custom input undervoltage lockout using external resistor divider from VIN to RTN. |
| Operating Junction Temp | –40°C to +125°C - validated for industrial and automotive environments; RθJA = 41.3°C/W (WSON-8). |
Pinout & Package
LM5018SDX/NOPB is housed in an 4.00 mm × 4.00 mm WSON-8 package with exposed thermal pad (EP) requiring connection to RTN for optimal thermal performance (RθJCbot = 3.2°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 RTN | Ground reference | Primary GND connection for IC substrate and exposed pad; must be low-impedance path to system ground plane. |
| 2 VIN | Main power input | Accepts 7.5–100 V DC; powers internal VCC regulator and high-voltage gate drivers directly. |
| 3 UVLO | Undervoltage detection input | Resistor-divider node to program startup/shutdown thresholds; internal 20-μA hysteresis current source enables precise UVLO setpoint. |
| 4 RON | On-time programming | Connects to VIN via resistor to set COT on-time; minimum 100 ns required at max VIN for stable operation. |
| 5 FB | Feedback input | Compares output voltage (via resistive divider) to 1.225-V internal reference; requires ≥25 mV ripple for COT stability. |
| 6 VCC | Bias supply output | Regulated 7.6 V (6.25–8.55 V) output powering gate drivers and logic; internally current-limited to 26 mA. |
| 7 BST | Bootstrap supply | Charged from VCC through internal diode when SW is low; drives high-side MOSFET gate via 0.01-μF ceramic capacitor to SW. |
| 8 SW | Power switching node | Drives external inductor; connects to BST capacitor and output filter; withstands –1.5 V to VIN + 0.3 V. |
| EP | Exposed thermal pad | Electrically connected to RTN; mandatory solder connection to PCB ground plane for thermal management. |
Key Features
| Feature | Design Value |
|---|---|
| No external Schottky diode required | Synchronous rectification eliminates conduction loss and heat generation of external diode in buck topology. |
| Fly-Buck™ capability | Enables isolated output generation using coupled inductor without optocoupler or secondary-side regulation circuitry. |
| Ultra-fast transient response | COT architecture provides immediate on-time adjustment to load steps - no phase-margin tuning or compensation network needed. |
| Intelligent peak current limit | Off-time scales inversely with FB voltage (TOFF(ILIM) = 0.07×VIN/(VFB + 0.2 V)), minimizing foldback during moderate overloads. |
| Remote shutdown via UVLO pin | Pulling UVLO below 0.66 V forces low-current shutdown mode (<225 µA), enabling system-level power sequencing. |
Applications
| Smart Power Meters | Telecom 48-V Systems |
|---|---|
|
Use Scenario: Generating isolated 3.3-V or 5-V bias for metrology ICs and RF modules from 100-V DC mains input. IC Role / Device Role / Timing Role: Primary synchronous buck controller implementing Fly-Buck™ topology with transformer-coupled secondary output. Use Value: Eliminates need for separate isolated DC/DC converter; achieves >85% efficiency at 100-V input while meeting IEC 62053 creepage requirements. |
Use Scenario: Point-of-load conversion from 48-V telecom bus to 12-V or 5-V intermediate rail for line-card processors and PHYs. IC Role / Device Role / Timing Role: High-input-voltage synchronous buck regulator delivering stable 300-mA output with fast load-step response. Use Value: Maintains regulation across wide input transients (e.g., 48-V ±10%) without compensation redesign; supports hot-swap compliance. |
| Automotive Body Control Modules | Industrial PLC I/O Isolation |
|
Use Scenario: Converting 12–24-V battery rail (with load-dump tolerance up to 100 V) to 3.3-V MCU supply in BCM head units. IC Role / Device Role / Timing Role: Input-robust buck regulator with programmable UVLO and thermal shutdown for harsh automotive environments. Use Value: Survives ISO 7637-2 pulse 5a (100 V/0.1 s) without latch-off; operates continuously from –40°C to +125°C junction temperature. |
Use Scenario: Providing galvanically isolated 5-V supply for digital I/O channel isolators in programmable logic controllers. IC Role / Device Role / Timing Role: Fly-Buck™ controller driving center-tapped transformer to generate dual-polarity isolated rails. Use Value: Replaces discrete flyback + optocoupler solution with single IC; reduces BOM count by 7 components and board area by 40%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5017SDX/NOPB | Same COT architecture but rated for 65-V max input; lower RDS(ON) (0.5 Ω high-side); no Fly-Buck™-optimized timing. | Best suited for 24–48-V industrial inputs where 100-V rating is unnecessary; lacks UVLO hysteresis programming flexibility. | Select LM5017SDX/NOPB only if input never exceeds 65 V and higher efficiency at mid-range VIN is prioritized. |
| LM5164QDDARQ1 | Automotive-grade (AEC-Q100), 100-V input, but uses current-mode control; requires loop compensation; 500-mA output. | Designed for ASIL-B functional safety systems; includes spread-spectrum clocking and enhanced ESD protection (±4 kV HBM). | Choose LM5164QDDARQ1 when automotive qualification, fault reporting, or higher output current is mandatory - not a drop-in replacement. |
Compared with LM5017SDX/NOPB, LM5018SDX/NOPB delivers full 100-V operation and Fly-Buck™ timing optimization at the cost of slightly higher RDS(ON); versus LM5164QDDARQ1, it trades automotive qualification and current-mode stability for simpler layout, zero compensation, and lower system cost in non-safety-critical designs.
Availability
LM5018SDX/NOPB is available at Aetrix Electronics and suitable for smart power meters, telecom 48-V systems, and automotive body control modules requiring stable component supply across extended temperature and input voltage ranges.
Supply support for LM5018SDX/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 specializing in analog, embedded processing, and power management technologies with over 90 years of innovation in high-reliability power conversion solutions.
The LM5018 belongs to TI's high-voltage DC/DC regulator product line, designed specifically for efficient, compact, and robust step-down conversion in 48-V telecom, industrial, and automotive applications where wide input range and integrated FETs reduce system complexity.
FAQ
What is the maximum input voltage supported by LM5018SDX/NOPB?
The LM5018SDX/NOPB supports a maximum input voltage of 100 V, verified across absolute maximum ratings and recommended operating conditions. This enables direct connection to 48-V telecom buses with load-dump margin and 24-V automotive systems with ISO 7637-2 pulse 5a tolerance. Operation above 100 V risks permanent damage per Section 6.1 of the datasheet.
Does LM5018SDX/NOPB require external compensation components?
No, LM5018SDX/NOPB does not require external compensation components due to its constant-on-time (COT) control architecture. The device achieves stable regulation and ultra-fast transient response without loop compensation networks - confirmed in Sections 1, 3, and 7.3.1 of the datasheet.
Can LM5018SDX/NOPB be used in Fly-Buck™ isolated configurations?
Yes, LM5018SDX/NOPB is explicitly designed for Fly-Buck™ isolated topologies, as stated in the title, features list, and Section 2 Applications. Its timing characteristics, synchronous rectification, and bootstrap gate drive support transformer-coupled secondary outputs without optocouplers or secondary-side regulation.
What package type is used for LM5018SDX/NOPB?
LM5018SDX/NOPB uses the WSON-8 (NGU) package: 4.00 mm × 4.00 mm body size with exposed thermal pad (EP). Pin configuration matches Figure 5-2 and Table 5-1 in the datasheet; thermal metrics include RθJA = 41.3°C/W and RθJCbot = 3.2°C/W.
How is the switching frequency adjusted on LM5018SDX/NOPB?
Switching frequency on LM5018SDX/NOPB is adjusted by selecting the RON resistor value between Pin 4 (RON) and VIN. On-time follows TON = (10⁻¹⁰ × RON)/VIN, resulting in nearly constant frequency across input voltage; maximum frequency reaches 1 MHz with appropriate RON and VIN combination per Section 6.6.
LM5018SDX/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, Isolation Capable
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 7.5V
- Voltage - Input (Max):
- 100V
- Voltage - Output (Min/Fixed):
- 1.225V
- Voltage - Output (Max):
- 90V
- Current - Output:
- 300mA
- Frequency - Switching:
- Adj to 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-WSON (4x4)
LM5018SDX/NOPB FAQ
1.How can I place an order for LM5018SDX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5018SDX/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 LM5018SDX/NOPB reliable?
The price and inventory of LM5018SDX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5018SDX/NOPB is usually 5 days.
3.What payment methods are accepted for LM5018SDX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5018SDX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5018SDX/NOPB?
LM5018SDX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5018SDX/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 LM5018SDX/NOPB?
For technical support, including LM5018SDX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5018SDX/NOPB requirements.
6.How does Aetrix verify that LM5018SDX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM5018SDX/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 LM5018SDX/NOPB meets industry standards.
7.What is the process for return or replacement of LM5018SDX/NOPB?
All LM5018SDX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM5018SDX/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 LM5018SDX/NOPB part is unused and in its original packaging.
Return procedure for LM5018SDX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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