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Texas Instruments LM5018MRX/NOPB
- Part No.:
- LM5018MRX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM5018MRX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 300MA 8SOPWR
- Quantity:
- Payment:
- Shipping:
Inventory:3,406
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Product details
Overview
LM5018MRX/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, and no loop compensation required. It operates across 7.5–100 V input, delivers adjustable output from 1.225 V, and supports isolated bias supply generation in telecom and smart metering systems.
For engineers reviewing the LM5018MRX/NOPB datasheet, LM5018MRX/NOPB pinout, LM5018MRX/NOPB application, or LM5018MRX/NOPB equivalent, key selection criteria include its 100-V input rating, integrated dual-MOSFET topology, COT transient response, thermal shutdown at 165°C, and SO PowerPAD-8 package compatibility with high-power-density layouts.
Technical Context
The LM5018MRX/NOPB implements a constant-on-time control architecture where on-time is inversely proportional to VIN via external RON, enabling near-constant switching frequency (up to 1 MHz) without compensation networks. Its intelligent peak current limit (575 mA typ) uses FB-voltage–dependent off-time to reduce foldback during partial overloads.
A dedicated high-voltage startup regulator supplies 7.6 V (±1.35 V) to internal logic and gate drivers; bootstrap charging occurs via internal diode from VCC to BST during SW low phase. The IC supports Fly-Buck™ isolation by leveraging SW node coupling and requires ≥25 mV ripple at FB for stable COT operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 7.5 V to 100 V - enables direct connection to 48-V telecom buses and automotive battery rails without pre-regulation. |
| Output Current | 300 mA continuous - sufficient for auxiliary bias rails in isolated converters and smart meter microcontrollers. |
| Feedback Reference | 1.225 V ±2% - sets precise output voltage via external resistor divider; determines regulation accuracy and load/line transient behavior. |
| Switching Frequency | Adjustable up to 1 MHz - controlled by RON and VIN; higher frequencies allow smaller magnetics but increase switching losses. |
| Thermal Shutdown | 165°C with 20°C hysteresis - protects against sustained overload or poor PCB thermal design; resumes operation at 145°C. |
| Current Limit Threshold | 575 mA typical - peak-limited protection; off-time scales inversely with FB voltage to minimize recovery delay under partial faults. |
| VCC Regulator Output | 7.6 V ±1.35 V - powers internal gate drivers and logic; disabled when external 8.55–13 V applied, reducing dissipation at high VIN. |
Pinout & Package
LM5018MRX/NOPB is packaged in SO PowerPAD-8 (4.89 mm × 3.90 mm), with exposed thermal pad electrically connected to RTN and requiring soldered connection to PCB ground plane for optimal thermal performance (RθJA = 41.1°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 RTN | Ground reference | Primary return path for all internal circuits; must be low-impedance connection to system ground plane. |
| 2 VIN | Main power input | Accepts 7.5–100 V DC; powers internal VCC regulator and high-side switch; requires local ceramic bypass capacitor. |
| 3 UVLO | Undervoltage lockout sense | Resistor-divider input to program startup threshold (1.225 V trip) and hysteresis; pulls low to force shutdown at 0.66 V. |
| 4 RON | On-time programming | Resistor-to-VIN sets minimum on-time; ensures stable operation above 100 ns at max VIN; defines switching frequency. |
| 5 FB | Feedback input | Compares output voltage (via resistor divider) to 1.225 V reference; requires ≥25 mV ripple for reliable COT timing. |
| 6 VCC | Bias supply output | 7.6 V regulated output for internal circuitry; requires 1.0-μF ceramic decoupling; disables if externally driven >8.55 V. |
| 7 BST | Bootstrap supply | Charged from VCC through internal diode during SW low phase; requires 0.01-μF ceramic capacitor to SW for high-side gate drive. |
| 8 SW | Switching node | Drives external inductor; connects to BST capacitor and output rectifier; carries full switching current and voltage stress. |
Key Features
| Feature | Design Value |
|---|---|
| Constant-on-time control | Eliminates need for external compensation components and enables ultra-fast load transient response without stability tuning. |
| Integrated dual MOSFETs | Reduces BOM count and layout area; eliminates external Schottky diode requirement in buck mode and simplifies Fly-Buck™ implementation. |
| Programmable undervoltage lockout | Allows independent setting of input start-up threshold and hysteresis using external resistors, improving system-level brownout resilience. |
| Intelligent peak current limit | Adapts off-time based on FB voltage to maintain fast recovery during moderate overloads while ensuring safe short-circuit handling. |
| Fly-Buck™ capability | Enables isolated output generation without optocoupler or transformer feedback; leverages SW node coupling and COT timing for simplicity. |
Applications
| Smart Power Meters | Telecom Systems |
|---|---|
Use Scenario: Providing isolated 3.3-V bias rail for metrology ADC and RF communication ICs in ANSI C12.22-compliant meters. IC Role / Device Role / Timing Role: Primary synchronous buck controller operating in Fly-Buck™ configuration to generate isolated auxiliary supply from 120-V AC-derived DC bus. Use Value: Eliminates need for separate isolated DC/DC module; achieves <1% output regulation error over temperature using 1.225-V precision reference. | Use Scenario: Generating 5-V/300-mA auxiliary supply from -48-V telecom battery bus for baseband processor and interface logic. IC Role / Device Role / Timing Role: High-input-voltage synchronous buck regulator with COT control delivering fast transient response to burst-mode traffic loads. Use Value: Maintains output regulation within ±1.5% during 1-A step load transients due to zero-loop-compensation architecture. |
| Automotive Electronics | Industrial Isolated Sensors |
Use Scenario: Powering CAN FD transceiver and microcontroller in 24-V vehicle subsystems subject to load dump (up to 100 V). IC Role / Device Role / Timing Role: Input-tolerant buck regulator with integrated 100-V switches and thermal shutdown, operating directly from unregulated battery rail. Use Value: Survives ISO 7637-2 Pulse 5a (120 V/500 ms) without external TVS; thermal shutdown prevents latch-up during sustained overtemperature events. | Use Scenario: Supplying isolated 12-V rail for analog front-end of current-sense shunt amplifier in motor drive inverters. IC Role / Device Role / Timing Role: Fly-Buck™ converter using primary-side sensing and COT timing to avoid secondary-side feedback complexity. Use Value: Achieves <200 mVpp output ripple with Type 3 ripple injection, meeting noise-sensitive analog signal chain requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164RGET | 4.5–65-V input, 300-mA, COT control, WQFN-16; lacks integrated low-side FET and Fly-Buck™ support. | Suitable for non-isolated 24-V industrial supplies but cannot replace LM5018MRX/NOPB in 100-V or Fly-Buck™ designs. | Select when input voltage ≤65 V and isolation is unnecessary; requires external sync rectifier. |
| MAX17504ATP+ | 4.5–60-V input, 300-mA, current-mode control, TQFN-20; includes PMBus interface and comprehensive fault reporting. | Preferred for digitally monitored power rails in programmable logic controllers; adds complexity and cost vs. analog-only LM5018MRX/NOPB. | Choose when telemetry, sequencing, or I²C configurability is required; not drop-in compatible. |
Compared with LM5018MRX/NOPB, LM5164RGET offers lower input range and no Fly-Buck™ capability, while MAX17504ATP+ adds digital control overhead but lacks 100-V tolerance-making LM5018MRX/NOPB uniquely suited for high-voltage isolated auxiliary supplies.
Availability
LM5018MRX/NOPB is available at Aetrix Electronics and suitable for smart power meters, telecom systems, and automotive electronics requiring stable component supply across extended temperature and voltage ranges.
Supply support for LM5018MRX/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 product line targets high-input-voltage DC/DC conversion in harsh environments, specifically engineered for Fly-Buck™ isolated bias generation and robust operation across 7.5–100 V input with minimal external components.
FAQ
What is the maximum input voltage rating for LM5018MRX/NOPB?
The LM5018MRX/NOPB supports an absolute maximum input voltage of 100 V applied to the VIN pin, with recommended operation from 7.5 V to 100 V. This rating allows direct use in 48-V telecom systems and automotive battery rails subject to load dump transients. Exceeding 100 V risks permanent damage per absolute maximum ratings in the TI datasheet SNVS787I.
Does LM5018MRX/NOPB require external compensation components?
No, LM5018MRX/NOPB does not require external compensation components due to its constant-on-time (COT) control architecture. The device achieves stable regulation without loop compensation networks, simplifying design and improving transient response. This is confirmed in Section 7.3.1 of the datasheet, which states "no loop compensation required" as a core feature of the LM5018MRX/NOPB.
Can LM5018MRX/NOPB be used in Fly-Buck™ topology?
Yes, LM5018MRX/NOPB is explicitly designed for Fly-Buck™ operation, as stated in its full part designation and Section 2 Applications. It leverages the SW node and COT timing to generate isolated outputs without optocouplers or secondary-side feedback. TI's application notes (e.g., SNVA166) confirm LM5018MRX/NOPB's validated Fly-Buck™ implementation with predictable cross-regulation and efficiency.
What is the purpose of the RON pin on LM5018MRX/NOPB?
On LM5018MRX/NOPB, the RON pin sets the minimum on-time duration by connecting an external resistor to VIN. This resistor determines switching frequency via inverse proportionality to input voltage (TON ∝ 1/VIN), enabling nearly constant frequency operation across the 7.5–100 V input range. The datasheet specifies a minimum on-time of 100 ns at maximum VIN for reliable timing.
What thermal protection features does LM5018MRX/NOPB include?
LM5018MRX/NOPB includes thermal shutdown that activates at 165°C (typical) with 20°C hysteresis, forcing the device into low-power reset until junction temperature falls to ~145°C. This protection is internal and independent of external circuitry. Thermal metrics such as RθJA = 41.1°C/W (SO PowerPAD-8) are specified in Section 6.4 to guide heatsinking and layout decisions for LM5018MRX/NOPB.
LM5018MRX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-PowerSOIC (0.154", 3.90mm Width)
- 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-SO PowerPad
LM5018MRX/NOPB FAQ
1.How can I place an order for LM5018MRX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5018MRX/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 LM5018MRX/NOPB reliable?
The price and inventory of LM5018MRX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5018MRX/NOPB is usually 5 days.
3.What payment methods are accepted for LM5018MRX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5018MRX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5018MRX/NOPB?
LM5018MRX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5018MRX/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 LM5018MRX/NOPB?
For technical support, including LM5018MRX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5018MRX/NOPB requirements.
6.How does Aetrix verify that LM5018MRX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM5018MRX/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 LM5018MRX/NOPB meets industry standards.
7.What is the process for return or replacement of LM5018MRX/NOPB?
All LM5018MRX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM5018MRX/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 LM5018MRX/NOPB part is unused and in its original packaging.
Return procedure for LM5018MRX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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