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Texas Instruments LM25018MRX/NOPB
- Part No.:
- LM25018MRX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM25018MRX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 325MA 8SOPWR
- Quantity:
- Payment:
- Shipping:
Inventory:4,964
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Product details
Overview
LM25018MRX/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-designed for isolated bias supplies in telecom and industrial power systems.
For engineers reviewing the LM25018MRX/NOPB datasheet, LM25018MRX/NOPB pinout, LM25018MRX/NOPB application, or LM25018MRX/NOPB equivalent, key selection criteria include its COT architecture eliminating loop compensation, intelligent peak current limit (575 mA typ), adjustable switching frequency up to 1 MHz via RON, thermal shutdown at 165°C, and dual-package availability (WSON-8 and SO PowerPAD-8).
Technical Context
The LM25018MRX/NOPB implements a constant on-time (COT) control scheme where on-time is inversely proportional to VIN and set by an external RON resistor, enabling near-constant frequency across 7.5–48 V input and eliminating need for loop compensation. Its forced off-time varies with FB voltage and VIN to provide intelligent current limiting during overload or short-circuit conditions.
It integrates a 7.6-V internal VCC regulator with 4.5-V UVLO, bootstrap gate drive (BST–SW requires 0.01-μF ceramic), and dual-level undervoltage lockout (UVLO) with independently programmable threshold (1.225 V) and hysteresis via external resistive divider-supporting remote shutdown when UVLO < 0.66 V.
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 external pre-regulation |
| Output Current | 325 mA - continuous load capability with integrated synchronous MOSFETs (RDS(ON) HS = 1.8 Ω max, LS = 1.0 Ω max) |
| Feedback Reference | 1.225 V ±2% - sets output voltage via external resistor divider; enables precise regulation down to ~1.23 V |
| Switching Frequency | Adjustable up to 1 MHz - set by RON and VIN; typical 240 kHz at VIN=48 V, RON=100 kΩ |
| Current Limit Threshold | 390–750 mA - peak-limited protection with adaptive off-time (16 µs max at short-circuit) |
| Thermal Shutdown | 165°C with 20°C hysteresis - disables switch and VCC regulator to prevent junction damage |
| Operating Junction Temp | –40°C to +125°C - validated for industrial ambient environments with proper PCB thermal design |
Pinout & Package
LM25018MRX/NOPB is packaged in an 8-pin SO PowerPAD (DDA) with 4.89 mm × 3.90 mm body size and thermally enhanced exposed pad soldered to RTN for improved heat dissipation (θJC(bot) = 2.4°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 RTN | Ground reference | System ground connection; exposed pad must be soldered to RTN plane for thermal and electrical integrity |
| 2 VIN | Main input supply | Accepts 7.5–48 V; powers internal VCC regulator and high-voltage logic |
| 3 UVLO | Undervoltage detection input | Resistor-divider programmable start-up threshold (1.225 V) and hysteresis; <0.66 V forces shutdown |
| 4 RON | On-time programming | Resistor to VIN sets minimum on-time (≥100 ns at 48 V); determines switching frequency |
| 5 FB | Feedback input | Compares output voltage (via resistor divider) to 1.225 V reference; ripple-sensitive node requiring ≥25 mV AC component |
| 6 VCC | Bias supply output | 7.6 V regulated output (6.25–8.55 V) for gate drivers and internal circuits; UVLO at 4.5 V |
| 7 BST | Bootstrap supply | Charged via internal diode from VCC when SW is low; requires 0.01-μF ceramic capacitor to SW |
| 8 SW | Power switching node | Drives external inductor; connects to BST capacitor and output filter; handles full switching current |
Key Features
| Feature | Design Value |
|---|---|
| No loop compensation required | Constant on-time control eliminates external compensation network-reducing BOM count and layout sensitivity |
| Ultra-fast transient response | COT architecture enables immediate on-time retriggering upon FB dip-critical for dynamic load steps in metering and telecom |
| Intelligent peak current limit | Off-time scales with FB voltage and VIN-minimizing foldback during moderate overloads while ensuring safe short-circuit operation |
| Isolated Fly-Buck™ capability | Integrated synchronous rectifier and COT control enable transformer-coupled isolated outputs without optocoupler or secondary-side sensing |
| Programmable UVLO with hysteresis | External resistor divider allows precise input brown-in/brown-out thresholds-essential for reliable startup in fluctuating 24/48 V industrial rails |
Applications
| Industrial Power Supplies | Smart Electricity Meters |
|---|---|
Use Scenario: Regulating 48 V DC bus to 3.3 V or 5 V for microcontrollers, sensors, and communication ICs in factory automation controllers. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator delivering stable, efficient 325-mA output with minimal external components. Use Value: Eliminates need for external compensation and Schottky diode-reducing solution size and cost while maintaining >90% efficiency at 24 V input. | Use Scenario: Generating isolated 12 V bias for metrology ADCs and RS-485 transceivers in revenue-grade smart meters. IC Role / Device Role / Timing Role: Fly-Buck™ topology controller using transformer coupling to derive isolated output without secondary feedback. Use Value: Achieves reinforced isolation compliance with single-chip solution-no optocoupler, TL431, or secondary-side controller required. |
| Telecom Line Cards | Industrial IoT Gateways |
Use Scenario: Point-of-load conversion of –48 V telecom supply (with polarity inversion) to 3.3 V for FPGA configuration and Ethernet PHYs. IC Role / Device Role / Timing Role: High-input-voltage synchronous buck regulator operating reliably across –48 V ±10% line variations. Use Value: Withstands 53 V absolute max input and features robust 2-kV HBM ESD rating-ensuring field reliability in dense line-card layouts. | Use Scenario: Powering ARM Cortex-M7 MCU, Wi-Fi/BLE module, and analog front-end in edge gateway enclosures with limited airflow. IC Role / Device Role / Timing Role: Thermally optimized regulator leveraging SO PowerPAD exposed pad for conduction cooling in sealed housings. Use Value: 2.4°C/W junction-to-case (bottom) thermal resistance enables 325 mA continuous output at 65°C ambient without heatsink. |
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), wider 3–65 V input, 1 A output, requires external compensation | Designed for automotive infotainment and ADAS; not drop-in due to different control architecture and pinout | Choose for automotive qualification and higher current; avoid if seeking COT simplicity or Fly-Buck™ capability |
| TPS54240DGQR | 3.5–42 V input, 2.5 A output, current-mode control with internal compensation, no integrated low-side FET | Requires external sync rectifier; lacks Fly-Buck™ support and programmable UVLO hysteresis | Prefer for higher current and simpler layout with external diode; not suitable for isolated bias or ultra-fast transient loads |
Compared with LM5164QDRCRQ1 and TPS54240DGQR, LM25018MRX/NOPB uniquely combines COT control (no compensation), integrated synchronous FETs, and Fly-Buck™ topology support in a compact 8-pin package-making it optimal for space-constrained, isolated, and fast-transient industrial power designs.
Availability
LM25018MRX/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 LM25018MRX/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 broad industrial, automotive, and communications portfolio coverage.
The LM25018MRX/NOPB belongs to TI's high-voltage DC/DC regulator product line, engineered specifically for efficient, compact, and robust power conversion in 24 V and 48 V industrial and telecom infrastructure applications.
FAQ
What is the maximum input voltage rating for LM25018MRX/NOPB?
The LM25018MRX/NOPB has an absolute maximum input voltage (VIN to RTN) of 53 V, with recommended operating range from 7.5 V to 48 V. Exceeding 53 V risks permanent damage per Absolute Maximum Ratings. The device includes internal protection against transient overvoltage on the SW node (up to VIN + 0.3 V for 100 ns), but sustained operation above 48 V is not supported.
Does LM25018MRX/NOPB support Fly-Buck™ topology out of the box?
Yes, LM25018MRX/NOPB natively supports Fly-Buck™ isolated converter operation without additional ICs. Its constant on-time control, integrated synchronous rectifier, and ability to regulate based on primary-side feedback enable transformer-coupled isolated outputs-confirmed in TI's official application notes and typical circuit diagrams for LM25018MRX/NOPB.
What is the minimum on-time requirement for stable operation of LM25018MRX/NOPB?
The LM25018MRX/NOPB requires a minimum on-time of 100 ns at maximum input voltage (48 V) to ensure reliable switching and bootstrap capacitor recharge. This is enforced by selecting RON such that TON ≥ 100 ns per Equation 3 in the datasheet. Violating this causes erratic regulation or failure to start.
Can LM25018MRX/NOPB operate without an external bootstrap capacitor?
No, LM25018MRX/NOPB requires a 0.01-μF ceramic capacitor between BST and SW pins. This capacitor supplies gate drive voltage to the high-side MOSFET during on-time. Omitting it prevents proper high-side switching, resulting in no output regulation or potential damage due to shoot-through.
How does the current limit function in LM25018MRX/NOPB differ from fixed-time foldback?
LM25018MRX/NOPB uses intelligent peak current limiting where off-time scales inversely with FB voltage and VIN-shortening recovery time during mild overloads (e.g., 200 mA overload) while extending off-time to 16 µs during hard shorts (FB ≈ 0 V). This avoids excessive foldback and enables faster restart after transient faults compared to fixed-foldback controllers.
LM25018MRX/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
- 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-SO PowerPad
LM25018MRX/NOPB FAQ
1.How can I place an order for LM25018MRX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25018MRX/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 LM25018MRX/NOPB reliable?
The price and inventory of LM25018MRX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25018MRX/NOPB is usually 5 days.
3.What payment methods are accepted for LM25018MRX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM25018MRX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM25018MRX/NOPB?
LM25018MRX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25018MRX/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 LM25018MRX/NOPB?
For technical support, including LM25018MRX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25018MRX/NOPB requirements.
6.How does Aetrix verify that LM25018MRX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM25018MRX/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 LM25018MRX/NOPB meets industry standards.
7.What is the process for return or replacement of LM25018MRX/NOPB?
All LM25018MRX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM25018MRX/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 LM25018MRX/NOPB part is unused and in its original packaging.
Return procedure for LM25018MRX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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