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Texas Instruments LM25018MR/NOPB
- Part No.:
- LM25018MR/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM25018MR/NOPB.pdf
- Description:
- IC REG BUCK ADJ 325MA 8SOPWR
- Quantity:
- Payment:
- Shipping:
Inventory:2,172
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Product details
Overview
LM25018MR/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 smart metering.
For engineers reviewing the LM25018MR/NOPB datasheet, LM25018MR/NOPB pinout, LM25018MR/NOPB application, or LM25018MR/NOPB equivalent, key selection criteria include COT-based transient response, programmable UVLO/switching frequency via external resistors, thermal shutdown at 165°C, and SO PowerPAD-8 package thermal performance (θJA = 41.1°C/W).
Technical Context
The LM25018MR/NOPB implements a constant on-time control architecture where on-time is inversely proportional to VIN and set by RON, enabling no loop compensation and near-constant switching frequency across input voltage. Its intelligent peak current limit uses FB-voltage-dependent off-time to reduce foldback during overload.
It integrates a 7.6-V internal VCC regulator with 4.5-V UVLO, bootstrap gate drive requiring 0.01-μF BST–SW ceramic capacitor, and dual-level UVLO (0.66 V shutdown, 1.225 V enable) with externally programmable hysteresis via resistor divider.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 7.5 V to 48 V - supports direct connection to industrial 24-V/48-V rails without pre-regulation |
| Output Current | 325 mA - continuous load capability with integrated synchronous FETs |
| Feedback Reference | 1.225 V ±2% - sets output voltage via RFB1/RFB2 divider; enables precise 3.3-V/5-V/12-V regulation |
| Switching Frequency | Adjustable up to 1 MHz - set by RON and VIN; typical 240 kHz at 48 V/10 V out |
| Current Limit Threshold | 390–750 mA - peak-limited protection with FB-dependent off-time for short-circuit safety |
| Thermal Shutdown | 165°C with 20°C hysteresis - disables switch and VCC regulator to prevent junction damage |
| Package Thermal Resistance | θJA = 41.1°C/W (SO PowerPAD-8) - enables >2 W dissipation with minimal heatsinking |
Pinout & Package
LM25018MR/NOPB is packaged in an 8-pin SO PowerPAD™ (DDA) with 4.89 mm × 3.90 mm body size and exposed thermal pad soldered to RTN for enhanced heat transfer.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 RTN | Ground reference | System ground return for all internal circuits; exposed pad must be soldered to PCB ground plane |
| 2 VIN | Main power input | Accepts 7.5–48 V; powers internal VCC regulator and high-voltage logic |
| 3 UVLO | Undervoltage detection input | Resistor divider from VIN sets startup threshold; pulled below 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 to 1.225 V reference; requires ≥25 mV ripple for stable COT operation |
| 6 VCC | Bias supply output | 7.6 V regulated output for gate drivers; requires 1-μF decoupling capacitor |
| 7 BST | Bootstrap supply | Connects to SW via 0.01-μF ceramic capacitor; charges through internal diode when SW is low |
| 8 SW | Power switching node | Drives external inductor; connects to BST capacitor and output filter |
Key Features
| Feature | Design Value |
|---|---|
| Constant on-time (COT) control | Eliminates need for external compensation network; delivers ultra-fast transient response without stability tuning |
| Integrated synchronous FETs | 325-mA high-side and low-side N-MOSFETs reduce BOM count and eliminate external Schottky diode |
| Programmable UVLO with hysteresis | Independent threshold (1.225 V) and hysteresis (via RUV2) enable robust brown-out recovery in noisy industrial environments |
| Intelligent peak current limit | Off-time scales inversely with FB voltage-short-circuit protection with minimal foldback, faster recovery under partial overload |
| Fly-Buck™ topology support | Enables isolated auxiliary outputs using coupled inductor; no optocoupler or secondary controller required |
Applications
| Industrial Power Supply | Smart Electricity Meter |
|---|---|
Use Scenario: Regulating 48-V DC bus to 3.3-V/5-V for microcontroller, RTC, and sensor interfaces in factory automation PLCs. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering isolated bias via Fly-Buck™ configuration for communication modules. Use Value: Eliminates need for separate isolated DC/DC converter; achieves >85% efficiency at 100–300 mA while maintaining <100-ns transient response. | Use Scenario: Generating isolated 5-V and 12-V rails from 24-V battery backup in revenue-grade smart meters. IC Role / Device Role / Timing Role: Fly-Buck™ controller providing galvanically isolated auxiliary supplies for metrology ADC and RF transceiver sections. Use Value: Meets IEC 62053 creepage/clearance requirements without transformer redesign; supports 10-year field life with thermal shutdown at 165°C. |
| Telecom Base Station | Isolated Sensor Interface |
Use Scenario: Bias supply for optical transceivers and FPGA configuration in remote radio units operating from 48-V PoE++ infrastructure. IC Role / Device Role / Timing Role: High-input-voltage synchronous buck regulator with fast load-step response for burst-mode digital signal processing loads. Use Value: Maintains output regulation within ±1% during 100-mA load steps in <5 μs; operates reliably across –40°C to +85°C ambient. | Use Scenario: Powering isolated analog front-ends (e.g., current-loop transmitters) in hazardous-area process instrumentation. IC Role / Device Role / Timing Role: Fly-Buck™ converter generating reinforced-isolation 15-V/–15-V rails from non-isolated 24-V plant supply. Use Value: Achieves 3.75 kV RMS isolation rating using standard off-the-shelf coupled inductors; eliminates need for discrete gate drivers or optocouplers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164RNTT | Wider 3–100 V input, 300-mA output, integrated 100-V high-side FET only (asynchronous rectification) | Lacks synchronous low-side FET and Fly-Buck™ capability; requires external Schottky diode | Choose for ultra-high-input-voltage (>48 V) non-isolated applications where efficiency >90% is not critical |
| TPS54240DGQR | 3.5–42 V input, 2-A output, current-mode control with external compensation | Higher current but larger solution size; lacks Fly-Buck™ topology support and integrated low-side FET | Prefer when designing for >500-mA loads or when loop bandwidth tuning is required for specific EMI profiles |
Compared with LM5164RNTT and TPS54240DGQR, the LM25018MR/NOPB uniquely combines 48-V rating, integrated synchronous FETs, Fly-Buck™ capability, and COT control-enabling compact, isolated, high-transient-response power supplies without compensation design effort.
Availability
LM25018MR/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 RoHS-compliant packaging.
Supply support for LM25018MR/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 and embedded processing solutions for industrial, automotive, and communications markets.
The LM25018MR/NOPB belongs to TI's high-voltage DC/DC regulator product line, engineered specifically for reliable, isolated, and compact power conversion in 24-V/48-V industrial and utility infrastructure applications.
FAQ
What is the maximum input voltage rating for the LM25018MR/NOPB?
The LM25018MR/NOPB has an absolute maximum input voltage rating of 53 V, with recommended operating range from 7.5 V to 48 V. Operation above 48 V is not advised for sustained use due to increased VCC regulator power dissipation and thermal stress-verified per Section 6.1 Absolute Maximum Ratings and Section 6.3 Recommended Operating Conditions in the official datasheet SNVS953G.
Does the LM25018MR/NOPB support Fly-Buck™ topology out of the box?
Yes, the LM25018MR/NOPB natively supports Fly-Buck™ operation without firmware or external timing components. Its constant on-time control, integrated synchronous rectifier, and bootstrap gate drive architecture allow direct implementation of isolated outputs using a coupled inductor-confirmed in Section 2 Applications and Figure 8-2 of the LM25018MR/NOPB datasheet.
What is the purpose of the RON pin on the LM25018MR/NOPB?
The RON pin on the LM25018MR/NOPB sets the minimum on-time via an external resistor to VIN, directly determining switching frequency and ensuring stable COT operation. For example, a 100-kΩ resistor yields ~250 ns on-time at 48 V-critical for avoiding sub-harmonic oscillation and maintaining frequency stability across input voltage variation, as defined in Equation 3 and Figure 6-5 of the LM25018MR/NOPB datasheet.
Can the LM25018MR/NOPB operate without an external bootstrap capacitor?
No-the LM25018MR/NOPB requires a 0.01-μF ceramic capacitor between BST and SW pins for proper high-side gate drive. This capacitor is charged through the internal VCC-to-BST diode during SW low-time; omission causes immediate high-side FET failure due to insufficient gate voltage-explicitly mandated in Section 5 Pin Functions and Section 7.3.7 of the LM25018MR/NOPB datasheet.
How does the LM25018MR/NOPB handle overcurrent conditions?
The LM25018MR/NOPB employs intelligent peak current limiting: if inductor current exceeds 575 mA (typ), the on-time terminates immediately and a FB-voltage-dependent off-time begins-ranging from 144 ns (light overload) to 16 μs (short circuit). This prevents thermal runaway while minimizing output voltage sag, as detailed in Section 7.3.6 and Table 6-5 Electrical Characteristics of the LM25018MR/NOPB datasheet.
LM25018MR/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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
LM25018MR/NOPB FAQ
1.How can I place an order for LM25018MR/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25018MR/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 LM25018MR/NOPB reliable?
The price and inventory of LM25018MR/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25018MR/NOPB is usually 5 days.
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LM25018MR/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25018MR/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 LM25018MR/NOPB?
For technical support, including LM25018MR/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25018MR/NOPB requirements.
6.How does Aetrix verify that LM25018MR/NOPB is sourced from the original manufacturer or authorized distributors?
All LM25018MR/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 LM25018MR/NOPB meets industry standards.
7.What is the process for return or replacement of LM25018MR/NOPB?
All LM25018MR/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM25018MR/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 LM25018MR/NOPB part is unused and in its original packaging.
Return procedure for LM25018MR/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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