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Texas Instruments LM25017SD/NOPB
- Part No.:
- LM25017SD/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-WDFN Exposed Pad
- Datasheet:
-
LM25017SD/NOPB.pdf
- Description:
- IC REG BUCK ADJ 650MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:385
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Product details
Overview
LM25017SD/NOPB from Texas Instruments is a 48-V, 650-mA synchronous buck/Fly-Buck™ regulator with integrated high-side and low-side N-channel MOSFETs, constant on-time (COT) control, no loop compensation required, and precision 1.225-V feedback reference. It delivers isolated bias supply in telecom systems and industrial equipment using Fly-Buck topology.
For engineers reviewing the LM25017SD/NOPB datasheet, LM25017SD/NOPB pinout, LM25017SD/NOPB application, or LM25017SD/NOPB equivalent, key selection criteria include input voltage range (7.5–48 V), adjustable switching frequency up to 1 MHz via RON, intelligent peak current limit (1.02 A), remote shutdown capability, and thermal shutdown at 165°C.
Technical Context
The LM25017SD/NOPB implements constant on-time (COT) control with VIN-inversely proportional on-time, enabling near-constant frequency across 7.5–48 V input and eliminating need for external loop compensation. Its forced off-time varies with FB voltage and VIN to provide intelligent short-circuit protection.
It integrates a 7.6-V internal VCC regulator with 4.5-V UVLO, bootstrap gate drive (BST–SW capacitor ≥0.01 µF), and dual-level undervoltage detection (UVLO pin thresholds: 0.66 V shutdown, 1.225 V enable). The synchronous rectifier operates without diode emulation, maintaining CCM under all loads.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 7.5 V to 48 V - supports wide industrial and telecom rails without pre-regulation |
| Output Current | 650 mA continuous - determined by integrated MOSFET RDS(ON) (buck: 1.8 Ω max, sync: 1.0 Ω max) |
| Feedback Reference | 1.225 V ±2% - sets output voltage via external resistor divider (VOUT = 1.225 × (1 + RFB1/RFB2)) |
| Switching Frequency | Adjustable up to 1 MHz via RON resistor - enables compact magnetics and EMI optimization |
| Current Limit Threshold | 1.02 A (typ) - peak-limited protection with VIN- and VFB-dependent off-time for safe short-circuit response |
| Thermal Shutdown | 165°C with 20°C hysteresis - disables switch and VCC regulator to prevent junction damage |
| UVLO Threshold | 1.225 V rising (enable), 0.66 V falling (shutdown) - programmable via external resistor divider from VIN |
Pinout & Package
LM25017SD/NOPB is packaged in an 8-pin HSOP (DDA) with exposed PowerPAD, measuring 4.89 mm × 3.90 mm. Thermal performance is optimized via RTN-connected exposed pad (RθJA = 41.1°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 RTN | Ground reference | System ground connection; must connect exposed pad to RTN for thermal and electrical integrity |
| 2 VIN | Main power input | Supplies 7.5–48 V to IC and internal VCC regulator; requires local ceramic input capacitance |
| 3 UVLO | Undervoltage lockout control | Resistor-divider input to set startup threshold and hysteresis; <0.66 V forces shutdown mode |
| 4 RON | On-time programming | Resistor to VIN sets minimum on-time (e.g., 100 kΩ → ~250 ns at 48 V); determines operating frequency |
| 5 FB | Feedback input | Compares against 1.225-V internal reference; requires ≥25 mV ripple for stable COT operation |
| 6 VCC | Bias supply output | 7.6-V regulated output (26 mA limit); powers gate drivers and logic; UVLO at 4.5 V |
| 7 BST | Bootstrap supply | Connects to SW via 0.01-µF ceramic capacitor; charged by internal VCC-to-BST diode during SW low phase |
| 8 SW | Power switching node | Drives external inductor; connects to BST capacitor and output filter; handles full switching current |
Key Features
| Feature | Design Value |
|---|---|
| Constant On-Time (COT) Control | Eliminates loop compensation components and enables ultra-fast transient response across wide VIN range |
| Integrated Dual MOSFETs | Reduces BOM count and layout complexity - no external high-side driver or Schottky diode needed |
| Fly-Buck™ Topology Support | Enables isolated auxiliary outputs without optocoupler or transformer feedback - ideal for bias supplies |
| Intelligent Peak Current Limit | Provides VIN- and VFB-dependent off-time to minimize fold-back during overload while ensuring safety at 48 V |
| Programmable UVLO & Remote Shutdown | Allows system-level brown-out management and power sequencing via single resistor divider or direct pin control |
Applications
| Industrial Power Supply | Telecom Isolated Bias |
|---|---|
|
Use Scenario: Regulating 24-V or 48-V backplane to 3.3-V/5-V logic rails in PLCs and motor drives. IC Role / Device Role / Timing Role: Primary synchronous buck controller delivering 650 mA with COT stability under dynamic load steps. Use Value: Eliminates compensation network and reduces component count versus voltage-mode controllers. |
Use Scenario: Generating isolated -5-V or +12-V auxiliary bias from 48-V telecom line for interface ICs. IC Role / Device Role / Timing Role: Fly-Buck™ converter operating in discontinuous conduction mode with inherent isolation. Use Value: Achieves galvanic isolation without optocoupler or secondary-side regulation circuitry. |
| Smart Meter Auxiliary Rail | Remote Sensor Node Supply |
|
Use Scenario: Powering metrology ADC, RTC, and RF transceiver from 12-V battery or energy-harvesting source. IC Role / Device Role / Timing Role: High-efficiency buck regulator supporting wide input (7.5–48 V) and low quiescent current (50 µA shutdown). Use Value: Maintains regulation during brown-out events and extends battery life via programmable UVLO hysteresis. |
Use Scenario: Providing stable 3.3-V supply to LoRaWAN or NB-IoT modules in harsh outdoor environments. IC Role / Device Role / Timing Role: Robust DC/DC with thermal shutdown (165°C) and ESD protection (±2000 V HBM). Use Value: Ensures reliable operation over –40°C to +125°C junction temperature range without derating. |
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 | 42-V input, 1-A output, valley-current-mode control, requires compensation network | Automotive AEC-Q100 qualified; lacks Fly-Buck™ support and integrated bootstrap diode | Choose for automotive-grade reliability where COT is not required and higher output current is needed |
| TPS54240DGQR | 40-V input, 2.5-A output, voltage-mode control, external MOSFETs, 100-μA IQ | No integrated switches; supports wider VIN but adds complexity and footprint | Choose when >650 mA load or adjustable soft-start is mandatory; avoid if board space is constrained |
Compared with LM25017SD/NOPB, LM5164QDRCRQ1 offers AEC-Q100 qualification and higher current but sacrifices Fly-Buck™ capability and COT simplicity; TPS54240DGQR provides greater output current and lower quiescent current but requires external FETs and compensation design effort.
Availability
LM25017SD/NOPB is available at Aetrix Electronics and suitable for industrial equipment, smart power meters, and telecom systems requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM25017SD/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 ICs, with decades of expertise in high-reliability power conversion solutions.
The LM25017SD/NOPB belongs to TI's high-voltage synchronous buck regulator product line, designed specifically for industrial and telecom applications demanding wide-input operation, Fly-Buck™ isolation, and minimal external components.
FAQ
What is the maximum recommended input voltage for LM25017SD/NOPB?
The absolute maximum input voltage rating for LM25017SD/NOPB is 53 V, but the recommended operating range is 7.5 V to 48 V. Operation above 48 V risks exceeding thermal limits due to increased VCC regulator dissipation and reduced efficiency. At 48 V input, the internal VCC regulator may dissipate up to 336 mW - proper PCB thermal design with exposed pad soldering is essential for sustained 650-mA operation.
Does LM25017SD/NOPB support Fly-Buck™ topology out of the box?
Yes, LM25017SD/NOPB natively supports Fly-Buck™ operation without additional ICs or optocouplers. Its constant on-time control, integrated synchronous rectifier, and robust UVLO/thermal protection enable stable isolated auxiliary outputs. Designers use the SW node to drive a coupled inductor, with secondary windings referenced to isolated grounds - TI provides validated reference designs (e.g., TIDA-01389) confirming ±3% regulation across load and line variations.
How is the switching frequency set on LM25017SD/NOPB?
LM25017SD/NOPB switching frequency is set by connecting a resistor (RON) between the RON pin and VIN. The on-time is inversely proportional to VIN per TON = (9×10⁻¹¹ × RON)/VIN, yielding nearly constant frequency across input range. For example, a 100-kΩ resistor yields ~250 ns on-time at 48 V → ~240 kHz; reducing RON to 49.9 kΩ increases frequency to ~450 kHz. Minimum on-time must exceed 100 ns for reliable operation.
What is the purpose of the BST pin on LM25017SD/NOPB?
The BST pin on LM25017SD/NOPB supplies gate drive voltage to the high-side N-channel MOSFET. It requires a 0.01-µF ceramic capacitor connected between BST and SW pins. During the SW low phase, the internal VCC-to-BST diode charges this capacitor; during the high phase, the stored charge drives the high-side gate. A minimum 144-ns off-time ensures sufficient recharge - undersized BST capacitance causes gate drive collapse and erratic switching.
Can LM25017SD/NOPB operate in discontinuous conduction mode (DCM)?
No - LM25017SD/NOPB's synchronous rectifier has no diode emulation mode and is designed to maintain continuous conduction mode (CCM) across all load conditions, including light loads. This eliminates audible noise and improves light-load efficiency but requires careful output capacitor ESR selection to ensure ≥25 mV ripple at FB for stable COT operation. For DCM-sensitive applications, external diode emulation is not supported.
LM25017SD/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:
- 650mA
- 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)
LM25017SD/NOPB FAQ
1.How can I place an order for LM25017SD/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25017SD/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 LM25017SD/NOPB reliable?
The price and inventory of LM25017SD/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25017SD/NOPB is usually 5 days.
3.What payment methods are accepted for LM25017SD/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM25017SD/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM25017SD/NOPB?
LM25017SD/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25017SD/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 LM25017SD/NOPB?
For technical support, including LM25017SD/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25017SD/NOPB requirements.
6.How does Aetrix verify that LM25017SD/NOPB is sourced from the original manufacturer or authorized distributors?
All LM25017SD/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 LM25017SD/NOPB meets industry standards.
7.What is the process for return or replacement of LM25017SD/NOPB?
All LM25017SD/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM25017SD/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 LM25017SD/NOPB part is unused and in its original packaging.
Return procedure for LM25017SD/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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