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Texas Instruments LM5019SDX/NOPB
- Part No.:
- LM5019SDX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-WDFN Exposed Pad
- Datasheet:
-
LM5019SDX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 100MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,139
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Product details
Overview
LM5019SDX/NOPB from Texas Instruments is a 100-V, 100-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 7.5–100-V input range-designed for isolated bias supplies in telecom and automotive power systems.
For engineers reviewing the LM5019SDX/NOPB datasheet, LM5019SDX/NOPB pinout, LM5019SDX/NOPB application, or LM5019SDX/NOPB equivalent, key selection criteria include its no-loop-compensation COT architecture, programmable on-time via RON, 144-ns minimum off-time for bootstrap recharge, intelligent peak current limit (150–300 mA), and dual-package availability (SO PowerPAD-8 and WSON-8).
Technical Context
The LM5019SDX/NOPB implements a constant-on-time control scheme where on-time is inversely proportional to VIN and set by an external RON resistor, enabling near-constant switching frequency across 7.5–100 V input without loop compensation. Its internal 7.6-V VCC regulator powers gate drivers and logic, with bootstrap charging via internal diode from VCC to BST during SW low periods.
It features dual-level undervoltage lockout (UVLO) with independently programmable threshold (1.225 V) and hysteresis via external divider, plus intelligent current limiting where off-time scales inversely with FB voltage-reducing foldback during partial overloads while ensuring 16-μs safety hold-off under short-circuit conditions at 48 V.
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 Capability | 100 mA - determined by integrated MOSFET RDS(ON) (high-side: 0.8–1.8 Ω; sync: 0.45–1 Ω) and thermal limits in SO PowerPAD/WSON packages. |
| Feedback Reference | 1.225 V ±2.5% - sets output voltage via external resistor divider; enables precise regulation down to ~1.23 V. |
| Switching Frequency Range | Adjustable up to 1 MHz - controlled by RON and VIN; typical operation at 240 kHz with stable ripple-based timing. |
| Minimum Off-Time | 144 ns - ensures reliable bootstrap capacitor recharge during each cycle, critical for gate driver functionality. |
| Current Limit Threshold | 150–300 mA (peak) - provides overload protection with adaptive off-time scaling to minimize foldback in partial faults. |
| Thermal Shutdown | 165°C activation with 20°C hysteresis - disables switching and VCC regulator to prevent junction damage above safe operating temperature. |
Pinout & Package
LM5019SDX/NOPB is supplied in an 8-pin SO PowerPAD package (4.89 mm × 3.90 mm) with exposed thermal pad connected to RTN. The PowerPAD enhances thermal performance (RθJA = 41.1°C/W) and requires PCB copper area for heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 RTN | Ground reference | Common return path for internal circuits and exposed PowerPAD; must be low-impedance connection to system ground plane. |
| 2 VIN | Main input supply | Accepts 7.5–100 V DC; powers internal VCC regulator and high-voltage gate drivers directly. |
| 3 UVLO | Undervoltage detection input | Resistor-divider programmable start-up threshold (1.225 V) and hysteresis; pulling below 0.66 V forces shutdown mode. |
| 4 RON | On-time programming | Resistor-to-VIN sets switch on-time inversely proportional to VIN; minimum 100 ns required at max VIN for stability. |
| 5 FB | Feedback input | Compares output voltage (via resistor 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 sourcing up to 26 mA; powers internal logic and gate drivers; UVLO at 4.5 V. |
| 7 BST | Bootstrap supply | Connects to external 0.01-μF ceramic capacitor between BST and SW; charged from VCC during SW low phase. |
| 8 SW | Switching node | Drives external inductor; connects to BST capacitor and output filter; handles full input-to-output voltage transitions. |
Key Features
| Feature | Design Value |
|---|---|
| No external Schottky diode required | Integrated synchronous rectifier eliminates conduction loss and thermal management burden of discrete diodes in buck topology. |
| Constant-on-time (COT) control | Enables ultra-fast transient response and stable operation without compensation network-reducing BOM count and layout complexity. |
| Programmable undervoltage lockout | Independent threshold and hysteresis setting via UVLO pin divider allows tailored brown-in/brown-out behavior for system-level sequencing. |
| Intelligent peak current limit | Off-time scales with FB voltage-shorter recovery during moderate overloads, longer hold-off during shorts-improving reliability and startup robustness. |
| Isolated Fly-Buck™ capability | Supports transformer-coupled secondary outputs without optocoupler or auxiliary winding-enabling compact isolated bias generation. |
Applications
| Smart Power Meters | Telecom Power Systems |
|---|---|
Use Scenario: Generating isolated 3.3-V or 5-V bias rails from 100-V DC distribution lines in utility-grade meters. IC Role / Device Role / Timing Role: Primary synchronous buck controller implementing Fly-Buck™ topology with transformer-coupled secondary output. Use Value: Eliminates need for optocouplers or auxiliary windings while maintaining >85% efficiency at 50-mA load and meeting IEC 62053 creepage requirements. |
Use Scenario: Providing regulated 12-V bias for PoE controllers and line-card supervisors in 48-V telecom infrastructure. IC Role / Device Role / Timing Role: High-input-voltage step-down regulator with fast transient response to handle burst-mode Ethernet traffic loads. Use Value: Delivers stable output under 10-A input transients with <10-μs recovery due to COT architecture and 1.225-V reference accuracy. |
| Automotive Body Control Modules | Industrial Isolated Sensors |
Use Scenario: Converting 12–60-V battery-supplied rail to 5-V microcontroller supply in under-hood ECUs subject to load dump. IC Role / Device Role / Timing Role: Input-tolerant buck regulator with 100-V absolute maximum rating and thermal shutdown for fault containment. Use Value: Survives ISO 7637-2 Pulse 5a (120-V/100-ms) without external TVS, reducing component count and board space. |
Use Scenario: Powering isolated analog front-ends in current-sensing modules requiring galvanic separation from main HV bus. IC Role / Device Role / Timing Role: Fly-Buck™ controller generating floating 3.3-V supply referenced to secondary ground via transformer coupling. Use Value: Achieves >4 kV RMS isolation with single transformer and no optocoupler feedback-meeting IEC 61000-4-5 surge immunity standards. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5160QDGSRQ1 | 4.5–65-V input, 600-mA output, integrated 65-V high-side FET only (asynchronous); requires external sync rectifier. | Higher output current but narrower input range; lacks Fly-Buck™ support and internal synchronous rectifier. | Select when >100-mA load current is needed and isolation is not required; verify external diode thermal design. |
| LM5017MRX/NOPB | Same 7.5–100-V input, but 600-mA output; uses voltage-mode control with full compensation network required. | Higher power capability and fixed-frequency operation, but increased design complexity and slower transient response than COT. | Choose for higher-current non-isolated applications where predictable EMI profile and loop stability verification are prioritized. |
Compared with LM5019SDX/NOPB, LM5160QDGSRQ1 offers greater output current but sacrifices Fly-Buck™ capability and synchronous rectification, while LM5017MRX/NOPB delivers higher power with voltage-mode control-requiring compensation design effort and yielding slower load-step response than the LM5019SDX/NOPB's inherent COT advantages.
Availability
LM5019SDX/NOPB is available at Aetrix Electronics and suitable for smart metering, telecom power conversion, and automotive body electronics requiring stable component supply, long-term lifecycle support, and qualified high-voltage DC-DC regulation.
Supply support for LM5019SDX/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, embedded processing, and connectivity solutions with emphasis on reliability, energy efficiency, and system integration.
The LM5019SDX/NOPB belongs to TI's high-voltage DC-DC regulator product line, engineered specifically for cost-sensitive, space-constrained applications needing wide-input-range buck or isolated Fly-Buck™ conversion without external diodes or compensation networks.
FAQ
What is the recommended minimum on-time for stable operation of the LM5019SDX/NOPB?
The LM5019SDX/NOPB requires a minimum on-time of 100 ns at maximum input voltage (100 V) to ensure proper COT timing and stable regulation. This is enforced by selecting RON such that TON = (10−10 × RON) / VIN ≥ 100 ns. For example, at 100 V, RON must be ≥ 100 kΩ. Violating this causes erratic switching and potential loss of regulation in the LM5019SDX/NOPB.
Can the LM5019SDX/NOPB operate in Fly-Buck™ mode without optocoupler feedback?
Yes-the LM5019SDX/NOPB supports transformer-coupled Fly-Buck™ operation using primary-side regulation only. It regulates based on reflected output voltage sampled at the FB pin through the transformer turns ratio, eliminating need for optocouplers or secondary-side sensing. This is validated in TI's SNVA166 application report and confirmed in the LM5019SDX/NOPB datasheet Figure 8-2.
How does the LM5019SDX/NOPB handle bootstrap capacitor charging at light loads?
The LM5019SDX/NOPB guarantees bootstrap capacitor recharge via its 144-ns minimum off-time, which remains active regardless of load. During light-load CCM operation, the SW node goes low long enough each cycle for the internal VCC-to-BST diode to replenish the 0.01-μF BST capacitor. This ensures gate drive integrity even at 1-mA output currents-confirmed in Section 7.3.7 of the LM5019SDX/NOPB datasheet.
What is the purpose of the RC resistor in the feedback network of the LM5019SDX/NOPB?
The RC resistor in series with the output capacitor (COUT) generates resistive ripple at the FB pin required for stable COT operation. Since capacitive ripple is out-of-phase with inductor current, RC ensures ≥25 mV of in-phase ripple at FB-suppressing noise-induced multiple on-time bursts. Its value is selected so RC × gsw × (RFB1∥RFB2) > 25 mV, as specified in LM5019SDX/NOPB Application Note SNVA166.
Does the LM5019SDX/NOPB require external compensation components?
No-the LM5019SDX/NOPB uses constant-on-time (COT) control with no external compensation required. Its regulation relies on feedback ripple timing rather than error amplifier loop stability. This eliminates compensation capacitors and resistors, simplifying design and improving transient response. All necessary control circuitry is fully integrated within the LM5019SDX/NOPB die.
LM5019SDX/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):
- 100V
- Voltage - Output (Min/Fixed):
- 1.225V
- Voltage - Output (Max):
- 90V
- Current - Output:
- 100mA
- 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)
LM5019SDX/NOPB FAQ
1.How can I place an order for LM5019SDX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5019SDX/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 LM5019SDX/NOPB reliable?
The price and inventory of LM5019SDX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5019SDX/NOPB is usually 5 days.
3.What payment methods are accepted for LM5019SDX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5019SDX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5019SDX/NOPB?
LM5019SDX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5019SDX/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 LM5019SDX/NOPB?
For technical support, including LM5019SDX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5019SDX/NOPB requirements.
6.How does Aetrix verify that LM5019SDX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM5019SDX/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 LM5019SDX/NOPB meets industry standards.
7.What is the process for return or replacement of LM5019SDX/NOPB?
All LM5019SDX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM5019SDX/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 LM5019SDX/NOPB part is unused and in its original packaging.
Return procedure for LM5019SDX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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