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Texas Instruments LM34914SDX/NOPB
- Part No.:
- LM34914SDX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LM34914SDX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 1.25A 10WSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,374
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Product details
Overview
LM34914SDX/NOPB from Texas Instruments is an ultra-small, 1.25A step-down switching regulator with integrated 44V N-channel buck switch, valley current limiting, and constant on-time control. It operates from 8V to 40V input, delivers adjustable output voltage (via FB pin), and achieves up to 95% efficiency in high-voltage POL applications such as industrial power supplies and automotive post-regulators.
For engineers reviewing the LM34914SDX/NOPB datasheet, LM34914SDX/NOPB pinout, LM34914SDX/NOPB application, or LM34914SDX/NOPB equivalent, key selection considerations include its programmable soft-start, no-loop-compensation architecture, thermal shutdown at 175°C, and WSON-10 (3 mm × 3 mm) thermally enhanced package with exposed pad.
Technical Context
The LM34914SDX/NOPB employs a constant on-time (COT) control scheme where tON scales inversely with VIN via external RON resistor, enabling near-constant switching frequency (up to 1.3 MHz) across line and load variations. Its valley current limit threshold dynamically adjusts with both VIN and VOUT to prevent inductor saturation under high-line/high-load conditions.
Feedback regulation uses a precision 2.50V internal reference with overvoltage protection at 2.9V, while startup is managed by an integrated 7.0V regulator (VCC) with UVLO at 5.7V. Current sensing occurs during off-time via ISEN/SGND path, and shutdown is controlled through the RON/SD pin with 0.8V rising-edge threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8.0V to 40V - supports wide-range industrial and automotive inputs without pre-regulation. |
| Output Current | 1.25A continuous - rated for sustained load delivery with thermal derating above 125°C junction. |
| Switch RDS(on) | 0.33Ω typical - minimizes conduction loss in high-current buck stage. |
| Switching Frequency | Up to 1.3 MHz - enables compact magnetics and fast transient response without external compensation. |
| FB Reference Voltage | 2.50V ±1.8% - sets precise output voltage via resistive divider (VOUT = 2.5 × (R1+R2)/R2). |
| Valley Current Limit | 0.9A–1.4A range - varies with VIN/VOUT to reduce peak inductor current during overload or saturation risk. |
| Soft-Start Time | Programmable via SS capacitor - internal 12.5µA current source charges external cap to 2.5V for controlled ramp-up. |
| Thermal Shutdown | 175°C with 20°C hysteresis - protects against catastrophic failure; resumes operation at ~155°C. |
Pinout & Package
LM34914SDX/NOPB is housed in a thermally enhanced 10-pin WSON package (3 mm × 3 mm) with exposed thermal pad (EP) for PCB ground connection. The package supports high-power density designs with low θJA of 30°C/W (4-layer board, 4 vias).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 SW | Switching Node | Connects to inductor, diode cathode, and BST capacitor - carries high-frequency AC current and must be routed with minimal loop area. |
| 2 BST | Bootstrap Supply | Charges external 0.022µF capacitor from VCC during off-time to drive high-side gate. |
| 3 ISEN | Current Sense Input | Senses recirculating inductor current during off-time to enable valley current limiting. |
| 4 SGND | Sense Ground | Return path for current sense resistor - separate from RTN to avoid noise coupling into regulation loop. |
| 5 RTN | Circuit Ground | Reference for internal comparators and bias circuits - connects to system ground plane near EP. |
| 6 FB | Feedback Input | Compares output voltage (via resistor divider) to 2.5V reference - determines regulation setpoint and triggers overvoltage shutdown at 2.9V. |
| 7 SS | Soft-Start Control | Internal 12.5µA current source ramps external capacitor to 2.5V - controls output voltage rise time and inrush current. |
| 8 RON/SD | On-Time Programming / Shutdown | Resistor-to-VIN sets tON; grounding shuts down regulator with <160µA quiescent current. |
| 9 VCC | Startup Regulator Output | 7.0V regulated supply for internal circuitry - can be externally powered (8V–14V) to reduce dissipation. |
| 10 VIN | Main Input Supply | Accepts 8V–40V input - powers internal regulator and buck switch; requires local 0.1µF ceramic bypass (C5). |
| EP | Exposed Thermal Pad | Internally connected to substrate - must be soldered to PCB ground plane with multiple vias for thermal management. |
Key Features
| Feature | Design Value |
|---|---|
| No loop compensation required | Constant on-time architecture eliminates external compensation network - reduces BOM count and layout sensitivity. |
| Ultra-fast transient response | Regulation recovers within microseconds after load step - enabled by COT control and absence of phase-margin constraints. |
| Intelligent valley current limit | Threshold adapts to VIN and VOUT - prevents inductor saturation while maintaining stable constant-current foldback behavior. |
| Integrated start-up regulator | VCC delivers 7.0V at up to 11mA - powers gate driver and control logic before main switch begins switching. |
| Programmable soft-start | SS pin accepts external capacitor - allows user-defined ramp time to prevent output overshoot and inrush stress. |
| Thermal shutdown with hysteresis | 175°C trip with 20°C hysteresis - ensures safe recovery without oscillation during thermal overload events. |
Applications
| Industrial Point-of-Load Regulation | Automotive High-Voltage Post-Regulation |
|---|---|
Use Scenario: Powering FPGA I/O banks or microcontroller cores from 24V rail in factory automation controllers. IC Role / Device Role / Timing Role: Primary non-isolated buck converter delivering stable 3.3V/1.25A with fast load transients. Use Value: Eliminates need for external compensation and reduces solution size by 40% vs. traditional current-mode controllers. | Use Scenario: Regulating 12V output from 28V vehicle battery system in ADAS camera modules. IC Role / Device Role / Timing Role: Secondary buck regulator providing clean, low-noise supply with thermal robustness in confined enclosures. Use Value: Valley current limiting prevents inductor saturation during cold-crank (low VOUT) and high-line (40V) conditions. |
| High-Efficiency Telecom Bias Supply | Programmable Power Module Core |
Use Scenario: Generating 5V/1.25A for optical transceiver bias in access network equipment. IC Role / Device Role / Timing Role: High-frequency (1.3 MHz) step-down regulator minimizing EMI and enabling small filter components. Use Value: Achieves >90% efficiency at full load across 8V–40V input range - reduces heat sink requirements. | Use Scenario: Core regulator in modular DC-DC power brick supporting configurable output voltages. IC Role / Device Role / Timing Role: Adjustable-output buck controller with programmable soft-start and shutdown interface. Use Value: RON/SD pin enables digital enable/disable; FB and SS pins support remote voltage programming and sequencing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QWRGRRQ1 | Wettable flank QFN-10, AEC-Q100 qualified, 3.5V–65V input, 1A output, integrated FET, but requires external compensation. | Targeted for automotive safety-critical systems requiring qualification and higher input voltage tolerance. | Choose when AEC-Q100 compliance and extended input range outweigh need for simplified design. |
| TPS54240DGQR | MSOP-10, 3.5V–42V input, 2A output, current-mode control, requires external compensation and has slower transient response. | Better suited for cost-sensitive industrial applications needing higher current and wider input range than LM34914SDX/NOPB. | Choose when higher output current and lower BOM cost are prioritized over ultra-fast transient performance. |
Compared with LM34914SDX/NOPB, LM5164QWRGRRQ1 adds automotive qualification and higher VIN rating but sacrifices loop simplicity, while TPS54240DGQR offers higher current and lower minimum VIN but requires compensation and delivers slower load-step recovery.
Availability
LM34914SDX/NOPB is available at Aetrix Electronics and suitable for industrial point-of-load regulation, automotive post-regulation, telecom bias supply, and programmable power module core applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM34914SDX/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 decades of expertise in high-reliability power conversion ICs.
The LM34914SDX/NOPB belongs to TI's high-voltage buck regulator product line, designed specifically for compact, high-efficiency, no-compensation POL solutions in space-constrained industrial and automotive systems.
FAQ
What is the maximum allowable input voltage for the LM34914SDX/NOPB?
The absolute maximum VIN to RTN rating for the LM34914SDX/NOPB is 44V, but the recommended operating range is 8.0V to 40V per datasheet specifications. Exceeding 40V may trigger overvoltage stress on internal components, and operation above 44V risks permanent damage. Always maintain ≥2V margin below 44V for reliability in transient-prone environments.
Does the LM34914SDX/NOPB require external compensation components?
No, the LM34914SDX/NOPB does not require external compensation components. Its constant on-time control architecture eliminates the need for loop compensation networks, simplifying design, reducing BOM count, and improving stability across line and load variations - a key differentiator versus traditional current-mode buck controllers.
How is the switching frequency set on the LM34914SDX/NOPB?
The switching frequency of the LM34914SDX/NOPB is determined by the external RON resistor and input voltage (VIN) using the formula: FS ≈ VOUT × (VIN − 1.5) / [1.15 × 10⁻¹⁰ × (RON + 1.4k) × VIN]. For example, with VIN = 12V, VOUT = 5V, and RON = 200kΩ, FS ≈ 275 kHz. Frequency remains nearly constant across load and VIN changes due to inverse VIN scaling of tON.
What is the purpose of the ISEN and SGND pins on the LM34914SDX/NOPB?
The ISEN pin senses recirculating inductor current during the off-time to implement valley current limiting, while SGND serves as the dedicated return path for the current-sense resistor - isolated from RTN to prevent noise from corrupting the regulation loop. This separation ensures accurate current detection and stable operation under high dI/dt conditions.
Can the LM34914SDX/NOPB be used with an external VCC supply?
Yes, the LM34914SDX/NOPB supports external powering of the VCC pin with 8V–14V, which bypasses the internal startup regulator and reduces thermal dissipation. When externally powered, the internal VCC regulator is disabled, and the device draws only gate drive and bias current - beneficial in high-input-voltage applications where internal VCC dropout would cause excessive self-heating.
LM34914SDX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 1.25A
- Frequency - Switching:
- 1.3MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-WSON (3x3)
LM34914SDX/NOPB FAQ
1.How can I place an order for LM34914SDX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM34914SDX/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 LM34914SDX/NOPB reliable?
The price and inventory of LM34914SDX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM34914SDX/NOPB is usually 5 days.
3.What payment methods are accepted for LM34914SDX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM34914SDX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM34914SDX/NOPB?
LM34914SDX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM34914SDX/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 LM34914SDX/NOPB?
For technical support, including LM34914SDX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM34914SDX/NOPB requirements.
6.How does Aetrix verify that LM34914SDX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM34914SDX/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 LM34914SDX/NOPB meets industry standards.
7.What is the process for return or replacement of LM34914SDX/NOPB?
All LM34914SDX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM34914SDX/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 LM34914SDX/NOPB part is unused and in its original packaging.
Return procedure for LM34914SDX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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