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Texas Instruments LM34910SDX/NOPB
- Part No.:
- LM34910SDX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 10-WDFN Exposed Pad
- Datasheet:
-
LM34910SDX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 1.25A 10WSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,694
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Product details
Overview
LM34910SDX/NOPB from Texas Instruments is a high-voltage, 40V N-channel buck switching regulator with integrated switch, delivering up to 1.25A output current. It operates from 8V to 36V input, features hysteretic control (no loop compensation), 2.5V internal reference, and valley current limiting at 1.25A - designed for point-of-load regulation in telecom and industrial power systems.
For engineers reviewing the LM34910SDX/NOPB datasheet, LM34910SDX/NOPB pinout, LM34910SDX/NOPB application, or LM34910SDX/NOPB equivalent, key selection criteria include input voltage range (8–36V), constant-frequency operation via RON-programmed on-time, thermal shutdown (175°C), WSON-10 package with exposed thermal pad, and softstart via external capacitor on SS pin.
Technical Context
The LM34910SDX/NOPB implements a hysteretic buck controller using an on-time timer whose duration varies inversely with VIN (e.g., 740 ns at 36V, 2.75 µs at 10V with 200 kΩ RON), enabling near-constant switching frequency across line and load. Regulation relies on feedback comparison against a precision 2.5V reference, with overvoltage protection triggered at 2.875V.
Current limiting occurs during off-time by sensing recirculating current through ISEN–SGND (130 mΩ internal sense resistance), holding the switch off until current falls below 1.25A. Startup uses an integrated 7V series regulator (VCC) with 5.8V UVLO, while gate drive employs a bootstrap circuit (BST–SW) requiring a 0.022 µF capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8.0 V to 36 V - supports wide-range industrial and telecom inputs; absolute max 40 V transient tolerance. |
| Output Current | 1.25 A - valley current limit set internally; peak switch current rated to 3.5 A. |
| Switch RDS(on) | 0.45 Ω (typ) - determines conduction loss and thermal rise under full load. |
| Feedback Reference | 2.5 V ±2% - sets output voltage via resistor divider (VOUT = 2.5 × (R1 + R2)/R2). |
| Operating Frequency | Constant vs. load & line - achieved via VIN-inverse on-time control; typical 100–730 kHz depending on RON and VIN. |
| Softstart Current | 11.5 µA - charges external SS capacitor linearly to 2.5 V for controlled output ramp-up. |
| Thermal Shutdown | 175 °C (typ), 20 °C hysteresis - disables switch and grounds SS pin to prevent damage during overload or poor heatsinking. |
Pinout & Package
LM34910SDX/NOPB is housed in a thermally enhanced 4 mm × 4 mm WSON-10 package (DPR) with exposed thermal pad for PCB heat dissipation. Pin 1 is SW (switching node); pin 10 is VIN. The package is RoHS-compliant, moisture sensitivity level (MSL) 1, and rated for −40°C to +125°C operating junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1) | Switching node | Connects to inductor, freewheeling diode, and BST capacitor; carries high di/dt pulsed current. |
| BST (2) | Bootstrap supply | Drives high-side gate via 0.022 µF capacitor to SW; internal diode recharges it each off-cycle. |
| ISEN (3) | Current sense input | Senses recirculating current from SGND; triggers 1.25A valley limit; internal 130 mΩ sense path. |
| SGND (4) | Sense ground | Return for current-sense path only; must be routed separately from RTN to avoid noise coupling. |
| RTN (5) | Circuit ground | Reference for internal logic, comparators, and regulation; connects to system ground plane. |
| FB (6) | Feedback input | Compares output voltage (via R1/R2 divider) to 2.5V reference; requires ≥25 mV ripple for stable hysteretic operation. |
| SS (7) | Softstart control | Internal 11.5 µA current source ramps voltage to 2.5V; grounded during UVLO, thermal shutdown, or shutdown. |
| RON/SD (8) | On-time programming & shutdown | Resistor to VIN sets on-time; grounding disables regulator and forces SS low. |
| VCC (9) | Startup regulator output | 7.0 V regulated output (6.6–7.4 V); powers internal circuits; can be externally biased (8–14 V) to reduce dissipation. |
| VIN (10) | Main input supply | Accepts 8–36 V; internal diode connects to VCC; absolute max 40 V. |
Key Features
| Feature | Design Value |
|---|---|
| No loop compensation required | Hysteretic control eliminates external compensation components, reducing BOM count and layout sensitivity. |
| Ultra-fast transient response | On-time timer reacts within nanoseconds to FB voltage drop, minimizing output droop during load steps. |
| Adjustable output voltage | Set precisely via external R1/R2 divider; regulation threshold fixed at 2.5 V with ±2% tolerance. |
| Integrated start-up regulator | VCC pin delivers regulated 7 V (9 mA limited) - enables direct connection to high-input rails without external bias supply. |
| Exposed thermal pad | WSON-10 package includes bottom-side copper pad soldered to PCB ground plane for enhanced thermal performance. |
Applications
| High Efficiency Point-of-Load (POL) Regulator | Non-Isolated Telecommunication Buck Regulator |
|---|---|
Use Scenario: Powering FPGA I/O banks or ASIC core rails in compact telecom line cards where space and efficiency are critical. IC Role / Device Role / Timing Role: Primary buck regulator converting 24 V backplane to 1.2 V or 3.3 V with minimal external components. Use Value: Delivers 1.25 A at >90% efficiency with no compensation network, reducing design cycle time and board area. | Use Scenario: Generating intermediate 5 V or 12 V rails from 48 V telecom distribution in base station subsystems. IC Role / Device Role / Timing Role: High-voltage step-down converter handling 40 V transients common in -48 V DC plant environments. Use Value: Withstands 40 V input surges and maintains regulation down to 8 V, ensuring robustness in noisy telecom infrastructure. |
| Secondary High Voltage Post Regulator | Industrial Control System Power Supply |
Use Scenario: Down-converting 24 V or 36 V industrial bus voltage to 5 V for microcontroller, sensor, and interface ICs. IC Role / Device Role / Timing Role: Secondary regulator following front-end AC/DC or isolated DC/DC stage, providing clean local power. Use Value: Integrated 40 V N-channel switch eliminates need for external MOSFET, simplifying bill of materials and improving reliability. | Use Scenario: Powering PLC modules, motor drivers, or fieldbus interfaces in factory automation equipment. IC Role / Device Role / Timing Role: Main 1.25 A DC-DC converter supplying isolated or non-isolated logic and analog circuitry. Use Value: Thermal shutdown (175°C) and current limiting protect against short-circuit faults in harsh industrial environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM34914SDX/NOPB | Same WSON-10 package, 40 V input, but higher 2 A current limit and 0.35 Ω RDS(on). | Supports heavier loads; requires revised inductor and output capacitor sizing for 2 A continuous operation. | Select when >1.25 A output current or lower conduction loss is required; pinout and control scheme are identical. |
| TPS54240DGQR | 40 V input, 2.5 A output, but uses current-mode PWM control (requires compensation) and SOIC-8 package. | Offers adjustable frequency and sync capability; lacks integrated BST diode and requires external bootstrap components. | Choose for designs needing synchronization or tighter output voltage accuracy; not drop-in due to different pinout and compensation requirements. |
Compared with LM34910SDX/NOPB, LM34914SDX/NOPB provides higher current capacity in identical footprint, while TPS54240DGQR trades hysteretic simplicity for greater flexibility in frequency control and loop tuning - making LM34910SDX/NOPB optimal for cost-sensitive, fast-transient POL applications where minimal external parts are prioritized.
Availability
LM34910SDX/NOPB is available at Aetrix Electronics and suitable for high-efficiency point-of-load regulation, telecom secondary power conversion, and industrial control system power supplies requiring stable component supply and long-term manufacturability.
Supply support for LM34910SDX/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 LM34910SDX/NOPB belongs to TI's high-voltage buck regulator product line, engineered for efficient, low-component-count DC-DC conversion in telecom, industrial, and automotive auxiliary power applications.
FAQ
What is the maximum input voltage rating for the LM34910SDX/NOPB?
The LM34910SDX/NOPB has an absolute maximum input voltage rating of 40 V, with recommended operating range from 8.0 V to 36 V. Exceeding 40 V may cause permanent damage. Transient spikes up to 40 V are tolerated per datasheet specifications, but sustained operation above 36 V is not advised. The VIN pin also connects internally to the VCC regulator via a diode, influencing startup behavior under marginal input conditions.
How does the LM34910SDX/NOPB achieve constant switching frequency despite varying input voltage and load?
The LM34910SDX/NOPB achieves near-constant frequency through its hysteretic on-time control architecture: the on-time duration is inversely proportional to VIN (e.g., shorter on-time at higher VIN), while minimum off-time is fixed at 280 ns. This compensates for line and load variations, maintaining stable operation between ~100 kHz and 730 kHz depending on RON value and input voltage - eliminating need for traditional PWM frequency compensation networks.
Can the LM34910SDX/NOPB be used without an external bootstrap capacitor?
No - the LM34910SDX/NOPB requires a 0.022 µF ceramic capacitor between BST and SW pins to sustain gate drive for the integrated N-channel buck switch. This capacitor is charged via an internal diode during the off-time from VCC. Omitting it prevents proper high-side gate turn-on, resulting in no switching action or immediate failure. TI specifies X7R or better dielectric and low-ESR construction for reliable recharge.
What is the purpose of the ISEN and SGND pins on the LM34910SDX/NOPB, and how should they be routed?
The ISEN pin senses recirculating current during off-time to implement valley current limiting at 1.25 A, while SGND serves as the dedicated return path for that current sense path. These pins must be connected through a Kelvin sense configuration: SGND and ISEN should route directly to opposite ends of the same low-inductance, low-resistance PCB trace or dedicated sense resistor (not shared with RTN). Improper routing introduces noise or offset, causing premature current limiting or instability.
Does the LM34910SDX/NOPB require output capacitor ESR for stable operation, and why?
Yes - the LM34910SDX/NOPB requires ≥25 mVp-p ripple voltage at the FB pin for reliable hysteretic regulation. Since FB monitors output voltage via a resistor divider, this necessitates sufficient ESR in the output capacitor (C2) - or addition of series resistor R3 - to generate the required ripple from inductor current. Low-ESR ceramic capacitors alone often fail to meet this; insufficient ripple causes erratic switching or failure to regulate. TI recommends calculating minimum ESR based on load current and divider ratio.
LM34910SDX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-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):
- 8V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 33V
- Current - Output:
- 1.25A
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-WSON (4x4)
LM34910SDX/NOPB FAQ
1.How can I place an order for LM34910SDX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM34910SDX/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 LM34910SDX/NOPB reliable?
The price and inventory of LM34910SDX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM34910SDX/NOPB is usually 5 days.
3.What payment methods are accepted for LM34910SDX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM34910SDX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM34910SDX/NOPB?
LM34910SDX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM34910SDX/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 LM34910SDX/NOPB?
For technical support, including LM34910SDX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM34910SDX/NOPB requirements.
6.How does Aetrix verify that LM34910SDX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM34910SDX/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 LM34910SDX/NOPB meets industry standards.
7.What is the process for return or replacement of LM34910SDX/NOPB?
All LM34910SDX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM34910SDX/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 LM34910SDX/NOPB part is unused and in its original packaging.
Return procedure for LM34910SDX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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