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Texas Instruments LM34910SD
- Part No.:
- LM34910SD
- Manufacturer:
- Texas Instruments
- Package:
- 10-WDFN Exposed Pad
- Datasheet:
-
LM34910SD.pdf
- Description:
- IC REG BUCK ADJ 1.25A 10WSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,656
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Product details
Overview
LM34910SD 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, uses hysteretic control with no loop compensation, and features valley current limiting at 1.25A, 2.5V internal reference, and WSON-10 thermal-enhanced package. It targets point-of-load regulation in telecom and industrial power systems.
For engineers reviewing the LM34910SD datasheet, LM34910SD pinout, LM34910SD application, or LM34910SD equivalent, key selection criteria include input voltage range (8–36V), fixed 2.5V feedback threshold, 1.25A valley current limit, on-time programmability via RON resistor, and thermal shutdown at 175°C - all critical for robust high-voltage DC-DC design.
Technical Context
The LM34910SD implements a hysteretic buck controller with inverse VIN-dependent on-time timing, enabling near-constant switching frequency across line and load variations. Its regulation relies on comparing FB voltage to a precision 2.5V internal reference, while over-voltage protection triggers at 2.875V.
Current limiting occurs during off-time by sensing recirculating current at ISEN relative to SGND, with threshold set at 1.25A and response time of 150 ns. Startup is managed by an integrated 7.0V start-up regulator (VCC), which enables operation only after reaching 5.8V UVLO threshold and provides gate drive bias.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8.0 V to 36 V - supports wide industrial and telecom supply rails; absolute max 40 V transient tolerance. |
| Output Current Capability | 1.25 A valley current limit - defines maximum sustainable load before cycle-by-cycle current limiting engages. |
| Feedback Reference | 2.5 V ±60 mV - sets regulated output via external resistor divider; enables precise adjustable VOUT configurations. |
| Switch RDS(on) | 0.45 Ω typical - determines conduction loss and thermal rise under full load; measured at 200 mA test current. |
| Thermal Shutdown | 175 °C activation with 20 °C hysteresis - protects die integrity during overload or poor heatsinking; resumes at ≈155 °C. |
| Softstart Current Source | 11.5 µA - charges external SS capacitor linearly to 2.5 V, controlling ramp rate of output voltage during startup. |
| Minimum Off-Time | 280 ns - ensures sufficient time for BST capacitor recharge and guarantees stable operation at high frequencies. |
Pinout & Package
LM34910SD is housed in a thermally enhanced 4 mm × 4 mm WSON-10 package with exposed thermal pad (DPR suffix), rated for −40°C to +125°C operating junction temperature and compliant with Level-1 MSL reflow profile.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Switching Node | Connection to inductor, freewheeling diode, and BST capacitor; carries high di/dt pulsed current. |
| BST | Bootstrap Supply | Drives high-side gate via 0.022 µF capacitor to SW; internal diode recharges it each off-cycle. |
| ISEN | Current Sense Input | Senses recirculating current during off-time; 1.25A threshold triggers current limiting. |
| SGND | Sense Ground | Return path for current sense resistor; must be routed separately from RTN to avoid noise coupling. |
| RTN | Circuit Ground | Reference for internal comparators and logic; connects to system ground plane but isolated from power return paths. |
| FB | Feedback Input | Compares output-derived voltage to 2.5V reference; requires ≥25 mV ripple for stable hysteretic operation. |
| SS | Softstart Control | Internal 11.5 µA current source ramps voltage to 2.5V; grounded during UVLO, thermal shutdown, or SD assertion. |
| RON/SD | On-Time Set / Shutdown | Resistor-to-VIN sets on-time; grounding disables regulator and forces SS low. |
| VCC | Start-Up Regulator Output | 7.0V ±0.4V regulated supply for internal circuitry; can be externally biased (8–14V) to reduce dissipation. |
| VIN | Main Input Supply | Primary power input (8–36V); powers start-up regulator and supplies energy to buck stage via SW node. |
Key Features
| Feature | Design Value |
|---|---|
| No loop compensation required | Hysteretic control eliminates external compensation network - reduces BOM count and layout sensitivity. |
| Ultra-fast transient response | On-time control and comparator-based regulation enable sub-microsecond load step recovery without phase-margin tuning. |
| Adjustable output voltage | 2.5V feedback reference allows precise VOUT setting via R1/R2 divider - supports 2.5V to >30V outputs with proper component selection. |
| Integrated 40V N-channel buck switch | Eliminates external MOSFET and driver - simplifies design, improves efficiency, and reduces footprint in space-constrained POL applications. |
| Exposed thermal pad (WSON-10) | Enables direct solder connection to PCB ground plane - lowers thermal resistance and sustains 1.25A continuous output under 60°C ambient. |
Applications
| Telecom Secondary Post-Regulator | Industrial Point-of-Load Converter |
|---|---|
Use Scenario: Regulating 48V telecom bus down to 3.3V/5V for FPGA I/O or DSP core supplies in base station equipment. IC Role / Device Role / Timing Role: Primary buck controller managing high-efficiency, high-reliability local DC-DC conversion with fast transient immunity. Use Value: 1.25A current capability and 36V max input support direct use on -48V nominal telecom rails; thermal shutdown prevents field failure under sustained overload. | Use Scenario: Powering PLC I/O modules or sensor signal chains from 24V industrial bus with tight voltage tolerance requirements. IC Role / Device Role / Timing Role: Standalone step-down regulator delivering stable, low-noise bias voltage with minimal external components. Use Value: No-loop-compensation architecture ensures stability across temperature and aging; 2.5V reference enables accurate 3.3V/5V/12V outputs using standard resistor values. |
| High-Voltage Automotive Subsystem Supply | Test Equipment Auxiliary Rail Generator |
Use Scenario: Generating 5V auxiliary rail from 12V/24V vehicle battery in infotainment head units or ADAS camera modules. IC Role / Device Role / Timing Role: High-input-voltage buck regulator handling cold-crank (6V) to load-dump (40V) transients without external protection. Use Value: 40V switch rating and 8–36V operating range cover automotive transients; valley current limit prevents MOSFET overstress during short-circuit events. | Use Scenario: Providing clean, adjustable bias voltage for op-amp test fixtures or calibration reference circuits in bench instrumentation. IC Role / Device Role / Timing Role: Programmable-output regulator with softstart and shutdown control for sequenced power-up in multi-rail test systems. Use Value: RON/SD pin enables remote enable/disable; SS pin allows controlled ramp rate to prevent inrush into capacitive DUT loads. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QDDARQ1 | Automotive-grade (AEC-Q100), 100V input, 0.6A output, current-mode control requiring compensation. | Designed for automotive front-end supplies; higher voltage rating but lower current and added complexity. | Choose when automotive qualification, >36V input, or tighter EMI control via fixed-frequency operation is required. |
| TPS54202DDCR | 2.5–17V input, 2A output, integrated FETs, current-mode control with internal compensation. | Optimized for low-voltage, high-current POL; lacks high-voltage capability and valley current limiting. | Prefer when input is ≤17V and higher output current (2A) is needed without sacrificing integration or thermal performance. |
Compared with LM5164QDDARQ1 and TPS54202DDCR, the LM34910SD offers unique value in 8–36V industrial/telecom applications requiring 1.25A output with zero-compensation simplicity, fast transient response, and proven thermal reliability in WSON-10 - without automotive overhead or low-input limitations.
Availability
LM34910SD is available at Aetrix Electronics and suitable for telecom secondary regulation, industrial point-of-load conversion, and high-voltage automotive subsystem supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM34910SD 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 LM34910SD belongs to TI's high-voltage buck regulator product line, engineered for efficient, compact, and robust DC-DC conversion in telecom infrastructure, industrial automation, and transportation systems where input transients and thermal constraints demand rugged integration.
FAQ
What is the maximum input voltage the LM34910SD can withstand?
The LM34910SD has an absolute maximum VIN rating of 40V, with guaranteed operation from 8.0V to 36V. This makes it suitable for applications exposed to telecom line transients or automotive load-dump conditions. The integrated 40V N-channel buck switch and internal protection circuits ensure reliable operation within this range. Always observe derating guidelines and thermal management when operating near absolute maximum ratings in the LM34910SD design.
Does the LM34910SD require external compensation components?
No, the LM34910SD uses a hysteretic control architecture that eliminates the need for external loop compensation components. Its regulation relies on comparing the FB pin voltage to a 2.5V internal reference and initiating fixed on-times based on VIN and RON. This simplifies design, reduces bill-of-materials cost, and improves transient response - a key differentiator versus current-mode or voltage-mode controllers. The LM34910SD achieves stable operation without any compensation network.
How is output voltage adjusted on the LM34910SD?
Output voltage is set using an external resistor divider connected between VOUT, FB, and RTN. The LM34910SD regulates the FB pin to 2.5V, so VOUT = 2.5 × (R1 + R2) / R2, where R1 connects from VOUT to FB and R2 from FB to RTN. Standard 1–10 kΩ resistors are recommended. The LM34910SD requires ≥25 mV peak-to-peak ripple at FB for proper hysteretic operation, often achieved via C2 ESR or added R3.
What is the purpose of the RON/SD pin on the LM34910SD?
The RON/SD pin serves dual functions: it sets the on-time via an external resistor to VIN (determining operating frequency), and acts as a shutdown input - pulling it below 0.65V disables the LM34910SD, grounds the SS pin, and reduces quiescent current to ≤250 µA. This enables both programmable frequency control and system-level power sequencing. The LM34910SD's RON/SD pin thus integrates timing and enable functionality in a single terminal.
Can the LM34910SD operate without an external bootstrap capacitor?
No - the LM34910SD requires a 0.022 µF ceramic capacitor between BST and SW pins to sustain high-side gate drive. This capacitor is charged through an internal diode from VCC during the off-time and supplies gate charge during the on-time. Omitting it causes gate drive failure and immediate malfunction. The LM34910SD datasheet specifies C4 = 0.022 µF as mandatory; deviation risks unreliable switching or device damage due to insufficient gate voltage.
LM34910SD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-WDFN 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):
- 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)
LM34910SD FAQ
1.How can I place an order for LM34910SD through Aetrix?
Please submit a Request for Quotation (RFQ) for LM34910SD 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 LM34910SD reliable?
The price and inventory of LM34910SD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM34910SD is usually 5 days.
3.What payment methods are accepted for LM34910SD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM34910SD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM34910SD?
LM34910SD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM34910SD 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 LM34910SD?
For technical support, including LM34910SD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM34910SD requirements.
6.How does Aetrix verify that LM34910SD is sourced from the original manufacturer or authorized distributors?
All LM34910SD 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 LM34910SD meets industry standards.
7.What is the process for return or replacement of LM34910SD?
All LM34910SD units undergo pre-shipment inspection (PSI). If there is an issue with LM34910SD, 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 LM34910SD part is unused and in its original packaging.
Return procedure for LM34910SD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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