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Texas Instruments LM34917ATL/NOPB
- Part No.:
- LM34917ATL/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 12-WFBGA
- Datasheet:
-
LM34917ATL/NOPB.pdf
- Description:
- IC REG BUCK ADJ 1.25A 12DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:250
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Product details
Overview
LM34917ATL/NOPB from Texas Instruments is a constant on-time, 8V–33V input, 1.25A synchronous buck switching regulator with integrated N-channel MOSFET, valley current limiting, and programmable soft-start. It delivers high-efficiency point-of-load regulation in ultra-small 12-bump DSBGA (YZR0012UNA) package for space-constrained industrial and telecom power supplies.
For engineers reviewing the LM34917ATL/NOPB datasheet, LM34917ATL/NOPB pinout, LM34917ATL/NOPB application, or LM34917ATL/NOPB equivalent, key selection criteria include its VIN range (8–33V), valley current limit scaling with VIN/VOUT, 2 MHz max switching frequency, no-loop-compensation architecture, and intelligent shutdown features including input over-voltage (34.8V) and thermal protection.
Technical Context
The LM34917ATL/NOPB employs a constant on-time control scheme where tON ∝ 1/VIN, enabling near-constant switching frequency across line and load variations. Its valley current limit threshold dynamically adjusts with both VIN and feedback voltage (VFB), preventing inductor saturation under high-line/high-load conditions.
Operation integrates an internal 7.0V startup regulator, bootstrap gate drive (BST–SW capacitor = 0.022 µF), and cycle-by-cycle on-time reduction (~50%) during current limit detection. The FB pin regulates to 2.50V ±50 mV and triggers over-voltage shutdown at 2.9V, while RON/SD enables remote shutdown via sub-0.65V assertion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8.0V to 33V operating; 34.8V over-voltage shutdown threshold ensures robustness against transient surges. |
| Output Current Capability | 1.25A continuous load current; peak switch current limited to 2A with valley current limit scaling per VIN/VOUT. |
| Switching Frequency | Up to 2 MHz; frequency remains stable across load and input voltage due to inverse VIN–tON relationship. |
| Feedback Reference | 2.50V ±50 mV internal reference at FB pin; enables precise output voltage setting via external resistor divider. |
| Current Limit Threshold | 1.05–1.55A range (VIN=8–30V, VFB=2.4V); varies with input/output to prevent inductor saturation and reduce peak currents. |
| Soft-Start Control | Internal 11.6 µA current source charges external SS capacitor to 2.5V; enables controlled ramp-up of VOUT and limits inrush. |
| Package | 12-bump DSBGA (YZR0012UNA); 1.5 mm × 1.5 mm footprint with 0.4 mm pitch supports ultra-dense PCB layouts. |
Pinout & Package
LM34917ATL/NOPB uses a 12-bump DSBGA package (Package Number YZR0012UNA), measuring 1.5 mm × 1.5 mm with 0.4 mm bump pitch. Thermal resistance θJA is 58°C/W (0 LFPM air flow). Bump-side layout follows standard DSBGA orientation with SGND, RTN, FB, ISEN, RON/SD, SS, VIN, VCC, BST, and SW terminals.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1: SGND | Sense ground | Carries recirculating current to external sense resistor; must be routed separately from power ground to avoid noise coupling into current limit path. |
| A2: RTN | Circuit ground | Reference for all internal circuitry except current sensing; connects to system ground plane with low-impedance path. |
| A3: FB | Feedback input | Monitors regulated output via resistor divider; internal 2.5V comparator sets regulation point and triggers OVP at 2.9V. |
| B1: ISEN | Current sense output | Outputs recirculating inductor current during off-time; used by internal valley current comparator for adaptive current limiting. |
| B2: RON/SD | On-time programming / shutdown | External resistor to VIN sets tON; grounding this pin disables regulator and discharges SS capacitor. |
| B3: SS | Soft-start capacitor node | Charged by internal 11.6 µA current source to 2.5V; controls VOUT ramp rate and prevents inrush stress. |
| C1,C2: VIN | Main input supply | Accepts 8–33V DC; supports transient up to 50V; requires local 0.1 µF ceramic bypass to RTN. |
| C3: VCC | Startup regulator output | Nominally 7.0V; powers internal bias circuits; can accept external 8–14V supply to reduce dissipation. |
| D1,D2: SW | Switching node | Connects to inductor, freewheeling diode, and BST capacitor; carries high dI/dt switching current. |
| D3: BST | Bootstrap capacitor connection | Connected to SW via 0.022 µF capacitor; supplies gate drive voltage for high-side N-MOSFET during on-time. |
Key Features
| Feature | Design Value |
|---|---|
| No loop compensation required | Constant on-time architecture eliminates external compensation components, simplifying design and improving transient response. |
| Valley current limit scaling | Threshold adapts to VIN and VOUT to maintain safe peak inductor current across full operating range without foldback. |
| Intelligent on-time reduction in current limit | Reduces tON by ~50% cycle-by-cycle when current limit is active, lowering peak current and enabling smooth constant-current mode. |
| Integrated start-up regulator | Generates stable 7.0V VCC from VIN ≥9V, eliminating need for external bias supply and enabling single-rail operation. |
| Input over-voltage shutdown | Disables switching at ≈34.8V VIN to protect downstream components; resumes automatically when VIN falls below threshold. |
Applications
| High-Efficiency Point-of-Load (POL) Regulator | Non-Isolated Buck Regulator |
|---|---|
Use Scenario: Powering FPGA core voltage rails in compact telecom baseband cards where board area is constrained and efficiency >90% is required at 1–1.25A loads. IC Role / Device Role / Timing Role: Primary buck controller delivering regulated 1.2V or 1.8V from 12V intermediate bus; manages switching, current sensing, and soft-start autonomously. Use Value: Enables 1.5 mm × 1.5 mm DSBGA footprint and 2 MHz operation to minimize output capacitance and inductor size while maintaining fast load transient response. | Use Scenario: Generating 5V/1.25A from 24V industrial PLC backplane for microcontroller and I/O peripherals. IC Role / Device Role / Timing Role: Standalone non-isolated step-down converter with integrated MOSFET; handles input transients up to 50V and provides thermal/over-voltage protection. Use Value: Eliminates need for external high-voltage MOSFET and gate driver; valley current limiting prevents inductor saturation during short-circuit events. |
| Secondary High-Voltage Post Regulator | Compact Telecom DC-DC Module |
Use Scenario: Down-converting 48V intermediate bus to 3.3V for Ethernet PHYs in small-form-factor switches where EMI and thermal density are critical. IC Role / Device Role / Timing Role: Secondary-stage buck regulator accepting wide-input rail; implements constant on-time control to maintain stable frequency despite 48V ±10% variation. Use Value: Delivers ultra-fast transient response without compensation, reducing output voltage deviation during burst-mode Ethernet traffic. | Use Scenario: Embedded power module in 5G small-cell radio units requiring minimal footprint, high reliability, and support for 8–33V input from diverse power sources. IC Role / Device Role / Timing Role: Fully integrated buck controller with intelligent shutdown (OVP, thermal, UVLO) and programmable soft-start for seamless integration into modular designs. Use Value: Reduces bill-of-materials count by integrating startup regulator, gate driver, and current sense amplifier - validated for -40°C to +125°C junction operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QPWPRQ1 | 4.5–65V input, 1.5A, adjustable frequency (100kHz–2.2MHz), requires external MOSFETs and compensation. | Automotive AEC-Q100 qualified; suited for harsh environments but larger solution size and higher design complexity. | Select when input exceeds 33V or automotive qualification is mandatory; not drop-in due to different topology and pinout. |
| TPS54202DDCR | 4.5–28V input, 2A, integrated FETs, current-mode control, requires compensation network. | Lower VIN range and fixed 2A rating; optimized for cost-sensitive consumer applications rather than high-voltage industrial use. | Choose for ≤28V systems needing higher current; LM34917ATL/NOPB remains preferred for 30–33V operation and superior transient response. |
Compared with LM5164QPWPRQ1 and TPS54202DDCR, the LM34917ATL/NOPB uniquely combines 33V max input, valley current limiting with VIN/VOUT scaling, and no-loop-compensation operation in a 1.5 mm × 1.5 mm DSBGA - offering smallest footprint and fastest transient response for 8–33V POL applications.
Availability
LM34917ATL/NOPB is available at Aetrix Electronics and suitable for high-efficiency point-of-load regulation, non-isolated buck conversion, and secondary high-voltage post-regulation requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for LM34917ATL/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 LM34917A product line delivers ultra-small, high-voltage buck regulators targeting space-constrained industrial, telecom, and test equipment where input ranges exceed 24V and board area is at a premium.
FAQ
What is the maximum input voltage the LM34917ATL/NOPB can withstand without damage?
The LM34917ATL/NOPB has an absolute maximum VIN-to-RTN rating of 50V for transient conditions, with built-in input over-voltage shutdown activating at ≈34.8V to halt switching and protect downstream circuitry. Continuous operation is rated from 8.0V to 33V. Exceeding 33V continuously risks triggering shutdown or exceeding thermal limits, so design margins should keep steady-state VIN ≤33V.
How does the valley current limit in the LM34917ATL/NOPB adapt to different input and output voltages?
The LM34917ATL/NOPB's valley current limit threshold changes with both VIN and VFB (which reflects VOUT), as documented in the "Valley Current Limit Threshold vs. VFB and VIN" graph. At VIN = 8V and VFB = 2.4V, the limit is 1.35A (typ); at VIN = 30V and same VFB, it drops to 1.2A (typ). This scaling reduces peak inductor current under high-line/high-load conditions, preventing saturation without foldback behavior.
Can the LM34917ATL/NOPB operate without an external bootstrap capacitor?
No - the LM34917ATL/NOPB requires a 0.022 µF ceramic capacitor between BST and SW pins to supply gate drive voltage for its integrated N-channel buck switch. Without this capacitor, the high-side MOSFET cannot turn on properly, resulting in failure to regulate. TI specifies C4 = 0.022 µF with low ESR and placement adjacent to BST/SW bumps for reliable bootstrapping.
What is the purpose of the ISEN pin on the LM34917ATL/NOPB, and how is it connected?
The ISEN pin on the LM34917ATL/NOPB senses recirculating inductor current during the off-time to implement valley current limiting. It connects externally to the cathode of the freewheeling Schottky diode (D1), allowing current to flow out of ISEN through D1 to the inductor. This path enables accurate valley detection independent of switch conduction losses, ensuring precise current limiting across temperature and process variations.
Does the LM34917ATL/NOPB require external loop compensation components?
No - the LM34917ATL/NOPB uses a constant on-time control architecture that inherently stabilizes the feedback loop without external compensation components. This eliminates the need for RC networks or type-II/type-III compensators, simplifies PCB layout, reduces BOM count, and delivers ultra-fast load transient response - a key advantage over traditional voltage-mode or current-mode controllers.
LM34917ATL/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 12-WFBGA
- 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):
- 33V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 30V
- Current - Output:
- 1.25A
- Frequency - Switching:
- 2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-DSBGA
LM34917ATL/NOPB FAQ
1.How can I place an order for LM34917ATL/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM34917ATL/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 LM34917ATL/NOPB reliable?
The price and inventory of LM34917ATL/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM34917ATL/NOPB is usually 5 days.
3.What payment methods are accepted for LM34917ATL/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM34917ATL/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM34917ATL/NOPB?
LM34917ATL/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM34917ATL/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 LM34917ATL/NOPB?
For technical support, including LM34917ATL/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM34917ATL/NOPB requirements.
6.How does Aetrix verify that LM34917ATL/NOPB is sourced from the original manufacturer or authorized distributors?
All LM34917ATL/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 LM34917ATL/NOPB meets industry standards.
7.What is the process for return or replacement of LM34917ATL/NOPB?
All LM34917ATL/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM34917ATL/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 LM34917ATL/NOPB part is unused and in its original packaging.
Return procedure for LM34917ATL/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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