Texas Instruments LM34917ATLX/NOPB

Overview

LM34917ATLX/NOPB from Texas Instruments is a constant on-time, 33V-input, 1.25A synchronous buck switching regulator with integrated N-channel MOSFET, valley current limiting, and programmable soft-start. It operates from 8V to 33V input, delivers adjustable output voltage via resistor divider, and targets high-efficiency point-of-load regulation in space-constrained industrial and telecom power supplies.

For engineers reviewing the LM34917ATLX/NOPB datasheet, LM34917ATLX/NOPB pinout, LM34917ATLX/NOPB application, or LM34917ATLX/NOPB equivalent, key selection considerations include its 12-bump DSBGA package, 2 MHz max switching frequency, no-loop-compensation architecture, intelligent VIN/VOUT-dependent current limit, and input over-voltage shutdown at ≊34.8V.

Technical Context

The LM34917ATLX/NOPB employs a constant on-time (COT) control scheme where t_ON is inversely proportional to VIN, enabling near-constant switching frequency across line and load variations. Its valley current limit dynamically adjusts with both VIN and VOUT to prevent inductor saturation under high-line/high-load conditions.

Regulation relies on a 2.5V internal reference compared against FB pin voltage; over-voltage protection triggers at 2.9V on FB. The integrated start-up regulator provides 7.0V (±0.4V) bias for gate drive and logic, eliminating need for external bias supply in most applications.

Key Specifications

Pinout & Package

LM34917ATLX/NOPB is housed in a 12-bump DSBGA package (Package Number YZR0012UNA), optimized for low thermal resistance and minimal PCB area. Bump-side layout follows standard DSBGA orientation with SGND, RTN, and VIN distributed for optimal ground return and input decoupling.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck regulator applications.

Compared with LM34917TLX/NOPB, LM34917ATLX/NOPB offers direct compatibility with YZR0012UNA land patterns, while TPS54202HDDCR provides higher current and lower minimum input voltage but cannot replace LM34917ATLX/NOPB in 33V-input or high-transient environments.

Availability

LM34917ATLX/NOPB is available at Aetrix Electronics and suitable for industrial point-of-load regulation, telecom secondary post-regulation, and high-voltage embedded power supplies requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature and input voltage ranges.

Supply support for LM34917ATLX/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 for space-constrained POL applications where input voltage exceeds 24V and fast transient response is critical - designed specifically for industrial, telecom, and automotive subsystems.

FAQ

What is the maximum input voltage rating for LM34917ATLX/NOPB?

The LM34917ATLX/NOPB has an absolute maximum VIN-to-RTN rating of 50V for transient survival, with built-in input over-voltage shutdown activating at ≊34.8V during steady-state operation. This dual-level protection allows safe use in 33V nominal systems exposed to common industrial or telecom surges without external clamping circuitry.

Does LM34917ATLX/NOPB require external compensation components?

No, LM34917ATLX/NOPB uses a constant on-time (COT) control architecture that eliminates the need for external compensation networks. Its regulation loop is inherently stable across line and load variations, reducing design complexity and component count while enabling ultra-fast load transient response - typically under 10 µs.

How does the valley current limit function in LM34917ATLX/NOPB?

The LM34917ATLX/NOPB implements valley current limiting by monitoring recirculating current at the ISEN pin during the off-time. The threshold adapts dynamically with both VIN and VOUT to prevent inductor saturation under high-line/high-load conditions, and reduces on-time by ~50% when triggered - enabling smooth transition to constant-current mode without foldback.

What package type is used for LM34917ATLX/NOPB?

LM34917ATLX/NOPB uses a 12-bump DSBGA package (Package Number YZR0012UNA), measuring approximately 2.0 mm × 1.6 mm with 0.5 mm bump pitch. This ultra-compact, thermally enhanced package supports high-density layouts and achieves θ_JA = 58°C/W with standard PCB copper pours.

Can LM34917ATLX/NOPB operate without an external bootstrap capacitor?

No, LM34917ATLX/NOPB requires a 0.022 µF ceramic capacitor connected between BST and SW pins to supply gate drive voltage for the integrated N-channel buck switch. This capacitor is recharged each off-time via an internal diode from VCC; omitting it will prevent proper high-side FET turn-on and cause regulator failure.