Texas Instruments LM26480SQX-BF/NOPB

Overview

LM26480SQX-BF/NOPB from Texas Instruments is a dual-buck + dual-LDO power management IC for low-power digital systems, integrating two 1.5-A synchronous step-down regulators (0.8–2 V and 1–3.3 V outputs) and two 300-mA LDOs (1–3.5 V), all with individual enables, ±3% feedback accuracy, and 2-MHz PWM switching. It serves as the primary voltage regulation solution in portable applications processors requiring tightly regulated core and I/O rails.

For engineers reviewing the LM26480SQX-BF/NOPB datasheet, LM26480SQX-BF/NOPB pinout, LM26480SQX-BF/NOPB application, or LM26480SQX-BF/NOPB equivalent, this device supports critical design tasks including multi-rail sequencing, thermal-aware buck/LDO co-design, low-noise analog supply generation, and flexible POR timing configuration via nPOR and UVLO thresholds.

Technical Context

The LM26480SQX-BF/NOPB implements voltage-mode control for both buck converters with automatic PWM-to-PFM mode transition under light load, enabling high efficiency (up to 96%) across 10 mA–1.5 A output range. Its dual LDOs use PMOS pass devices with 25 mV typical dropout at 50 mA, supporting stable no-load operation and low-output-noise (150 µV_RMS) performance for analog circuitry.

Each regulator features independent enable inputs (ENSW1/ENSW2/ENLDO1/ENLDO2), dedicated feedback pins (FB1/FB2/FBL1/FBL2), and integrated protections including thermal shutdown (160°C), current limiting (2.4 A peak per buck), and undervoltage lockout (2.7–2.9 V on VIN). The nPOR open-drain output provides synchronized reset assertion for Buck1 and Buck2 with 60-ms default delay.

Key Specifications

Pinout & Package

LM26480SQX-BF/NOPB is housed in a thermally enhanced 4.0 mm × 4.0 mm WQFN-24 package (RTW) with exposed thermal pad (DAP) for improved heat dissipation. Pin assignment follows TI's standard RTW footprint, with dedicated grounds (GND_SW1, GND_SW2, GND_L, GND_C) and separate analog/digital power domains (VINLDO12, AVDD).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-rail PMU applications.

Compared with TPS65217C and MAX20029ATP+, the LM26480SQX-BF/NOPB offers optimal balance of compact size, dual-buck precision, and dedicated nPOR functionality for portable digital systems where board area and deterministic dual-rail reset behavior are critical.

Availability

LM26480SQX-BF/NOPB is available at Aetrix Electronics and suitable for mobile applications processor core power, digital radio baseband supply, robot drive motor control logic, and image transmission module designs requiring stable component supply and long-term production continuity.

Supply support for LM26480SQX-BF/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-efficiency DC-DC conversion and low-noise LDO design.

The LM26480 product line was engineered specifically for portable, low-power digital applications-delivering tightly regulated multi-rail power with minimal external components and robust protection features for processors, FPGAs, and communication ICs.

FAQ

What is the function of the SYNC pin on the LM26480SQX-BF/NOPB?

The SYNC pin on the LM26480SQX-BF/NOPB is not functional - it is reserved for the LM26480SQ-BF variant, which supports external 13 MHz clock synchronization. On LM26480SQX-BF/NOPB, the SYNC pin must be grounded per datasheet guidance. Using it as an input on this part number will not alter oscillator behavior or enable external clocking; the internal 2-MHz oscillator remains active and unmodified.

Does the LM26480SQX-BF/NOPB support independent voltage sequencing between its four regulators?

Yes, the LM26480SQX-BF/NOPB supports full independent sequencing via four dedicated enable inputs: ENSW1, ENSW2, ENLDO1, and ENLDO2. Each is logic-high active and electrically isolated, allowing designers to assert enables in any order and timing - for example, powering LDO2 before Buck1 to bias analog interfaces prior to digital core activation. No internal dependency or forced sequence is imposed.

What is the minimum input voltage required for the LDOs on the LM26480SQX-BF/NOPB?

The LM26480SQX-BF/NOPB LDOs (LDO1 and LDO2) require a minimum input voltage of 1.74 V on their respective VINLDO1 and VINLDO2 pins when enabled, as specified in the Electrical Characteristics table. This allows operation from low-headroom sources such as buck converter outputs (e.g., 1.8 V → 1.5 V LDO), provided the dropout condition (VIN ≥ VOUT + 25 mV typ.) is met at the intended load current.

How does the nPOR signal behave during undervoltage conditions on the LM26480SQX-BF/NOPB?

The nPOR signal on the LM26480SQX-BF/NOPB is asserted low whenever either Buck1 or Buck2 output falls below 82% of its target voltage (falling threshold) or fails to rise above 92% during startup (rising threshold). It remains low until both outputs stabilize within that window, providing a hardware-enforced reset signal to downstream processors - independent of software or external supervision circuits.

Can the LM26480SQX-BF/NOPB operate with ceramic output capacitors only, or are electrolytics required?

The LM26480SQX-BF/NOPB is fully compatible with ceramic output capacitors only - in fact, the datasheet specifies low-ESR MLCCs (e.g., 10 µF for bucks, 0.47 µF for LDOs) as the recommended and validated solution. Electrolytic or tantalum capacitors are neither required nor recommended, as their higher ESR can degrade transient response and stability margins. All typical performance curves and layout examples assume ceramic capacitor usage.