Texas Instruments LM26420Q1XSQ/NOPB

Overview

LM26420Q1XSQ/NOPB from Texas Instruments is a dual-channel synchronous buck DC/DC converter delivering 2 A per channel at 2.5 V and 1.2 V outputs, operating from 3 V to 5.5 V input, with 2.2 MHz fixed switching frequency and internal 0.8 V reference (±1.5%), designed for FPGA core and I/O power in automotive-qualified systems.

For engineers reviewing the LM26420Q1XSQ/NOPB datasheet, LM26420Q1XSQ/NOPB pinout, LM26420Q1XSQ/NOPB application, or LM26420Q1XSQ/NOPB equivalent, key selection criteria include dual independent enable/power-good signaling, 180° phase interleaving for reduced input ripple, current-mode PWM control with internal compensation, thermal shutdown at 165°C, and compliance with CISPR25 Class 5 conducted emissions.

Technical Context

The LM26420Q1XSQ/NOPB integrates two independent current-mode PWM controllers with fixed 2.2 MHz switching frequency, 180° phase shift between channels, and internal 75 mΩ PMOS top switch / 50 mΩ NMOS bottom switch per channel. It features independent precision enable thresholds (1.04 V typical, 150 mV hysteresis) and open-drain power-good indicators with ±40 mV hysteresis.

Operation relies on internal 0.8 V reference (±1.5%), soft-start ramping over ~600 µs, cycle-by-cycle current limiting at 3.3 A (typical), and overvoltage protection triggered at 15% above VREF. Undervoltage lockout activates below 2.628 V (rising) with 330 mV hysteresis.

Key Specifications

Pinout & Package

LM26420Q1XSQ/NOPB uses the HTSSOP-20 package (6.50 mm × 4.40 mm), with exposed die attach pad (DAP) connected to system ground for optimal thermal performance and low-impedance return path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM26420Q1YSQ/NOPB, the LM26420Q1XSQ/NOPB delivers superior high-frequency transient response and smaller passive components, while the TPS65263-1QRGERQ1 adds rail flexibility at the cost of reduced per-channel configurability and independent fault reporting.

Availability

LM26420Q1XSQ/NOPB is available at Aetrix Electronics and suitable for automotive infotainment, FPGA power management, and USB-powered industrial sensor hubs requiring stable component supply, AEC-Q100 qualification, and long-term production continuity.

Supply support for LM26420Q1XSQ/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 automotive-grade product development and manufacturing expertise.

The LM26420 product line delivers high-density dual-buck regulation for safety-critical automotive electronics, emphasizing EMI robustness, thermal resilience, and precise voltage control in harsh environments.

FAQ

What is the switching frequency of the LM26420Q1XSQ/NOPB?

The LM26420Q1XSQ/NOPB operates at a fixed 2.2 MHz switching frequency. This high frequency enables compact external components - typically 1.0–2.2 µH inductors and 10–22 µF ceramic output capacitors - while maintaining excellent transient response and low output voltage ripple. The frequency is factory-set and not adjustable.

Does the LM26420Q1XSQ/NOPB support start-up into a prebiased output?

Yes, the LM26420Q1XSQ/NOPB supports start-up into prebiased outputs. Its control architecture prevents reverse current flow during enable by monitoring the feedback pin voltage and delaying top-switch activation until the output begins rising. This feature is critical for hot-swap applications and systems with multiple power domains sharing common rails.

What is the purpose of the separate VINC and VIND pins on the LM26420Q1XSQ/NOPB?

The LM26420Q1XSQ/NOPB separates VINC (control circuit supply) from VIND1/VIND2 (power switch supplies) to isolate noise-sensitive analog circuitry from high-current switching paths. VINC powers the reference, error amplifier, and logic; it requires local RC filtering. VIND pins deliver raw input power to the internal MOSFETs - enabling optimized layout and reduced coupling between control and power stages.

How does the LM26420Q1XSQ/NOPB implement power sequencing between its two outputs?

The LM26420Q1XSQ/NOPB provides independent EN1/EN2 and PG1/PG2 pins, enabling flexible sequencing. For example, EN1 can be tied to a supervisor output to enable Buck 1 first, then use PG1 to drive EN2 for cascaded startup. No internal sequencing logic exists - timing is fully controlled externally via these dedicated pins, supporting both simultaneous and staggered power-up.

Is the LM26420Q1XSQ/NOPB qualified for automotive applications?

Yes, the LM26420Q1XSQ/NOPB is AEC-Q100 qualified for automotive applications. It is rated for operation from –40°C to +125°C junction temperature, features built-in thermal shutdown (165°C), overvoltage protection, and meets CISPR25 Class 5 conducted emissions standards - making it suitable for infotainment, ADAS, and body electronics systems.