TI LM27403SQE

Mfr. Part

LM27403SQE

Manufacturer

Luminary Micro / Texas Instruments

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Detailed Description

High-performance synchronous buck PWM controller for step-down DC/DC converters. Designed for point-of-load rails that need fast transient response, tight regulation, and high efficiency. Drives external N-channel MOSFETs (high-side and low-side), supports programmable soft-start and tracking, includes power-good, UVLO, OVP, and cycle-by-cycle current limit. Suitable for wide VIN systems and low VOUT rails common in modern digital and industrial designs. Main Category: Integrated Circuits (ICs). Small Classification: Specialized ICs.

Key Features

Synchronous buck controller topology (external MOSFETs) for high efficiency

Wide input voltage capability (typical family range covers low-to-mid VIN applications; check datasheet for exact VIN limits)

Fast transient response with advanced control (LM2740x family uses enhanced current-mode techniques for stable, simple compensation)

Adjustable switching frequency (typical hundreds of kHz to MHz, sync/clocking options available on family devices)

Precision reference for tight output regulation

Programmable soft-start and voltage tracking/sequencing

Power Good (PG) indicator for system monitoring

Pre-bias startup support (does not discharge a pre-biased output)

Over-voltage protection (OVP), under-voltage lockout (UVLO), and robust cycle-by-cycle current limit

Strong gate drivers for efficient, low-RDS(on) MOSFETs

Thermal shutdown and fault handling

Industrial temperature range

Key Advantages

High efficiency across load range due to synchronous operation and optimized gate drive

Stable control with straightforward compensation, easing design effort

Compact solution size enabled by high frequency operation and QFN package with exposed pad

Excellent transient performance helps keep output within tight tolerance for CPUs, FPGAs, and ASICs

Rich protection set improves system reliability and safety

Flexible soft-start, tracking, and enable simplify multi-rail sequencing

Uses widely available external MOSFETs and passives, giving BOM flexibility and cost control

Packaging

Type: Lead-free QFN with exposed thermal pad (TI orderable code “SQ” corresponds to a 16‑pin WQFN in this family)

Material: Molded epoxy encapsulation, copper leadframe, matte tin plating (RoHS compliant)

Size: Nominal 4 x 4 mm body, low profile (approx. 0.8–1.0 mm height). See datasheet package drawing for exact dimensions and tolerances

Pin configuration: 16 pins plus exposed thermal pad. Typical pins include VCC bias, BOOT, high-side gate (DH), low-side gate (DL), SW/PHASE, AGND/PGND, FB, COMP, SS/TRK, EN, PGOOD, UV/UVLO (exact names and pinout per datasheet)

Thermal characteristics: Exposed pad for heat spreading to PCB; typical RθJA for a 4x4 mm WQFN-16 with EP on a 4‑layer JEDEC board is in the ~40–60 °C/W range; RθJC typically in the single‑digit °C/W range. Actual values depend on layout, copper area, and airflow. Refer to datasheet for measured values

Electrical properties (controller-level): Gate driver designed for external N‑MOSFETs; precision reference for VOUT setpoint; adjustable switching frequency in the hundreds of kHz to MHz range; protection thresholds for OVP/UVLO/current limit defined in datasheet

Shipment form: Tape-and-reel for automated assembly. Typical reel count aligns with your request of 2400 units (2400 pcs/reel is common for this package)

Package/Case code: 1057 (distributor internal code). TI “SQ” package maps to WQFN-16 with exposed pad; verify exact package drawing on the datasheet/package section

Lifecycle

Status: As of the latest market check, LM27403 family devices are generally listed as Active by Texas Instruments (not approaching end-of-life)

Form-fit-function equivalents or close alternatives (selection depends on exact specs such as VIN, FSW, control method, and features; verify against your requirements):

- LM27402 (same family synchronous buck controller with related control scheme)

- LM27404 (same family variant with feature differences)

- TPS40140 (dual-phase synchronous buck controller for higher current rails)

- TPS40170 (wide-VIN synchronous buck controller; different operating range and features)

- TPS51116 / TPS51120 (specialized controllers for DDR/POI rails if you need integrated tracking/REF options)

- Note: If you require drop-in footprint compatibility, contact Y-IC to confirm pin-to-pin and behavior matches. For other alternatives or if your constraints are unique, please contact our sales team via our website for tailored cross-references and availability

Key Application Areas

Point-of-load regulators for CPUs, GPUs, FPGAs, and ASICs

Core and auxiliary rails in servers, storage, and networking equipment

Telecom/datacom power cards and distributed power architectures

Industrial control, test and measurement, and factory automation

Embedded computing, high-speed I/O, and memory rails (DDR core/aux rails with tracking)

Automotive infotainment and ADAS subsystems (when used within the device’s specified temperature and qualification limits; check AEC-Q requirements)

Datasheet

Our website hosts the most authoritative, up-to-date datasheet for LM27403SQE. We recommend downloading it on this page to review the exact pinout, electrical limits, thermal data, recommended operating conditions, and application schematics.

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