Texas Instruments TPS65281RGVR

Overview

TPS65281RGVR from Texas Instruments is a precision adjustable current-limited power distribution switch with integrated 3-A synchronous buck regulator. It delivers regulated 5-V output from 4.5–18-V input, provides programmable current limiting (75 mA–2.7 A), features over-current latch-off protection, reverse-voltage protection, and operates in a thermally enhanced 4-mm × 4-mm 16-pin QFN (RGV) package. It is used in USB ports and hubs for robust hot-swap and short-circuit protection.

For engineers reviewing the TPS65281RGVR datasheet, TPS65281RGVR pinout, TPS65281RGVR application, or TPS65281RGVR equivalent, key selection considerations include its dual-function architecture (power switch + buck), ±6% current-limit accuracy at 1.7 A, 1-ms internal soft-start, 300-kHz to 1.4-MHz programmable switching frequency, and nFAULT open-drain fault signaling for system-level monitoring.

Technical Context

The TPS65281RGVR integrates two independent functional blocks: an N-channel back-to-back power distribution switch with adjustable current limit via RLIM pin and built-in reverse-voltage comparator, and a peak-current-mode synchronous buck converter with internal 90-mΩ high-side and 70-mΩ low-side MOSFETs. Both blocks share thermal shutdown (160°C trip for buck, 145°C for switch) but differ in fault response-TPS65281RGVR latches off on over-current, while TPS65281-1 enters constant-current mode.

Control logic is decoupled: EN enables the entire device (including buck and bias supplies), while EN_SW independently controls only the power switch. The nFAULT pin asserts low for >10 ms during over-current or >4 ms during reverse-voltage events, with deglitching preventing false triggers during capacitive load startup. The ROSC pin sets switching frequency via external resistor or fixed values (270 kHz, 600 kHz).

Key Specifications

Pinout & Package

TPS65281RGVR is housed in a 16-lead QFN (RGV) package measuring 4 mm × 4 mm with exposed thermal pad. The pad must be soldered to PCB ground with multiple thermal vias for optimal junction-to-board thermal resistance (θ_JB = 14.7 °C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power distribution switch + buck regulator applications.

Compared with TPS2557DRCT and TPS65261RHBR, the TPS65281RGVR uniquely combines a programmable current-limit switch with an integrated 5-V buck in one package, delivering both USB port protection and local 5-V generation without external components - critical for space-constrained USB host designs.

Availability

TPS65281RGVR is available at Aetrix Electronics and suitable for USB ports and hubs, digital TV power rails, and set-top box subsystems requiring stable component supply, precise current limiting, and integrated fault reporting.

Supply support for TPS65281RGVR 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 solutions.

The TPS65281RGVR belongs to TI's precision power distribution switch + integrated buck PMIC product line, engineered specifically for USB-compliant hot-swap applications where short-circuit resilience, reverse-voltage blocking, and compact 5-V rail generation are essential.

FAQ

What is the primary function of the TPS65281RGVR?

The TPS65281RGVR is a dual-function PMIC combining a precision adjustable current-limited power distribution switch and a synchronous buck regulator. Its primary role is to deliver regulated 5-V output from 4.5–18-V input while providing programmable over-current protection (75 mA–2.7 A) and reverse-voltage blocking for USB ports, digital TVs, and set-top boxes. The TPS65281RGVR integrates all necessary control, protection, and power conversion circuitry in a single 4-mm × 4-mm QFN package.

How does the TPS65281RGVR implement over-current protection?

The TPS65281RGVR implements over-current protection via its RLIM pin, which sets a precise current-limit threshold between 75 mA and 2.7 A using an external resistor. When load current exceeds this threshold, the device enters constant-current mode, reducing output voltage to maintain the programmed limit. It features ±6% accuracy at 1.7 A and a 10-ms deglitch timer before asserting nFAULT. Unlike TPS65281-1, the TPS65281RGVR latches off permanently until EN or power is cycled.

Can the TPS65281RGVR generate a 5-V output from a 12-V input?

Yes, the TPS65281RGVR can generate a stable 5-V output from a 12-V input. Its integrated synchronous buck converter supports 4.5–18-V input and uses a 0.8-V ±1% internal reference with external FB resistor divider to regulate precisely to 5 V. With internal 90-mΩ high-side and 70-mΩ low-side MOSFETs, it achieves high efficiency across 0.3–2.7-A loads, and its programmable 300-kHz to 1.4-MHz switching frequency allows optimization for EMI and component size.

What is the purpose of the nFAULT pin on the TPS65281RGVR?

The nFAULT pin on the TPS65281RGVR is an active-low open-drain output that signals fault conditions to the host system. It asserts low during over-current (>10 ms), reverse-voltage (>4 ms), or over-temperature events. For the TPS65281RGVR, nFAULT remains asserted while the device is latched off and de-asserts only after power cycling or toggling EN. This enables real-time system monitoring and coordinated fault response without requiring external comparators or timers.

Does the TPS65281RGVR require external components for basic operation?

Yes, the TPS65281RGVR requires several external components for full functionality: an inductor and output capacitor for the buck stage; input ceramic capacitor (≥10 µF) at VIN; bootstrap capacitor (47 nF) between BST and LX; feedback resistors for 5-V regulation; RLIM resistor for current limiting; and optional soft-start capacitor on SS. However, it integrates power MOSFETs, gate drivers, charge pump, and protection circuitry - eliminating discrete switches, sense resistors, and external fault logic.