Texas Instruments TPS65281-1RGVR

Overview

TPS65281-1RGVR 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 auto-recovery over-current protection, and operates in a thermally enhanced 4-mm × 4-mm 16-pin QFN (RGV) package. It is deployed in USB ports, set-top boxes, and tablet PCs requiring robust short-circuit and reverse-voltage protection.

For engineers reviewing the TPS65281-1RGVR datasheet, TPS65281-1RGVR pinout, TPS65281-1RGVR application, or TPS65281-1RGVR equivalent, key selection considerations include its auto-recovery current-limit behavior (vs. latch-off in TPS65281), 0.8-V ±1% feedback reference, 10-ms over-current deglitch, reverse-voltage comparator with 4-ms response, and integrated back-to-back 100-mΩ N-channel MOSFETs.

Technical Context

The TPS65281-1RGVR integrates two independent functional blocks: a precision current-limited power distribution switch with auto-recovery fault handling, and a peak-current-mode synchronous buck converter with programmable 300-kHz–1.4-MHz switching frequency. Its power switch uses back-to-back N-channel MOSFETs with 100-mΩ on-resistance and reverse-voltage detection that disables the switch when V_{SW_OUT} exceeds V_{SW_IN} by >135 mV for >4 ms.

The buck regulator features a fixed 0.8-V feedback reference, internal 1-ms soft-start, cycle-by-cycle current limit (4-A typical), and supports external compensation via COMP pin. It employs constant-frequency peak-current-mode control for fast transient response and includes thermal shutdown at 145°C (power switch) and 160°C (buck), both with hysteresis.

Key Specifications

Pinout & Package

TPS65281-1RGVR is housed in a 16-lead thermally enhanced QFN (RGV) package measuring 4 mm × 4 mm with an exposed thermal pad soldered to PCB ground for optimal thermal performance. The pinout follows TI's standard RGV top-view layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS2557DRCT, TPS65281-1RGVR adds integrated 5-V buck conversion and reverse-voltage protection but occupies larger area; compared with TPS65281RGVR, it replaces latch-off with thermal cycling for improved availability in benign overload environments - making it optimal for USB hubs and portable media devices.

Availability

TPS65281-1RGVR is available at Aetrix Electronics and suitable for USB ports, set-top boxes, digital TVs, and tablet PCs requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for TPS65281-1RGVR 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 for consumer and industrial markets.

The TPS65281 family was designed specifically for USB-compliant power distribution in space-constrained consumer electronics, integrating precision current limiting, reverse-voltage protection, and efficient buck conversion into a single QFN package.

FAQ

What distinguishes TPS65281-1RGVR from TPS65281RGVR?

The TPS65281-1RGVR implements auto-recovery over-current protection: it limits output current to the programmed threshold and thermally cycles (145°C trip, 10°C hysteresis) during sustained overload. In contrast, the TPS65281RGVR latches off permanently after a 10-ms over-current deglitch period and requires power cycle or EN toggle to resume operation. Both share identical pinout, package, buck regulator specs, and thermal pad layout.

How is the current limit threshold set on TPS65281-1RGVR?

The current limit threshold for the power switch in TPS65281-1RGVR is set by an external resistor connected between RLIM (Pin 4) and AGND. Using RLIM = 14.3 kΩ yields ~1.76 A (typical), while 20 kΩ gives ~1.26 A and 50 kΩ gives ~0.5 A. The device achieves ±6% accuracy at higher thresholds and supports 75 mA–2.7 A range with recommended RLIM values from 15 kΩ to 232 kΩ.

Does TPS65281-1RGVR support reverse-voltage protection, and how does it behave?

Yes, TPS65281-1RGVR includes reverse-voltage protection: its internal comparator disables the power switch when SW_OUT exceeds SW_IN by >135 mV for >4 ms. Upon removal of the reverse condition, the TPS65281-1RGVR automatically re-enables the switch after the same 4-ms deglitch window. This prevents damage to upstream supplies during hot-plug events or backup battery backfeed scenarios.

What is the role of the nFAULT pin on TPS65281-1RGVR?

The nFAULT pin on TPS65281-1RGVR is an active-low open-drain fault indicator that asserts during over-current (>10 ms), reverse-voltage (>4 ms), or over-temperature conditions. Unlike the latch-off version, TPS65281-1RGVR de-asserts nFAULT automatically once the fault clears and normal operation resumes - enabling host microcontrollers to monitor status without requiring hardware reset signals.

Can TPS65281-1RGVR generate a 5-V output, and what supports that function?

Yes, TPS65281-1RGVR delivers a precise 5-V output via its integrated synchronous buck converter. This is achieved using a 0.8-V ±1% internal feedback reference, external resistor divider on FB (Pin 10), and internal 90-mΩ high-side / 70-mΩ low-side MOSFETs. With VIN = 12 V and typical 4.7-µH inductor, it sustains 3-A continuous output at >90% efficiency and supports programmable 300-kHz–1.4-MHz switching via ROSC (Pin 3).