Texas Instruments TPS54821RHLR

Overview

TPS54821RHLR from Texas Instruments is a 4.5 V to 17 V input, 8 A synchronous step-down DC/DC converter in a thermally enhanced 3.5 mm × 3.5 mm VQFN-14 package with exposed thermal pad. It integrates 26 mΩ high-side and 19 mΩ low-side MOSFETs, supports 200 kHz–1.6 MHz adjustable switching frequency via RT resistor or external clock synchronization, and delivers ±1% 0.6 V reference accuracy over temperature for precision point-of-load regulation in digital TV and set-top box power rails.

For engineers reviewing the TPS54821RHLR datasheet, TPS54821RHLR pinout, TPS54821RHLR application, or TPS54821RHLR equivalent, key selection considerations include its hiccup-mode overcurrent protection, monotonic startup into pre-biased outputs, adjustable input UVLO using EN pin biasing, power-good monitoring with 92–106% VREF hysteresis, and thermal shutdown at 160°C with 10°C hysteresis.

Technical Context

This device implements constant-frequency peak current-mode control with internal slope compensation to prevent subharmonic oscillation across full duty cycle range. Its dual-rail architecture separates PVIN (1.6–17 V) for power stage and VIN (4.5–17 V) for control circuitry, enabling flexible split-rail designs and consistent startup behavior.

The error amplifier is a transconductance type (1300 µA/V) with COMP pin serving as both output and current comparator input. Protection includes high-side current limit (10.5–17 A), bidirectional low-side sourcing/sinking limits (9.5–15 A / 2–4 A), BOOT-PH UVLO (2.1–3 V), and thermal hiccup shutdown with 16384-cycle restart delay.

Key Specifications

Pinout & Package

TPS54821RHLR uses a 14-pin VQFN package (RHL) with 3.5 mm × 3.5 mm body and exposed thermal pad (pin 15) requiring solder connection to PCB ground plane for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down converter applications.

Compared with TPS54821RHLR, TPS54824RHLR adds digital control at the expense of analog design simplicity, while MP8770GQ-Z sacrifices configurability for lower BOM count and reduced layout sensitivity - neither offers direct pin compatibility nor identical protection behavior.

Availability

TPS54821RHLR is available at Aetrix Electronics and suitable for digital TV power supplies, set-top box core rails, and Blu-ray disc player AVDD generation requiring stable component supply, long-term lifecycle support, and traceable sourcing for production programs.

Supply support for TPS54821RHLR 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 and embedded processing technologies, with decades of expertise in power management IC design and manufacturing.

The TPS54821RHLR belongs to TI's SWIFT™ family of high-current synchronous buck converters, engineered specifically for space-constrained, high-efficiency point-of-load applications in consumer electronics and digital entertainment systems.

FAQ

What is the maximum continuous output current capability of the TPS54821RHLR?

The TPS54821RHLR delivers up to 8 A continuous output current under recommended operating conditions (TJ ≤ 125°C). This rating is enabled by its integrated 26 mΩ high-side and 19 mΩ low-side MOSFETs, thermally enhanced VQFN-14 package with exposed pad, and efficient current-mode control architecture. Derating applies above 125°C junction temperature per datasheet thermal specifications.

How does the TPS54821RHLR support power supply sequencing in multi-rail systems?

The TPS54821RHLR supports sequencing via its SS/TR pin, which accepts either an external capacitor for controlled soft-start or a resistor divider for tracking another supply voltage. Combined with the open-drain PWRGD output and EN pin with adjustable UVLO, it enables precise turn-on/turn-off ordering across multiple rails - critical for FPGA, SoC, and memory subsystems in digital TV and set-top box designs.

Can the TPS54821RHLR operate with a single input supply, or does it require separate VIN and PVIN connections?

The TPS54821RHLR can operate with a single input supply by connecting VIN and PVIN together (4.5–17 V range), or with split rails: PVIN as low as 1.6 V for the power stage while VIN remains at 4.5–17 V for control circuitry. This flexibility allows optimization for low-VOUT, high-current applications such as 1.2 V core rails where minimizing dropout improves efficiency.

What protection features are built into the TPS54821RHLR?

The TPS54821RHLR includes cycle-by-cycle high-side current limiting (10.5–17 A), bidirectional low-side current limiting (9.5–15 A sourcing / 2–4 A sinking), BOOT-PH UVLO (2.1–3 V), output overvoltage lockout (PWRGD asserts low if VSENSE > 106% VREF), thermal shutdown at 160°C with 10°C hysteresis, and hiccup-mode recovery (512-cycle fault detection, 16384-cycle restart delay).

Is the TPS54821RHLR pin-compatible with other devices in the TPS548xx family?

Yes, the TPS54821RHLR shares identical pinout and package (VQFN-14 RHL) with TPS54822RHLR, TPS54823RHLR, and TPS54824RHLR. However, functional differences exist: TPS54822RHLR supports higher 12 A current, TPS54823RHLR adds light-load efficiency modes, and TPS54824RHLR integrates PMBus. Pin compatibility enables drop-in replacement only when electrical specs match target application requirements.