Texas Instruments TPS54320RHLT

Overview

TPS54320RHLT from Texas Instruments is a 4.5–17-V input, 3-A synchronous step-down DC/DC converter with integrated 57-mΩ/50-mΩ MOSFETs, 0.8-V ±1% reference, and adjustable 200–1200-kHz switching frequency. It delivers regulated output for FPGA/DSP point-of-load rails, features monotonic start-up into prebiased outputs, and includes power-good monitoring via open-drain PWRGD.

For engineers reviewing the TPS54320RHLT datasheet, TPS54320RHLT pinout, TPS54320RHLT application, or TPS54320RHLT equivalent, key selection considerations include split-rail PVIN/VIN operation (1.6–17 V / 4.5–17 V), hiccup overcurrent protection, BOOT-PH UVLO threshold (2.1 V), thermal shutdown at 160–175°C, and compatibility with WEBENCH® Power Designer.

Technical Context

The TPS54320RHLT implements constant-frequency peak current mode control with internal slope compensation to prevent subharmonic oscillation across 0–100% duty cycle. Its dual-input architecture separates control supply (VIN) from power stage input (PVIN), enabling low-voltage biasing of the power train while maintaining full control functionality.

It integrates a transconductance error amplifier (1300 μA/V) referenced to either the internal 0.8-V bandgap or external SS/TR voltage, supports external clock synchronization via RT/CLK pin, and uses boot capacitor recharge logic to sustain high-side gate drive-allowing true 100% duty cycle operation when BOOT-PH remains above 2.1 V.

Key Specifications

Pinout & Package

The TPS54320RHLT is housed in a thermally enhanced 14-pin VQFN package (3.5 mm × 3.5 mm) with an exposed thermal pad that must be soldered to PCB ground for proper thermal performance and electrical stability.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck converter applications.

Compared with TPS54320RHLT, TPS54620RHLT offers higher current capacity in identical footprint, while LMZ31503RVQR trades configurability for integration-making the TPS54320RHLT optimal for cost-sensitive, layout-controlled, and frequency-tuned point-of-load designs.

Availability

TPS54320RHLT is available at Aetrix Electronics and suitable for broadband infrastructure, medical imaging equipment, and industrial PLC I/O modules requiring stable component supply, long-term lifecycle support, and TI-qualified automotive-grade traceability.

Supply support for TPS54320RHLT 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 delivering analog and embedded processing solutions, with over 50 years of power management innovation and broad distribution across industrial, automotive, and communications markets.

The TPS54320RHLT belongs to TI's SWIFT™ synchronous buck converter family, engineered for high-density, high-efficiency point-of-load regulation in FPGA, DSP, and ASIC applications where thermal performance, precision voltage control, and design flexibility are critical.

FAQ

What is the minimum input voltage required for TPS54320RHLT to operate in split-rail mode?

The TPS54320RHLT supports split-rail operation with PVIN as low as 1.6 V while maintaining VIN at 4.5–17 V. This allows the power stage to run from a partially discharged battery or low-voltage auxiliary rail, while control circuitry remains fully functional. The device will not switch if VIN falls below its internal 4.5-V UVLO threshold, regardless of PVIN level.

Can TPS54320RHLT achieve 100% duty cycle, and what conditions must be met?

Yes, the TPS54320RHLT can operate at 100% duty cycle when the BOOT-PH voltage remains above 2.1 V-the BOOT-PH UVLO threshold. This requires proper sizing and placement of the BOOT capacitor (typically 0.1 µF X7R ceramic) and low-impedance PH node routing. At very low dropout (e.g., 5-V input → 4.8-V output), sustained 100% duty cycle is achievable without forced discontinuous mode.

How does the SS/TR pin function during power sequencing with multiple TPS54320RHLT regulators?

The SS/TR pin on each TPS54320RHLT accepts an external capacitor to set individual soft-start time or a resistor divider to track another supply. When cascading regulators, connect the SS/TR of downstream devices to the PWRGD of upstream units to enforce strict turn-on order. For simultaneous ramping, tie all SS/TR pins together with matched capacitors to ensure synchronized voltage rise.

What is the recommended PCB layout practice for the exposed thermal pad of TPS54320RHLT?

The exposed thermal pad of the TPS54320RHLT must be soldered to a solid copper plane tied to GND using ≥4 thermal vias (0.3-mm diameter, spaced ≤1 mm apart) connecting to inner-layer ground planes. TI recommends a 3.3-mm × 3.3-mm stencil aperture with 70% paste coverage. Inadequate pad soldering causes thermal resistance to exceed 3.9°C/W (RθJC(bot)), risking premature thermal shutdown at >2.2 A load.

Does TPS54320RHLT support external clock synchronization, and how is it configured?

Yes, the TPS54320RHLT supports external clock synchronization via the RT/CLK pin. To enable CLK mode, drive the pin with a clean CMOS clock signal (1–5 V, 200–1200 kHz) and leave the RT resistor unconnected. The internal PLL locks to the falling edge of the external clock. Frequency deviation is ±0.5% over temperature, ensuring deterministic timing for noise-sensitive applications like high-speed data converters.