Texas Instruments TPS54318RTET

Overview

TPS54318RTET from Texas Instruments is a 2.95-V to 6-V input, 3-A synchronous step-down DC/DC converter with integrated 30-mΩ high- and low-side MOSFETs, 2-MHz switching frequency capability, ±1% voltage reference accuracy over –40°C to 150°C, and thermally enhanced 3 mm × 3 mm WQFN-16 package. It delivers point-of-load regulation for FPGAs and microprocessors in space-constrained industrial and communications systems.

For engineers reviewing the TPS54318RTET datasheet, TPS54318RTET pinout, TPS54318RTET application, or TPS54318RTET equivalent, key selection criteria include its adjustable soft-start, external clock synchronization, power-good output with 2% hysteresis, cycle-by-cycle current limiting, and safe startup into prebiased outputs - all critical for reliable power sequencing and transient response in high-density designs.

Technical Context

The TPS54318RTET implements peak-current-mode control with internal slope compensation to prevent subharmonic oscillation across 0–100% duty cycle. Its PLL-synchronized RT/CLK pin supports external clock locking from 300 kHz to 2 MHz, enabling noise-sensitive system timing alignment.

It integrates a boot regulator with UVLO monitoring (2.1 V BOOT–PH threshold), a transconductance error amplifier (225 µS normal / 70 µS soft-start mode), and a dual-threshold PWRGD comparator asserting low when VSENSE falls below 93% or rises above 107% of nominal - providing precise undervoltage/overvoltage fault detection without external circuitry.

Key Specifications

Pinout & Package

TPS54318RTET uses a thermally enhanced 3 mm × 3 mm, 16-pin WQFN package with exposed PowerPad for PCB-level heat dissipation. The PowerPad must be soldered to a multi-via ground plane per TI layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS54318RTET, TPS54319RTET adds spread-spectrum modulation without changing footprint or basic regulation, while MP2332HGTL-Z trades advanced features for lower unit price and simpler layout - making TPS54318RTET the optimal balance of integration, reliability, and design flexibility for industrial and communications infrastructure.

Availability

TPS54318RTET is available at Aetrix Electronics and suitable for FPGA power delivery, optical transceiver biasing, and automotive ADAS domain controllers requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for TPS54318RTET 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 technologies, with decades of expertise in high-efficiency DC/DC conversion.

The TPS54318RTET belongs to TI's SWIFT™ synchronous buck converter family, designed specifically for high-density, high-transient-response point-of-load regulation in networking, computing, and industrial systems.

FAQ

What is the minimum input voltage required for TPS54318RTET to start switching?

The TPS54318RTET has an internal undervoltage lockout (UVLO) threshold of 2.6 V (typical), with hysteresis ensuring reliable startup. When VIN rises above 2.6 V, the device begins soft-start sequencing. If using the EN pin for custom UVLO, the falling threshold can be set as low as 1.18 V, but the fundamental input rail must still exceed 2.6 V for internal circuitry to power up. Below 2.6 V, the TPS54318RTET remains in shutdown regardless of EN state.

Can TPS54318RTET safely start up into a precharged output voltage?

Yes, the TPS54318RTET supports safe prebias startup: when enabled into a precharged output, it disables the high-side MOSFET until the feedback loop stabilizes, preventing reverse current flow through the low-side FET. This behavior is inherent to its current-mode architecture and internal control logic - no external components are needed. The SS pin is actively discharged before restart after any fault, ensuring repeatable prebias recovery for TPS54318RTET.

What is the recommended capacitor value for the BOOT pin on TPS54318RTET?

Texas Instruments specifies a 0.1-µF ceramic capacitor between BOOT and PH pins for the TPS54318RTET. An X7R or X5R dielectric with ≥10-V rating is required to maintain capacitance stability across temperature and bias voltage. Larger values (e.g., 0.22 µF) do not improve performance and may delay boot capacitor recharge; smaller values risk insufficient gate drive under heavy load or high-frequency operation. This capacitor is critical for sustaining high-side MOSFET conduction in the TPS54318RTET.

How does the RT/CLK pin function in clock synchronization mode for TPS54318RTET?

In CLK mode, the RT/CLK pin of the TPS54318RTET accepts an external square-wave clock (300–2000 kHz) and locks the internal oscillator's rising edge to the falling edge of that signal via an integrated PLL. The minimum pulse width is 75 ns, and VIH/VIL thresholds are 1.6 V / 0.6 V. Once locked (within 14 µs), the TPS54318RTET eliminates beat frequencies and aligns switching noise - critical for meeting CISPR-22 Class B emissions in multi-rail systems.

What thermal derating applies to TPS54318RTET at 100°C ambient temperature?

With standard JEDEC 4-layer board (2 oz copper, 4 thermal vias), the TPS54318RTET has R_θJA = 37°C/W. At 100°C ambient and 150°C max junction, allowable power dissipation is (150 − 100)/37 ≈ 1.35 W. For 3-A output at 1.2 V (3.6 W output), assuming 90% efficiency (0.4 W loss), junction rise is ~15°C - well within limit. No derating needed at 100°C ambient for typical loads; full 3-A operation is supported up to 125°C ambient with proper layout for the TPS54318RTET.