Texas Instruments TPS54040ADRCT

Overview

TPS54040ADRCT from Texas Instruments is a 42-V input, 0.5-A synchronous step-down DC-DC converter with integrated 200-mΩ high-side MOSFET, Eco-Mode™ for 116-μA quiescent current at light load, adjustable 100 kHz–2.5 MHz switching frequency via RT/CLK pin, and precision 0.8-V reference. It delivers regulated 5-V output in industrial power supplies requiring wide VIN range and low-noise operation.

For engineers reviewing the TPS54040ADRCT datasheet, TPS54040ADRCT pinout, TPS54040ADRCT application, or TPS54040ADRCT equivalent, key selection criteria include UVLO adjustability via EN pin, PWRGD open-drain monitoring with ±3% threshold hysteresis, BOOT-PH UVLO protection at 2.1 V, thermal shutdown at 182°C, and MSOP-10 PowerPAD package compatibility with high-power-density layouts.

Technical Context

The TPS54040ADRCT employs peak current-mode control with slope compensation to ensure stability across 0–100% duty cycle, including dropout operation enabled by BOOT-PH UVLO monitoring. Its internal PLL on the RT/CLK pin supports synchronization to external clocks or resistor-set frequency tuning between 100 kHz and 2.5 MHz.

It integrates a transconductance error amplifier (97 μA/V nominal, 25 μA/V during slow start) referenced to either the 0.8-V internal bandgap or externally tracked SS/TR voltage, enabling precise output regulation and sequencing. The device uses frequency foldback during overload and thermal shutdown at 182°C for robust fault protection.

Key Specifications

Pinout & Package

The TPS54040ADRCT is housed in a 3.00 mm × 3.00 mm MSOP-10 PowerPAD package with exposed thermal pad electrically connected to GND for enhanced thermal performance (θJB = 28°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMR14006XDDAR and MP2451DT-LF-Z, the TPS54040ADRCT offers superior system-level integration-its PWRGD, adjustable UVLO, SS/TR sequencing, and MSOP-10 PowerPAD enable robust, compact, and production-ready industrial power designs not achievable with simpler alternatives.

Availability

TPS54040ADRCT is available at Aetrix Electronics and suitable for industrial automation, automotive aftermarket electronics, and portable medical devices requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for TPS54040ADRCT 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, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

The TPS54040A product line delivers high-efficiency, wide-input buck converters optimized for rugged 12-V/24-V systems with demanding transient, thermal, and reliability requirements.

FAQ

What is the minimum input voltage required for TPS54040ADRCT to regulate a 5-V output?

The TPS54040ADRCT requires a minimum input voltage of approximately 5.95 V to sustain 5-V output regulation under full 0.5-A load, accounting for MOSFET R_DS(on), inductor DCR, and diode drop. With light loads, regulation can be maintained down to ~5.2 V due to reduced conduction losses. The internal UVLO defaults to 2.5 V but is adjustable upward via the EN pin to prevent operation below safe input levels.

How does the TPS54040ADRCT achieve 100% duty cycle operation?

The TPS54040ADRCT achieves 100% duty cycle by monitoring the BOOT-to-PH voltage with an internal UVLO circuit set at 2.1 V. As long as this voltage remains above threshold, the high-side MOSFET stays on continuously. When BOOT-PH falls below 2.1 V, the MOSFET turns off to allow the bootstrap capacitor to recharge through the low-side path-enabling dropout operation beyond typical buck limitations.

Can the TPS54040ADRCT be synchronized to an external clock, and what are the timing requirements?

Yes, the TPS54040ADRCT supports external clock synchronization via the RT/CLK pin. When pulled above 2.2 V, it enters CLK mode and accepts TTL/CMOS-compatible clock edges. Minimum pulse width is 40 ns, and PLL lock time is typically 100 μs. This allows precise EMI control and phase alignment with system clocks in multi-rail power architectures.

What is the purpose of the SS/TR pin on the TPS54040ADRCT, and how is it used in practice?

The SS/TR pin on the TPS54040ADRCT controls output voltage ramp rate during startup (slow start) or tracks another voltage rail (tracking). A capacitor to ground sets rise time; a resistor divider from another supply enables sequencing. During faults, the pin is actively discharged to ensure repeatable restart behavior-critical for reliable power-up in complex embedded systems using TPS54040ADRCT.

Does the TPS54040ADRCT require an external boot diode, and why or why not?

No, the TPS54040ADRCT does not require an external boot diode because it integrates a boot recharge diode internally. This eliminates one external component, reduces board area, and improves reliability-especially in high-reliability applications like industrial controls. The internal diode charges the BOOT-to-PH capacitor during the low-side conduction phase, enabling efficient gate drive for the integrated 200-mΩ high-side MOSFET.