Texas Instruments TPS54240DGQR

Overview

TPS54240DGQR from Texas Instruments is a 42-V input, 2.5-A synchronous step-down DC-DC converter with integrated 200-mΩ high-side MOSFET, Eco-Mode™ for light-load efficiency, 138-μA quiescent current, and adjustable 100-kHz to 2.5-MHz switching frequency - used in industrial 24-V power rails requiring regulated 3.3-V/5-V outputs.

For engineers reviewing the TPS54240DGQR datasheet, TPS54240DGQR pinout, TPS54240DGQR application, or TPS54240DGQR equivalent, key selection considerations include input voltage range (3.5–42 V), pulse-skipping Eco-Mode operation, PWRGD open-drain power-good signaling, RT/CLK synchronization capability, and thermal performance in HVSSOP-10 PowerPAD™ packaging.

Technical Context

This current-mode buck regulator implements fixed-frequency PWM control with slope compensation to prevent subharmonic oscillation across full duty cycle range. Its internal error amplifier drives COMP with transconductance of 310 μS (typ) and 70 μS during slow-start, enabling stable loop compensation with external RC networks.

The device integrates boot UVLO (2.1 V threshold), frequency foldback during overload, thermal shutdown at 182°C, and an open-drain PWRGD comparator asserting outside 94–107% of nominal VSENSE. The EN pin supports adjustable UVLO via resistor divider and provides 1.25-V threshold with ±50-mV hysteresis.

Key Specifications

Pinout & Package

HVSSOP-10 package with exposed thermal pad (PowerPAD™); 3.0 mm × 3.0 mm body size; requires PCB thermal via connection to ground plane for junction-to-board thermal resistance of 28°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM5164QDDARQ1 and MP2451DT-LF-Z, the TPS54240DGQR uniquely balances industrial input range, 2.5-A capability, Eco-Mode efficiency, and comprehensive supervision features - making it optimal for non-automotive 24-V embedded systems requiring reliability and design flexibility.

Availability

TPS54240DGQR is available at Aetrix Electronics and suitable for industrial 24-V power systems, GSM/GPRS module power, and eMeter power supply applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for TPS54240DGQR 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 conversion solutions.

The TPS54240DGQR belongs to TI's SWIFT™ family of integrated DC-DC converters, engineered specifically for industrial and commercial applications demanding wide-input, high-efficiency, and robust protection features in compact packages.

FAQ

What is the minimum input voltage required for TPS54240DGQR to start switching?

The TPS54240DGQR has an internal undervoltage lockout threshold of 2.5 V, but startup requires sufficient voltage to charge the BOOT capacitor and bias internal circuitry. With EN floating, the device begins switching when VIN reaches approximately 2.5 V; however, reliable operation with full 2.5-A output requires ≥3.5 V per recommended operating conditions. The EN pin can be used to raise this threshold using an external resistor divider.

Does TPS54240DGQR support synchronization to an external clock signal?

Yes, the TPS54240DGQR supports external clock synchronization via the RT/CLK pin. When the voltage on this pin exceeds 2.2 V (typ), the internal oscillator disables and the pin becomes a high-impedance clock input to the internal PLL. It accepts external clock frequencies from 300 kHz to 2.2 MHz, with minimum pulse width of 40 ns. The PLL achieves lock within 100 μs.

How does the Eco-Mode™ function in TPS54240DGQR improve light-load efficiency?

TPS54240DGQR enters Eco-Mode™ when output load current drops below a pulse-skipping threshold - typically around 5 mA for standard 3.3-V designs. In this mode, the high-side MOSFET is inhibited, COMP is clamped at 500 mV, and switching ceases until VOUT decays enough to trigger a correction pulse. This reduces gate drive and switching losses, lowering quiescent current to 138 μA and maintaining >85% efficiency at light loads.

What is the purpose of the SS/TR pin on TPS54240DGQR, and how is it configured?

The SS/TR pin on TPS54240DGQR controls soft-start time and enables voltage tracking for power supply sequencing. A capacitor (e.g., 10 nF) from SS/TR to GND sets the output ramp time; larger values increase rise time. For tracking, a resistor divider from another rail's output can be connected to SS/TR to force proportional startup. During faults, the pin is actively discharged to ensure repeatable restart behavior.

Can TPS54240DGQR operate in 100% duty cycle, and what limits dropout performance?

Yes, TPS54240DGQR supports 100% duty cycle operation as long as the BOOT-to-PH voltage remains above 2.1 V. Dropout is limited by the BOOT UVLO circuit: if input voltage sags or load decreases, the BOOT capacitor may deplete, forcing the high-side MOSFET off until PH is pulled low enough by inductor current to recharge it. To extend dropout, use low-ESR output capacitors and minimize PCB trace resistance between VIN, PH, and GND.