Texas Instruments TPS5450DDA

Overview

TPS5450DDA from Texas Instruments is a 5-A, wide-input (5.5 V to 36 V), synchronous step-down DC/DC converter with integrated 110-mΩ high-side N-channel MOSFET, fixed 500-kHz switching frequency, and adjustable output down to 1.22 V (±1.5% initial accuracy). It delivers regulated 5-V/5-A power for LCD displays and 24-V industrial power systems.

For engineers reviewing the TPS5450DDA datasheet, TPS5450DDA pinout, TPS5450DDA application, or TPS5450DDA equivalent, key selection criteria include input voltage feed-forward for line transient response, internal compensation reducing external parts, thermal shutdown at 135°C, ENA-controlled 18-μA shutdown current, and PowerPAD-enabled thermal performance in HSOP-8.

Technical Context

The TPS5450DDA implements constant-frequency voltage-mode control with integrated voltage feed-forward to maintain stable modulator gain across input voltage variations, improving line regulation and transient response. Its internal 1.221-V bandgap reference is trimmed to ±1.5% accuracy at 25°C and drifts <±10 mV over –40°C to 125°C junction temperature.

Protection architecture includes cycle-by-cycle overcurrent limiting (6–9 A trip), hiccup-mode fault recovery, overvoltage protection at 112.5% × VREF, undervoltage lockout with 5.3 V start threshold and 330 mV hysteresis, and thermal shutdown at 135°C with 14°C hysteresis. The BOOT-PH bootstrap circuit drives the integrated MOSFET using an external 0.01-μF ceramic capacitor.

Key Specifications

Pinout & Package

TPS5450DDA uses an 8-pin HSOP PowerPAD™ package (4.89 mm × 3.90 mm) with thermally enhanced exposed pad (Pin 9, GND) requiring PCB soldering for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2678-5.0 and TPS5430DDAR, the TPS5450DDA provides higher output current, integrated compensation, and voltage feed-forward-enabling faster design cycles and better line regulation in variable-input industrial systems without sacrificing thermal robustness.

Availability

TPS5450DDA is available at Aetrix Electronics and suitable for high-density point-of-load regulators, LCD display power supplies, and 24-V distributed power systems requiring stable component supply across production lifecycles.

Supply support for TPS5450DDA 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 over 90 years of innovation in industrial, automotive, and communications markets.

The TPS5450DDA belongs to TI's SWIFT™ family of integrated DC/DC converters, designed specifically for high-efficiency, space-constrained industrial and display power applications requiring wide input range and robust protection.

FAQ

What is the minimum input voltage required for TPS5450DDA to start switching?

The TPS5450DDA incorporates an undervoltage lockout (UVLO) circuit with a typical start threshold of 5.3 V and 330 mV hysteresis. Below 5.3 V, the device remains disabled and will not initiate switching-even if the ENA pin is asserted. Once VIN exceeds 5.3 V, the internal slow-start begins and the TPS5450DDA ramps output voltage linearly over ~8 ms. This ensures reliable startup from 12-V and 24-V rails while rejecting brownout noise.

Can TPS5450DDA operate with an output voltage lower than 1.22 V?

No, the TPS5450DDA cannot regulate below its internal 1.221-V reference voltage. The feedback loop compares VSENSE to this fixed bandgap reference; therefore, the lowest achievable output is set by the resistor divider ratio yielding VOUT = 1.221 × (1 + R1/R2). For example, with R2 = 10 kΩ and R1 = 0 Ω, VOUT = 1.221 V. Attempting sub-1.22-V operation results in loss of regulation and uncontrolled drop-out behavior. The TPS5450DDA datasheet specifies 1.22 V as the absolute minimum adjustable output.

How is thermal performance affected if the PowerPAD on TPS5450DDA is not soldered to the PCB?

If the exposed PowerPAD (Pin 9) of the TPS5450DDA is not soldered to a thermally conductive PCB copper area, junction-to-board thermal resistance degrades from 0.8°C/W to >10°C/W, causing rapid thermal runaway above ~2 A load. The device will trigger thermal shutdown within seconds at full 5-A load. TI specifies mandatory soldering of the PowerPAD to a minimum 100 mm² copper pour with ≥4 thermal vias. Without this, RθJA increases to ~42°C/W, violating SOA limits and voiding performance guarantees.

Does TPS5450DDA support adjustable switching frequency?

No, the TPS5450DDA uses an internally set free-running oscillator fixed at 500 kHz (typical), with tolerance of ±100 kHz over temperature and input voltage. There is no external frequency sync pin, resistor programming option, or register interface to adjust switching frequency. This fixed frequency simplifies EMI filter design and enables consistent inductor sizing but precludes optimization for ultra-low-noise or high-efficiency light-load operation. Designs requiring variable frequency must select alternatives like TPS54620 or LM5143A.

What protection features are built into TPS5450DDA?

The TPS5450DDA integrates five core protections: (1) cycle-by-cycle overcurrent limiting (6–9 A trip), (2) hiccup-mode recovery for sustained faults, (3) overvoltage protection at 112.5% × VREF, (4) thermal shutdown at 135°C with 14°C hysteresis, and (5) undervoltage lockout with 5.3 V start threshold. All functions operate autonomously without external components. Notably, the OVP and thermal shutdown force the high-side MOSFET off and hold it off until fault clearance-ensuring fail-safe behavior in safety-critical industrial power rails.