Texas Instruments TPS54340BDDA

Overview

TPS54340BDDA from Texas Instruments is a 42-V input, 3.5-A synchronous step-down DC/DC converter with integrated 92-mΩ high-side MOSFET, Eco-mode™ pulse-skipping for light-load efficiency, and adjustable 100-kHz to 2.5-MHz switching frequency. It delivers regulated output voltages as low as 0.8 V in industrial power supplies requiring wide VIN range and thermal robustness.

For engineers reviewing the TPS54340BDDA datasheet, TPS54340BDDA pinout, TPS54340BDDA application, or TPS54340BDDA equivalent, key selection criteria include input UVLO adjustability via EN pin, BOOT-recharge FET for low-dropout operation, cycle-by-cycle current limiting, thermal shutdown at 176°C, and compatibility with external clock synchronization.

Technical Context

The TPS54340BDDA implements fixed-frequency peak-current-mode control with internal slope compensation to prevent subharmonic oscillation above 50% duty cycle. Its transconductance error amplifier (350 μS typical) drives the COMP pin for loop compensation, while the RT/CLK pin supports both resistor-programmed frequency and PLL-synchronized external clock mode.

It integrates a bootstrap recharge FET to sustain high-duty-cycle operation down to near-V_OUT, with BOOT-SW UVLO monitoring at 2.1 V. Protection includes thermal shutdown (176°C), overvoltage transient protection (OVP), frequency foldback during overload, and accurate cycle-by-cycle current limit (4.5–6.8 A depending on conditions).

Key Specifications

Pinout & Package

TPS54340BDDA is housed in an 8-pin HSOIC PowerPAD™ package (4.89 mm × 3.90 mm) with exposed thermal pad electrically connected to GND for enhanced heat dissipation. The PowerPAD must be soldered to a thermally optimized PCB copper area per TI layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM5164PWPR and TPS54540DDAR, the TPS54340BDDA offers optimal balance of 3.5-A capability, Eco-mode efficiency, and flexible frequency tuning-making it ideal for cost- and thermally constrained 12/24-V industrial designs where 42-V max input suffices.

Availability

TPS54340BDDA is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, ruggedized communications equipment, and programmable logic controllers requiring stable component supply across extended temperature and voltage ranges.

Supply support for TPS54340BDDA 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 TPS54340B belongs to TI's SWIFT™ DC/DC converter portfolio, designed specifically for high-input-voltage industrial and automotive applications demanding robust thermal performance, wide VIN tolerance, and feature-rich protection.

FAQ

What is the minimum input voltage required for TPS54340BDDA to regulate a 5-V output?

The minimum input voltage depends on output current, inductor DCR, diode forward drop, and MOSFET R_DS(on). For a 5-V/3.5-A output with typical components, Equation 1 in the datasheet yields ~6.2 V minimum at full load. At light load, TPS54340BDDA can operate down to ~5.1 V due to its integrated BOOT recharge FET enabling near-100% duty cycle. Always verify using worst-case component tolerances and temperature drift.

Can TPS54340BDDA synchronize to an external clock, and what are the valid frequency and voltage levels?

Yes, TPS54340BDDA supports external clock synchronization via the RT/CLK pin. It accepts TTL/CMOS-compatible clocks from 160 kHz to 2.3 MHz with logic-high threshold of 1.55–2.0 V and logic-low threshold of 0.5–1.2 V. The internal PLL locks within 78 μs, and clock edges must be clean and monotonic; missing edges revert the device to RT-resistor mode.

How does the Eco-mode™ operation of TPS54340BDDA affect output voltage ripple and transient response?

In Eco-mode™, TPS54340BDDA pulses at variable frequency to maintain regulation, increasing low-frequency output ripple (typically <10 mV_PP at 24 mA load). Transient response degrades slightly versus forced-PWM mode due to longer off-times, but remains adequate for non-critical logic rails. For sensitive analog loads, disable Eco-mode using the EN pin or select forced-PWM variants like TPS54340DDA (non-B version).

What is the recommended BOOT capacitor value and dielectric type for TPS54340BDDA?

Texas Instruments specifies a 0.1-μF ceramic capacitor between BOOT and SW pins. Use X7R or X5R dielectric with 10-V or higher voltage rating to ensure stable capacitance across temperature and bias. Place the capacitor as close as possible to the pins with short, low-inductance traces; avoid Y5V/Z5U due to severe capacitance loss at DC bias and temperature extremes.

Does TPS54340BDDA require an external catch diode, or is it fully integrated?

TPS54340BDDA integrates the high-side MOSFET and BOOT recharge FET but does not integrate the low-side power path. An external Schottky diode (or synchronous MOSFET driven by a gate driver) is required from SW to GND to complete the buck power stage. The IC monitors BOOT-SW voltage and disables the high-side switch if the BOOT capacitor discharges below 2.1 V, allowing the external diode to conduct and recharge it.