Texas Instruments LMR51430YFDDCR

Overview

LMR51430YFDDCR from Texas Instruments is a synchronous buck DC-DC converter IC designed for industrial power conditioning, delivering up to 3-A continuous output current with 4.5-V to 36-V input range, fixed 1.1-MHz switching frequency, and FPWM operation mode for constant-frequency, low-ripple regulation in compact SOT-23-6 packages.

For engineers reviewing the LMR51430YFDDCR datasheet, LMR51430YFDDCR pinout, LMR51430YFDDCR application, or LMR51430YFDDCR equivalent, key selection criteria include its 1.1-MHz FPWM mode, ±1.5% reference voltage tolerance, 70-ns minimum on-time, integrated bootstrap driver, and precision enable with adjustable UVLO capability.

Technical Context

The LMR51430YFDDCR implements fixed-frequency peak-current mode control with internal compensation, supporting FPWM operation to maintain constant 1.1-MHz switching across full load while minimizing output voltage ripple. Its architecture integrates high-side and low-side NMOS power switches with cycle-by-cycle current limiting and hiccup-mode short-circuit protection.

It features a precision 0.6-V internal reference, programmable output via resistor divider on FB, and a dedicated CB pin for bootstrap capacitor coupling to SW - enabling efficient high-side gate drive without external charge pump circuitry. Thermal shutdown triggers at 163°C with 22°C hysteresis.

Key Specifications

Pinout & Package

LMR51430YFDDCR is housed in a 6-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for high-density PCB layouts and thermal performance on 2-layer boards (R_θJA ≈ 80°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMR51430YDDCR and TPS54302DRCT, the LMR51430YFDDCR uniquely combines 1.1-MHz FPWM operation, 36-V input rating, and hiccup-mode protection - making it optimal for industrial applications demanding consistent switching behavior, wide input tolerance, and robust fault handling without layout changes.

Availability

LMR51430YFDDCR is available at Aetrix Electronics and suitable for industrial motor drives, building automation sensors, appliance control boards, and general-purpose wide-VIN power supplies requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for LMR51430YFDDCR 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-reliability power conversion solutions.

The LMR51430 family was developed for rugged industrial point-of-load applications requiring wide input range, compact footprint, and simplified design - targeting cost-sensitive, space-constrained systems where ease-of-use and thermal resilience are critical.

FAQ

What is the switching frequency of the LMR51430YFDDCR and how does it affect design?

The LMR51430YFDDCR operates at a fixed 1.1-MHz switching frequency. This enables use of smaller magnetics and output capacitors, reducing solution size and cost. The constant frequency simplifies EMI filtering and ensures predictable ripple behavior across all load conditions - unlike PFM variants that vary frequency at light loads. Designers can select standard 1.5-µH or 2.2-µH shielded inductors rated for ≥3.5-A saturation current.

Does the LMR51430YFDDCR support adjustable output voltage, and what is the reference voltage accuracy?

Yes, the LMR51430YFDDCR supports fully adjustable output voltage via an external resistor divider on the FB pin. It uses a precision 0.6-V internal reference with ±1.5% tolerance over –40°C to +150°C, enabling accurate regulation from 0.6 V up to 95% of VIN. For example, with a 100-kΩ top resistor and 12.1-kΩ bottom resistor, the device delivers 3.3 V ±2.5% over temperature and line.

How does the enable (EN) pin function on the LMR51430YFDDCR, and can it be used for system-level UVLO?

The EN pin on the LMR51430YFDDCR is a precision enable input with 1.1 V to 1.36 V rising threshold and 0.95 V to 1.22 V falling threshold. It supports system-level UVLO by connecting two external resistors (RENT and RENB) between VIN and GND - allowing custom turn-on/off thresholds independent of the IC's internal UVLO. This feature is used in battery-powered or utility-fed systems to prevent operation outside safe input ranges.

What protection features are built into the LMR51430YFDDCR?

The LMR51430YFDDCR includes cycle-by-cycle overcurrent limiting on both high-side and low-side FETs, hiccup-mode short-circuit protection (135-ms off-time), thermal shutdown at 163°C with 22°C hysteresis, and input undervoltage lockout (UVLO) with 0.3-V hysteresis. These protections operate autonomously without external components, safeguarding the IC and downstream circuitry during fault conditions such as output shorts, excessive ambient temperature, or input brownouts.

Is the LMR51430YFDDCR pin-compatible with other TI buck converters, and what does that mean for design reuse?

Yes, the LMR51430YFDDCR is pin-to-pin compatible with the TPS54202 and TPS54302. This means identical PCB layout, footprint, and external component placement can be reused across these devices - accelerating design iteration and enabling direct upgrades (e.g., from 2-A to 3-A output capability or from 28-V to 36-V input range). No schematic or layout changes are required when substituting within this compatible group.