STMicroelectronics LD39150DT12-R

Overview

LD39150DT12-R from STMicroelectronics is a fixed-output 1.2 V ultra-low-dropout linear regulator in DFN6 (3×3 mm) package, delivering up to 1.5 A output current with 200 mV typical dropout at full load and 1 µA max quiescent current in shutdown mode. It operates from 2.5 V to 6 V input, features logic-controlled inhibit, internal current/thermal limiting, and ±1.5% output voltage tolerance at 25 °C - designed for low-voltage microprocessor core power supply in space-constrained embedded systems.

For engineers reviewing the LD39150DT12-R datasheet, LD39150DT12-R pinout, LD39150DT12-R application, or LD39150DT12-R equivalent, key selection criteria include dropout voltage under 1.5 A load, shutdown current <1 µA, stability with 2.2 µF ceramic output capacitor, and thermal resistance of 40 °C/W (junction-to-ambient with PCB ground plane heatsink).

Technical Context

The LD39150DT12-R uses BiCMOS process technology to decouple quiescent current from load current - enabling 1 mA typical IQ at 1.5 A output while maintaining fast transient response. Its error amplifier drives an N-channel pass transistor with integrated current sensing and thermal foldback protection.

It implements a dedicated inhibit input (VINH) with 0.3 V low threshold and 2 V high threshold, requiring external pull-up or active drive - no internal biasing. Output voltage is internally trimmed to 1.2 V (not adjustable), eliminating external feedback resistors and simplifying layout for fixed-rail applications.

Key Specifications

Pinout & Package

LD39150DT12-R is housed in a thermally enhanced DFN6 (3 × 3 mm) package with exposed thermal pad (TAB) electrically connected to GND. The 6-pin configuration supports compact two-layer PCB layouts and efficient heat dissipation via bottom-side copper pour.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-dropout linear regulator applications.

Compared with XC6216D122MR-G and BD39150FP-E2, LD39150DT12-R uniquely combines 1.5 A capability, 200 mV dropout, 1 µA shutdown, and DFN6 thermal efficiency - making it optimal for space- and power-constrained 1.2 V core supplies.

Availability

LD39150DT12-R is available at Aetrix Electronics and suitable for mobile baseband power, FPGA core rail supply, and automotive infotainment SoC applications requiring stable component supply, extended temperature support (-40 to 125 °C), and long-term industrial lifecycle assurance.

Supply support for LD39150DT12-R 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing silicon solutions for automotive, industrial, and consumer markets since 1987.

The LD39150 belongs to ST's high-performance linear regulator product line, engineered specifically for low-voltage, high-current digital core power delivery where ultra-low dropout, minimal quiescent current, and ceramic-capacitor compatibility are mandatory.

FAQ

What is the minimum input voltage required for 1.2 V output at 1.5 A load?

The LD39150DT12-R requires a minimum input voltage of 1.4 V to maintain regulation at 1.5 A, based on its 200 mV typical dropout voltage. At worst-case (400 mV max dropout), 1.6 V input is needed. Input must stay within absolute maximum rating of 6.5 V.

Can the LD39150DT12-R be used without an input capacitor?

No - a minimum 1 µF ceramic input capacitor is mandatory and must be placed ≤1 cm from the VI pin with direct low-inductance GND connection. Omitting it risks instability, voltage overshoot during startup, and failure to meet ESD immunity specifications per IEC 61000-4-2.

Is the thermal pad (TAB) required to be soldered to PCB ground?

Yes - the TAB is electrically connected to GND and thermally critical. To achieve the specified 40 °C/W junction-to-ambient thermal resistance, it must be fully soldered to ≥2 cm² of inner/outer layer PCB copper connected to solid ground plane. Floating or undersized pads cause thermal derating and premature shutdown.

Does the LD39150DT12-R support adjustable output voltages?

No - LD39150DT12-R is a fixed 1.2 V output variant. Adjustable versions (e.g., LD39150PU-R) use the VSENSE pin for external feedback, but DT12-R has VSENSE unconnected and internally trimmed. Using it as adjustable would result in undefined output voltage and potential instability.