STMicroelectronics LD29080DT33R

Overview

LD29080DT33R from STMicroelectronics is a fixed-output 3.3 V, 800 mA low-dropout linear regulator in DPAK package, featuring 400 mV typical dropout at full load, ±1% output voltage accuracy over temperature, and logic-controlled electronic shutdown. It delivers stable power for microcontroller core supplies, FPGA I/O banks, and industrial sensor interfaces where low quiescent current (14–35 mA at 800 mA load) and high PSRR (52–67 dB at 120 Hz) are critical.

For engineers reviewing the LD29080DT33R datasheet, LD29080DT33R pinout, LD29080DT33R application, or LD29080DT33R equivalent, key selection criteria include guaranteed 800 mA output current, thermal shutdown with internal current limiting, adjustable inhibit control (VIH ≥ 2 V), and compatibility with 10 µF ceramic output capacitance for stability.

Technical Context

The LD29080DT33R implements a PNP-based LDO architecture with internal reference (1.23 V typ.), enabling ultra-low dropout by minimizing saturation voltage across the pass transistor. Its inhibit input (INHIBIT pin) provides active-high enable control without internal pull-up, requiring external bias ≥2 V to maintain regulation.

Designed for post-regulation after switching converters, it maintains ±0.5% line regulation (VI = 4.3–13 V) and ±1.0% load regulation (IO = 10–800 mA), while delivering 132 µV_RMS output noise (10 Hz–100 kHz) under 100 mA load - critical for noise-sensitive analog and RF subsystems.

Key Specifications

Pinout & Package

DPAK (TO-252) package: thermally enhanced surface-mount outline with exposed drain pad for improved heat dissipation (R_thJA = 100 °C/W, R_thJC = 8 °C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with TSM10833DCQ and MCP1703T-3302E/MB, the LD29080DT33R uniquely combines 800 mA capability, 0.4 V dropout, and logic-enable functionality in a thermally optimized DPAK - making it the only option among the three qualified for high-current, low-headroom, and remotely controllable applications.

Availability

LD29080DT33R is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical patient monitoring sensors, and networking edge devices requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LD29080DT33R 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 LD29080 series belongs to ST's high-accuracy, medium-current LDO portfolio, engineered specifically for post-regulation in power-constrained systems where ultra-low dropout, thermal resilience, and enable control are mandatory.

FAQ

What is the minimum load current required for stable operation?

The LD29080DT33R requires a minimum load current of 2 mA across its full operating temperature range (−40 °C to +125 °C) to prevent output voltage rise caused by internal leakage currents. This is not a recommendation but a design requirement specified in the datasheet to ensure output accuracy remains within ±1% tolerance.

Can the INHIBIT pin be left unconnected?

No - the INHIBIT pin has no internal pull-up. Leaving it floating may result in unpredictable enable/disable behavior due to noise coupling. To guarantee ON-mode operation, connect INHIBIT to VI through a resistor or directly to a logic-high source ≥2 V. For OFF-mode default, tie it to GND.

Is an external capacitor required on the INHIBIT pin?

No external capacitor is required or recommended on the INHIBIT pin. The pin is a high-impedance CMOS input with ≤10 µA leakage current. Adding capacitance would slow enable/disable transitions and is unnecessary for noise immunity given its 0.8 V/2 V logic thresholds and specified 5–10 µA input current.

What output capacitor value and type ensure stability?

A minimum 10 µF ceramic capacitor (X5R/X7R, 6.3 V rating) is required at the VO pin for guaranteed stability across all operating conditions. The datasheet confirms stability with CO ≥ 10 µF and ESR ≤ 100 mΩ; tantalum or aluminum electrolytics are not recommended due to higher ESR and aging effects.