STMicroelectronics LD29300V33

Overview

LD29300V33 from STMicroelectronics is a 3.3 V, 3 A fixed-output low-dropout linear voltage regulator in D2PAK package, featuring 400 mV typical dropout at full load, ±1 % output voltage tolerance at 25 °C, internal current and thermal limiting, and logic-controlled electronic shutdown. It serves as a post-regulator in switching power supplies and powers core logic in battery-operated systems requiring stable, low-noise 3.3 V rails.

For engineers reviewing the LD29300V33 datasheet, LD29300V33 pinout, LD29300V33 application, or LD29300V33 equivalent, key selection criteria include dropout performance at 3 A, ground current behavior under varying load, thermal resistance (R_thJC = 3 °C/W), and compatibility with 10 µF ceramic output capacitance for stability.

Technical Context

The LD29300V33 employs a PNP pass transistor architecture enabling ultra-low dropout-defined as the input-to-output differential at which output drops to 99 % of nominal-of 0.4 V typ. at 3 A across –40 to 125 °C. Its internal bandgap reference and error amplifier deliver ±1 % initial accuracy and <1.0 % load regulation over 10 mA–3 A.

It integrates an inhibit (INH) input for logic-level ON/OFF control (V_IL ≤ 0.8 V, V_IH ≥ 2 V), draws only 130–180 µA quiescent current in shutdown, and maintains stability with ≥10 µF output capacitance without ESR requirements-enabling use with low-ESR ceramic capacitors.

Key Specifications

Pinout & Package

LD29300V33 is housed in a surface-mount D2PAK (TO-263) package with exposed thermal pad, optimized for high-power dissipation and automated assembly. Pin configuration is identical across fixed-output variants: Input (VI), Ground (GND), Output (VO), and Inhibit (INH).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A4700RGWR and NCP1117ST33T3G, LD29300V33 uniquely balances 3 A capability, 0.4 V dropout, integrated shutdown, and D2PAK thermal efficiency-making it the sole option among the three for high-current, battery-critical, and thermally constrained 3.3 V regulation.

Availability

LD29300V33 is available at Aetrix Electronics and suitable for power supply post-regulation, computer system core rails, and battery-powered systems requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.

Supply support for LD29300V33 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 LD29300 series belongs to ST's high-current LDO portfolio, engineered specifically for post-regulation in space-constrained, thermally demanding applications where low dropout and robust protection are mandatory.

FAQ

What is the minimum input voltage required for LD29300V33 to regulate at 3 A?

The minimum input voltage is VO + V_DROP = 3.3 V + 0.4 V = 3.7 V under typical conditions at 3 A and 25 °C. At –40 to 125 °C, worst-case dropout is 0.7 V, so VI must be ≥4.0 V to guarantee regulation across temperature. Input below 2.5 V is prohibited per absolute maximum ratings.

Can LD29300V33 operate without an input bypass capacitor?

No. A minimum 330 nF ceramic capacitor (CI) is required between VI and GND, placed as close as possible to the input pins. Omitting CI risks instability and increased noise susceptibility due to PCB trace inductance interacting with internal control loop dynamics.

Is the INH pin internally pulled up or does it require an external resistor?

The INH pin has no internal pull-up; it must be actively driven high (≥2 V) to enable regulation or pulled low (≤0.8 V) to disable. Leaving INH floating may cause undefined output state and is not recommended-use a 10 kΩ pull-up to VI if always-on operation is intended.

What thermal derating applies when using LD29300V33 on a 2-layer PCB without a heatsink?

With R_thJA = 60 °C/W (D2PAK), ambient temperature of 50 °C, and max junction temperature of 125 °C, allowable power dissipation is (125–50)/60 ≈ 1.25 W. At 3.3 V output and 3 A load, VI must be ≤3.3 V + (1.25 W / 3 A) ≈ 3.72 V-so dropout operation is only viable near the lower input range.