STMicroelectronics LD29150PT33R

Overview

LD29150PT33R from STMicroelectronics is a 3.3 V fixed-output, 1.5 A low-dropout linear regulator in PPAK package, featuring 400 mV typical dropout at full load, ±1% output voltage accuracy over temperature, and integrated thermal shutdown and current limiting. It delivers stable post-regulation for CPU core supplies in embedded computers and battery-powered instrumentation where ultra-low dropout and ground current are critical.

For engineers reviewing the LD29150PT33R datasheet, LD29150PT33R pinout, LD29150PT33R application, or LD29150PT33R equivalent, key selection criteria include dropout voltage at 1.5 A, quiescent current under load, thermal resistance (R_thJC = 8 °C/W), and logic-controlled shutdown capability - all confirmed in ST's DocID9614 Rev 20.

Technical Context

The LD29150PT33R uses a PMOS pass transistor architecture enabling 400 mV dropout at 1.5 A while maintaining 15–80 mA quiescent current across load and temperature. Its internal reference (1.23 V for adjustable variants) is trimmed to ±1% at 25 °C and drifts <±2% over –40 to +125 °C junction range.

It integrates an inhibit input (VINH) compatible with TTL/CMOS logic levels (V_IL ≤ 0.8 V, V_IH ≥ 2 V), enabling system-level power sequencing. Thermal shutdown activates at 150 °C, and short-circuit current is limited to 2.2 A independent of input-output differential.

Key Specifications

Pinout & Package

LD29150PT33R is housed in a thermally enhanced PPAK (Power Package) surface-mount package with exposed thermal pad, optimized for high-current DC/DC post-regulation. The 3-pin configuration supports compact layout and efficient PCB heat spreading.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LD29150PT33R, TSM10833D offers marginally lower dropout but sacrifices system-level power control, while MCP1826T-3302E/OT trades output accuracy for ultra-low shutdown current - making LD29150PT33R optimal for applications needing both precision regulation and integrated sequencing.

Availability

LD29150PT33R is available at Aetrix Electronics and suitable for industrial PLC I/O modules, portable medical monitors, embedded computer power systems, and smart home hubs requiring stable component supply with guaranteed long-term availability.

Supply support for LD29150PT33R 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 LD29150 series belongs to ST's high-current LDO portfolio, engineered specifically for post-regulation in space-constrained, thermally demanding applications such as computing peripherals and battery-powered instrumentation.

FAQ

What is the minimum input voltage required for LD29150PT33R to regulate 3.3 V at 1.5 A?

The minimum input voltage is 3.7 V, calculated as V_OUT + V_DROP = 3.3 V + 0.4 V (typical dropout at 1.5 A). At 125 °C junction temperature, worst-case dropout rises to 0.7 V, requiring ≥4.0 V input for guaranteed regulation under full load and high temperature.

Does LD29150PT33R require an external capacitor on the VINH pin for noise immunity?

No external capacitor is specified or required on VINH. The inhibit input has built-in hysteresis and accepts TTL/CMOS logic levels directly; its input current is ≤10 µA across –40 to +125 °C, enabling robust interfacing with microcontroller GPIOs without filtering components.

Can LD29150PT33R be used in parallel to increase output current beyond 1.5 A?

Parallel operation is not supported. The device lacks current-sharing features such as current-sense outputs or master-slave synchronization. Attempting parallel connection risks thermal runaway due to mismatched dropout voltages and unbalanced load distribution.

What is the recommended PCB layout practice for thermal performance of the PPAK package?

Maximize copper area connected to the exposed thermal pad using ≥4 thermal vias (0.3 mm diameter) to an internal or bottom-layer ground plane. Maintain ≥1.5 mm clearance between the pad and adjacent traces, and avoid solder mask over the pad to ensure optimal thermal conduction to the PCB.