STMicroelectronics LD29150PT18R

Overview

LD29150PT18R from STMicroelectronics is a 1.5 A, fixed 1.8 V low-dropout linear voltage regulator in PPAK package, featuring 400 mV typical dropout at full load, ±1% output voltage accuracy over temperature, and logic-controlled electronic shutdown. It delivers stable power to noise-sensitive core rails in portable computing, embedded controllers, and post-regulation stages after DC-DC converters.

For engineers reviewing the LD29150PT18R datasheet, LD29150PT18R pinout, LD29150PT18R application, or LD29150PT18R equivalent, key selection criteria include dropout performance at 1.5 A, thermal shutdown threshold (150 °C), quiescent current under load (≤80 mA at 1.5 A), and PPAK package thermal resistance (R_thJC = 8 °C/W).

Technical Context

The LD29150PT18R implements a high-accuracy bandgap reference with internal error amplifier and PMOS pass transistor, enabling ultra-low dropout operation without external compensation. Its fixed 1.8 V output is trimmed at wafer level for ±1% initial accuracy across –40 °C to +125 °C junction temperature.

It integrates logic-compatible inhibit control (V_IL ≤ 0.8 V, V_IH ≥ 2 V), thermal shutdown at 150 °C, and internal current limiting. The device operates with input voltages from 3.0 V to 30 V but enters automatic shutdown above 14 V.

Key Specifications

Pinout & Package

LD29150PT18R uses the PPAK (Power Package) thermally enhanced surface-mount package (6.0 × 6.6 × 2.4 mm), optimized for low R_thJC (8 °C/W) and high power density. The exposed drain pad serves as both thermal path and ground connection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TSM1085CP and MCP1826T-1802E/DB, LD29150PT18R uniquely combines PPAK's 8 °C/W junction-to-case thermal resistance, logic-controlled shutdown, and 150 °C thermal cutoff-enabling reliable 1.5 A operation in space-constrained, thermally demanding embedded systems without external thermal management.

Availability

LD29150PT18R is available at Aetrix Electronics and suitable for portable computing core rails, industrial PLC I/O modules, battery-powered sensor nodes, and set-top box memory interfaces requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LD29150PT18R 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 analog, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

LD29150PT18R belongs to ST's high-current LDO family engineered for post-regulation in power management systems where ultra-low dropout, precision output, and robust thermal behavior are mandatory.

FAQ

What is the minimum input voltage required for LD29150PT18R to regulate 1.8 V at 1.5 A?

The minimum input voltage is calculated as V_OUT + V_DROP = 1.8 V + 0.4 V = 2.2 V. However, the datasheet specifies a minimum operating input of 3.0 V for guaranteed performance across temperature and line regulation. Below 3.0 V, output accuracy and transient response degrade due to insufficient headroom for internal biasing.

Can LD29150PT18R be used without an input capacitor?

No. A minimum 330 nF ceramic input capacitor (CI) is required per the datasheet for stability and to limit input voltage spikes during transient load changes. Omitting CI risks oscillation, overshoot, or damage from reverse current during rapid load removal.

How does the INH pin behave during power-up sequencing?

The INH pin must be held low (<0.8 V) or floating (via internal 100 kΩ pull-down) during power-up to ensure controlled start-up. If driven high before IN reaches valid voltage, the device may latch or exhibit erratic enable behavior. Recommended practice is to tie INH to GND until system controller asserts enable.

Is the exposed thermal pad electrically isolated in the PPAK package?

No. The exposed drain pad is internally connected to GND and serves as the primary thermal and electrical return path. It must be soldered to a dedicated GND plane with ≥4 thermal vias (0.3 mm diameter) to achieve the specified R_thJC = 8 °C/W and prevent thermal runaway under full load.