STMicroelectronics LD29150DT18R

Overview

LD29150DT18R from STMicroelectronics is a 1.5 A, fixed-output (1.8 V), very low-dropout linear voltage regulator in PPAK package. It delivers ±1% output accuracy over -40 °C to +125 °C, achieves 400 mV dropout at full load (1.5 A), and features logic-controlled electronic shutdown, internal current/thermal limiting, and 72 µV_RMS output noise (10 Hz–100 kHz). It is used in post-regulation of switching supplies for CPU core rails in embedded computing systems.

For engineers reviewing the LD29150DT18R datasheet, LD29150DT18R pinout, LD29150DT18R application, or LD29150DT18R equivalent, key selection criteria include guaranteed 1.5 A output current, sub-0.5 V dropout at rated load, shutdown control input compatibility with 0.8 V / 2 V logic thresholds, and thermal shutdown activation at 150 °C - all critical for compact, high-efficiency power delivery in space-constrained industrial and computing designs.

Technical Context

The LD29150DT18R implements a PNP-based LDO architecture with integrated pass transistor, enabling ultra-low dropout by minimizing V_CE(sat) dependency. Its reference voltage is trimmed to 1.23 V with ±1% tolerance, and output is fixed via internal resistor divider - eliminating external feedback components.

It integrates an inhibit (shutdown) input with 5–10 µA leakage, compatible with standard CMOS logic levels (V_IL ≤ 0.8 V, V_IH ≥ 2 V), and employs thermal foldback to limit junction temperature to 150 °C. Quiescent current remains stable across load (15–40 mA at 0.75 A, 30–80 mA at 1.5 A) and drops to 130–180 µA in shutdown mode.

Key Specifications

Pinout & Package

The LD29150DT18R is housed in a thermally enhanced PPAK (Power Package) surface-mount package with exposed thermal pad, offering R_thJC = 8 °C/W for efficient heat transfer to PCB copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TSM1083-18 and MCP1826-1802E/DB, the LD29150DT18R uniquely combines ±1% accuracy, 0.4 V dropout at full load, and a dedicated logic-compatible shutdown pin - making it optimal for applications requiring precise, controllable, and thermally robust 1.8 V regulation in compact industrial and computing platforms.

Availability

LD29150DT18R is available at Aetrix Electronics and suitable for embedded computing power, FPGA I/O supply, battery-powered instrumentation, and TV/display post-regulation requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for LD29150DT18R 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 industrial, automotive, and consumer markets.

The LD29150 series belongs to ST's high-current LDO portfolio, engineered specifically for post-regulation in power-constrained systems where ultra-low dropout, high accuracy, and integrated protection are mandatory - targeting computing, display, and portable instrumentation applications.

FAQ

What is the minimum input voltage required for the LD29150DT18R to regulate 1.8 V at 1.5 A?

The minimum input voltage is 2.2 V, derived from the 1.8 V output plus the typical 0.4 V dropout at 1.5 A. The datasheet specifies that regulation is maintained down to VI = VO + V_DROP, and absolute minimum VI is 3.0 V for guaranteed performance across temperature and process variation - but functional regulation begins at 2.2 V under nominal conditions.

Does the LD29150DT18R require an external capacitor on the INH pin for stable shutdown operation?

No external capacitor is required on the INH pin. The inhibit input has TTL/CMOS-compatible thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2 V) and draws only 5–10 µA leakage current. A simple pull-up resistor to VI or direct MCU GPIO connection suffices; no filtering or debouncing capacitor is specified or needed per the datasheet.

Can the LD29150DT18R be used without the recommended 10 µF output capacitor?

No - the 10 µF ceramic output capacitor is mandatory for stability, as confirmed by Figure 18 (Stability vs. C_O) in the datasheet. Using less capacitance risks oscillation or excessive ringing under load transients. The device is not internally compensated for lower values, and operation without it violates the design conditions under which electrical characteristics are guaranteed.

How does thermal performance differ between the PPAK and DPAK packages for the LD29150DT18R?

Both PPAK and DPAK packages share identical R_thJC = 8 °C/W and R_thJA = 100 °C/W per Table 3, meaning junction-to-case and junction-to-ambient thermal resistance are equal. The PPAK variant offers identical thermal performance in a smaller footprint (6.0 × 6.4 mm vs. DPAK's 6.2 × 6.6 mm) and improved manufacturability due to its gull-wing leadframe design, but no thermal advantage is claimed in the datasheet.