STMicroelectronics LD29150DT33

Overview

LD29150DT33 from STMicroelectronics is a fixed-output 3.3 V, 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 FPGA core supplies, embedded microcontroller I/O rails, and battery-powered industrial sensors where ultra-low dropout and low ground current are critical.

For engineers reviewing the LD29150DT33 datasheet, LD29150DT33 pinout, LD29150DT33 application, or LD29150DT33 equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation guidance, and confirmed alternative options with functional trade-offs.

Technical Context

The LD29150DT33 uses a PNP pass transistor architecture enabling 0.4 V dropout at 1.5 A, with internal reference trimmed to ±1% at 25 °C and maintained across –40 °C to +125 °C junction range. Its quiescent current remains below 80 mA at full load and drops to 130–180 µA in logic-controlled shutdown mode.

It integrates an inhibit input (INH) compatible with TTL/CMOS logic levels (VIL ≤ 0.8 V, VIH ≥ 2 V), enabling system-level power sequencing. Output noise is specified at 132 µVRMS (10 Hz–100 kHz), and supply voltage rejection reaches 67 dB at 120 Hz under 0.75 A load.

Key Specifications

Pinout & Package

LD29150DT33 is housed in a thermally enhanced PPAK (Power Package) surface-mount package with exposed thermal pad, optimized for high-power dissipation in compact layouts. The package measures 6.0 × 6.4 mm with 1.0 mm height and supports JEDEC-standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LD29150DT33R, the base part offers identical performance in tube packaging; versus TLV1117-33CDCYR, it delivers 50% higher current, 67% lower dropout, tighter accuracy, and integrated enable-making it essential for demanding industrial and medical power rails.

Availability

LD29150DT33 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, FPGA-based edge gateways, battery-powered sensor nodes, and portable medical diagnostics requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LD29150DT33 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.

The LD29150 series belongs to ST's high-current LDO portfolio, engineered specifically for post-regulation in power-constrained, thermally demanding systems where minimal dropout and precise voltage stability are non-negotiable.

FAQ

What is the minimum input voltage required for LD29150DT33 to regulate 3.3 V at 1.5 A?

The minimum input voltage is 3.7 V: 3.3 V output plus 0.4 V typical dropout. At 1.5 A load and –40 °C to +125 °C, dropout rises to 0.7 V max, so 4.0 V input ensures regulation across full temperature and process variation. Input must remain ≥4.3 V per datasheet test condition for guaranteed 3.3 V accuracy.

Can LD29150DT33 be used without the INH pin connected?

Yes-the INH pin is internally pulled up; leaving it unconnected defaults the device to ON mode. However, for deterministic startup and ESD robustness, ST recommends tying INH to VIN through a 10 kΩ resistor or directly to a controlled logic signal. Floating INH may cause erratic behavior in noisy environments.

What output capacitor value and type are required for stability?

A minimum 10 µF low-ESR ceramic capacitor (X5R/X7R, ≤100 mΩ ESR) is required at the OUT pin, placed within 5 mm of the device. Larger values (e.g., 22 µF) improve transient response but do not affect stability. Aluminum polymer or tantalum caps are acceptable if ESR is 10–100 mΩ; avoid high-ESR electrolytics.

How does thermal performance differ between PPAK and DPAK packages for LD29150DT33?

Both packages share identical R_thJC = 8 °C/W, but PPAK offers superior R_thJA in optimized layouts due to its exposed thermal pad design. With 10 cm² 2-oz copper pour, PPAK achieves ~35 °C/W vs. DPAK's ~45 °C/W. This allows 1.5 A continuous operation at up to 75 °C ambient in PPAK, versus ~65 °C for DPAK under identical PCB conditions.