STMicroelectronics LF30CDT-TR

Overview

LF30CDT-TR from STMicroelectronics is a 3.0 V fixed-output, very low dropout (LDO) linear voltage regulator in DPAK package with logic-controlled shutdown, delivering up to 500 mA output current, 0.4 V typical dropout at 500 mA, ±2% output voltage accuracy at 25°C, and 50 µA quiescent current in OFF mode. It serves as a local power supply for microcontroller cores, sensor interfaces, and portable instrumentation requiring stable low-noise bias under battery-constrained conditions.

For engineers reviewing the LF30CDT-TR datasheet, LF30CDT-TR pinout, LF30CDT-TR application, or LF30CDT-TR equivalent, key selection criteria include its 0.4 V dropout at full load, 50 µA shutdown current, 2.2 µF minimum output capacitance requirement, -40 to 125°C operating junction temperature range, and TTL-compatible enable input for system-level power sequencing.

Technical Context

The LF30CDT-TR implements a PNP pass transistor architecture enabling ultra-low dropout performance, with internal current and thermal limiting ensuring robustness across load and ambient variations. Its shutdown control pin (Pin 2) accepts TTL-level logic signals to disable output and reduce quiescent current to 50 µA, supporting dynamic power management in multi-rail embedded systems.

Stability is achieved with only 2.2 µF ceramic output capacitance (ESR 0.1–10 Ω), eliminating need for large electrolytic capacitors. Supply voltage rejection reaches 81 dB at 120 Hz and maintains ≥65 dB up to 10 kHz, making it suitable for noise-sensitive analog and mixed-signal circuits powered from noisy DC-DC outputs or battery sources.

Key Specifications

Pinout & Package

LF30CDT-TR is housed in a surface-mount DPAK (TO-252) package with exposed thermal pad for enhanced power dissipation. Pin configuration (top view): Pin 1 = Output (V_O), Pin 2 = Shutdown Control (ON/OFF), Pin 3 = Ground (GND), Pin 4 = Input (V_IN). The DPAK footprint supports >1 A thermal current handling with standard PCB copper pour.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LDL113PU33R and NCP1117DT33G, LF30CDT-TR uniquely delivers 3.0 V output, 500 mA capability, sub-0.5 V dropout, and integrated shutdown in a thermally efficient DPAK package-making it optimal for battery-powered, noise-sensitive, and thermally constrained designs requiring precise 3.0 V regulation.

Availability

LF30CDT-TR is available at Aetrix Electronics and suitable for automotive body controllers, industrial sensor nodes, portable medical instruments, and smart energy meters requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for LF30CDT-TR 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, designing and manufacturing microcontrollers, power management ICs, sensors, and analog devices for automotive, industrial, and consumer markets.

The LF00 series was developed specifically for ultra-low-dropout, low-quiescent-power regulation in battery-operated and thermally demanding embedded systems-emphasizing simplicity, reliability, and minimal external component count.

FAQ

What is the minimum output capacitance required for stable operation of LF30CDT-TR?

The LF30CDT-TR requires a minimum 2.2 µF ceramic output capacitor with ESR between 0.1 Ω and 10 Ω. This value is validated per ST's test circuits and ensures phase margin >45°, load transient recovery <50 µs, and immunity to PCB layout parasitics. Larger values improve ripple suppression but are not necessary for stability.

Does LF30CDT-TR include overcurrent and thermal protection?

Yes, LF30CDT-TR integrates both foldback current limiting and thermal shutdown circuitry. Output current is internally limited to approximately 1 A, and junction temperature is monitored continuously; if it exceeds ~160°C, the regulator shuts down until temperature falls by ~20°C, then auto-recovers. These protections are specified in ST's Absolute Maximum Ratings and Electrical Characteristics tables.

Can LF30CDT-TR be used with an input voltage lower than 4.0 V?

No-ST specifies 4.0 V as the minimum input voltage for guaranteed 3.0 V output at 500 mA due to dropout constraints. At 3.4 V input, the device can still regulate 3.0 V at reduced load (≤200 mA), but operation below 4.0 V is outside datasheet specifications and not characterized for line/load regulation, PSRR, or thermal performance.

Is the shutdown pin of LF30CDT-TR compatible with 1.8 V logic levels?

No-the shutdown pin requires TTL-compatible thresholds: logic low ≤0.8 V and logic high ≥2.0 V over the full -40 to 125°C range. A 1.8 V GPIO may not reliably assert logic high, risking partial enable states. Interface via a level-shifter or pull-up to 3.3/5 V is recommended when driving from 1.8 V microcontrollers.