STMicroelectronics LF30CDT

Overview

LF30CDT from STMicroelectronics is a 3.0 V fixed-output, very low dropout (LDO) linear regulator in TO-220FP package with logic-controlled shutdown, 500 mA output current capability, 0.4 V typical dropout at 500 mA, ±2% output voltage accuracy at 25°C, and operation over –40 to +125°C junction temperature range. It serves as a local power supply for microcontroller cores, sensor interfaces, and low-power communication modules in battery-powered industrial and automotive systems.

For engineers reviewing the LF30CDT datasheet, LF30CDT pinout, LF30CDT application, or LF30CDT equivalent, this page delivers verified electrical specs, validated shutdown control behavior, thermal resistance data (R_thJC = 5°C/W), stability requirements (2.2 µF ceramic output capacitor), and real-world use context for embedded power rail design.

Technical Context

The LF30CDT implements a PNP pass transistor architecture enabling ultra-low dropout voltage-0.4 V typ. at 500 mA load-and supports logic-controlled electronic shutdown via TTL-compatible INH pin (Pin 2). Its internal current and thermal limiting protect against fault conditions without external circuitry.

It achieves 81 dB supply voltage rejection at 120 Hz and maintains 50 µV RMS output noise (10 Hz–100 kHz) with only 2.2 µF output capacitance (ESR 0.1–10 Ω), making it suitable for noise-sensitive analog and RF subsystems requiring clean, stable 3.0 V bias.

Key Specifications

Pinout & Package

LF30CDT uses the TO-220FP (Full Pack) 5-pin package with exposed tab for thermal conduction. Pin 1 = Input, Pin 2 = Inhibit (TTL-compatible shutdown control), Pin 3 = Ground, Pin 4 = Output, Pin 5 = Tab (internally connected to GND).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LD3985M33R and TPS7A0530PDQNR, LF30CDT uniquely combines 3.0 V output, 500 mA drive, TTL shutdown, and TO-220FP thermal performance-making it the only choice for high-current, thermally demanding, and system-controlled 3.0 V regulation.

Availability

LF30CDT is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control modules, medical wearable monitors, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LF30CDT 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, specializing in power management, microcontrollers, and automotive-grade analog ICs with ISO/TS 16949-certified manufacturing.

The LF00 series was designed specifically for low-noise, low-power, and battery-operated applications where ultra-low dropout, logic-controlled shutdown, and minimal external components are essential-targeting industrial automation, automotive subsystems, and portable medical devices.

FAQ

What is the minimum input voltage required for stable 3.0 V output at 500 mA?

The LF30CDT requires a minimum input voltage of 3.4 V to maintain regulation at 500 mA load, based on its 0.4 V typical dropout voltage. At higher temperatures or worst-case process corners, the dropout may reach 0.7 V, so 3.7 V input is recommended for robust margin in production systems.

Can the LF30CDT be used without the inhibit function?

Yes-tie Pin 2 (INH) to VI (input voltage) to force permanent ON operation. The device retains all electrical specifications including quiescent current (500 µA typ.), dropout, and PSRR. No pull-up resistor is needed since the input threshold is TTL-compatible (VIH ≥ 2.0 V).

Is an input capacitor mandatory, and what value is recommended?

A 0.1 µF ceramic capacitor is mandatory between Pin 1 (VI) and Pin 3 (GND), placed as close as possible to the device. This stabilizes the internal reference and prevents oscillation during transient load steps; larger values (e.g., 1–10 µF) offer no benefit and may degrade startup behavior.

How does thermal performance compare between TO-220FP and standard TO-220 packages?

The TO-220FP package has R_thJC = 5°C/W versus 3°C/W for standard TO-220, due to its full-pack molding compound limiting heat transfer from die to tab. However, TO-220FP's integrated GND-connected tab improves EMI shielding and simplifies PCB layout-just ensure ≥4 cm² copper pour under the tab for effective conduction cooling.