STMicroelectronics LF80ABPT-TR

Overview

LF80ABPT-TR from STMicroelectronics is a 5.0 V fixed-output, 500 mA very low dropout (LDO) linear regulator in PENTAWATT-5 package with logic-controlled shutdown, ±1% output voltage accuracy at 25°C, 0.4 V typical dropout at 500 mA, and 50 µA quiescent current in OFF mode. It serves as a local power supply for microcontroller cores, sensor interfaces, and RF front-ends in battery-powered industrial and automotive control modules.

For engineers reviewing the LF80ABPT-TR datasheet, LF80ABPT-TR pinout, LF80ABPT-TR application, or LF80ABPT-TR equivalent, key selection criteria include dropout voltage at full load, shutdown logic compatibility (TTL), thermal resistance (R_thJC = 3°C/W), stability with 2.2 µF ceramic output capacitor, and operation across –40°C to +125°C junction temperature.

Technical Context

The LF80ABPT-TR implements a PNP pass transistor architecture enabling ultra-low dropout voltage (0.4 V typ. at 500 mA) and high PSRR (76 dB at 120 Hz). Its internal bandgap reference and error amplifier maintain tight output regulation under line (±25 mV) and load (±25 mV) variations across temperature.

Shutdown is controlled via TTL-compatible INH pin (Pin 2), drawing only 50 µA in OFF mode while fully disabling output. The device integrates thermal shutdown and current limiting, and achieves stability with a minimum 2.2 µF ceramic output capacitor (ESR 0.1–10 Ω), eliminating need for electrolytic or tantalum types.

Key Specifications

Pinout & Package

PENTAWATT-5 (5-pin vertical mount) package with exposed tab for thermal dissipation; R_thJC = 3°C/W, R_thJA = 50°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LDL112PU50R and LD3985M50R, LF80ABPT-TR uniquely combines 500 mA capability, TTL shutdown control, PENTAWATT thermal performance (R_thJC = 3°C/W), and through-hole mounting-making it optimal for ruggedized, thermally demanding, or legacy-compatible designs.

Availability

LF80ABPT-TR is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O modules, portable medical sensors, and smart energy metering systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LF80ABPT-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 analog, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

The LF00 series was developed specifically for low-noise, low-power, high-reliability local regulation in harsh environments-emphasizing ultra-low dropout, wide temperature operation, and minimal external components.

FAQ

What is the minimum input voltage required for 5.0 V output at 500 mA?

The LF80ABPT-TR requires a minimum input voltage of 5.4 V to maintain regulation at 500 mA load, based on its typical 0.4 V dropout voltage. At elevated temperatures or worst-case process corners, dropout may reach 0.7 V, so 5.7 V input is recommended for margin. Input must remain within absolute maximum rating of 40 V.

Can the INH pin be left unconnected, or does it require a pull-up/down?

The INH pin must not be left floating. It defaults to ON when open, but leakage or noise may cause erratic shutdown. STMicroelectronics specifies a pull-up resistor to V_IN (≤100 kΩ) for guaranteed ON operation, or a direct connection to GND for forced OFF. TTL-compatible logic drive is required for active control.

Is the exposed tab electrically isolated, and how should it be connected on the PCB?

No, the exposed tab (Pin 5) is internally connected to GND and must be soldered to a dedicated GND plane or thermal pad. It serves as both thermal conduction path and low-impedance ground return. Isolation is not possible; using insulating thermal pads defeats its purpose and violates safe operating area limits.

Does LF80ABPT-TR require an input capacitor, and what value is recommended?

Yes-an input bypass capacitor is mandatory. STMicroelectronics specifies a minimum 0.1 µF ceramic capacitor placed as close as possible to the IN and GND pins. This suppresses high-frequency noise and prevents oscillation due to input trace inductance; larger values (e.g., 1–10 µF) improve low-frequency ripple rejection but are not required for stability.