STMicroelectronics LF50ABPT

Overview

LF50ABPT from STMicroelectronics is a 5.0 V, ±1% tolerance, very low dropout linear regulator in TO-220FP package, delivering up to 500 mA output current with 0.4 V typical dropout at 500 mA, 50 µA quiescent current in shutdown mode, and operation across –40°C to +125°C junction temperature. It integrates logic-controlled electronic shutdown (TTL-compatible enable pin), internal current/thermal limiting, and requires only a 2.2 µF ceramic output capacitor for stability - optimized for battery-powered and low-noise embedded systems.

For engineers reviewing the LF50ABPT datasheet, LF50ABPT pinout, LF50ABPT application, or LF50ABPT equivalent, key selection considerations include its 0.4 V dropout at full load, ±1% output voltage accuracy over temperature, shutdown current draw of 50 µA, and compatibility with low-ESR ceramic capacitors - critical for portable medical sensors, automotive body control modules, and industrial IoT edge nodes requiring high reliability under thermal stress.

Technical Context

The LF50ABPT implements a PNP-based LDO architecture with integrated pass transistor, enabling ultra-low dropout performance without external P-channel MOSFETs. Its shutdown control (pin 2) accepts TTL-level logic inputs (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V) and reduces quiescent current to 50 µA, supporting system-level power gating.

Thermal design is enabled by a 5 °C/W junction-to-case thermal resistance (TO-220FP package) and internal thermal foldback protection. The regulator maintains ±1% output accuracy over –25°C to +85°C ambient and supports input voltages from 6 V to 16 V while sustaining 500 mA continuous output current.

Key Specifications

Pinout & Package

LF50ABPT is housed in a TO-220FP (Full Pack) thermally enhanced 5-pin package with isolated tab, featuring vertical mounting capability and improved heat dissipation versus standard TO-220. Pin 1 = Input, Pin 2 = Shutdown (active-low), Pin 3 = Ground, Pin 4 = Output, Pin 5 = Bypass (not used in basic configuration; tied to ground per datasheet).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout regulator applications.

Compared with LDL1150PT50R and TPS7A1650DRBR, LF50ABPT offers superior thermal robustness (5 °C/W R_thJC) and integrated protection - making it preferred for high-reliability, thermally demanding deployments where board-level heatsinking is feasible and fault resilience is mandatory.

Availability

LF50ABPT is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O modules, and portable medical instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LF50ABPT 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 microcontrollers, power management ICs, sensors, and automotive-grade components with ISO/TS 16949 and AEC-Q200 compliance.

The LF00 series was developed specifically for low-power, high-reliability embedded systems requiring ultra-low dropout, wide temperature operation, and minimal external components - targeting automotive, industrial, and medical applications where efficiency and robustness are non-negotiable.

FAQ

What is the maximum input voltage rating for LF50ABPT?

The absolute maximum DC input voltage is 40 V, but the device enters shutdown above 18 V per datasheet Table 1. For normal regulated operation, the recommended input range is 6 V to 16 V. Exceeding 16 V continuously risks thermal overstress unless heatsinking is significantly enhanced, and operation above 18 V disables regulation regardless of load condition.

Can LF50ABPT be used without the bypass (pin 5) connection?

No - pin 5 (Bypass) must be connected to ground as specified in the test circuit (Figure 2, page 2) and application notes. Leaving it floating or unconnected violates the stability condition and may cause oscillation or increased output noise. The internal bias network relies on this grounded node to maintain loop compensation integrity.

Does LF50ABPT require an input capacitor?

Yes - a minimum 0.1 µF ceramic capacitor is required between pin 1 (Input) and pin 3 (Ground), as specified in all electrical characteristic tables. This capacitor suppresses high-frequency noise from upstream sources and ensures stability during transient load steps; omitting it risks line regulation degradation and potential instability under dynamic loads.

How does the shutdown function behave during cold temperature operation?

The shutdown input (pin 2) remains fully functional from –40°C to +125°C, with guaranteed V_IL ≤ 0.8 V and V_IH ≥ 2.0 V across the full junction temperature range. Quiescent current stays at 50 µA (typ.) even at –40°C, enabling reliable deep-sleep control in outdoor or automotive cold-soak environments without additional level-shifting circuitry.