STMicroelectronics LF80CPT-TR

Overview

LF80CPT-TR from STMicroelectronics is a 5 V fixed-output, 500 mA very low dropout (LDO) linear regulator in PENTAWATT-5 package with logic-controlled shutdown (TTL-compatible enable), 0.4 V typical dropout at 500 mA, ±2% output voltage accuracy over temperature, and 50 µA quiescent current in OFF mode. It serves as a local power rail regulator in battery-powered portable instrumentation requiring stable low-noise 5 V supply.

For engineers reviewing the LF80CPT-TR datasheet, LF80CPT-TR pinout, LF80CPT-TR application, or LF80CPT-TR equivalent, key selection criteria include dropout voltage at full load, shutdown current, output accuracy across -40°C to 125°C, thermal resistance (R_thJC = 3°C/W), and minimum required output capacitance (2.2 µF).

Technical Context

The LF80CPT-TR implements a PNP pass transistor architecture enabling ultra-low dropout operation - delivering regulated 5 V output with input as low as 5.4 V at 500 mA load. Its internal circuit integrates thermal shutdown, current limiting, and a dedicated TTL-compatible control input (pin 2) that pulls the regulator into sub-50 µA quiescent state when driven low.

Stability is achieved with only 2.2 µF ceramic output capacitor (ESR 0.1–10 Ω), eliminating need for large electrolytic capacitors. Supply voltage rejection exceeds 76 dB at 120 Hz and remains >60 dB up to 10 kHz, supporting noise-sensitive analog and mixed-signal loads.

Key Specifications

Pinout & Package

PENTAWATT-5 (vertical mounting, 5-pin, through-hole) package with integrated heat slug; pin 1 = Input, pin 2 = Shutdown (TTL-compatible), pin 3 = Ground, pin 4 = Output, pin 5 = Bypass (not used in LF80CPT-TR; tied internally).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LDL1117S50R and TPS7A0550PDBVR, LF80CPT-TR uniquely balances 500 mA capability, 0.4 V dropout, integrated TTL shutdown, and PENTAWATT thermal performance - making it optimal for thermally demanding, battery-conscious 5 V systems needing precise, controllable regulation.

Availability

LF80CPT-TR is available at Aetrix Electronics and suitable for portable medical sensors, automotive body control modules, industrial IoT edge nodes, and smart energy meters requiring stable component supply with long-term manufacturability.

Supply support for LF80CPT-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, analog chips, and MEMS sensors for industrial, automotive, and consumer markets.

The LF00 series was developed specifically for low-noise, low-quiescent-current local regulation in battery-powered and thermally constrained systems - emphasizing dropout minimization, shutdown control, and minimal external component count.

FAQ

What is the minimum input voltage required for 5 V output at 500 mA?

The LF80CPT-TR maintains regulation with input as low as 5.4 V at 500 mA load, based on its 0.4 V typical dropout voltage. At 200 mA, dropout drops to 0.2 V, allowing operation from 5.2 V. Input must remain ≥5.4 V under worst-case conditions (high temperature, low VIN tolerance) to guarantee 5.0 V ±2% output.

Can the BP (bypass) pin be left unconnected or grounded externally?

No - pin 5 (BP) is internally connected to ground in the LF80CPT-TR variant and must not be externally biased. Leaving it floating or applying voltage may cause instability or damage. The datasheet explicitly states this pin is unused and internally tied; no external connection is permitted or required.

Is a heatsink required for continuous 500 mA operation at 125°C ambient?

With R_thJC = 3°C/W and R_thJA = 50°C/W (PENTAWATT-5), junction temperature rise at 500 mA with 1 V dropout (0.5 W dissipation) is ~1.5°C above case and ~25°C above ambient - well within 125°C limit. A copper pour under the heat slug is sufficient; no external heatsink is needed for standard PCB layouts.

Does the LF80CPT-TR support ceramic output capacitors with ESR below 0.1 Ω?

No - the LF00 series requires output capacitor ESR between 0.1 Ω and 10 Ω for guaranteed stability. Using ultra-low-ESR ceramics (<0.05 Ω) without added series resistance risks oscillation. ST recommends X5R/X7R 2.2 µF ceramics with typical ESR of 0.15–0.3 Ω; if lower-ESR types are used, a 0.1–1 Ω resistor in series with CO restores phase margin.