STMicroelectronics LF120CPT

Overview

LF120CPT from STMicroelectronics is a 12 V fixed-output, very low dropout (LDO) linear voltage regulator in PENTAWATT-5 package with logic-controlled shutdown, 500 mA output current capability, 0.45 V typical dropout at 200 mA, and ±2% output voltage accuracy at 25°C. It operates across –40 to 125°C junction temperature and targets battery-powered systems requiring low quiescent current (50 µA in OFF mode) and high PSRR (80 dB typ. at 120 Hz).

For engineers reviewing the LF120CPT datasheet, LF120CPT pinout, LF120CPT application, or LF120CPT equivalent, this page delivers verified electrical specs, validated 5-pin PENTAWATT pin functions, real-world use cases in portable instrumentation and automotive body control modules, and two confirmed drop-in alternatives with documented voltage/accuracy trade-offs.

Technical Context

The LF120CPT implements a PNP-based pass transistor architecture enabling ultra-low dropout (0.45 V typ. at 200 mA), internal thermal and current limiting, and TTL-compatible enable control on Pin 2. Its 2.2 µF minimum output capacitance requirement supports compact PCB layouts without external compensation.

It delivers stable 12 V regulation across input voltages from 12.5 V to 16 V (min. VI for 500 mA load), maintains 80 dB PSRR at 120 Hz, and achieves 50 µV RMS output noise over 10 Hz–100 kHz - critical for analog sensor front-ends and RF power supply rails.

Key Specifications

Pinout & Package

PENTAWATT-5 (vertical mount, 5-pin) package with integrated heat slug; TO-220FP footprint compatibility; 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 12 V LDO regulator applications.

Compared with LD1086CS12TR and TLV1117-12CDR, the LF120CPT uniquely combines ultra-low dropout (0.45 V), integrated shutdown, and through-hole PENTAWATT packaging - making it irreplaceable in space-tolerant, battery-critical, and thermally demanding 12 V applications where minimal input headroom and low OFF-mode current are non-negotiable.

Availability

LF120CPT is available at Aetrix Electronics and suitable for portable medical devices, automotive body electronics, industrial PLC I/O modules, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LF120CPT 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 ultra-low-dropout, low-quiescent-current regulation in battery-powered and thermally constrained systems - emphasizing simplicity, reliability, and minimal external components.

FAQ

What is the minimum input voltage required for 500 mA output at 12 V?

The LF120CPT requires a minimum input voltage of 12.5 V to sustain 500 mA output at 12 V, based on its 0.45 V typical dropout and 12 V output specification. At 200 mA, dropout drops to 0.45 V; at full 500 mA, it rises to 0.7 V per datasheet Table 9, so 12.7 V is recommended for margin.

Can LF120CPT be used without the shutdown pin connected?

Yes - Pin 2 (ON/OFF) can be tied directly to IN for permanent enable operation. The device will draw 500 µA quiescent current and deliver full 500 mA output. No pull-up or pull-down resistor is required; floating Pin 2 is not permitted and may cause undefined behavior.

Is an input capacitor required for stability?

An input capacitor (CI = 0.1 µF ceramic) is specified in all test circuits and strongly recommended to suppress high-frequency noise and prevent oscillation due to source impedance. While not strictly mandatory for basic DC operation, omitting it risks instability under dynamic load or noisy input conditions.

Does LF120CPT support ceramic output capacitors with ESR below 0.1 Ω?

No - the datasheet specifies CO stability requires ESR between 0.1 Ω and 10 Ω. Ceramic capacitors with ultra-low ESR (<0.1 Ω) may cause phase-margin loss and oscillation. Use X5R/X7R ceramics rated for 2.2 µF with 0.5–2 Ω ESR, or add a small series resistor if using low-ESR types.