STMicroelectronics L7924CV

Overview

L7924CV from STMicroelectronics is a three-terminal fixed negative voltage regulator delivering -24 V output at up to 1.5 A, featuring thermal overload protection, short-circuit protection, and SOA-limited output transition. It operates with input voltages up to -40 V, supports local on-card regulation, and is designed for split-supply systems alongside L78xx positive regulators.

For engineers reviewing the L7924CV datasheet, L7924CV pinout, L7924CV application, or L7924CV equivalent, this device is selected for stable negative rail generation in industrial power supplies, analog instrumentation, and dual-rail op-amp circuits where precise -24 V regulation, thermal robustness, and board-level decoupling are required.

Technical Context

The L7924CV implements a monolithic PNP pass transistor architecture with internal current limiting, thermal shutdown, and safe operating area (SOA) protection-ensuring reliable operation under transient overloads and sustained short-circuit conditions. Its feedback loop maintains output regulation across load currents from 5 mA to 1.5 A and input voltages from -19 V to -40 V.

Designed for fixed-output use without external components, it accepts standard 2.2 µF input and 1 µF output capacitors (solid tantalum recommended) for stability. Dropout voltage is 1.1 V at 1 A, and supply voltage rejection exceeds 54 dB at 120 Hz-critical for noise-sensitive analog subsystems.

Key Specifications

Pinout & Package

Supplied in TO-220FP package: 3-pin vertical mounting configuration with metal tab electrically connected to the common (GND) terminal. Requires minimum 5 °C/W thermal resistance heatsink for full 1.5 A operation at ambient ≤ 50 °C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar negative fixed-voltage regulator applications.

Compared with LM337T and MC7924CT, the L7924CV provides superior thermal resilience (150 °C shutdown), lower dropout (1.1 V vs. 2.0 V), and SOA-limited transitions-making it optimal for industrial and telecom applications demanding fault tolerance and minimal power loss.

Availability

L7924CV is available at Aetrix Electronics and suitable for industrial power supplies, analog instrumentation, and telecom line interface cards requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for L7924CV 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, and analog devices for industrial, automotive, and consumer markets.

The L79xxC series was developed to provide robust, pin-compatible negative complements to the L78xx positive regulators-enabling simplified split-supply design in industrial control, test equipment, and analog signal chains.

FAQ

What is the minimum input voltage required for stable -24 V output?

The L7924CV requires a minimum input voltage of -25.1 V (i.e., |V_IN| ≥ 25.1 V) to maintain regulation at full load and temperature extremes. This accounts for the 1.1 V dropout voltage plus output tolerance. Operation below this level results in unregulated output and potential instability.

Can L7924CV be used in parallel for higher current?

No-L7924CV is not designed for parallel operation. Its output voltage tolerance (±5%) and lack of current-sharing features cause unequal load division and possible thermal runaway. For >1.5 A, use a single higher-current regulator or switch-mode solution instead.

Is an input capacitor mandatory?

Yes-an input capacitor (minimum 2.2 µF solid tantalum) is required if the regulator is located more than 10 cm from the main filter capacitor. It prevents oscillation and improves transient response by reducing source impedance at high frequencies.

Does L7924CV require a heat sink at 1 A load?

Yes-when delivering 1 A continuously at ambient temperatures above 30 °C, a heatsink with thermal resistance ≤25 °C/W is required. Without it, junction temperature exceeds 150 °C due to power dissipation of ~1.1 W (1 A × 1.1 V dropout) plus quiescent loss.