STMicroelectronics L7915ACV

Overview

L7915ACV from STMicroelectronics is a three-terminal fixed negative voltage regulator delivering -15 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 down to -18.5 V and up to -30 V, supports local on-card regulation for split-supply systems, and is commonly used in ±15 V analog power rails for op-amp and ADC circuits.

For engineers reviewing the L7915ACV datasheet, L7915ACV pinout, L7915ACV application, or L7915ACV equivalent, key selection criteria include guaranteed -15 V output tolerance (±2 %), dropout voltage of 1.1 V at 1 A, load regulation ≤150 mV, junction temperature range (0–125 °C), and TO-220 package thermal resistance (R_thJA = 50 °C/W).

Technical Context

The L7915ACV implements a monolithic PNP pass transistor architecture with internal current limiting, thermal shutdown, and safe operating area (SOA) protection-ensuring robust operation under transient overloads and sustained short circuits. Its feedback loop maintains output stability across line (VI = -18.5 V to -30 V) and load (IO = 5 mA to 1.5 A) variations without external compensation.

Designed as a complement to the L78xxA positive regulator series, it enables symmetrical dual-rail supplies (e.g., ±15 V @ 1 A) with matched thermal and electrical characteristics. The device requires only two external capacitors (CI = 2.2 µF solid tantalum, CO = 1 µF) for stable operation per ST's recommended test circuit.

Key Specifications

Pinout & Package

Supplied in TO-220 package (3-pin, vertical mounting, metal tab connected to GND), with standard pinout: Pin 1 = Input (IN), Pin 2 = Ground (GND), Pin 3 = Output (OUT). Thermal performance relies on proper heatsinking: 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 negative fixed-voltage regulator applications.

Compared with LM337T and MC7915CT, the L7915ACV offers superior output accuracy, lower thermal resistance, and integrated SOA protection - making it optimal for precision analog and high-reliability split-rail systems where fixed –15 V is sufficient.

Availability

L7915ACV is available at Aetrix Electronics and suitable for industrial process control, audio power amplification, and test & measurement equipment requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.

Supply support for L7915ACV 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, analog chips, and MEMS sensors for industrial, automotive, and consumer markets.

The L79xxAC series belongs to ST's legacy linear regulator product line, engineered specifically for robust, low-cost, fixed-output negative voltage regulation in dual-rail analog systems - emphasizing thermal resilience, fault protection, and compatibility with complementary L78xxA devices.

FAQ

What is the minimum input voltage required for stable –15 V output at 1 A?

The L7915ACV requires a minimum input voltage of –16.1 V to maintain regulation at 1 A, based on its 1.1 V dropout voltage (V_d) and –15 V nominal output. Operation below this threshold causes output collapse; ST recommends VI ≥ –18.5 V for full-spec compliance across temperature and line variation.

Can L7915ACV be used in parallel for higher current?

No - the L7915ACV lacks built-in current-sharing capability or master-slave control. Parallel connection risks thermal runaway due to mismatched V_BE and SOA characteristics. For >1.5 A, ST recommends using the high-current configuration shown in Figure 7 (with external pass transistor) or selecting a dedicated high-current regulator.

Is a heat sink mandatory for 1.5 A operation?

Yes - at 1.5 A and ambient temperatures above 40 °C, a heat sink is mandatory. With R_thJA = 50 °C/W, dissipation of ~1.65 W (at VI = –23 V) raises junction temperature by 82.5 °C above ambient; exceeding 125 °C T_J triggers thermal shutdown. A 10 °C/W heatsink reduces rise to ~26 °C, enabling full-load operation up to 99 °C ambient.

Does L7915ACV require an input bypass capacitor?

Yes - ST specifies a 2.2 µF solid tantalum capacitor (C_I) between IN and GND, especially if the regulator is located >2 inches from the main filter capacitor. This suppresses high-frequency input noise and prevents oscillation; aluminum electrolytic types require ≥22 µF due to higher ESR.