STMicroelectronics L7912CV-DG

Overview

L7912CV-DG from STMicroelectronics is a fixed-output, three-terminal negative voltage regulator delivering -12 V at up to 1.5 A, featuring thermal overload protection, short-circuit protection, and output transition SOA protection. It operates with input voltages down to -35 V (for VO = -5 to -18 V), supports local on-card regulation in split-supply systems, and is widely used in industrial power supplies and analog circuitry requiring stable negative bias.

For engineers reviewing the L7912CV-DG datasheet, L7912CV-DG pinout, L7912CV-DG application, or L7912CV-DG equivalent, key selection criteria include guaranteed -12 V output tolerance (±4.2% at 25°C), dropout voltage of 1.1 V at 1 A, junction temperature range of 0–150°C, thermal resistance R_thJC = 5 °C/W (TO-220FP), and compatibility with standard ±15 V dual-rail designs.

Technical Context

This device implements a monolithic PNP pass transistor-based linear regulation architecture with internal current limiting, thermal shutdown, and safe operating area (SOA) protection for output transients. Its feedback loop maintains output stability across load currents from 5 mA to 1.5 A and input variations from -15.5 V to -27 V under specified conditions.

Designed for fixed-voltage operation, it accepts no external adjustment pins but supports external capacitors (CI ≥ 2.2 µF solid tantalum, CO ≥ 1 µF) for stability and transient response. The regulator's supply voltage rejection (54–60 dB at 120 Hz) and low output noise (200 µV RMS, 10 Hz–100 kHz) make it suitable for noise-sensitive analog stages.

Key Specifications

Pinout & Package

The L7912CV-DG is supplied in the TO-220FP (Full Pack) package - a thermally enhanced variant of TO-220 with insulated tab and dual-gauge leadframe, compliant with ECOPACK® environmental standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM337T/NOPB and MC7912CTG, the L7912CV-DG offers superior thermal robustness in insulated-mount configurations (TO-220FP), tighter initial output tolerance (±4.2% vs. ±5% for MC7912CTG), and lower noise - making it optimal for space-constrained industrial analog systems where layout-driven reliability is critical.

Availability

L7912CV-DG is available at Aetrix Electronics and suitable for industrial power supplies, analog sensor interfaces, audio preamplifier biasing, and legacy control board refurbishment requiring stable component supply and long-term lifecycle support.

Supply support for L7912CV-DG 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 L79xxC series was developed specifically for cost-effective, robust local regulation in dual-rail analog and industrial control systems - emphasizing thermal resilience, ease of use, and compatibility with the complementary L78xx positive regulator family.

FAQ

What is the maximum input voltage for L7912CV-DG?

The absolute maximum DC input voltage is -35 V when regulating -12 V output, per Table 2 of the datasheet. Operation above -27 V is permitted only under limited duty cycle or with strict thermal management, as power dissipation rises sharply. For continuous operation, ST recommends VI ≤ -22 V to maintain safe junction temperature with standard heatsinking.

Can L7912CV-DG be used in parallel for higher current?

No - the L7912CV-DG lacks built-in current-sharing features such as matching output impedance or master-slave control. Parallel connection risks thermal runaway due to minor unit-to-unit V_OUT mismatches. For >1.5 A, ST recommends using a single higher-current regulator (e.g., L79L12 for low current or discrete pass transistor augmentation per Figure 7 in the datasheet).

Is an input capacitor mandatory?

Yes - a minimum 2.2 µF solid tantalum capacitor (CI) is required at the input if the regulator is located more than 10 cm from the main filter capacitor, per Figure 4 and Section 6 of the datasheet. This prevents oscillation and improves transient response; aluminum electrolytic types require ≥22 µF due to higher ESR.

Does L7912CV-DG require a heat sink in all applications?

A heat sink is required whenever power dissipation exceeds ~1.5 W - for example, at 1 A output with 5 V input-to-output differential (-12 V out, -17 V in). With R_thJC = 5 °C/W and R_thCA ≈ 30 °C/W (typical small clip-on heatsink), junction temperature remains below 125°C up to ~1.3 A at 25°C ambient. Board copper area alone is insufficient for full 1.5 A operation.