STMicroelectronics L7915ACD2T-TR

Overview

L7915ACD2T-TR from STMicroelectronics is a fixed-output, three-terminal negative linear voltage regulator delivering -15 V at up to 1.5 A, featuring thermal overload protection, short-circuit current limiting, and output transition SOA protection. It operates with input voltages down to -30 V (for -15 V output), supports local on-card regulation in split-supply systems, and is commonly used in industrial power supplies requiring stable dual-rail ±15 V operation.

For engineers reviewing the L7915ACD2T-TR datasheet, L7915ACD2T-TR pinout, L7915ACD2T-TR application, or L7915ACD2T-TR equivalent, key selection criteria include guaranteed -15 V output tolerance (±2 %), dropout voltage of 1.1 V at 1 A, junction temperature range of 0–125 °C, and D2PAK package thermal resistance (R_thJA = 62.5 °C/W).

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 voltage accuracy across load (5 mA to 1.5 A) and line (VI = -18.5 V to -30 V) variations while sustaining 54–60 dB supply voltage rejection at 120 Hz.

The L7915ACD2T-TR is designed for fixed-voltage operation but supports external adjustment via resistor networks for higher output voltages or current boosting. It requires minimum 2.2 µF solid tantalum input capacitance and 1 µF output capacitance for stability per ST's test conditions.

Key Specifications

Pinout & Package

Supplied in D2PAK (TO-263) surface-mount package with exposed thermal pad for enhanced heat dissipation; footprint matches JEDEC MO-211AB standard and supports reflow soldering per ST's recommended land pattern (12.2 mm × 9.75 mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM337MDT-TR and MC7915CD2TG, the L7915ACD2T-TR offers superior thermal reliability in surface-mount industrial PCBs due to its D2PAK package and integrated SOA protection, while eliminating external components required by adjustable alternatives.

Availability

L7915ACD2T-TR is available at Aetrix Electronics and suitable for industrial instrumentation, audio amplifier bias rails, test & measurement equipment, and motor control boards requiring stable component supply and long-term obsolescence management.

Supply support for L7915ACD2T-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, 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 cost-sensitive, high-reliability negative rail generation in dual-supply analog and mixed-signal systems.

FAQ

What is the minimum input voltage required for stable -15 V output?

The L7915ACD2T-TR requires a minimum input voltage of -18.5 V to maintain regulation across full load (1.5 A) and temperature (0–125 °C). Below this, dropout occurs-output voltage drops linearly with input. At 1 A load and 25 °C, dropout is specified at 1.1 V, meaning -16.1 V input is sufficient for nominal operation.

Can this regulator be used in parallel for higher current?

No-L7915ACD2T-TR is not designed for direct parallel operation. Its output voltage tolerance (±2 %) and thermal gradients cause current imbalance, risking thermal runaway. For >1.5 A, ST recommends using external pass transistors with current-sharing resistors or selecting a higher-current alternative like the L7915CV in TO-220 with heatsink.

Is an input capacitor mandatory, and what type is recommended?

Yes-an input capacitor is mandatory for stability and transient immunity. ST specifies ≥2.2 µF solid tantalum with ESR ≤ 1 Ω. Aluminum electrolytic types require ≥22 µF due to higher ESR; ceramic capacitors alone are insufficient without series resistance to damp resonance with PCB inductance.

Does this part support reverse-polarity input protection?

No-the L7915ACD2T-TR has no internal reverse-polarity protection. Applying positive voltage to the IN pin relative to GND will cause immediate device failure. External protection (e.g., series Schottky diode or PMOS FET) must be added if input polarity reversal is possible in the system.