STMicroelectronics L7905ACD2T-TR

Overview

L7905ACD2T-TR from STMicroelectronics is a fixed-output -5 V, 1.5 A negative linear voltage regulator in D2PAK package, featuring thermal overload protection, short-circuit protection, and SOA output transition protection. It delivers stable local regulation for split-supply systems, power management in industrial control interfaces, and analog signal conditioning circuits requiring low-noise, high-rejection negative rails.

For engineers reviewing the L7905ACD2T-TR datasheet, L7905ACD2T-TR pinout, L7905ACD2T-TR application, or L7905ACD2T-TR equivalent, key selection criteria include dropout voltage (1.4 V @ 1 A), load regulation (±100 mV), supply voltage rejection (54–60 dB), and junction temperature range (0–125 °C) under real-world thermal and line/load transient conditions.

Technical Context

This three-terminal monolithic regulator operates as a series pass device with internal current limiting, thermal shutdown, and safe operating area (SOA) protection-ensuring robustness during output short circuits and input overvoltage events. Its architecture relies on a PNP pass transistor controlled by an error amplifier referenced to an internal bandgap voltage.

Designed for fixed-voltage operation, it supports external configuration for adjustable outputs or higher-current applications via external pass transistors. The device maintains regulation across input voltages from –8 V to –20 V at full load, with output voltage drift of –0.4 mV/°C and 100 µV RMS noise (10 Hz–100 kHz).

Key Specifications

Pinout & Package

D2PAK (TO-263) surface-mount package with exposed thermal pad; thermally optimized for PCB heat spreading and rated for 1.5 A continuous output when properly heatsinked.

Key Features

Applications

Equivalent & Alternatives

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

Compared with L7905ACV, the D2PAK variant offers superior thermal performance for high-current SMT production; versus LM7905CT, it delivers tighter output tolerance, lower noise, and better ripple suppression-critical for precision analog systems.

Availability

L7905ACD2T-TR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, audio signal processing boards, bipolar op-amp power supplies, and legacy instrumentation requiring stable component supply with long-term lifecycle support.

Supply support for L7905ACD2T-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, sensors, and analog components for industrial, automotive, and consumer markets.

L7905ACD2T-TR belongs to the L79xxAC series of three-terminal negative linear regulators, engineered for reliable local regulation in split-supply systems and industrial analog signal chains where simplicity, ruggedness, and thermal resilience are prioritized.

FAQ

What is the minimum input voltage required for stable –5 V output at 1.5 A?

The L7905ACD2T-TR requires a minimum input voltage of –6.4 V (–5 V output + 1.4 V dropout) at 25 °C. For full-load operation across temperature, ST specifies –8 V as the lower limit to maintain regulation under worst-case dropout and thermal drift conditions.

Can this regulator be used in parallel for higher current capability?

No-L7905ACD2T-TR lacks built-in current-sharing features such as current-sense terminals or master-slave control. Parallel connection risks thermal runaway due to mismatched dropout voltages and is not supported by ST's design guidelines or application notes.

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

Yes-an input capacitor is mandatory for stability. ST specifies a minimum 2.2 µF solid tantalum capacitor placed within 10 mm of the IN pin. Aluminum electrolytic types require ≥22 µF due to higher ESR; ceramic capacitors alone are insufficient without series resistance to damp resonance.

Does this device support adjustable output voltage configurations?

Yes-though designed as a fixed –5 V regulator, external resistors and a Zener diode can configure it for adjustable negative outputs per Figure 6 in the datasheet. However, accuracy, line/load regulation, and thermal performance degrade versus fixed-voltage operation and require careful compensation.