STMicroelectronics L7905ACV

Overview

L7905ACV from STMicroelectronics is a fixed-output, three-terminal negative linear voltage regulator delivering -5 V at up to 1.5 A output current with ±2 % initial accuracy, thermal overload protection, and short-circuit current limiting. It operates across an input voltage range of -8 V to -20 V and is commonly used in split-rail power supplies for op-amp circuits, analog instrumentation, and industrial control modules requiring stable local regulation.

For engineers reviewing the L7905ACV datasheet, L7905ACV pinout, L7905ACV application, or L7905ACV equivalent, this part is selected for its proven reliability in low-noise analog rails, compatibility with L78xxA positive regulators, and availability in TO-220 package with validated thermal performance (R_thJA = 50 °C/W).

Technical Context

The L7905ACV implements a monolithic PNP pass transistor architecture with internal current limiting, thermal shutdown, and safe operating area (SOA) protection during output transients. Its regulation loop maintains output stability under load steps from 5 mA to 1.5 A while rejecting supply ripple via 54–60 dB SVR at 120 Hz.

It requires minimal external components: a 2.2 µF input capacitor (solid tantalum recommended) and 1 µF output capacitor for stability. Dropout voltage is specified at 1.4 V (IO = 1 A, ΔVO = 100 mV), and junction temperature must remain within 0–125 °C for full-spec operation.

Key Specifications

Pinout & Package

Supplied in TO-220 package (3-pin, vertical mounting, metal tab connected to GND), with standard pinout: Pin 1 = Input, Pin 2 = Ground, Pin 3 = Output. The metal tab serves as thermal path and electrical ground connection - PCB copper pour and thermal vias are required for sustained 1.5 A operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM7905CT and MC7905BT, the L7905ACV offers superior initial accuracy (±2 % vs ±4 %), lower quiescent current (3 mA vs 6.5 mA), and tighter line/load regulation - critical for precision analog systems where rail symmetry and noise matter.

Availability

L7905ACV is available at Aetrix Electronics and suitable for analog instrumentation, industrial control modules, audio pre-amplifier stages, and split-rail op-amp circuits requiring stable component supply with consistent parametric performance across production lots.

Supply support for L7905ACV 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 L79xxAC series belongs to ST's legacy linear regulator product line, engineered specifically for robust, low-cost local regulation in dual-rail analog systems - emphasizing thermal resilience, fault protection, and compatibility with complementary L78xxA devices.

FAQ

What is the maximum input voltage for L7905ACV?

The absolute maximum DC input voltage is -35 V for output voltages from -5 V to -18 V. For reliable operation at full 1.5 A output, ST recommends keeping input between -8 V and -20 V to maintain thermal safety margin and meet dropout specifications.

Can L7905ACV be used in adjustable configurations?

Yes - though designed as a fixed -5 V regulator, it can be configured as an adjustable negative regulator using two external resistors per Figure 6 in the datasheet. The output voltage becomes VO = -5 V × (1 + R1/R2), with R2 connected between output and adjust pin (GND terminal repurposed as reference).

Is a heatsink required for 1.5 A operation?

Yes - with R_thJA = 50 °C/W and power dissipation exceeding 7.5 W at 1.5 A (e.g., VI = -15 V → PD ≈ 15 W), a heatsink capable of ≤10 °C/W junction-to-ambient is required to keep TJ ≤ 125 °C. PCB copper area alone is insufficient for continuous 1.5 A loads.

What capacitor types are recommended for stability?

ST specifies 2.2 µF solid tantalum at the input and 1 µF solid tantalum at the output. If aluminum electrolytic capacitors are used instead, values must be increased by at least 10× (i.e., ≥22 µF input, ≥10 µF output) due to higher ESR, which affects phase margin and transient response.