STMicroelectronics L7820CV

Overview

L7820CV from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 20 V output at up to 1.5 A, featuring thermal overload protection, short-circuit protection, and safe operating area (SOA) protection. It operates across an input voltage range of 24–40 V and maintains ±2 % output voltage tolerance over 0 to 125 °C junction temperature, commonly used in industrial power supplies and local on-card regulation for microcontroller subsystems.

For engineers reviewing the L7820CV datasheet, L7820CV pinout, L7820CV application, or L7820CV equivalent, key selection considerations include dropout voltage (2 V @ 1 A), load regulation (≤100 mV), supply voltage rejection (57 dB @ 120 Hz), and thermal resistance (R_thJA = 50 °C/W in TO-220 package).

Technical Context

The L7820CV implements a monolithic series pass transistor with internal current limiting, thermal shutdown, and SOA protection-enabling robust operation without external protection circuitry. Its architecture relies on a bandgap reference and error amplifier driving a PNP pass element, with no external compensation required.

It functions as a fixed-output linear regulator requiring only two external capacitors: 0.33 µF input and 0.1 µF output (ceramic or tantalum). Minimum load current is 5 mA; operation is guaranteed from 0 to 125 °C junction temperature in the C-grade version.

Key Specifications

Pinout & Package

Supplied in TO-220 package with standard 3-pin configuration: Input (Pin 1), Ground (Pin 2), Output (Pin 3). The metal tab is electrically connected to Pin 2 (Ground) and serves as thermal path to heatsink.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output linear regulator applications.

Compared with LM7820CT and MC7820ACT, the L7820CV offers superior supply voltage rejection and tighter load regulation-critical for industrial instrumentation-while matching thermal performance and pin compatibility in TO-220.

Availability

L7820CV is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, test equipment power rails, and legacy instrumentation requiring stable component supply with long lifecycle support.

Supply support for L7820CV 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, specializing in power management, microcontrollers, and analog ICs with strong industrial and automotive focus.

The L78 series is ST's flagship family of fixed-output linear regulators designed for rugged, cost-effective local regulation in harsh environments-emphasizing protection integrity and wide temperature operation.

FAQ

What is the minimum input voltage required for L7820CV to regulate at full 1.5 A load?

The L7820CV requires a minimum input voltage of 22 V to maintain regulation at 1.5 A, based on its 2 V dropout specification. However, the absolute minimum rated input is 24 V per datasheet limits-ensuring reliable operation across temperature and line variations. Operating below 24 V risks loss of regulation under worst-case conditions.

Can L7820CV be used in parallel to increase output current?

No-L7820CV is not designed for parallel operation. Its output voltage tolerance (±2 %) and lack of current-sharing features make mismatched load sharing likely, risking thermal runaway. For >1.5 A, use a higher-current regulator or switch-mode solution instead.

Is a heat sink mandatory for L7820CV at 1 A output current?

A heat sink is strongly recommended at 1 A. With 20 V output and 24 V minimum input, power dissipation reaches ~4 W. At R_thJA = 50 °C/W, junction temperature rise would exceed 200 °C without heatsinking-well above the 125 °C max. A modest 10 °C/W heatsink keeps T_J within spec.

Does L7820CV require both input and output capacitors, and what values are acceptable?

Yes-both are mandatory for stability. Use ≥0.33 µF ceramic or tantalum at the input (within 2 cm of Pin 1) and ≥0.1 µF ceramic at the output (within 2 cm of Pin 3). Larger values (e.g., 10 µF electrolytic + 100 nF ceramic) improve transient response and ripple suppression without compromising stability.