STMicroelectronics L7805CP

Overview

L7805CP from STMicroelectronics is a three-terminal positive fixed-voltage linear regulator delivering 5 V ±2% output at up to 1.5 A, featuring thermal overload protection, short-circuit protection, and safe operating area (SOA) protection. It operates with input voltages up to 35 V and requires only 5 mA minimum load current, making it suitable for local on-card regulation in industrial control power supplies and embedded microcontroller systems.

For engineers reviewing the L7805CP datasheet, L7805CP pinout, L7805CP application, or L7805CP equivalent, key selection considerations include dropout voltage (2 V @ 1 A), output noise (40 µV/√Hz), supply voltage rejection (62 dB @ 120 Hz), and thermal resistance (R_thJA = 60 °C/W in TO-220FP package).

Technical Context

The L7805CP implements a monolithic bipolar linear regulator architecture with internal current limiting, thermal shutdown, and SOA protection-enabling robust operation without external protection circuitry. Its feedback loop maintains regulation across line (VI = 7–25 V) and load (IO = 5 mA–1.5 A) variations while holding output drift to −1.1 mV/°C.

Designed for fixed-output use, it supports basic external adjustment via the ADJ pin in non-standard configurations but is not internally adjustable. The device's 2 V dropout voltage and 17 mΩ output resistance define its low-noise, high-stability DC performance under dynamic load conditions typical of MCU and sensor power rails.

Key Specifications

Pinout & Package

Package: TO-220FP (3-lead, vertical mounting, insulated tab). Thermal pad electrically isolated; tab connected to ground for mechanical mounting and heat transfer.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM7805CT and MC7805BDTRKG, the L7805CP offers superior supply rejection and tighter output tolerance-critical for noise-sensitive digital systems-while its insulated TO-220FP package simplifies compliance with isolation requirements in medical and industrial safety standards.

Availability

L7805CP is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control units, medical patient monitors, and point-of-sale terminals requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for L7805CP 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 silicon solutions for automotive, industrial, and consumer markets.

The L78 series belongs to ST's legacy linear regulator product line, engineered specifically for cost-effective, robust local regulation in industrial control, instrumentation, and embedded power systems where simplicity, reliability, and thermal resilience are prioritized over ultra-low quiescent current.

FAQ

What is the minimum input voltage required for stable 5 V output from the L7805CP?

The L7805CP requires a minimum input voltage of 7 V to maintain regulation under full 1.5 A load, based on its 2 V dropout specification. At lighter loads (<100 mA), input as low as 6.5 V may sustain regulation, but design margins should retain ≥7.5 V to accommodate line tolerance and ripple. Input below 7 V risks output collapse during transients or temperature rise.

Can the L7805CP be used without an input bypass capacitor?

No-STMicroelectronics specifies a minimum 0.33 µF ceramic capacitor between input and ground, placed within 1 cm of the input pin. Omitting it risks oscillation due to parasitic inductance in PCB traces, especially with long leads or high-impedance sources. This capacitor stabilizes the internal control loop and absorbs high-frequency noise from upstream converters.

Does the L7805CP require a heatsink for 1 A continuous operation?

Yes-when delivering 1 A continuously at ambient temperatures above 45 °C, a heatsink is mandatory. With R_thJA = 60 °C/W and power dissipation of ~2 W (at VI = 9 V), junction temperature rises ~120 °C above ambient. A 20 °C/W heatsink reduces total thermal resistance to ~80 °C/W, keeping T_J < 125 °C at 50 °C ambient. Mounting torque and thermal interface material significantly affect actual performance.

How does the L7805CP behave during output short-circuit conditions?

Under sustained short-circuit, the L7805CP limits output current to ~0.75 A (typical) and activates thermal shutdown when junction temperature reaches ~150 °C. After cooling below ~130 °C, it automatically recovers. Peak short-circuit current reaches 2.2 A briefly, but SOA protection prevents destructive second breakdown. No external current-limiting resistor is needed.