STMicroelectronics L7808CP

Overview

L7808CP from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 8 V 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 (for 8 V output), maintains ±2% output tolerance over temperature, and is commonly used in industrial power supplies, embedded control modules, and local on-card regulation for microcontroller systems.

For engineers reviewing the L7808CP datasheet, L7808CP pinout, L7808CP application, or L7808CP equivalent, key selection criteria include dropout voltage (2 V @ 1 A), load regulation (≤160 mV over 5 mA–1.5 A), supply voltage rejection (56 dB @ 120 Hz), quiescent current (8 mA), and thermal resistance (R_thJA = 50 °C/W in TO-220 package).

Technical Context

The L7808CP implements a monolithic series pass transistor architecture with internal current limiting, thermal shutdown, and SOA protection-enabling robust operation without external protection circuitry. Its fixed 8 V output is trimmed during manufacturing to ±2% tolerance at 25 °C and drifts only −0.8 mV/°C over temperature.

Designed for local regulation, it eliminates centralized supply distribution issues and supports stable operation with minimal external components: a 0.33 µF input capacitor and 0.1 µF output capacitor are sufficient for stability across its full load and temperature range (0 to 125 °C junction).

Key Specifications

Pinout & Package

Supplied in TO-220 package with standard 3-pin configuration: Input (Pin 1), Ground (Pin 2), Output (Pin 3). Requires mechanical mounting to heatsink via tab (Pin 2 connected to case).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM7808CDT/NOPB and MC7808BD2TR4G, the L7808CP offers tighter output tolerance across temperature, superior ripple rejection, lower noise, and higher thermal efficiency in TO-220-making it preferred for industrial and automotive applications demanding long-term stability and reliability.

Availability

L7808CP is available at Aetrix Electronics and suitable for industrial PLC power rails, automotive body control modules, embedded microcontroller boards, and legacy instrumentation supply requiring stable component supply, long-lifecycle support, and TO-220 package compatibility.

Supply support for L7808CP 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 was designed specifically for robust, low-cost, fixed-output linear regulation in harsh environments-emphasizing intrinsic protection, wide operating temperature, and ease of use in on-card power architectures.

FAQ

What is the minimum input voltage required for regulation with L7808CP?

The minimum recommended input voltage is 10.5 V, based on its 2 V dropout voltage at 1 A and 8 V output. Below this, regulation fails and output drops linearly with input. At light loads (<50 mA), regulation may hold down to ~9.5 V, but datasheet guarantees start at 10.5 V across full temperature and load range.

Can L7808CP be used without a heatsink?

Yes-for loads ≤300 mA at ambient ≤40 °C, the TO-220 package's R_thJA = 50 °C/W allows safe operation without a heatsink. At 1 A and 25 °C ambient, junction temperature rises ~100 °C above ambient (P_D ≈ 2 W), reaching ~125 °C-near the 125 °C limit. A heatsink is mandatory for continuous 1 A+ operation.

Does L7808CP require input and output capacitors?

Yes-STMicroelectronics specifies a minimum 0.33 µF ceramic capacitor at the input and 0.1 µF ceramic capacitor at the output, placed as close as possible to the pins. These prevent oscillation, improve transient response, and reduce high-frequency noise; omitting them risks instability or excessive output ripple under load steps.

How does L7808CP behave during short-circuit events?

It enters current-limit mode (~0.45 A typical short-circuit current), then activates thermal shutdown if junction temperature exceeds ~150 °C. After cooling below ~130 °C, it automatically recovers. This cycle repeats during sustained fault-preventing destruction while limiting average power dissipation to safe levels.