STMicroelectronics L7808ACD2T

Overview

L7808ACD2T 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 across 0 to 125 °C junction temperature and maintains ±2 % output voltage tolerance at 25 °C - used for local on-card regulation in industrial power supplies, embedded control modules, and sensor interface circuitry.

For engineers reviewing the L7808ACD2T datasheet, L7808ACD2T pinout, L7808ACD2T application, or L7808ACD2T equivalent, key selection criteria include dropout voltage (2 V @ 1 A), load regulation (≤100 mV over 5 mA–1.5 A), supply voltage rejection (62 dB @ 120 Hz), thermal resistance (R_thJA = 60 °C/W in TO-220FP), and guaranteed operation in extended temperature range.

Technical Context

The L7808ACD2T implements a monolithic series-pass regulator architecture with internal current limiting, thermal shutdown, and SOA protection - eliminating need for external protection components. Its feedback loop is internally compensated for stability with standard 0.33 µF input and 0.1 µF output capacitors.

It requires minimum 5 mA load current for regulation and exhibits −0.8 mV/°C output voltage drift. Dropout voltage remains fixed at 2 V under full 1 A load at 25 °C, independent of input voltage within specified ranges (VI = 10.6–25 V).

Key Specifications

Pinout & Package

Supplied in TO-220FP package - thermally enhanced variant of TO-220 with isolated tab, 3-pin vertical mounting configuration, and creepage/clearance optimized for industrial safety standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM340T-8.0 and MC7808CT, the L7808ACD2T delivers tighter output tolerance, lower quiescent current, superior supply rejection, and verified operation across 0–125 °C - making it the preferred choice for industrial and medical systems demanding long-term stability and protection integrity.

Availability

L7808ACD2T is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical patient monitoring sensors, and test & measurement front-ends requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for L7808ACD2T 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 for industrial, automotive, and consumer markets.

The L78 series belongs to ST's legacy positive voltage regulator product line, designed specifically for robust, cost-effective local regulation in harsh environments - emphasizing intrinsic protection, wide temperature operation, and ease of use with minimal external components.

FAQ

What is the minimum input voltage required for stable 8 V output at 1 A?

The L7808ACD2T requires a minimum input voltage of 10.6 V under nominal conditions (IO = 1 A, TJ = 25 °C), based on its 2 V dropout specification. For reliable operation across temperature and load extremes, ST recommends maintaining VI ≥ 11 V - especially when ambient temperatures exceed 60 °C or heatsinking is limited.

Can L7808ACD2T be used without a heatsink?

At ≤100 mA load and ambient temperature ≤40 °C, the TO-220FP package can operate without a heatsink due to its 60 °C/W R_thJA. However, at 1 A continuous load, junction temperature rise exceeds 100 °C even at 25 °C ambient - requiring a heatsink rated ≤20 °C/W to maintain TJ ≤ 125 °C per datasheet limits.

Does L7808ACD2T require input and output capacitors?

Yes - ST specifies a minimum 0.33 µF ceramic or tantalum capacitor at the input and 0.1 µF ceramic capacitor at the output, placed as close as possible to the respective pins. Omitting either compromises stability, increases ripple, and may trigger oscillation or thermal shutdown under dynamic loads.

How does the L7808ACD2T behave during short-circuit events?

Under short-circuit, the device limits peak current to 2.2 A momentarily, then reduces sustained output to ~0.45 A while activating thermal shutdown if junction temperature exceeds ~165 °C. Once cooled below ~145 °C, it automatically recovers - providing self-protecting behavior without latch-up or external intervention.