L4931 series – Very low drop voltage regulators with inhibit

Category: Electronics, Regulators, ST Microelectronics Inc

Overview

The L4931 series comprises very low drop voltage regulators designed for applications that emphasize low noise and low power consumption, making them ideal for battery-powered systems. These voltage regulators offer a uniquely low dropout voltage and quiescent current, which significantly enhance their efficiency and battery life in portable devices.

Key Features

Key features of the L4931 series include a dropout voltage of only 0.4V and an exceptionally low quiescent current of approximately 50 µA when off and 60 µA when on. These regulators are capable of delivering an output current of up to 250 mA and are available in various fixed output voltages ranging from 1.5V to 12V.

In terms of performance, these regulators have an internal current and thermal limit for protection and ensure system stability with a requirement of only a 2.2 µF external capacitor. They also feature high supply voltage rejection (70 dB typ. for the 5V version) and operate within a wide temperature range (-40 to 125°C).

The precision of output voltage is guaranteed by two options of output voltage tolerance, ±1% (AB) or ±2% (C), measured at 25°C.

Functional Capabilities

With the addition of a logic-controlled electronic shutdown feature, available in PPAK and SO-8 packages, these regulators can be made TTL compatible for Shutdown Logic Control. This enables selective power-down of parts of an electronic board, offering further power savings—a crucial feature for increasing the efficiency of battery-operated devices.

Package Options

The L4931 series voltage regulators are offered in several package types to suit diverse applications, including TO-220, TO-92, PPAK, DPAK, and SO-8. The availability of these packages allows for flexibility in design and caters to space and layout requirements of various electronic assemblies.

Schematic and Revision

The datasheet provides a schematic diagram illustrating the functional blocks within the regulator, indicating components such as the error amplifier, driver, current limit, start inhibit, and term protection, which collectively contribute to the device’s functionality and reliability. Rev: 12 of the datasheet indicates ongoing revisions and updates to the provided technical information, ensuring that readers have access to the latest data.

Documentation Details

This concise overview is derived from the datasheet titled “L4931 series – Very low drop voltage regulators with inhibit”, revised in June 2006 with document identifier CS12740. The datasheet is documented over 40 pages, with the information summarized herein extracted from the first two pages.