Reverse polarity switches protect mobile devices against damage from dangerous reverse bias and over-voltage transient events

August 20, 2012 // By Paul Buckley
To help protect both electronic devices and their users, Fairchild Semiconductor is offering a new line of low-power, application-specific, reverse polarity protection switches which also feature optional over-voltage transient protection.

Improperly installed batteries, hot-plug transients, faulty connections, and reversible third party USB chargers can all generate a dangerous reverse bias or reverse transient situation as well as over-voltage spikes. These complications may lead to device failure and returns, lost revenue, and damaged brand reputations.

The new devices provide low resistance, fast response, and with nearly 50X less power consumption than a traditional series Schottky solution at 1 Amp, they offer noticeable power savings all while protecting the system from dangerous reverse polarity. To simplify design and remove the guesswork, these reverse polarity protection switches have been optimized for the application to provide an easy 'plug and play' implementation solution.

Part of Fairchild’s initial offering in the reverse polarity family are the FR011L5J low-side reverse polarity protector and the FR014H5JZ high-side reverse polarity protector with integrated over-voltage transient suppression (OVS). In the event of a reverse bias condition, both devices shut off power and provide a full voltage block to help protect downstream circuits.

Both protectors dissipate less than 0.02 W during 1 A normal operation, and less than 20 µW in a 16 V reverse bias event, a performance not possible with a diode solution. The low dissipation of the FR0XXX5J series minimizes the need for heat sinking and allows for smaller package sizes, reduced board space requirements and lowered component costs. Additionally, the devices’ nSec scale reverse bias blocking response time blocks negative transients and other potentially damaging DC events. The FR014H5JZ and FR011L5J parts are both USB tested and compatible.

The FR014H5JZ in a 3.3 mm x 3.3 mm package offers -30 V reverse polarity protection offers wide range protection from multiple common reversible sources including household, industrial and automotive DC power sources.

The FR011L5J in a 2 mm x 2 mm package features a11 mΩ typical series resistance at 5 V decreases power consumption, voltage drop and heat sinking board level requirements.

Availability


Samples are available upon