Automotive Protection Circuit in Surface Mount Power Package

Developed specifically for the automotive market by SGS-THOMSON Microelectronics, the RBO40-40M is a surface mounting device that protects sensitive automotive circuits against reversed battery connection and load dump over-voltages. Built with the company's proprietary Application Specific Discretes (ASD) technology, the RBO40-40M can handle average forward currents 40A and has maximum clamping voltages of Å40V.

The RBO40-40M contains a series diode for reverse battery protection, a bi-directional Transil diode to clamp negative over-voltages and a power Transil that protects against load dumps - high energy transients that occur when the battery is disconnected while the alternator is generating. The typical load dump waveform has a fast rise followed by a slower exponential decay, with the surge current taking tens of milliseconds to fall to half of its peak value. The RBO40-40M is specified with a 40ms surge capability, enabling it to handle realistic load dump waveforms reliably. Other key features include a peak load dump over-voltage of 80V and a minimum breakdown voltage of 24V, enabling the devices to withstand twice the 12V battery voltage to allow jump starting with two batteries in series.

Application Specific Discretes (ASD) technology is a proprietary SGS-THOMSON technology that allows conventional discrete structures such as thyristors, triacs, Zener diodes and Schottky rectifiers to be combined into a single monolithic device tailored to a specific application. The key to this capability is a bipolar technology in which both sides of the wafer are masked and processed, allowing current to flow through the bulk silicon. By combining the functions of several discrete devices into a monolithic "integrated discrete" device, SGS-THOMSON's ASD products combine the low cost, high reliability, small PCB area and other benefits of monolithic construction with the ruggedness and current-handling capacity of discrete devices.

The PowerSO-10 package, which was also originally developed by SGS-THOMSON, is a 10-lead small outline plastic package with an integral metal slug and is fully compatible with SMT requirements such as automatic placement, easy inspection of the soldered joints (including tab to substrate) and lead and tab co-planarity.

The combination of monolithic ASD technology and PowerSO-10 packaging means that the RBO40-40M offers an unrivaled combination of power density, optimal heat conduction, compactness, quality and reliability in car radios, GPS equipment and all other automotive electronics applications.

PowerSO-10, ASD and Transil are trademarks of SGS-THOMSON Microelectronics

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