IEC 1000-4-2 ESD Immunity and Transient Current Capability for the SP72X Series Protection Arrays

The SP720, SP721, SP723, and SP724 are protection ICs with an array of SCR/Diode bipolar structures for ESD and over-voltage protection of sensitive input circuits. They have 2 protection SCR/Diode device structures per input. The SP720 is supplied in 16 lead DIP and SOIC packages and has a total of 14 available inputs that can be used to protect up to 14 external signal or bus lines. The SP721 and SP723 are 8 pin devices with the same protection structures and have the same package options. The SP723 has dual cell structures for each input to achieve substantially improved ESD and Transient Current capability. The SP724 is a four section array in a 6-lead SOT-23. Its cell structure has been redesigned for improved ESD immunity. The SCR structures are designed for fast triggering at a threshold of one +VBE diode threshold above V+ (positive supply terminal) or a -VBE diode threshold below V- (negative or ground). A clamp to V+ is activated at each protection input if a transient pulse causes the input to be increased to a voltage level greater than one VBE above V+. A similar clamp to V- is activated if a negative pulse, one VBE less than V-, is applied to an input.