Electrostatic discharge protection device for high speed transmission lines

Abstract

A semiconductor device for coupling a transient voltage at an input node to a reference node, the device having a bipolar transistor adapted to couple its collector to an input node and its emitter to the reference node and a driver device adapted to be coupled between the input node and the base terminal of the transistor such that the driver device is responsive to a transient voltage at the input node to turn on the transistor, thereby shunting the transient voltage to the reference node. Preferably, the input node is coupled to a high speed data transmission line that operates below 5v and the reference node is coupled to ground and the transistor is an NPN transistor. The driver may preferably be a gate-drain connected MOS transistor with its gate-drain terminal coupled to the collector terminal of the transistor and its source terminal coupled to the base terminal of the transistor. Alternatively, the driver may be a light emitting diode (LED) or any other diode with a different material (band-gap) and die size than the LED, connected to the bipolar transistor to create a low voltage clamping device.

1 . A semiconductor device for coupling a transient voltage from an input node to a reference node, the device comprising: 
 a) a bipolar transistor adapted to couple its collector to said input node and its emitter to the reference node; and    b) a driver device adapted to be coupled between the input node and the base terminal of the transistor such that the driver device is responsive to a transient voltage at the input node to turn on the transistor, thereby shunting the transient voltage to the reference node.    
   
   
       2 . A device as defined in  claim 1 , said transistor being an NPN device.  
   
   
       3 . A device as defined in  claim 1 , said transistor being an PNP device.  
   
   
       4 . A device as defined in  claim 1 , said driver device being a gate-drain coupled n-channel MOSFET device.  
   
   
       5 . A device as defined in  claim 1 , said driver device being an LED.  
   
   
       6 . A device as defined in  claim 1 , said input node being coupled to a high speed data transmission line.  
   
   
       7 . A device as defined in  claim 6  said transmission line operating below 5v and the reference node being coupled to ground terminal.  
   
   
       8 . A method for coupling a transient voltage from an input node to a reference node, said method comprising the steps of: 
 a) coupling a collector terminal of a bipolar transistor to the input node and its emitter terminal to the reference node; and    b) coupling a driver device between the input node and the base terminal of the transistor such that the driver device is responsive to a transient voltage at the input node to turn on the transistor, thereby shunting the transient voltage to the reference node.    
   
   
       9 . A device as defined in  claim 1 , said device having a plurality of input nodes and a corresponding number of transistor and driver devices.