Insulated-gate semicustom integrated circuit
First Claim
1. An insulated-gate semicustom integrated circuit comprising:
- a protection circuit comprisingfirst protective diodes each having one end connected to a first signal line, anda resistor element inserted in said first signal line, said first signal line having one end connected to one end of a first input pad and a first output pad; and
a second protective diode comprising a pull-up/down MOS transistor having a drain connected to a second signal line, a source remaining open, and a gate connected to a fixed potential, said second signal line connecting a second end of said first signal line to a first internal circuit.
1 Assignment
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Accused Products
Abstract
Incorporated in a MOS semicustom integrated circuit are pull-up and pull-down MOS transistors adapted for pulling up or down the potential of a signal line connecting a protection circuit with an internal circuit to be protected from electrostatic breakdown. The MOS transistors have their drains connected together to the signal line and their sources connected to a pull-up power supply node or pull-down power supply node as required. The MOS transistor acts as a pull-up or pull-down transistor when its source is connected to the pull-up or pull-down supply node by master slice wiring, and its drain junction acts as a protective diode when its source remains open. Thus, owing to the protection functions of the drain junction and diodes in the protection circuit, the electrostatic breakdown strength of the internal circuit can be increased without increase in the occupied area of the protection circuit in the integrated circuit.
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Citations
10 Claims
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1. An insulated-gate semicustom integrated circuit comprising:
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a protection circuit comprising first protective diodes each having one end connected to a first signal line, and a resistor element inserted in said first signal line, said first signal line having one end connected to one end of a first input pad and a first output pad; and a second protective diode comprising a pull-up/down MOS transistor having a drain connected to a second signal line, a source remaining open, and a gate connected to a fixed potential, said second signal line connecting a second end of said first signal line to a first internal circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification