Semiconductor integrated circuit
AssigneeFuji Electric Co., Ltd.
InventorsMutsuo Nishikawa, Kazuhiro Matsunami, Yuko Fujimoto
Life of this patent
Estimating the term…
Abstract
A semiconductor integrated circuit that exhibits an enhanced surge withstand voltage of a nonvolatile memory and has a reduced chip area, having a nonvolatile memory and a Zener diode connected in parallel between a write terminal and a ground terminal. The nonvolatile memory is connected to the write terminal by a write terminal line and to a common connection point by a first ground line. The cathode of the Zener diode is connected to the write terminal line. The anode of the Zener diode is connected to the specified connection point by a second ground line. The first ground line and the second ground line are connected to the specified connection point.
Claims7
A semiconductor integrated circuit comprising:
- a write terminal to which a specified voltage is applied;
- a ground terminal to which a ground potential is applied;
- a nonvolatile memory circuit that is connected between the write terminal and the ground terminal and stores a specified data by performing a writing operation based on the specified voltage;
- a protection device that is connected between the write terminal and the ground terminal in parallel with the memory circuit, and protects the memory circuit against an overvoltage;
- a first ground line that connects a specified connection point and the memory circuit;
- a second ground line that connects the specified connection point and the protection device;
- and
- a common ground line that connects the ground terminal and the specified connection point;
- wherein a resistance value r1v of a parasitic resistance r1 of the common ground line satisfies an inequality:
- r1v>(Vd−Vbm)/Iak
- where Vd is the specified voltage applied to the write terminal, Vbm is a breakdown voltage of the memory circuit, and Iak is a current that flows from the protection device to the second ground line when the overvoltage is applied to the write terminal.
Dependencies are inferred from the claim text.