发明名称 |
SEMICONDUCTOR MEMORY DEVICE |
摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a semiconductor memory which evaluates its characteristics even when a threshold voltage is a negative potential by a test method which is similar to a case of a positive potential. <P>SOLUTION: The semiconductor memory includes a plurality of memory cells for storing data. When a test signal is input, the semiconductor memory device changes from a normal mode to a test mode for evaluating characteristics of the plurality of memory cells. The semiconductor memory device also includes: a memory cell selecting portion for selecting a memory cell; a constant voltage portion for generating a reference voltage; a constant current portion for generating a reference current; an X switch voltage switching control circuit for supplying one of an X selection signal and a voltage signal input from an external terminal to a gate of the memory cell; a Y switch portion for supplying the reference current to a drain of the memory cell selected by a Y selection signal; a comparator for detecting whether or not a drain voltage that is a voltage of the drain has exceeded the reference voltage; and a decision level changing portion for adjusting a current value of the reference current and a voltage value of the reference voltage so as to change a decision level of the comparator based on a control signal in the test mode. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
申请公布号 |
JP2009181619(A) |
申请公布日期 |
2009.08.13 |
申请号 |
JP20080018554 |
申请日期 |
2008.01.30 |
申请人 |
SEIKO INSTRUMENTS INC |
发明人 |
SATO YUTAKA;UTSUNOMIYA FUMIYASU;OKA TOMOHIRO |
分类号 |
G11C29/12;G01R31/28;G11C16/02;G11C16/06 |
主分类号 |
G11C29/12 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|