US4820974A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for measuring a characteristic of semiconductor memory device
Assignee: Panasonic Holdings Corp
•
Filing: 1986-12-11
•
Granted: 1989-04-11
•
Expires: 2006-12-11
Abstract
Abstract Method for measuring power supply current, e.g., standby current of a random access memory in which, before starting measurement of the power supply current, data is read-out from memory cell of the random access memory and opposite data is written in the memory cell so that the random access memory enters into an unstabilized state. By use of this method, the measurement of the maximum power supply current can be conducted precisely.
Inventors
- 👤 Joji Katsura
- 👤 Seiji Yamaguchi
- 👤 Kazuhiko Tsuji
- 👤 Eisuke Ichinohe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:21
CPC Classifications
G; G11; G11C; G11C29/00; G11C29/02; G11C29/021; G11C29/04; G11C29/50; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/41; G11C2029/5006
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
91 words
A method for measuring a characteristic of a semiconductor memory device having memory cells comprising: supplying a power supply voltage to a semiconductor memory device to be measured so that said semiconductor memory device enters into an operating state; reading out data which is stored in at least one memory cell of the semiconductor memory device; preparing opposite data which is opposite to the read-out data; writing said opposite data in said memory cell, thereby completing initialization of the semiconductor memory device; and measuring a characteristic of the semiconductor memory device.
Claim 2
Independent Claim
91 words
A method for measuring a characteristic of a semiconductor memory device having memory cells comprising: supplying a power supply voltage to a semiconductor memory device to be measured so that said semiconductor memory device enters into an operating state; reading out data which is stored in at least one memory cell of the semiconductor memory device; preparing opposite data which is opposite to the read-out data; writing said opposite data in said memory cell, thereby completing initialization of the semiconductor memory device; and measuring a characteristic of the semiconductor memory device.
Claim 3
Dependent Claim
26 words
A method as recited in claim 1, wherein said power supply voltage is turned off before supplying said power supply voltage to said semiconductor memory device.
Claim 4
Dependent Claim
17 words
A method as recited in claim 1, wherein said semiconductor memory device is a random access memory.
Claim 5
Dependent Claim
31 words
A method as recited in claim 1, wherein said data to be read out from said semiconductor memory device is all data which are stored in all of the memory cells.
Claim 6
Dependent Claim
23 words
A method as recited in claim 1, wherein said data which is opposite is formed by inverting said read-out data with an inverter.
Claim 7
Dependent Claim
29 words
A method as recited in claim 1, wherein right after data which is stored in one memory cell has been read-out, opposite data is written in said memory cell.
Claim 8
Dependent Claim
31 words
A method as recited in claim 1, wherein all of the data stored in all of the memory cells are read-out and thereafter opposite data are written in said memory cells.
Claim 9
Dependent Claim
17 words
A method as recited in claim 1, wherein said characteristic to be measured is power supply current.
Claim 10
Dependent Claim
24 words
A method as recited in claim 8, wherein said power supply current includes an operating power supply current and a standby power supply current.
Claim 11
Dependent Claim
24 words
A method as recited in claim 8, wherein said power supply current is measured in a chip selection mode of said semiconductor memory device.
Claim 12
Dependent Claim
19 words
A method as recited in claim 8, wherein said power supply current is measured in a non-chip selection made.
Claim 13
Dependent Claim
30 words
A method as recited in claim 1, wherein said characteristic to be measured includes data holding power supply current, operating current, refresh current, and refresh period of the memory device.
Claim 14
Independent Claim
94 words
A method for measuring power supply current of a random access memory having memory cells comprising: supplying a power supply voltage to a random access memory to be measured so that said random access memory enters into an operating state; reading out data which is stored in one memory cell of said random access memory; preparing opposite data which is opposite to the read-out data; writing said opposite data in said memory cells; repeating the steps of reading out, preparing opposite data and writing; and measuring power supply current of said random access memory.
Claim 15
Independent Claim
94 words
A method for measuring power supply current of a random access memory having memory cells comprising: supplying a power supply voltage to a random access memory to be measured so that said random access memory enters into an operating state; reading out data which is stored in one memory cell of said random access memory; preparing opposite data which is opposite to the read-out data; writing said opposite data in said memory cells; repeating the steps of reading out, preparing opposite data and writing; and measuring power supply current of said random access memory.
Claim 16
Dependent Claim
29 words
A method as recited in claim 13, wherein said repeating step is conducted until all data of all of the memory cells are changed to data which is opposite.
Claim 17
Independent Claim
87 words
A method for measuring power supply current of a random access memory having memory cells comprising: supplying power supply voltage to a random access memory to be measured so that said random access memory enters into an operating state; reading out all data which are stored in all of the memory cells of said random access memory; preparing opposite data which are opposite to the read-out data; writing said opposite data in all of the memory cells; and measuring power supply current of said random access memory.
Claim 18
Independent Claim
87 words
A method for measuring power supply current of a random access memory having memory cells comprising: supplying power supply voltage to a random access memory to be measured so that said random access memory enters into an operating state; reading out all data which are stored in all of the memory cells of said random access memory; preparing opposite data which are opposite to the read-out data; writing said opposite data in all of the memory cells; and measuring power supply current of said random access memory.
References Cited (Backward Citations)
US3576982A
Cited
US4045779A
Cited
US4271519A
Cited
US4553225A
Cited
US4637020A
Cited
US4686456A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-10 | 1992-10-10 | 1993-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-10 | 1996-10-10 | 1997-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-10 | 2000-10-10 | 2001-04-11 | $7700.00 | Window Closed / Lapsed |