High speed serial access semiconductor memory with fault tolerant feature
First Claim
1. A memory device comprising an array of rows and columns of memory cells formed in a face of a semiconductor body, the major part of said array being a data memory and a minor part of the array being an address memory, a commutator for sequentially addressing said rows one at a time and means for reading out address and data from columns when a row is addressed, a serial access register connected via transfer means to the means for reading out to receive data from columns of said array, address input means in said face and connected to receive a multibit address from external to the device, comparator means in said face responsive to an address in said address input means and to said means for reading out and producing a command when the address from external is the same as the address from the array, means to activate said transfer means for the serial access register in response to said command, and output means for reading said data from the serial access register to external to the device.
0 Assignments
0 Petitions
Accused Products
Abstract
A semiconductor memory device of the single-chip MOS/LSI one-transistor dynamic RAM cell array type stores both data and address in rows of the array and uses a high speed serial access shift register as its data input/output system. The serial shift register has a number of stages equal to the number of columns in the memory cell array, and data in the shift register is transferred into or out of the columns of the array when a comparator indicates that an address input matches the stored row address. The rows are sequentially activated by a commutator, so no row or column decoders are needed. The device may be made fault tolerant by use of an electrically programmable floating gate transistor connected to each row, and programming this transistor to blank input or output if the row includes bad cells. The fault tolerant feature is transparent to the computer system using the memory.
54 Citations
23 Claims
- 1. A memory device comprising an array of rows and columns of memory cells formed in a face of a semiconductor body, the major part of said array being a data memory and a minor part of the array being an address memory, a commutator for sequentially addressing said rows one at a time and means for reading out address and data from columns when a row is addressed, a serial access register connected via transfer means to the means for reading out to receive data from columns of said array, address input means in said face and connected to receive a multibit address from external to the device, comparator means in said face responsive to an address in said address input means and to said means for reading out and producing a command when the address from external is the same as the address from the array, means to activate said transfer means for the serial access register in response to said command, and output means for reading said data from the serial access register to external to the device.
- 8. A memory device comprising an array of rows and columns of memory cells formed in a face of a semiconductor body, the major part of said array being a data memory and a minor part of the array being an address memory, a commutator for sequentially addressing said rows one at a time and means for reading out address and data from columns when a row is addressed, a serial access register connected via transfer means to the means for reading out to receive data from columns of said array, address input means in said face and connected to receive a multibit address from external to the device, comparator means in said face responsive to an address at said address input means and to said means for reading out and producing a command when the address from external is the same as the address from the array, means to activate said transfer means for the serial access register in response to said command, output means for reading said data from the serial access register to external to the device, a programmable transistor connected to each row and coupled to blanking means, and means to program such transistor if one or more cells in such row test bad.
- 11. A memory device comprising an array of rows and columns of memory cells formed in a face of a semiconductor body, the major part of said array being a data memory and a minor part of the array being an address memory, means for addressing said rows one at a time and output means for reading out address and data from columns when a row is addressed, an access register connected via transfer means to said output means to receive data from columns of said array, address input means in said face and connected to receive a multibit address from external to the device, comparator means in said face responsive to an address at said address input means and to said output means and producing a command when the address from external is the same as the address from the array via said output means, means to activate said transfer means for the access register in response to said command, and means for reading said data from the access register to external to the device.
- 21. A memory device comprising an array of rows and columns of memory cells formed in a face of semiconductor body, means for addressing said rows one at a time and output means for reading out data from columns when a row is addressed, an access register connected via transfer means to the output to receive data from columns of said array, address input means in said face and connected to receive a multibit address from external to the device, means in said face responsive to an address in said address input means and producing a command when the address from external is of predetermined character, means to activate said transfer means for the access register in response to said command, and means for reading said data from the access register to external to the device programmble means connected to each row and coupled to blanking means, and means to program said programmable means if one or more cells in a row test bad.
Specification