Abstract: An address sequencer circuit for generating addresses for accessing a memory device. The address sequencer includes a plurality of address stages that are coupled together, and also includes a first clock generation circuit that receives an input clock and generates a first clock signal that is coupled to a first portion of the address stages. A second clock generation circuit is provided that receives the input clock and a toggle signal and generates a second clock signal that is coupled to a second portion of the address stages, thereby allowing the first and second portions of address stages to be clocked at different rates.

Abstract: A word line driver for flash memories using NMOS circuitry to reduce parasitic capacitance loading on boost circuitry in low-voltage applications. A delay scheme which delays turn-on of the driver's source-drain circuit for a short time after the turn-on of the driver transistors' gates allows the gate capacitance of the driver transistor to provide an extra boost.

Abstract: A semiconductor memory device has 2n word lines, a plurality of bit lines, a plurality of nonvolatile memory cells disposed at each intersection of the word lines and the bit lines, a write circuit for writing data to a memory cell located at an intersection of selected ones of the word lines and the bit lines, and a sense amplifier for reading data out of the memory cells. Further, the semiconductor memory device comprises a first unit for simultaneously selecting a block of 2m (n>m) word lines among the 2n word lines, and a second unit for not selecting a block of 2k (m>k) word lines among the 2m word lines. The second unit does not select the block of 2k word lines, and selects a block of 2k word lines prepared outside the 2n word lines when any one of the 2k word lines among the 2m word lines is defective. Consequently, redundant word lines are effectively employed, write and verify operations are stable, and thereby the yield and performance of the semiconductor memory device are improved.

Abstract: A burst mode architecture to provide burst mode access to a plurality of data words in a flash memory is described. The burst mode architecture includes a first circuit, a control circuit coupled to the first circuit, and a data buffer selectively coupled to the first circuit by the control circuit. The first circuit accesses a plurality of data words, beginning with an initial access of a first data word and a second data word. The control circuit generates a timing signal having pulses and a second signal. The second signal is generated upon completion of the initial access of the first data word and the second data word. The first circuit follows the initial access with subsequent accesses of the plurality of data words responsively to the second signal and the timing signal.

Abstract: A semiconductor memory device has 2n word lines, a plurality of bit lines, a plurality of nonvolatile memory cells disposed at each intersection of the word lines and the bit lines, a write circuit for writing data to a memory cell located at an intersection of selected ones of the word lines and the bit lines, and a sense amplifier for reading data out of the memory cells. Further, the semiconductor memory device comprises a first unit for simultaneously selecting a block of 2m (n>m) word lines among the 2n word lines, and a second unit for not selecting a block of 2k (m>k) word lines among the 2m word lines. The second unit does not select the block of 2k word lines, and selects a block of 2k word lines prepared outside the 2n word lines when any one of the 2k word lines among the 2m word lines is defective. Consequently, redundant word lines are effectively employed, write and verify operations are stable, and thereby the yield and performance of the semiconductor memory device are improved.

Abstract: A system and a method are disclosed for providing a power saving mode during reading a memory device. A new memory content is read from the memory and, before being put at the memory output bus, is compared with the previously read memory content, which is currently on the output bus of the memory device. If the result of the comparison indicates that more than half of the memory output bits have to be toggled in order to put the new memory content on the memory output bus, the new data is inverted internally in order to reduce the number of output pins toggles. Then, the memory device sends a signal to the microprocessor or microcontroller indicating that the new data is inverted, and that the new data has to be inverted back before being put on the memory output bus.

Abstract: A semiconductor memory device has 2n word lines, a plurality of bit lines, a plurality of nonvolatile memory cells disposed at each intersection of the word lines and the bit lines, a write circuit for writing data to a memory cell located at an intersection of selected ones of the word lines and the bit lines, and a sense amplifier for reading data out of the memory cells. Further, the semiconductor memory device comprises a first unit for simultaneously selecting a block of 2m (n>m) word lines among the 2n word lines, and a second unit for not selecting a block of 2k (m>k) word lines among the 2m word lines. The second unit does not select the block of 2k word lines, and selects a block of 2k word lines prepared outside the 2n word lines when any one of the 2k word lines among the 2m word lines is defective. Consequently, redundant word lines are effectively employed, write and verify operations are stable, and thereby the yield and performance of the semiconductor memory device are improved.

Abstract: System to set burst mode in a memory device. The system includes apparatus having a first signal buffer that receives an address control signal and produces a buffered address control signal. A mode detection circuit is included that receives the buffered address control signal and produces a burst control signal. The apparatus also includes a core access trigger circuit that receives the burst control signal and generates a core access signal that is used to begin a core access for burst mode operation of the memory.

Abstract: A system for a constant current source circuit utilizing CMOS technology. The system includes a constant current source circuit that includes a bias circuit that outputs a bias signal and a switch circuit that has a switch input coupled to receive the bias signal, a switch output, and a switch control that is coupled to receive an input signal. The current source circuit also includes an output circuit that has a first input coupled to the switch output and a second input coupled to the input signal. The output circuit provides an output signal that has constant current.

Abstract: A semiconductor memory device has 2n word lines, a plurality of bit lines, a plurality of nonvolatile memory cells disposed at each intersection of the word lines and the bit lines, a write circuit for writing data to a memory cell located at an intersection of selected ones of the word lines and the bit lines, and a sense amplifier for reading data out of the memory cells. Further, the semiconductor memory device comprises a first unit for simultaneously selecting a block of 2m (n>m) word lines among the 2n word lines, and a second unit for not selecting a block of 2k (m>k) word lines among the 2m word lines. The second unit does not select the block of 2k word lines, and selects a block of 2k word lines prepared outside the 2n word lines when any one of the 2k word lines among the 2m word lines is defective. Consequently, redundant word lines are effectively employed, write and verify operations are stable, and thereby the yield and performance of the semiconductor memory device are improved.

Abstract: An array threshold voltage test mode for a flash memory device is disclosed. During the test mode, a test voltage is routed directly to the gates of the flash memory transistors selected by a given address. If the test voltage causes the selected transistors to change state by crossing their threshold voltage level, the change will be reflected in the data outputs of the device. By varying the test voltages and the addresses and monitoring the data outputs, the array threshold voltage distribution can be determined for the entire device.

Abstract: A signal generator for generating a kickb signal used to reset a boost signal used to operate a memory device. The signal generator includes an address detector that receives one or more address lines and a clock signal to produce a detector output. A switch circuit is also included that receives the detector output, the clock signal and a feedback signal to produce a switch output. A delay circuit is coupled to receive the switch output to produce a delayed switch output, and an output circuit is coupled to receive the switch output and the delayed switch output to produce the kickb signal, where the kickb signal forms the feedback signal.

Abstract: A semiconductor memory device has 2n word lines, a plurality of bit lines, a plurality of nonvolatile memory cells disposed at each intersection of the word lines and the bit lines, a write circuit for writing data to a memory cell located at an intersection of selected ones of the word lines and the bit lines, and a sense amplifier for reading data out of the memory cells. Further, the semiconductor memory device comprises a first unit for simultaneously selecting a block of 2m (n>m) word lines among the 2n word lines, and a second unit for not selecting a block of 2k (m>k) word lines among the 2m word lines. The second unit does not select the block of 2k word lines, and selects a block of 2k word lines prepared outside the 2n word lines when any one of the 2k word lines among the 2m word lines is defective. Consequently, redundant word lines are effectively employed, write and verify operations are stable, and thereby the yield and performance of the semiconductor memory device are improved.

Abstract: A semiconductor memory device has 2n word lines, a plurality of bit lines, a plurality of nonvolatile memory cells disposed at each intersection of the word lines and the bit lines, a write circuit for writing data to a memory cell located at an intersection of selected ones of the word lines and the bit lines, and a sense amplifier for reading data out of the memory cells. Further, the semiconductor memory device comprises a first unit for simultaneously selecting a block of 2m (n>m) word lines among the 2n word lines, and a second unit for not selecting a block of 2k (m>k) word lines among the 2m word lines. The second unit does not select the block of 2k word lines, and selects a block of 2k word lines prepared outside the 2n word lines when any one of the 2k word lines among the 2m word lines is defective. Consequently, redundant word lines are effectively employed, write and verify operations are stable, and thereby the yield and performance of the semiconductor memory device are improved.

Abstract: A signal generator for generating a kickb signal used to reset a boost signal used to operate a memory device. The signal generator includes an address detector that receives one or more address lines and a clock signal to produce a detector output. A switch circuit is also included that receives the detector output, the clock signal and a feedback signal to produce a switch output. A delay circuit is coupled to receive the switch output to produce a delayed switch output, and an output circuit is coupled to receive the switch output and the delayed switch output to produce the kickb signal, where the kickb signal forms the feedback signal.

Abstract: A system for a constant current source circuit utilizing CMOS technology. The system includes a constant current source circuit that includes a bias circuit that outputs a bias signal and a switch circuit that has a switch input coupled to receive the bias signal, a switch output, and a switch control that is coupled to receive an input signal. The current source circuit also includes an output circuit that has a first input coupled to the switch output and a second input coupled to the input signal. The output circuit provides an output signal that has constant current.

Abstract: A method of charging a data line to a desired voltage level prior to the data line being sensed in a low power memory device by discharging the data line from a voltage level above the desired voltage level to approximately the desired voltage level. By using N-type transistors to discharge the data line to the desired voltage level, the voltage level can be reached faster with cheaper components.

Abstract: A protection system that protects a booster circuit used to boost operating signals in a memory device. The system includes a protection circuit for protecting an output transistor of the booster circuit. The protection circuit includes a transfer gate coupled to the output transistor and coupled to receive a first boost signal and a second boost signal. The transfer gate opens and closes in response to the second boost signal. When the transfer gate is closed, the first boost signal is uncoupled from the output transistor, and when the transfer gate is opened, the first boost signal is coupled to the output transistor. The circuit also includes a protection transistor coupled to the second boost signal, a supply voltage and the output transistor, where the protection transistor couples the supply voltage to the output transistor when the transfer gate is closed.

Abstract: System to set burst mode in a memory device. The system includes apparatus having a first signal buffer that receives an address control signal and produces a buffered address control signal. A mode detection circuit is included that receives the buffered address control signal and produces a burst control signal. The apparatus also includes a core access trigger circuit that receives the burst control signal and generates a core access signal that is used to begin a core access for burst mode operation of the memory.

Abstract: An address sequencer circuit for generating addresses for accessing a memory device. The address sequencer includes a plurality of address stages that are coupled together, and also includes a first clock generation circuit that receives an input clock and generates a first clock signal that is coupled to a first portion of the address stages. A second clock generation circuit is provided that receives the input clock and a toggle signal and generates a second clock signal that is coupled to a second portion of the address stages, thereby allowing the first and second portions of address stages to be clocked at different rates.