摘要:
In a synchronous semiconductor memory device, memory arrays (MA) forming activation units each are divided into a plurality of small memory arrays (MK). There are provided local I/O line pairs (LIO) each for two small memory arrays. The global I/O line pairs (GIO) crossing word lines are arranged in word line shunt regions (WS). The connection switches (BS) are arranged in the crossing between the local I/O line pairs and global I/O line pairs. Each small memory array in the activated memory array is connected to the corresponding global I/O line pair through the local I/O line pair. Thereby, a plurality of bits can be simultaneously read without increasing an area occupied by interconnections. The control of connection switch is made using a sense amplifier activation signal. Global I/O lines are precharged/equalized after data are transferred to read data registers provided for data output terminal for sequential data output or into selected memory cells. External clock signal is frequency-divided to produce phase-shifted internal clock signals which are used for producing internal voltage through charge operation.
摘要:
In a synchronous semiconductor memory device, memory arrays (MA) forming activation units each are divided into a plurality of small memory arrays (MK). There are provided local I/O line pairs (LIO) each for two small memory arrays. The global I/O line pairs (GIO) crossing word lines are arranged in word line shunt regions (WS). The connection switches (BS) are arranged in the crossing between the local I/O line pairs and global I/O line pairs. Each small memory array in the activated memory array is connected to the corresponding global I/O line pair through the local I/O line pair. Thereby, a plurality of bits can be simultaneously read without increasing an area occupied by interconnections. The control of connection switch is made using a sense amplifier activation signal. Global I/O lines are precharged/equalized after data are transferred to read data registers provided for data output terminal for sequential data output or into selected memory cells. External clock signal is frequency-divided to produce phase-shifted internal clock signals which are used for producing internal voltage through charge operation.
摘要:
A first clock signal for controlling the inputting of an external signal and for controlling internal operation and a second clock signal for controlling data output are applied to separate clock input nodes, respectively. Data output timing with respect to the first clock signal can be adjusted and thus clock access time and data hold time can be adjusted. Internal data read path is pipelined to include a first transfer gate responsive to the first clock signal for transferring internal read data and a second transfer gate responsive to the second clock signal for transferring the internal read data from the first transfer gate for external outputting through an output buffer. A synchronous semiconductor memory device is provided capable of setting clock access time and data hold time at the optimal values depending on the application and of reducing the clock access time.
摘要:
To one memory array, global signal input/output line pairs in two systems, a switch for connecting the global IO line pairs to a write buffer group alternately on a clock cycle basis, and another switch for connecting the global IO line pairs to an equalize circuit alternately on a clock cycle basis are provided. During one clock cycle, writing of data through one global IO line pair and equalization of the other global IO line pair can be carried out in parallel. Therefore, data can be written easily at a high frequency.
摘要:
A semiconductor memory device receives an external control signal repeatedly generated independently of an access to the memory device. The memory device includes an internal voltage generator for generating a desired internal voltage in response to the control signal. The internal voltage generator includes a charge pump circuit responsive to the control signal. The internal voltage may provide a negative voltage such as a substrate bias voltage, or may be a positive voltage boosted over an operating power supply voltage and used as a boosted word line drive signal. This scheme eliminates an oscillator for generating a repeated clock signal to the charge pump circuit, leading to reduced current consumption and reduced chip area for the semiconductor memory device.
摘要:
When an operating frequency is increased and a CAS latency is set longer, a data write end time is delayed by a specific time in response to the change of the CAS latency. The specific time is greater than a period corresponding to the CAS latency. The specific time may be the minimum time necessary for writing second-bit data. The write margin can also be enlarged by delaying the write timing (activation and inactivation) in the interior of a memory itself by one clock cycle of an external clock signal. Thus, a write period for second-bit data is ensured in an SDRAM, even if the operation frequency is increased.
摘要:
Memory arrays are divided into banks which can be operated independent from each other. Read data storing registers and write data storing registers operating independent from each other are provided for the banks. The memory array is divided into a plurality of small array blocks, local IO lines are arranged corresponding to each array block, and the local IO lines are connected to global IO lines. The global IO lines are connected to preamplifier groups and to write buffer groups. By control signal generating circuits and by a register control circuit, inhibition of writing of a desired bit only during successive writing operation can be done, data can be collectively written to the selected memory cells when the final data is input if the data writing should be stopped before reaching the wrap length in successive writing, and the timing for activating the memory array when the write cycle should be repeatedly carried out can be delayed. A synchronous semiconductor memory device having small chip area, high speed of operation, low power consumption and multiple functions is provided.
摘要:
Switches (11, 12) select either of refresh address counters (6a, 6b) in accordance with a refresh bank set signal (.phi.REFADD) when a bank refresh signal (.phi.BANKREF) is activated. An internal bank address (int.BA) serves as the refresh bank set signal (.phi.REFADD) to control the switch (12) and the refresh address counter (6a or 6b) designated by the internal bank address (int.BA) performs a count operation in synchronization with a refresh clock (.phi.REFCLK). The switch (11) outputs either of refresh addresses (Ref.Add.sub.-- A , Ref.Add.sub.-- B ) which is updated. With this configuration provided is an SDRAM which allows access to data during a refresh operation.
摘要:
A refresh control circuit of a DLL circuit responds to an auto refresh detection signal AR and a self refresh detection signal SR to inhibit input of clock signals ECLK and RCLK to a phase comparator and to a voltage control delay circuit. The DLL circuit can be stopped in a mode where an internal clock signal is not required to reduce power consumption.
摘要:
A semiconductor memory device includes a DRAM, an SRAM and a bi-direction transfer gate circuit provided between SRAM and DRAM. SRAM array includes a plurality of sets of word lines. Each set is provided in each row of SRAM array and each word line in each set is connected to a different group of memory cells of an associated row. An address signal for the SRAM and an address signal for the DRAM are separately applied to an address buffer. The semiconductor memory device further includes an additional function control circuit for realizing a burst mode and a sleep mode. A data transfer path from DRAM to the SRAM and a data transfer path from the SRAM to the DRAM are separately provided in the bi-directional transfer gate circuit. Data writing paths and data reading paths are separately provided in the DRAM array. By the above described structure, operation of the buffer circuit is stopped in the sleep mode, reducing power consumption. Since data writing path and data reading path are separately provided in the DRAM array, addresses to the DRAM array can be applied in non-multiplexed manner, so that data can be transferred at high speed from the DRAM array to the SRAM array, enabling high speed operation even at a cache miss.