A buffered DRAM that can be utilized in a DIMM or RDIMM package to reduce the load on the data lines connected to the package is presented. A buffered DRAM can include a DRAM memory cell; and a buffer coupled to receive data lines and strobe signals, the buffer further coupled to receive address and command signals. If data access is directed to a second DRAM, the buffer buffers the data and strobe signals for access by the second DRAM. If data access is directed to the buffered DRAM the buffer buffers the data and strobe signals for access by the DRAM memory cell.
1. A buffered DRAM, comprising:
a first DRAM memory cell;
a buffer coupled to the first DRAM memory cell and further coupled to receive and transmit data lines and strobe signals, the buffer further coupled to receive and transmit address and command signals, and
wherein if data access is directed to a DRAM coupled to the buffered DRAM, the buffer couples the data and strobe signals out of the buffered DRAM for access by the DRAM coupled to the buffered DRAM and if data access is directed to the buffered DRAM the buffer couples the data and strobe signals for access by the first DRAM memory cell; further wherein the first DRAM memory cell and the buffer comprise a single DRAM circuit; further wherein
only the buffered DRAM is coupled to data lines connected to a dual in line memory module (DIMM) connector.
2. A registered dual in-line memory module (RDIMM), comprising:
a first DRAM circuit comprising a first DRAM memory cell and a buffer coupled to the first DRAM memory cell and further coupled to transmit, receive and buffer data and strobe signals using data lines and strobe lines; wherein the first DRAM memory cell and the buffer comprise a single DRAM circuit;
a register coupled to receive and transmit control and address signals;
at least a second DRAM coupled to the first DRAM circuit to receive data and strobe signals from the first DRAM circuit and address and control signals from the register; wherein
only the first DRAM circuit is coupled to data lines connected to a dual in line memory module (DIMM) connector.
3. The RDIMM of claim 2 , wherein the first DRAM circuit comprises:
a DRAM memory cell;
a buffer coupled to receive and transmit data signals and strobe signals, the buffer further coupled to receive and transmit address and command signals, and
wherein if data access is directed to a second DRAM the buffer couples the data and strobe signals out of the first DRAM circuit for access by the second DRAM and if data access is directed to the first DRAM circuit the buffer couples the data and strobe signals for access by the memory cell in the first DRAM circuit.
4. A method of operating a registered dual in-line memory module (RDIMM), comprising:
receiving address and control signals into a register, the address and control signals corresponding to a memory access the RDIMM comprising a first memory chip having a memory circuit and a buffer, the memory circuit and the buffer comprising a single chip;
determining in a first memory chip whether access is to the first memory chip or a second memory chip coupled to the first memory chip; and
if the memory access is to the first memory chip, buffering in the first memory chip data and strobe signals between a memory cell of the first memory chip and data and strobe lines of the RDIMM;
if the memory access is to the second memory chip, buffering in the first memory chip data and strobe signals between a memory cell of the second memory chip and data and strobe lines of the RDIMM; and transferring the buffered data and strobe signals to the second memory chip; wherein
only the first memory chip is coupled to data lines connected to a dual in line memory module (DIMM) connector.