Hybrid memory system with increased bandwidth
A hybrid memory system with improved bandwidth is disclosed. In one aspect, a memory system is provided that increases bandwidth relative to the JEDEC low-power double data rate version 5 (LPDDR5) standard. This improvement is made possible by increasing a data conductor count from sixteen to twenty-four. Optionally, the bandwidth may be further improved by increasing a clock frequency from a first value to a second value. This allows the hybrid memory system to provide improved bandwidth without the complications of merely doubling pin counts or doubling clock speed. Further, coding techniques tailored to the pin count and pin layout are provided.
1. A memory device having a plurality of memory banks, comprising:
a first pseudo-channel coupled to a first group of the plurality of memory banks, comprising:
a first group of data conductors configured to receive or send data in the first pseudo-channel, wherein data signals and data mask signals are combined to encode a byte across a plurality of data conductors of the first group of data conductors;
a first differential write clock conductor pair configured to receive first clock signals for reading or writing the data in the first pseudo-channel; and
a first differential read strobe clock (RDQS) conductor pair configured to send first strobe signals during a read operation for the data in the first pseudo-channel; and
a second pseudo-channel coupled to a second group of the plurality of memory banks, comprising:
a second group of data conductors configured to receive or send data in the second pseudo-channel;
a second differential write clock conductor pair configured to receive second clock signals for reading or writing the data in the second pseudo-channel; and
a second differential RDQS conductor pair configured to send second strobe signals during a read operation for the data in the second pseudo-channel.
2. The memory device of claim 1 , wherein the first group of data conductors consists of 12 pins and the second group of data conductors consists of 12 pins.
3. The memory device of claim 1 , where the plurality of data conductors of the first group of data conductors is two, three, or four data conductors.
4. The memory device of claim 1 , where the plurality of data conductors of the first group of data conductors couples to a data register.
5. The memory device of claim 1 , wherein a clock signal on the first differential write clock conductor pair is 4.8 gigahertz (GHz) or 6.4 GHz.
6. The memory device of claim 1 , wherein the data conductors of the first group of data conductors are separated by other conductors and the data conductors of the second group of data conductors are separated by other conductors.
7. The memory device of claim 1 , wherein conductors of the first differential write clock conductor pair are adjacent to one another, conductors of the first differential RDQS conductor pair are adjacent to one another, conductors of the second differential write clock conductor pair are adjacent to one another, and conductors of the second differential RDQS conductor pair are adjacent to one another.
8. The memory device of claim 1 , where the first differential write clock conductor pair is coupled to a clock receiver and quad phase generator configured to generate four phase data clocks.
9. The memory device of claim 1 , further comprising a reset conductor configured to receive a reset signal that is common to both the first pseudo-channel and the second pseudo-channel.
10. The memory device of claim 1 , wherein the first pseudo-channel further comprises a first chip select conductor and first command and address conductors and wherein the second pseudo-channel further comprises a second chip select conductor and second command and address conductors.
11. The memory device of claim 1 , wherein the first group of the plurality of memory banks consists of 16 banks.
12. The memory device of claim 1 , wherein the memory device is coupled to a host system on a chip (SoC).
13. The memory device of claim 1 , wherein a data mask signal is provided through the first group of data conductors periodically.
14. The memory device of claim 13 , wherein a byte is encoded across three conductors and a data mask bit is encoded in the ninth slot for each byte.