Receiver Characterization with On-Die Eye Monitor (ODEM) in LPDDR5 and DDR5 SDRAM

As the speed of advanced memory products exceeding multi-GHz range, signal integrity (SI) analysis and receiver characterization becomes imperative to drive a robust I/O design and ensure good data valid window (DVW). Usually there is a gap between full channel system simulation and on-die high-speed I/O characterization. Non-linear equalization, for example a decision feedback equalizer (DFE), used in high-speed receiver (RX) makes RX characterization difficult in providing guidelines and insights during design phase. An on-die eye monitor (ODEM) is proposed with a close-loop simulation flow for full RX characterization. A programmable pattern generator is used to mimic channel response, and apply such data pattern to RX inputs. An on-chip eye diagram generator is also included to measure RX behaviors, including 1-tap DFE, under various use cases and conditions. The Char-flow and tool has been applied to 12Gbits LPDDR5 SDRAM product with a data rate up to 7500Mb/s/pin, and 16Gbits DDR5 SDRAM with 6400Mb/s/pin, using DRAM process.