IS61QDB42M18 Datasheet | ISSI

Features - 1M x 36 or 2M x 18. - On-chip delay-locked loop (DLL) for wide data valid window. - Separate read and write ports with concurrent read and write operations. - Synchronous pipeline read with late write operation. - Double data rate (DDR) interface for read and write input ports. - Fixed 4-bit burst for read and write operations. - Clock stop support. - Two input clocks (K and K) for address and control registering at rising edges only. - Two input clocks (C and C) for data output control. - Two echo clocks (CQ and CQ) that are delivered simultaneously with data. - +1.8V core power supply and 1.5, 1.8V VDDQ, used with 0.75, 0.9V VREF. - HSTL input and output levels. - Registered addresses, write and read controls, byte writes, data in, and data outputs. - Full data coherency. - Boundary scan using limited set of JTAG 1149.1 functions. - Byte write capability. - Fine ball grid array (FBGA) package - 15mm x 17mm body size - 1mm pitch - 165-ball (11 x 15) array - Programmable impedance output drivers via 5x user-supplied precision resistor. Description The 36Mb IS61QDB41M36 and IS61QDB42M18 are synchronous, high-performance CMOS static random access memory (SRAM) devices. These SRAMs have separate I/Os, eliminating the need for high-speed bus turnaround. The rising edge of K clock initiates the read/write operation, and all internal operations are self-timed. Refer to the Timing Reference Diagram for Truth Table on page 8 for a description of the basic operations of these QUAD (Burst of 4) SRAMs. Read and write addresses are registered on alternating rising edges of the K clock. Reads and writes are performed in double data rate. The following are registered internally on the rising edge of the K clock: - - - - - Read/write address Read enable Write enable Byte writes for burst addresses 1 and 3 Data-in for burst addresses 1 and 3 - Byte writes for burst addresses 2 and 4 - Data-in for burst addresses 2 and 4 Byte writes can change with the corresponding...