Cypress Semiconductor Corp CY7C1568XV18-633BZXC

Overview

CY7C1568XV18-633BZXC from Cypress Semiconductor is a 72-Mbit (4M × 18) DDR II+ Xtreme SRAM with 633 MHz clock frequency, 2.5-cycle read latency, and HSTL I/O interface operating at 1.4–1.6 V VDDQ. It features dual echo clocks (CQ/CQ), QVLD data-valid indicator, and PLL-based timing alignment for high-speed synchronous burst reads in networking line cards and packet buffer applications.

For engineers reviewing the CY7C1568XV18-633BZXC datasheet, CY7C1568XV18-633BZXC pinout, CY7C1568XV18-633BZXC application, or CY7C1568XV18-633BZXC equivalent, key selection criteria include DDR II+ burst timing compliance, 165-ball FBGA mechanical fit, DOFF-controlled latency mode switching, and JTAG 1149.1 test port integration for system-level validation.

Technical Context

This SRAM implements a synchronous pipelined architecture with two-word burst transfers initiated on alternate rising edges of complementary K/K clocks. All address, control, and data signals are registered synchronously to K or K, enabling deterministic timing at 1266 MT/s effective data rate.

The integrated PLL aligns output data edges to echo clocks CQ/CQ, while DOFF pin selects between 2.5-cycle DDR II+ mode (DOFF = HIGH) and 1-cycle DDR I mode (DOFF = LOW). ZQ pin enables programmable output impedance matching to 0.2 × RQ via external resistor to ground.

Key Specifications

Pinout & Package

Package: 165-ball fine-pitch ball grid array (FBGA), 13 mm × 15 mm × 1.4 mm body, RoHS-compliant Pb-free construction.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed burst SRAM applications.

Compared with AS7C36256PFS-15TIN and IS61WV102418BLL-10BLI, CY7C1568XV18-633BZXC delivers deterministic DDR II+ timing, eliminates board-level clock-data skew management, and supports runtime latency reconfiguration - critical for next-generation packet processing and test instrumentation.

Availability

CY7C1568XV18-633BZXC is available at Aetrix Electronics and suitable for network packet buffering, telecom line card memory, and high-speed protocol analyzer applications requiring stable component supply, long-lifecycle support, and verified Pb-free FBGA sourcing.

Supply support for CY7C1568XV18-633BZXC includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Cypress Semiconductor (now part of Infineon Technologies) designs high-performance memory and programmable solutions for industrial, automotive, and communications infrastructure markets.

CY7C1568XV18 belongs to the DDR II+ Xtreme SRAM product line, engineered specifically for deterministic, low-jitter burst memory access in packet-switched networking and high-speed test equipment where DDR I timing is insufficient and DDR2/3 SDRAM introduces unacceptable latency.

FAQ

What is the function of the DOFF pin on CY7C1568XV18-633BZXC?

The DOFF pin controls internal PLL operation: when asserted HIGH, it enables DDR II+ mode with 2.5-cycle read latency and full 633 MHz performance; when LOW, it disables the PLL and reverts the device to DDR I timing with 1-cycle latency and reduced maximum frequency (≤167 MHz). This allows runtime mode switching without changing clock generation circuitry.

How does the ZQ pin affect output drive strength?

ZQ connects to an external resistor (RQ) tied to ground, enabling on-die calibration of CQ, CQ, and DQ output impedance to 0.2 × RQ. This matches transmission line impedance on the PCB, minimizing reflections and signal integrity issues. If RQ is omitted, connecting ZQ to VDDQ enables minimum output drive strength.

Can CY7C1568XV18-633BZXC operate without the PLL enabled?

Yes - asserting DOFF LOW disables the PLL and places the device in DDR I mode, where timing follows standard DDR I specifications with 1-cycle read latency. In this mode, maximum operating frequency drops to 167 MHz, and echo clock alignment is no longer guaranteed, requiring external timing compensation.

What is the purpose of the QVLD signal in system design?

QVLD is a synchronous output that pulses edge-aligned with CQ/CQ to indicate exactly when DQ[17:0] data is valid. It replaces complex setup/hold margin calculations in FPGA capture logic, allowing designers to latch data on the QVLD-active edge rather than relying on fixed clock-phase relationships - essential for robust operation above 500 MHz.