Cypress Semiconductor Corp CY7C1568KV18-450BZC

Overview

CY7C1568KV18 from Cypress Semiconductor is a 72-Mbit (4M × 18) DDR II+ synchronous SRAM with two-word burst architecture, 2.5-cycle read latency at 450 MHz, HSTL I/O interface, and dual echo clocks (CQ/CQ) for precise data capture. It operates with core VDD = 1.8 V ± 0.1 V and I/O VDDQ = 1.4–1.8 V, and is used in high-bandwidth networking line cards requiring deterministic low-latency memory access.

For engineers reviewing the CY7C1568KV18 datasheet, CY7C1568KV18 pinout, CY7C1568KV18 application, or CY7C1568KV18 equivalent, key selection considerations include DDR II+ timing compliance, 165-ball FBGA package compatibility, DOFF-controlled latency mode switching (2.5-cycle vs. 1-cycle), and JTAG 1149.1 test port integration for system-level validation.

Technical Context

This SRAM implements a pipelined synchronous architecture where address and control signals (LD, R/W, BWS[1:0]) are registered on the rising edge of K clock only, while write data is latched on both K and K rising edges. Read data is driven synchronously on both K and K edges, enabling true double-data-rate throughput.

The device integrates an internal PLL for accurate data placement and uses echo clocks CQ/CQ-phase-aligned to K/K-to eliminate board-level skew compensation. QVLD provides edge-aligned valid-data indication, and ZQ 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 height, 0.8 mm ball pitch, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AS7C362000B-15JIN and IS61WV102418BLL-10BLI, CY7C1568KV18 uniquely combines programmable latency, integrated echo clocks, and JTAG testability-enabling higher bandwidth and lower system-level timing risk in new high-speed designs.

Availability

CY7C1568KV18 is available at Aetrix Electronics and suitable for telecom infrastructure, network test equipment, and high-performance embedded computing requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for CY7C1568KV18 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) is a fabless semiconductor company specializing in high-performance memory, microcontrollers, and connectivity solutions for industrial, automotive, and communications markets.

CY7C1568KV18 belongs to Cypress's DDR II+ SRAM product line, engineered specifically for deterministic, low-jitter memory interfacing in multi-gigabit networking and test instrumentation systems.

FAQ

What is the function of the DOFF pin, and how does it affect timing?

The DOFF pin is an active-LOW PLL disable control. When asserted LOW, it disables the internal PLL and forces the device into DDR I mode with 1-cycle read latency and maximum 167 MHz operation. When HIGH, the PLL enables DDR II+ mode with 2.5-cycle latency and up to 550 MHz operation. This dual-mode capability allows backward compatibility and performance scaling within the same footprint.

How are the echo clocks CQ and CQ used in system design?

CQ and CQ are free-running output clocks synchronized to K and K, respectively. They are routed alongside DQ[17:0] to the receiving logic (e.g., FPGA or ASIC) to serve as capture clocks for read data. Because CQ/CQ track K/K phase and jitter, they eliminate the need for board-level trace length matching or external DLLs-reducing timing closure effort and improving signal integrity at 450 MHz.

Can CY7C1568KV18 be used in depth-expanded memory configurations?

Yes. The device supports depth expansion using LD and R/W signals across multiple units. When one device is deselected, its outputs tristate automatically on the next K rising edge, allowing seamless handoff to the next device in the chain without wait states. This behavior is guaranteed by internal synchronous control logic and is validated in Cypress's application note AN91394.

What is the role of the ZQ pin, and how should it be connected?

ZQ is an impedance calibration reference pin. It must be connected to a precision resistor (typically 50 Ω) tied to ground to calibrate CQ, CQ, and DQ output drive strength to 0.2 × RQ (i.e., 10 Ω). Alternatively, connecting ZQ directly to VDDQ enables minimum-impedance mode (≈7 Ω). ZQ must never be left floating or tied to GND-doing so disables output tuning and risks signal integrity failure.