Cypress Semiconductor Corp CY7C2568KV18-400BZXC

Overview

CY7C2568KV18 from Cypress Semiconductor is a 72-Mbit synchronous pipelined SRAM with DDR II+ architecture, configured as 4M × 18-bit, operating at up to 400 MHz (2.5-cycle read latency), supporting 1.8V core and 1.4–1.8V I/O supply, and featuring on-die termination (ODT) for D[x:0], BWS[x:0], and K/K inputs - deployed in high-bandwidth networking line cards and packet buffer subsystems.

For engineers reviewing the CY7C2568KV18 datasheet, CY7C2568KV18 pinout, CY7C2568KV18 application, or CY7C2568KV18 equivalent, key selection criteria include burst depth (2-word), echo clock (CQ/CQ) timing alignment, QVLD data validity signaling, HSTL-compatible I/O drive, and FBGA-165 package compatibility with high-density PCB routing constraints.

Technical Context

The device implements a synchronous pipelined SRAM core with dual-clock DDR II+ interface: addresses latched on alternate rising edges of K/K, write data registered on both K and K rising edges, and read data driven synchronously on both K and K rising edges. It uses internal PLL for precise data placement and supports programmable ODT via ZQ calibration.

Read operations use 2.5-cycle latency when DOFF = HIGH and 1-cycle latency when DOFF = LOW; echo clocks CQ/CQ align with output data edges, and QVLD provides edge-aligned valid-data indication. All synchronous inputs pass through K/K-controlled registers, and writes are self-timed internally.

Key Specifications

Pinout & Package

Package: 165-ball Fine-Pitch Ball Grid Array (FBGA), 13 mm × 15 mm × 1.4 mm body, RoHS-compliant, with 0.8 mm ball pitch and standard JEDEC MO-270AB footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AS7C3256A-15JCIN and IS61WV102418BLL-10BLI, CY7C2568KV18 uniquely delivers DDR II+ burst bandwidth, echo-clock–assisted timing closure, and programmable ODT - essential for 10G+ data path integrity where asynchronous or single-rate alternatives fail to meet timing or signal integrity requirements.

Availability

CY7C2568KV18 is available at Aetrix Electronics and suitable for packet buffer memory, network processor interface, baseband processing buffer, and high-speed test equipment applications requiring stable component supply across extended product lifecycles.

Supply support for CY7C2568KV18 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.

CY7C2568KV18 belongs to the QDR II+ SRAM product line, designed specifically to replace legacy SRAMs in bandwidth-constrained DDR memory interfaces while maintaining pin- and function-compatibility with existing QDR II layouts.

FAQ

What is the function of the DOFF pin on CY7C2568KV18?

The DOFF (Double-Off) pin selects read latency mode: when asserted HIGH, it enables 2.5-cycle read latency for maximum bandwidth; when LOW, it reverts to 1-cycle latency like standard DDR I devices. This dual-mode capability allows system designers to optimize for either throughput or latency depending on real-time traffic patterns without hardware change.

How does on-die termination (ODT) work with the ZQ pin?

ODT uses the ZQ pin to calibrate internal termination resistors against an external 240 Ω reference resistor. During power-up initialization, the device measures ZQ and configures ODT strength accordingly. The ODT pin then selects between two calibrated ranges (LOW ≈ 175–350 Ω, HIGH ≈ 50–100 Ω), enabling impedance matching to varied PCB trace impedances without discrete resistors.

Can CY7C2568KV18 operate with only one clock (K) instead of K and K?

No - K and K are complementary differential clocks both required for proper DDR II+ operation. The device samples addresses on alternating K/K edges and transfers data on both rising edges. Using only K violates timing architecture and will cause functional failure; both clocks must be provided with matched trace lengths and controlled skew per datasheet AC specifications.

What is the purpose of the QVLD signal and how is it timed?

QVLD (Q Valid) is an edge-aligned output that indicates when DQ[17:0] data is valid and stable for capture. It transitions synchronously with the rising edges of CQ and CQ, providing a clean, jitter-free strobe for external latches. Its timing eliminates setup/hold uncertainty in high-speed systems where data eye widths shrink below 100 ps at 400 MHz operation.