Cypress Semiconductor Corp CY7C1543KV18-400BZC

Overview

CY7C1543KV18 from Cypress Semiconductor is a 4M × 18, 72-Mbit QDR® II+ SRAM with separate read/write ports, 450 MHz clock operation (900 Mbps DDR data rate), 2.0-cycle read latency, and 1.8 V core / 1.4–1.8 V I/O supply. It delivers concurrent high-bandwidth memory access for network packet buffering in telecom line cards.

For engineers reviewing the CY7C1543KV18 datasheet, CY7C1543KV18 pinout, CY7C1543KV18 application, or CY7C1543KV18 equivalent, key selection criteria include its four-word burst architecture, echo-clock–assisted timing closure at 450 MHz, HSTL I/O compatibility, and DOFF-pin–controlled QDR I/II+ mode switching.

Technical Context

This SRAM implements true dual-port synchronous pipelined architecture: independent K and K clocks drive separate read and write paths, with all inputs registered on rising edges and outputs edge-aligned to echo clocks CQ/CQ. The internal PLL enables precise 2.0-cycle read latency alignment and supports both QDR II+ (DOFF = HIGH) and QDR I (DOFF = LOW) timing modes.

It uses a single multiplexed 20-bit address bus latched alternately per port, with RPS/WPS enabling port-select depth expansion. Byte write select (BWS[1:0]) allows granular 9-bit writes per 18-bit word, and QVLD provides cycle-accurate output validity indication synchronized to CQ/CQ.

Key Specifications

Pinout & Package

Package: 165-ball FBGA (13 mm × 15 mm × 1.4 mm), RoHS-compliant, with 0.8 mm ball pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AS7C36256PFS-15BIN and IS61WV102418BLL-10BLI, CY7C1543KV18 uniquely delivers true concurrent dual-port DDR operation at 450 MHz - essential for eliminating bottlenecks in packet-forwarding and real-time signal processing pipelines.

Availability

CY7C1543KV18 is available at Aetrix Electronics and suitable for network packet buffering, high-speed switch fabric interface, telecom baseband processing, and test equipment data capture requiring stable component supply across extended production lifecycles.

Supply support for CY7C1543KV18 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 networking, automotive, and industrial applications.

CY7C1543KV18 belongs to the QDR® II+ SRAM product line, engineered specifically for deterministic, low-latency, concurrent memory access in high-speed communications infrastructure.

FAQ

What is the function of the DOFF pin on CY7C1543KV18?

The DOFF pin controls the internal PLL: when pulled HIGH, it enables QDR II+ mode with 2.0-cycle read latency and 450 MHz operation; when pulled LOW, it disables the PLL and reverts the device to QDR I timing (1-cycle latency, max 167 MHz). This pin must not be left floating and should be tied via ≤10 kΩ resistor to VDDQ for normal operation.

How does the ZQ pin affect signal integrity?

The ZQ pin connects to an external resistor to ground to calibrate the output driver impedance of Q[17:0], CQ, and CQ pins to 0.2 × RQ. This on-die termination matching minimizes reflections and improves eye diagram margins on high-speed PCB traces operating at 900 Mbps DDR rates, eliminating need for discrete series termination resistors.

Can CY7C1543KV18 perform partial writes without corrupting adjacent data?

Yes - using BWS0 and BWS1, the device supports byte-selective writes: BWS0 enables writing to D[8:0], BWS1 enables D[17:9]. When one BWS is deasserted, the corresponding 9-bit segment remains unaltered during the write burst, preserving data coherency across partial updates without requiring read-modify-write sequences.

What role do CQ and CQ play in system timing design?

CQ and CQ are free-running echo clocks synchronized to K and K, respectively. They provide receiver-side clock references aligned to data edges on Q[17:0], enabling source-synchronous capture in FPGAs or ASICs without complex PLL-based deskew. Their phase relationship eliminates setup/hold uncertainty at 450 MHz, reducing timing margin requirements by up to 300 ps versus system-clock–based capture.