Cypress Semiconductor Corp CY7C1543KV18-400BZI

Overview

CY7C1543KV18 from Cypress Semiconductor is a 72-Mbit QDR® II+ SRAM with 4M × 18 organization, 2.0-cycle read latency, 400 MHz clock operation (800 Mbps DDR per port), 1.8 V core supply, and 1.4–1.8 V I/O supply. It features separate read/write ports, echo clocks (CQ/CQ), QVLD data-valid indicator, and supports concurrent transactions in high-bandwidth networking buffers.

For engineers reviewing the CY7C1543KV18 datasheet, CY7C1543KV18 pinout, CY7C1543KV18 application, or CY7C1543KV18 equivalent, key selection criteria include burst depth (four 18-bit words), HSTL I/O compatibility, PLL-enabled timing control, and FBGA-165 package constraints for high-speed PCB layout.

Technical Context

The CY7C1543KV18 implements a synchronous pipelined QDR II+ architecture with independent read and write ports sharing a multiplexed 20-bit address bus. Address latching occurs on alternating rising edges of K and K clocks, enabling full-duplex operation without bus turnaround.

It uses a Phase-Locked Loop (PLL) to align output data with echo clocks CQ/CQ, ensuring precise 900 Mbps DDR timing at 400 MHz input clock. The DOFF pin selects between 2.0-cycle latency (PLL enabled, QDR II+ mode) and 1-cycle latency (PLL disabled, QDR I mode).

Key Specifications

Pinout & Package

Package: 165-ball Fine-Pitch Ball Grid Array (FBGA), 13 mm × 15 mm × 1.4 mm body, RoHS-compliant, with exposed thermal pad.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1543KV18-450BZI, this -400BZI variant trades 50 MHz bandwidth for relaxed timing margins and lower power; compared with AS7C3256B-15JIN, it provides 14× higher sustained throughput and deterministic dual-port concurrency - critical for data plane acceleration.

Availability

CY7C1543KV18-400BZI is available at Aetrix Electronics and suitable for high-speed network packet buffers, telecom line card memory, baseband processing subsystems, and ATE pattern generators requiring stable component supply across extended production lifecycles.

Supply support for CY7C1543KV18-400BZI 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 communications, industrial, and automotive systems, with emphasis on signal integrity and timing precision.

This device belongs to the QDR® II+ SRAM product line, engineered specifically for deterministic, high-throughput data buffering in packet-switched infrastructure where concurrent read/write and sub-cycle latency predictability are mandatory.

FAQ

What is the function of the DOFF pin on CY7C1543KV18-400BZI?

The DOFF pin controls the internal PLL: when pulled HIGH (via 10 kΩ pull-up), the device operates in QDR II+ mode with 2.0-cycle read latency and full 400 MHz capability; when pulled LOW, the PLL is disabled and the device reverts to QDR I timing with 1-cycle latency and reduced maximum frequency (≤167 MHz). This pin must not be left floating.

How does the ZQ pin affect output driver behavior?

The ZQ pin sets the output impedance of Q[17:0], CQ, and CQ by calibrating internal drivers against an external resistor (RQ) tied between ZQ and ground. Output impedance becomes 0.2 × RQ; if ZQ is tied directly to VDDQ, minimum impedance mode is activated. Connecting ZQ to GND or leaving it unconnected violates specification and risks signal integrity failure.

Can CY7C1543KV18-400BZI support partial-word writes without read-modify-write?

Yes - via BWS0 and BWS1 pins, which independently enable writing to D[8:0] and D[17:9]. When a BWS signal is deasserted (HIGH), the corresponding byte group is ignored during the write cycle, preserving existing data in those bits. This eliminates the need for external read-modify-write logic in applications requiring granular updates.

What is the role of QVLD in system timing validation?

QVLD is edge-aligned with CQ and CQ and asserts precisely when Q[17:0] carries valid burst data. Unlike clock-derived strobes, QVLD accounts for internal propagation delays and PLL skew, providing a hardware-verified, jitter-tolerant ready signal for FPGA capture registers - essential for achieving setup/hold compliance at 900 Mbps DDR rates.