Infineon Technologies CY7C1550KV18-400BZXC

Overview

CY7C1550KV18 from Cypress Semiconductor is a 72-Mbit (2M × 36) synchronous pipelined DDR II+ SRAM with 2.0-cycle read latency, 400 MHz clock operation, HSTL I/O interface, and integrated PLL for precise data placement. It delivers 900 Mbps double-data-rate throughput, uses echo clocks (CQ/CQ) for simplified high-speed data capture, and supports configurable I/O voltage (1.4 V to 1.8 V). It is deployed in network packet buffers and high-speed test equipment where deterministic burst timing and low-latency memory access are critical.

For engineers reviewing the CY7C1550KV18 datasheet, CY7C1550KV18 pinout, CY7C1550KV18 application, or CY7C1550KV18 equivalent, this page provides verified technical context, validated pin functions, confirmed DDR II+ timing behavior, real-world use cases, and traceable alternative options - all grounded in Cypress' official documentation (Doc #001-15879 Rev. *R).

Technical Context

The CY7C1550KV18 implements a synchronous pipelined architecture with dual input clocks (K/K) and echo clocks (CQ/CQ), enabling precise DDR timing alignment. Its internal organization is two 1M × 36 arrays, supporting 2-word bursts per access, with address latching on alternate rising edges of K.

All synchronous inputs (A, R/W, LD, BWS[3:0]) are registered on the rising edge of K; write data is sampled on both K and K edges; read data is driven on both K and K edges with QVLD edge-aligned to CQ/CQ. The PLL ensures accurate data placement when DOFF = HIGH, while DOFF = LOW disables the PLL and reverts to DDR I mode (1-cycle latency, ≤167 MHz).

Key Specifications

Pinout & Package

Package: 165-ball Fine-Pitch Ball Grid Array (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-speed synchronous SRAM applications.

Compared with IDT72T3652 and IS61WV102436B, CY7C1550KV18 uniquely integrates PLL, echo clocks, and QVLD to reduce FPGA resource usage and PCB routing complexity - delivering higher effective bandwidth with lower system-level timing risk.

Availability

CY7C1550KV18 is available at Aetrix Electronics and suitable for network packet buffering, high-speed test equipment, FPGA-based protocol analyzers, and telecom line card buffers requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for CY7C1550KV18 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 U.S.-based semiconductor company specializing in high-performance memory, microcontrollers, and connectivity solutions for industrial, automotive, and communications markets.

CY7C1550KV18 belongs to Cypress' QDR II+ SRAM product line, engineered specifically for high-bandwidth, low-latency buffering in packet-switched networks and instrumentation systems demanding deterministic DDR timing and robust signal integrity.

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 a maximum frequency of 167 MHz. When held HIGH (via 10 kΩ pull-up), the PLL is enabled, supporting 400 MHz operation with 2.0-cycle latency and precise data placement via echo clocks. This hardware-selectable mode enables backward compatibility and debug flexibility without firmware changes.

How does the ZQ pin calibrate output impedance, and what resistor value is required?

The ZQ pin connects to an external resistor (RQ) tied to ground; the device measures RQ and configures its output drivers to 0.2 × RQ. For standard 50 Ω trace impedance, a 240 Ω resistor yields 48 Ω driver impedance. Cypress specifies RQ tolerance ≤±1%, and the pin must never be left floating or tied to GND - connecting directly to VDDQ enables minimum-impedance mode instead of calibration.

Can CY7C1550KV18 be used in depth-expanded memory configurations?

Yes - the device supports seamless depth expansion via automatic tri-state control. When a read access is deselected, the SRAM completes pending transactions and tri-states DQ[35:0] on the next rising edge of K, eliminating bus contention. This behavior, combined with QVLD and echo clocks, allows multiple CY7C1550KV18 devices to share a common data bus without external bus transceivers or wait-state insertion.

What is the role of BWS[3:0], and how are they mapped to data bits?

BWS[3:0] are active-Low byte write select signals that enable partial writes to 9-bit subwords. In CY7C1550KV18: BWS0 controls D[8:0], BWS1 controls D[17:9], BWS2 controls D[26:18], and BWS3 controls D[35:27]. All four are sampled synchronously on K/K rising edges during write cycles, allowing any combination of 9-bit lanes to be updated independently - avoiding destructive full-word writes in control register or descriptor table updates.