Cypress Semiconductor Corp CY7C1550KV18-450BZC

Overview

CY7C1550KV18 from Cypress Semiconductor is a 72-Mbit synchronous pipelined DDR II+ SRAM with 2M × 36 organization, 450 MHz clock operation, 2.0-cycle read latency (when DOFF = HIGH), and HSTL I/O interface supporting 1.4–1.8 V VDDQ. It delivers 900 Mbps data transfer via double-data-rate outputs synchronized to K/K clocks and is used in high-bandwidth packet buffering for network switches and telecom line cards.

For engineers reviewing the CY7C1550KV18 datasheet, CY7C1550KV18 pinout, CY7C1550KV18 application, or CY7C1550KV18 equivalent, key selection criteria include burst depth (2-word), echo clock timing (CQ/CQ alignment), QVLD validity signaling, PLL-enabled latency mode control (DOFF), and FBGA-165 package compatibility with high-speed PCB layout constraints.

Technical Context

The CY7C1550KV18 implements a synchronous pipelined architecture where all address, control, and data signals are registered on rising edges of complementary K and K clocks. Read and write operations initiate on K's rising edge, with data output driven on both K and K edges-enabling true DDR behavior without external strobes.

Its internal 2M × 36 array is split into two 1M × 36 banks, supporting byte-write select (BWS[3:0]) for granular 9-bit writes. The integrated PLL ensures precise data placement relative to echo clocks CQ/CQ, while DOFF pin toggles between DDR II+ (2-cycle latency) and DDR I (1-cycle latency) modes-altering timing margins and max frequency (≤167 MHz in DDR I mode).

Key Specifications

Pinout & Package

Package: 165-ball fine-pitch ball grid array (FBGA), 13 mm × 15 mm × 1.4 mm body height, RoHS-compliant.

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, the CY7C1550KV18 uniquely delivers 72-Mbit density with DDR II+ timing, echo clocks, and programmable latency-enabling higher throughput and simpler system-level timing closure in new high-speed designs.

Availability

CY7C1550KV18 is available at Aetrix Electronics and suitable for network packet buffering, telecom line card memory, and high-speed test equipment requiring stable component supply, long-lifecycle support, and guaranteed FBGA-165 packaging consistency.

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) designs high-performance memory and programmable solutions for networking, automotive, and industrial applications, with emphasis on signal integrity and timing precision.

The CY7C15xxKV18 series targets high-bandwidth, low-latency buffering in systems demanding deterministic DDR timing-especially where echo clocks and QVLD simplify high-speed memory interface design.

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 operating frequency of 167 MHz. When HIGH (or pulled up), the PLL is active, enabling DDR II+ operation at up to 450 MHz with 2.0-cycle latency. This dual-mode capability allows backward compatibility with legacy DDR I controllers while supporting newer high-speed designs.

How do CQ and CQ echo clocks improve system-level timing?

CQ and CQ are free-running output clocks synchronized to the input K/K clocks, with minimal skew to corresponding DQ outputs. They eliminate the need for board-level strobe routing or per-device delay calibration, allowing source-synchronous data capture across multiple SRAMs using a common clock tree. This reduces timing closure complexity and improves robustness across voltage and temperature variations in high-speed systems.

Can CY7C1550KV18 operate with VDDQ = 1.5 V while VDD = 1.8 V?

Yes. The device explicitly supports VDDQ = 1.4 V to VDD (1.8 V), including 1.5 V operation. This allows interoperability with 1.5 V memory controllers or FPGAs without level-shifting circuitry. The HSTL Class I output drivers automatically adapt drive strength based on VDDQ, and ZQ calibration maintains impedance match across this range.

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

ZQ is an impedance calibration reference pin that tunes the output driver strength of DQ, CQ, and CQ pins. It must be connected to a 240 Ω resistor to ground-setting nominal output impedance to 48 Ω (0.2 × 240 Ω) for optimal 50 Ω PCB trace matching. Connecting ZQ directly to VDDQ enables minimum-impedance mode (~30 Ω); it must never be left floating or tied to GND.