Infineon Technologies CY7C1550KV18-400BZXI

Overview

CY7C1550KV18-400BZXI 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 165-ball FBGA (13 × 15 × 1.4 mm) package. It delivers 900 Mbps double-data-rate throughput, uses echo clocks (CQ/CQ) for precise data capture, and supports programmable impedance via ZQ pin for signal integrity in high-speed memory subsystems used in network packet buffers and baseband processing.

For engineers reviewing the CY7C1550KV18-400BZXI datasheet, CY7C1550KV18-400BZXI pinout, CY7C1550KV18-400BZXI application, or CY7C1550KV18-400BZXI equivalent, key selection criteria include its 2M × 36 organization, DOFF-controlled DDR I/DDR II+ mode switching, QVLD-valid data indicator, and dual-clock (K/K) synchronous timing architecture optimized for burst-aligned memory access in telecom infrastructure.

Technical Context

This SRAM implements a two-word burst architecture where each address access retrieves two consecutive 36-bit words on alternating rising edges of complementary K and K clocks. Internal pipelining enables back-to-back read initiation every K cycle, while synchronous self-timed write circuitry eliminates external write strobes.

The device integrates a PLL for accurate data placement and echo clocks (CQ/CQ) aligned to output data edges-eliminating board-level skew compensation. DOFF pin selection determines operational mode: HIGH enables DDR II+ with 2.0-cycle latency at up to 400 MHz; LOW disables PLL and reverts to DDR I timing with 1-cycle latency at ≤167 MHz.

Key Specifications

Pinout & Package

Package: 165-ball fine-pitch ball grid array (FBGA), 13 mm × 15 mm × 1.4 mm body, RoHS-compliant (BZXI suffix denotes Pb-free).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AS7C36256P-15TIN and IS61WV102432ALL-15BLI, CY7C1550KV18-400BZXI provides 4× higher effective bandwidth, deterministic DDR timing, and signal integrity features (QVLD, ZQ, echo clocks) essential for next-generation telecom and radar systems - but requires DDR-aware controller support and tighter layout controls.

Availability

CY7C1550KV18-400BZXI is available at Aetrix Electronics and suitable for network packet buffering, baseband signal processing, and telecom line card memory requiring stable component supply, long-lifecycle assurance, and RoHS-compliant packaging.

Supply support for CY7C1550KV18-400BZXI 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 demanding embedded and communications applications.

CY7C1550KV18 belongs to the QDR II+ SRAM product line, engineered specifically for ultra-low-latency, high-bandwidth buffering in networking, wireless infrastructure, and defense electronics where deterministic DDR timing and signal integrity are critical.

FAQ

What is the function of the DOFF pin on CY7C1550KV18-400BZXI?

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 maximum 167 MHz operation. When HIGH, the PLL is enabled and the device operates in DDR II+ mode with 2.0-cycle latency at up to 400 MHz. This pin must be pulled up via ≤10 kΩ resistor for normal DDR II+ operation.

How does the ZQ pin affect signal integrity in high-speed designs?

The ZQ pin connects to an external resistor to ground to calibrate the output driver impedance of DQ, CQ, and CQ pins to 0.2 × RQ. This ensures matched output impedance to PCB traces, minimizing reflections and improving eye diagram margins. Leaving ZQ unconnected or tying it to GND violates specifications and degrades signal integrity; connecting to VDDQ enables minimum-impedance mode.

Can CY7C1550KV18-400BZXI operate with VDDQ = 1.5 V?

Yes. The device supports VDDQ from 1.4 V to VDD (1.8 V), explicitly including 1.5 V operation. This allows interoperability with 1.5 V HSTL-15 receivers and eases voltage translation in mixed-supply systems. Core VDD remains fixed at 1.8 V ± 0.1 V regardless of VDDQ setting.

What role does the QVLD signal play during read operations?

QVLD is a synchronous output that asserts edge-aligned with CQ and CQ to indicate when DQ[35:0] carries valid read data. It eliminates the need for fixed delay chains or complex clock-data recovery circuits in receiving logic, directly enabling safe sampling of burst data on the same clock edge that drives QVLD - reducing FPGA resource usage and improving timing margin.