Cypress Semiconductor Corp CY7C1548KV18-450BZC

Overview

CY7C1548KV18 from Cypress Semiconductor is a 72-Mbit (4M × 18) DDR II+ synchronous SRAM with two-word burst architecture, 2.0-cycle read latency, and 450 MHz clock operation. It delivers 900 Mbps data transfer via double-data-rate interface, uses HSTL I/O with 1.8 V core/1.4–1.8 V I/O supply, and integrates echo clocks (CQ/CQ) and QVLD for precise high-speed data capture in networking and telecom buffer applications.

For engineers reviewing the CY7C1548KV18 datasheet, CY7C1548KV18 pinout, CY7C1548KV18 application, or CY7C1548KV18 equivalent, key selection criteria include DDR II+ timing compliance, 165-ball FBGA package compatibility, DOFF-controlled latency mode switching (2.0-cycle vs. 1-cycle), and JTAG 1149.1 test access support for system-level validation.

Technical Context

The device implements a synchronous pipelined SRAM core with dual-edge DDR interface: address and control signals are latched on rising edges of K clock only, while write data is registered on both K and K rising edges, and read data is driven synchronously on both K and K rising edges. Internal organization comprises two 2M × 18 arrays enabling concurrent burst access.

It features an integrated PLL for accurate data placement, echo clocks CQ/CQ aligned to K/K for simplified receiver timing, and QVLD signal edge-aligned to CQ/CQ to indicate valid output data windows. The DOFF pin selects between DDR II+ (2-cycle latency, up to 450 MHz) and DDR I mode (1-cycle latency, ≤167 MHz), with distinct AC timing requirements per mode.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with AS7C36256PFS-15BIN and IS61WV102418BLL-15BLI, CY7C1548KV18 uniquely delivers 450 MHz DDR II+ operation with integrated echo clocks and QVLD-enabling direct FPGA interface without external timing compensation, while its 72-Mbit density supports deeper buffering in space-constrained telecom and defense platforms.

Availability

CY7C1548KV18 is available at Aetrix Electronics and suitable for high-speed network packet buffers, telecom line card caches, baseband processing memories, and radar signal processing buffers requiring stable component supply and long-term industrial availability.

Supply support for CY7C1548KV18 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 fabless semiconductor company specializing in high-performance memory, microcontrollers, and programmable system-on-chip solutions for industrial, automotive, and communications markets.

CY7C1548KV18 belongs to Cypress's QDR II+/DDR II+ SRAM product line, designed specifically for deterministic, low-latency, high-bandwidth buffering in packet-switched infrastructure and real-time signal processing systems.

FAQ

What is the function of the DOFF pin?

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 (or pulled up via ≤10 kΩ resistor), the PLL is enabled for DDR II+ mode with 2.0-cycle latency and up to 450 MHz clocking. This pin directly determines timing mode and frequency capability.

How does ZQ calibration work and what external component is required?

ZQ calibration adjusts the output driver impedance of DQ, CQ, and CQ pins to match the system data bus. A precision resistor (RQ) must be connected between ZQ and ground; the device sets output impedance to 0.2 × RQ. For example, a 240 Ω resistor yields 48 Ω driver impedance. ZQ must never be left floating or tied to GND - doing so disables calibration and risks signal integrity failure.

Can CY7C1548KV18 operate with only the K clock, or is K mandatory?

K is mandatory for full DDR II+ functionality. While address and control signals use only K, write data registration and read data driving require both K and K rising edges. Omitting K breaks DDR timing: write data cannot be latched correctly, and read data will not appear on both clock edges. The device will not operate reliably in DDR mode without both differential clocks present and properly terminated.

What is the role of QVLD, and how should it be used in FPGA interface design?

QVLD is a synchronous output that pulses HIGH during valid data windows on DQ[17:0], edge-aligned precisely with CQ and CQ. In FPGA designs, QVLD should be used as the enable signal for the input register capturing DQ data - not as a clock. This avoids metastability and ensures sampling occurs only when data meets setup/hold relative to CQ/CQ, eliminating need for manual timing closure of wide DDR buses.