Cypress Semiconductor Corp CY7C1548KV18-400BZI

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 400 MHz clock operation. It uses HSTL I/O, dual input clocks (K/K), echo clocks (CQ/CQ), and QVLD for precise high-speed data capture in memory subsystems of networking switches and baseband processors.

For engineers reviewing the CY7C1548KV18 datasheet, CY7C1548KV18 pinout, CY7C1548KV18 application, or CY7C1548KV18 equivalent, key selection criteria include DDR II+ timing compliance, 1.8 V core / 1.4–1.8 V I/O supply support, PLL-enabled 2-cycle latency mode, and FBGA-165 package compatibility with high-density PCB layouts.

Technical Context

This SRAM implements a synchronous pipelined architecture where address and control signals are latched on rising edges of K, while write data is registered on both K and K edges. Read data bursts two 18-bit words per access, aligned to K and K rising edges, with output timing referenced to echo clocks CQ/CQ.

The device integrates a PLL for accurate data placement and supports dual operational modes: DDR II+ (DOFF = HIGH, 2-cycle latency, up to 450 MHz) and DDR I-compatible mode (DOFF = LOW, 1-cycle latency, ≤167 MHz). All I/O uses HSTL-18 signaling with programmable output impedance via ZQ calibration.

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-bandwidth synchronous SRAM applications.

Compared with AS7C362000B-15JIN and IS61WV102418BLL-10BLI, CY7C1548KV18 delivers 2.9× higher effective bandwidth at 400 MHz with burst-aligned data, eliminates external DLLs via integrated PLL and echo clocks, and supports modern 1.8 V system architectures - making it the sole option for new high-speed memory subsystems.

Availability

CY7C1548KV18 is available at Aetrix Electronics and suitable for networking switch fabric, wireless baseband processor cache, and high-speed test equipment requiring stable component supply, long-term lifecycle assurance, and Pb-free manufacturing compliance.

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 connectivity solutions for industrial, automotive, and communications markets.

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

FAQ

What is the function of the DOFF pin on CY7C1548KV18?

The DOFF (PLL Turn Off) pin is an active-low control that disables the internal PLL. When asserted LOW, the device reverts to DDR I timing with 1-cycle read latency and maximum 167 MHz operation. When HIGH, it enables full DDR II+ mode with 2-cycle latency and up to 450 MHz clocking. Pull-up to VDDQ via ≤10 kΩ resistor is required for normal operation.

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

ZQ connects to an external resistor to ground (typically 240 Ω) to calibrate the output driver impedance of DQ[17:0], CQ, and CQ pins to 0.2 × RQ ≈ 48 Ω. This matches standard 50 Ω PCB traces, minimizing reflections and ensuring clean eye diagrams at 900 MT/s. Leaving ZQ unconnected or tied to GND violates specification and degrades timing margins.

Can CY7C1548KV18 operate with different VDDQ and VDD voltages simultaneously?

Yes - VDD is strictly 1.8 V ± 0.1 V for the core, while VDDQ may be independently set between 1.4 V and 1.8 V to match the host interface's I/O standard (e.g., 1.5 V HSTL or 1.8 V HSTL-18). This dual-supply flexibility allows seamless integration into mixed-voltage SoC platforms without level-shifting circuitry.

What is the role of QVLD in system-level timing validation?

QVLD is a synchronous output that asserts coincident with the rising edges of CQ and CQ, indicating that the corresponding DQ[17:0] bits contain valid data from the current burst. Unlike static timing margins, QVLD provides dynamic, cycle-accurate validity signaling - enabling FPGA or ASIC logic to sample data safely even under PVT variation, without conservative guard-banding.