Cypress Semiconductor Corp CY7C1643KV18-400BZC

Overview

CY7C1643KV18 from Cypress Semiconductor is a 144-Mbit QDR® II+ SRAM with 8 M × 18 organization, 450 MHz clock support, 2.0-cycle read latency, and separate read/write DDR ports delivering 900 MT/s effective data rate. It operates at 1.8 V core (±0.1 V) and 1.4–1.8 V I/O supply, housed in a 165-ball FBGA (15 × 17 × 1.4 mm), and targets high-bandwidth packet buffering in network line cards.

For engineers reviewing the CY7C1643KV18 datasheet, CY7C1643KV18 pinout, CY7C1643KV18 application, or CY7C1643KV18 equivalent, key selection criteria include its quad-data-rate burst architecture, echo-clock–assisted timing closure, JTAG 1149.1 testability, DOFF-configurable latency mode, and HSTL-compatible I/O for 450 MHz system synchronization.

Technical Context

The device implements a true dual-port synchronous SRAM architecture with physically independent read and write data paths-no bus turnaround required. Its QDR II+ core uses two input clocks (K/K̄) to latch address and data on rising edges only, while echo clocks (CQ/CQ̄) align output data capture with system receivers.

An internal PLL enables precise data placement at 450 MHz; when disabled via DOFF low, it reverts to QDR I mode (≤167 MHz, 1-cycle latency). Depth expansion is supported via RPS/WPS and BWS[1:0], and all operations-including byte-write masking-are fully synchronous with pipelined addressing and self-timed writes.

Key Specifications

Pinout & Package

Package: 165-ball fine-pitch ball grid array (FBGA), 15 mm × 17 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 burst SRAM applications.

Compared with IDT72T36150 and IS61WV102418B, CY7C1643KV18 delivers higher bandwidth (900 vs. 700 MT/s), integrated impedance control (ZQ), and deterministic 2-cycle latency-making it optimal for new 450 MHz designs where signal integrity and timing closure are critical.

Availability

CY7C1643KV18 is available at Aetrix Electronics and suitable for network line cards, high-speed test instrumentation, telecom baseband units, and broadcast video encoders requiring stable component supply and long-term obsolescence management.

Supply support for CY7C1643KV18 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 logic solutions for industrial, automotive, and communications markets.

CY7C1643KV18 belongs to Cypress's QDR II+ SRAM product line, engineered specifically for deterministic, low-latency, high-throughput memory subsystems in networking and test equipment where bus turnaround overhead must be eliminated.

FAQ

What is the function of the DOFF pin, and how does it affect timing?

The DOFF pin disables the internal PLL when asserted low. In this state, the device operates in QDR I mode with 1-cycle read latency and a maximum clock frequency of 167 MHz. When DOFF is high, the PLL is active, enabling 2-cycle latency and full 450 MHz operation. Timing parameters differ significantly between modes-designers must select the correct datasheet table based on DOFF configuration.

How does the ZQ pin calibrate output impedance, and what external component is required?

ZQ connects to a precision resistor (RQ) tied to ground; the device measures RQ and adjusts driver strength so that CQ, CQ̄, and Q[17:0] output impedances equal 0.2 × RQ. A typical value is 240 Ω, yielding ~48 Ω output impedance. Direct connection to VDDQ enables minimum impedance mode (~30 Ω); floating or grounding ZQ is prohibited and may damage the device.

Can CY7C1643KV18 perform simultaneous read and write to the same memory location?

No. While the device supports concurrent read and write transactions on independent addresses, writing to an address currently being read from results in undefined data on Q[17:0]. The architecture guarantees coherency only for non-overlapping accesses; overlapping operations require external arbitration or address sequencing to avoid corruption.

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

QVLD is an edge-aligned validity indicator that asserts synchronously with CQ/CQ̄ to mark when Q[17:0] data is stable and ready for sampling. It must be routed with matched length to CQ/CQ̄ and used as a strobe or qualifier in the receiving FPGA/ASIC-never ignored or substituted with clock gating. Its timing is guaranteed across voltage and temperature per AC switching specs.