Cypress Semiconductor Corp CY7C1250KV18-400BZC

Overview

CY7C1250KV18 from Cypress Semiconductor is a 36-Mbit (1M × 36) synchronous DDR II+ SRAM with two-word burst architecture, 2.0-cycle read latency at 400 MHz, HSTL I/O, and integrated PLL for precise data placement. It operates with core VDD = 1.8 V ± 0.1 V and I/O VDDQ = 1.4 V to 1.8 V, and is used in high-bandwidth packet buffering and network switching ASIC interfaces.

For engineers reviewing the CY7C1250KV18 datasheet, CY7C1250KV18 pinout, CY7C1250KV18 application, or CY7C1250KV18 equivalent, key selection criteria include DDR II+ timing compliance, echo clock (CQ/CQ) synchronization, QVLD validity signaling, and FBGA-165 package compatibility with high-speed PCB layout constraints.

Technical Context

The CY7C1250KV18 implements a pipelined synchronous SRAM core with dual-edge DDR interface: address and control inputs are registered on K rising edges, while write data is latched on both K and K rising edges. Read data is driven synchronously on both K and K rising edges, with output timing aligned to echo clocks CQ/CQ.

It supports configurable latency modes via DOFF pin: when asserted HIGH, it operates as DDR II+ with 2.0-cycle read latency at up to 450 MHz; when LOW, it reverts to DDR I mode with 1-cycle latency and ≤167 MHz operation. Internal PLL ensures accurate data-eye placement relative to echo clocks.

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 burst SRAM applications.

Compared with IDT72T3615L10BG and IS61WV102436BLL-15BLI, the CY7C1250KV18 uniquely integrates PLL, echo clocks, and QVLD-reducing system-level timing validation effort and eliminating external clock forwarding components required by QDR II+ alternatives.

Availability

CY7C1250KV18 is available at Aetrix Electronics and suitable for network switching, telecom line cards, high-speed test instrumentation, and defense radar signal processing requiring stable component supply and long-term obsolescence management.

Supply support for CY7C1250KV18 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.

The CY7C1250KV18 belongs to Cypress's QDR II+/DDR II+ SRAM product line, engineered specifically for deterministic, high-bandwidth buffering in networking ASICs and FPGA-based signal processing systems.

FAQ

What is the function of the DOFF pin on CY7C1250KV18?

The DOFF pin controls the internal PLL: when pulled HIGH, the device operates in DDR II+ mode with 2.0-cycle read latency and up to 450 MHz clock rate; when pulled LOW, it disables the PLL and reverts to DDR I mode with 1-cycle latency and ≤167 MHz operation. This provides hardware-selectable performance vs. timing simplicity trade-off.

How does the ZQ pin affect signal integrity?

The ZQ pin connects to an external resistor to ground to calibrate the output driver impedance of DQ[35:0], CQ, and CQ pins to 0.2 × RQ. This matching minimizes reflections and improves eye diagram margin at 900 Mbps DDR rates, especially critical for long PCB traces in backplane applications.

Why are CQ and CQ necessary if K and K are already provided?

CQ and CQ are echo clocks-free-running, phase-aligned replicas of K and K generated internally and output with matched delay to DQ[35:0]. They eliminate routing skew between clock and data paths, allowing receivers to capture data using local CQ/CQ instead of globally distributed K/K, simplifying high-speed layout.

Can CY7C1250KV18 be used in depth-expanded memory configurations?

Yes - its synchronous tristate control and QVLD signal allow seamless depth expansion. When deselected, outputs automatically tristate after one K cycle, enabling interleaved access across multiple devices without wait states or external bus contention logic.