Infineon Technologies CY7C1321KV18-250BZCT

Overview

CY7C1321KV18-250BZCT from Cypress Semiconductor is a 18-Mbit synchronous pipelined DDR II SRAM configured as 512K × 36, operating at 250 MHz with 1.8 V core supply and HSTL I/O. It supports four-word burst reads/writes, dual-edge DDR data transfer (500 Mbps per pin), and uses echo clocks (CQ/CQ) for precise high-speed data capture in networking and telecom buffer applications.

For engineers reviewing the CY7C1321KV18-250BZCT datasheet, CY7C1321KV18-250BZCT pinout, CY7C1321KV18-250BZCT application, or CY7C1321KV18-250BZCT equivalent, key selection criteria include its 250 MHz K/K clock frequency, DOFF-configurable read latency (1 or 1.5 cycles), 165-ball FBGA package, 36-bit DDR interface, and JTAG 1149.1 test access support.

Technical Context

This SRAM implements a synchronous pipelined architecture with internal burst counter driven by A[1:0], delivering four sequential 36-bit words per access. All address, control, and data inputs are registered on rising edges of complementary K/K clocks, enabling precise timing alignment in high-speed systems.

The device supports dual-clock domain operation: K/K for address/control/data input registration and C/C for output data strobing, with echo clocks CQ/CQ synchronized to C/C to eliminate board-level skew. Its PLL ensures accurate data placement, and ZQ pin enables programmable output impedance matching to system bus termination.

Key Specifications

Pinout & Package

Package: 165-ball Fine-Pitch Ball Grid Array (FBGA), 13 mm × 15 mm × 1.4 mm body, RoHS-compliant, Pb-free option available.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AS7C331024B-250BIN and IS61WV102436BLL-250BLI, CY7C1321KV18-250BZCT uniquely delivers DDR II timing control, echo-clock–assisted data capture, and on-die impedance tuning - critical for maintaining signal integrity above 400 Mbps per pin in dense, multi-device memory subsystems.

Availability

CY7C1321KV18-250BZCT is available at Aetrix Electronics and suitable for telecom line card buffering, network packet switching, baseband processing in wireless infrastructure, and industrial real-time data acquisition requiring stable component supply across extended product lifecycles.

Supply support for CY7C1321KV18-250BZCT 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.

CY7C1321KV18 belongs to Cypress's DDR II SRAM product line, designed specifically for high-bandwidth, low-latency buffering in packet-switched networks and real-time signal processing systems demanding deterministic timing and robust signal integrity.

FAQ

What is the function of the DOFF pin on CY7C1321KV18-250BZCT?

The DOFF (Data Output OFF) pin configures read latency mode: when asserted HIGH, it enables DDR II operation with 1.5-cycle latency for improved timing margin; when LOW, it reverts to DDR I behavior with 1-cycle latency for backward compatibility. This pin is sampled synchronously on the rising edge of K and remains latched until the next LD assertion.

Can CY7C1321KV18-250BZCT operate without external C and C clocks?

Yes - the device supports single-clock mode using only K and K for both input capture and output strobing. In this mode, CQ and CQ are generated relative to K/K instead of C/C, and data output timing references the K/K edges. However, echo-clock–assisted deskewing is lost, requiring tighter board-level timing closure.

How does ZQ calibration affect system-level signal integrity?

ZQ calibration adjusts the output driver impedance of DQ, CQ, and CQ pins to match the system's characteristic trace impedance (typically 50 Ω). By connecting an external resistor (e.g., 240 Ω) between ZQ and GND, the device tunes its drive strength to minimize reflections and improve eye diagram margins - especially critical at 500 Mbps per pin.

Is CY7C1321KV18-250BZCT pin-compatible with CY7C1319KV18-250BZI?

No - although both share the same 165-ball FBGA package, their pinouts differ significantly: CY7C1319KV18-250BZI (1M × 18) uses DQ[17:0] and two BWS pins, while CY7C1321KV18-250BZCT (512K × 36) uses DQ[35:0] and four BWS pins. Signal assignments for BWS, DQ, and array-specific control lines are not interchangeable.