Cypress Semiconductor Corp CY7C1520KV18-250BZXI

Overview

CY7C1520KV18-250BZXI from Cypress Semiconductor is a 72-Mbit synchronous DDR-II SRAM configured as 2M × 36, operating at 250 MHz with 1.8 V core supply and HSTL I/O. It implements two-word burst architecture with dual input clocks (K/K) and dual output clocks (C/C), supports echo clocks (CQ/CQ) for timing alignment, and delivers 500 MB/s bandwidth via double-data-rate transfers on 36-bit bus.

For engineers reviewing the CY7C1520KV18-250BZXI datasheet, CY7C1520KV18-250BZXI pinout, CY7C1520KV18-250BZXI application, or CY7C1520KV18-250BZXI equivalent, key selection criteria include DDR-II read latency (1.5 cycles with DOFF HIGH), programmable output drive strength via ZQ calibration, JTAG 1149.1 test access, and FBGA-165 package compatibility with high-speed memory subsystems requiring precise clock skew management.

Technical Context

This device uses a synchronous pipelined architecture with internal burst counter driven by A0, enabling sequential two-word reads/writes per address latch. All synchronous inputs (R/W, LD, BWS[3:0], A[20:0]) are registered on rising edges of K and K clocks, while data outputs (DQ[35:0]) are edge-aligned to C/C or K/K in single-clock mode.

The DDR-II interface relies on phase-locked loop (PLL) circuitry for accurate data placement and employs echo clocks CQ/CQ referenced to C/C to eliminate board-level flight-time mismatches. Output impedance is dynamically calibrated via ZQ pin against external resistor to ground, setting DQ/CQ/CQ drive strength to 0.2 × RQ.

Key Specifications

Pinout & Package

Package: 165-ball fine-pitch ball grid array (FBGA), 13 mm × 15 mm × 1.4 mm body, 0.8 mm ball pitch, RoHS-compliant (BZXI suffix denotes Pb-free).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DDR-II SRAM applications.

Compared with AS7C3256A-25JCIN and IS61WV102432BLL-10BLI, CY7C1520KV18-250BZXI uniquely combines DDR-II burst efficiency, echo-clock–assisted timing closure, and ZQ-calibrated drive strength - making it optimal for bandwidth-constrained, high-speed serial fabric interfaces where deterministic latency and signal integrity are co-primary requirements.

Availability

CY7C1520KV18-250BZXI is available at Aetrix Electronics and suitable for telecom line cards, network packet buffers, medical imaging data acquisition, and test & measurement digitizers requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for CY7C1520KV18-250BZXI 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 communications, industrial, and automotive systems, with focus on signal integrity and timing precision.

The CY7C15xx KV18 series targets high-speed memory subsystems in networking and instrumentation, delivering DDR-II burst SRAMs optimized for deterministic latency, scalable bandwidth, and board-level timing convergence.

FAQ

What is the function of the DOFF pin on CY7C1520KV18-250BZXI?

The DOFF pin selects DDR-II read latency mode: when asserted HIGH, it enables 1.5-cycle read latency with enhanced timing margin for high-frequency operation; when LOW, the device operates in DDR-I mode with 1-cycle latency. This is a static configuration pin sampled at power-up and during reset - it does not support dynamic switching during active operation.

Can CY7C1520KV18-250BZXI 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 driving. In this mode, CQ and CQ are generated relative to K/K instead of C/C, and data output timing references K/K edges. However, echo-clock benefits (flight-time deskew) are lost, and system-level timing margin decreases at 250 MHz.

How is output impedance calibrated using the ZQ pin?

ZQ connects to an external precision resistor (typically 240 Ω) to ground, enabling internal calibration circuitry to set DQ, CQ, and CQ output driver strength to 0.2 × RQ (e.g., 48 Ω). The calibration occurs automatically at power-up and can be retriggered via JTAG instruction. ZQ must never be left floating or tied directly to GND or VDDQ.

Is CY7C1520KV18-250BZXI pin-compatible with CY7C1518KV18-250BZXI?

No - although both use 165-ball FBGA packages, their pinouts differ significantly: CY7C1518KV18 has DQ[17:0] and BWS[1:0], while CY7C1520KV18 has DQ[35:0] and BWS[3:0]. Address count differs (22 vs. 21 bits), and ball assignments for BWS, DQ, and auxiliary signals are not aligned. PCB layout is not interchangeable.