Infineon Technologies CY7C1021B-15VXI

Overview

CY7C1021B-15VXI from Cypress Semiconductor is a 1-Mbit (64K × 16) high-speed CMOS static RAM with 15 ns maximum access time, 5 V ±10% supply, industrial temperature range (–40°C to +85°C), and Pb-free 44-pin SOJ packaging. It supports independent byte write control via BHE/ BLE, automatic CE-driven power-down (ISB2 = 10 mA), and operates in systems requiring deterministic low-latency memory access - such as industrial PLCs and real-time data buffers.

For engineers reviewing the CY7C1021B-15VXI datasheet, CY7C1021B-15VXI pinout, CY7C1021B-15VXI application, or CY7C1021B-15VXI equivalent, key selection criteria include tAA = 15 ns read timing, dual-byte enable architecture, CE/OE/WE control logic compatibility with legacy 80C/8051 buses, and SOJ package thermal resistance (ΘJA = 64.32°C/W).

Technical Context

The CY7C1021B-15VXI implements a fully decoded 64K × 16 asynchronous SRAM array with separate upper- and lower-byte write enables (BHE/BLE), enabling partial-word writes without external gating. Its TTL/CMOS-compatible inputs accept VIH ≥ 2.2 V and VIL ≤ 0.8 V, and output drivers deliver VOH ≥ 2.4 V at –4 mA and VOL ≤ 0.4 V at 8 mA.

Power management relies on CE-controlled automatic power-down: when CE is HIGH, ISB2 drops to 10 mA (CMOS input condition), reducing active current by >90% versus ICC = 130 mA during full-speed operation. All I/O pins enter high-impedance state during deselect, OE HIGH, or write cycles - eliminating bus contention in multi-device systems.

Key Specifications

Pinout & Package

Package: 44-pin (400-mil) molded SOJ, Pb-free, JEDEC MS-024 compliant. Body width 0.400 inch ±0.010 inch; lead pitch 0.050 inch; seating plane coplanarity ≤0.004 inch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IS61LV102416-15TQLI and MC14LC5116FN, the CY7C1021B-15VXI uniquely delivers industrial-grade 15 ns timing in a Pb-free SOJ package with true dual-byte write control - making it irreplaceable in deterministic embedded systems requiring partial-word updates and legacy footprint compatibility.

Availability

CY7C1021B-15VXI is available at Aetrix Electronics and suitable for industrial PLCs, legacy microcontroller data expansion, automotive instrument clusters, and medical diagnostic loggers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CY7C1021B-15VXI 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-reliability memory and programmable logic solutions for industrial, automotive, and communications infrastructure.

The CY7C1021B series was engineered specifically for deterministic, low-latency parallel memory interfacing in legacy 8-bit/16-bit microcontroller systems - prioritizing timing predictability, industrial temperature resilience, and pinout compatibility over density scaling.

FAQ

Is CY7C1021B-15VXI compatible with 3.3 V logic interfaces?

No. The CY7C1021B-15VXI is strictly a 5 V ±10% device: VIH minimum is 2.2 V, but VCC must be 4.5–5.5 V. Driving its inputs from 3.3 V logic violates the VIH specification (requires ≥2.2 V but referenced to VCC, not VDD). Level-shifting circuitry is mandatory for 3.3 V host systems.

What is the maximum clock frequency supported for burst reads?

The CY7C1021B-15VXI is asynchronous - it has no internal clock. Maximum effective throughput is determined by tRC = 15 ns, yielding a theoretical peak rate of 66.7 MHz for consecutive reads. However, actual bus speed depends on host controller timing margins, trace routing, and load capacitance; 40 MHz sustained is typical in well-designed 5 V systems.

Does the automatic power-down feature require external circuitry?

No. Power-down is fully autonomous: asserting CE HIGH automatically reduces ICC from 130 mA to 10 mA (ISB2) without any external control signals, pull-ups, or configuration registers. This occurs within tPD = 15 ns and requires no firmware overhead or hardware modification.

Can I use only the lower 8 bits (I/O1–I/O8) and ignore BHE/I/O9–I/O16?

Yes. Tie BHE HIGH permanently and drive BLE as needed. I/O9–I/O16 will remain in high-impedance state when BHE = HIGH, even during reads/writes. This configuration functions as a 64K × 8 device with identical timing and power characteristics - confirmed in the truth table under "Read - Lower bits only" and "Write - Lower bits only" modes.