Infineon Technologies CYDM256B16-55BVXI

Overview

CYDM256B16-55BVXI from Cypress Semiconductor is a 16K × 16-bit (256 Kbit), 1.8 V asynchronous dual-port static RAM with true independent port access, 55 ns maximum access time, on-chip arbitration logic, and industrial temperature range (–40°C to +85°C). It supports simultaneous read/write to the same memory location and enables interprocessor communication in real-time embedded systems.

For engineers reviewing the CYDM256B16-55BVXI datasheet, CYDM256B16-55BVXI pinout, CYDM256B16-55BVXI application, or CYDM256B16-55BVXI equivalent, key selection criteria include dual-port contention resolution timing, port-independent I/O voltage support (1.8/2.5/3.0 V), semaphore-based software handshaking, and 100-ball vfBGA package compatibility with high-density PCB layouts.

Technical Context

This device implements fully asynchronous dual-port SRAM architecture with separate address, data, and control buses for left and right ports. Each port features independent Chip Enable (CE), Read/Write (R/W), Output Enable (OE), BUSY, and INT signals, enabling concurrent non-contending operations without external synchronization logic.

On-chip arbitration resolves memory contention via deterministic priority logic when both ports access the same address within tPS (2 ns), asserting BUSY to the losing port. Eight semaphores provide software-controlled mutual exclusion for shared resources, while mailbox-interrupt functionality at top two memory addresses (3FFF_H/3FFE_H) enables low-latency inter-processor messaging.

Key Specifications

Pinout & Package

Package: 100-ball, 0.5 mm pitch, 6 × 6 mm Pb-free very thin fine-pitch Ball Grid Array (vfBGA).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-port SRAM applications.

Compared with IDT70V27L15PF and IS61WV102416BLL-10TLI, CYDM256B16-55BVXI delivers lower standby current (2 µA vs. >100 µA), native 1.8 V operation, and integrated arbitration-reducing BOM count and firmware development effort for industrial edge devices.

Availability

CYDM256B16-55BVXI is available at Aetrix Electronics and suitable for industrial PLC communication buffers, dual-processor real-time control systems, and video frame buffer sharing requiring stable component supply across extended product lifecycles.

Supply support for CYDM256B16-55BVXI 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 solutions for industrial, automotive, and IoT applications.

CYDM256B16 belongs to the MoBL® (Mobile Low Power) Dual-Port SRAM product line, engineered specifically for deterministic interprocessor communication in space- and power-constrained embedded systems.

FAQ

What is the function of the M/S pin in CYDM256B16-55BVXI?

The M/S (Master/Slave) pin configures the device for 32-bit data bus expansion: when HIGH, BUSYR becomes an output to drive the BUSYL input of a slave device; when LOW, BUSYR functions as an input. This eliminates external logic for master/slave chaining and supports seamless word-width doubling without redesigning control firmware.

How does semaphore operation work without external software intervention?

Semaphores are implemented as eight dedicated hardware latches accessible via SEMR/SEML enable. Each latch can be locked/unlocked atomically by either port using standard read-modify-write sequences. No driver or OS kernel modification is needed-the hardware enforces mutual exclusion at the silicon level, ensuring thread-safe access to shared peripherals like ADCs or UARTs.

Can CYDM256B16-55BVXI operate with different I/O voltages on left and right ports?

Yes-VDDIOL and VDDIOR are independent power pins supporting 1.8 V, 2.5 V, or 3.0 V LVCMOS/LVTTL levels. The left port may interface with a 1.8 V FPGA fabric while the right port connects to a 3.0 V microcontroller, with no level-shifting circuitry required. Core VCC must be ≤ the lower of the two I/O voltages.

What happens during simultaneous access to the same memory location?

When both ports assert CE within 2 ns (tPS) and target the same address, on-chip arbitration grants access to one port while asserting BUSY to the other. The winning port completes the access in 55 ns; the losing port's BUSY remains asserted until the winning port releases the address. No data corruption occurs, and the operation is fully deterministic per datasheet timing.