Winbond Electronics Corporation W955N8MBYA5I TR

Overview

W955N8MBYA5I TR from Winbond Electronics is a 32Mb HyperRAM device implementing the HyperBus DDR interface for high-throughput, low-pin-count external memory expansion in resource-constrained embedded systems. It operates at 2.7–3.6V, supports up to 200MHz clock frequency (400 MT/s), and uses an 8-bit DQ bus with bidirectional RWDS strobe/mask for read/write synchronization - deployed in graphics buffer and firmware code execution applications.

For engineers reviewing the W955N8MBYA5I TR datasheet, W955N8MBYA5I TR pinout, W955N8MBYA5I TR application, or W955N8MBYA5I TR equivalent, key selection criteria include HyperBus timing compliance, configurable burst modes (wrapped/linear/hybrid), drive strength tuning, partial array refresh support, and compatibility with hybrid sleep and deep power-down states in battery-sensitive designs.

Technical Context

The W955N8MBYA5I TR implements a DDR-based HyperBus interface with dual-clock support (single-ended CK or differential CK/CK#), enabling deterministic latency control via RWDS-driven initial access timing. Its architecture separates VCC (core/buffer supply) and VCCQ (I/O output supply), supporting independent voltage scaling and noise isolation.

It features two programmable configuration registers governing burst behavior (wrapped/linear/hybrid), latency modes (fixed/initial), drive strength, deep power-down entry, and array refresh (full/partial). Memory space addressing uses 32-bit system word addresses split across CA0–CA2, with row/column boundaries determined by density-specific mapping.

Key Specifications

Pinout & Package

Package: 24-ball TFBGA (5×5 mm, 1-ball footprint, ball-down mounting).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar HyperRAM interface applications.

Compared with W955N8MBYA5I TR, the W956D8MBYA5I TR offers double capacity with identical electrical and mechanical compatibility, while the IS66WV12816EBLL-15BLI trades interface efficiency and power savings for legacy parallel SRAM familiarity - making the former a seamless upgrade and the latter a last-resort migration path.

Availability

W955N8MBYA5I TR is available at Aetrix Electronics and suitable for graphics frame buffer, firmware code execution, and industrial HMI data logging applications requiring stable component supply, long-term lifecycle assurance, and industrial temperature qualification.

Supply support for W955N8MBYA5I TR 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

Winbond Electronics is a Taiwan-based semiconductor company specializing in specialty memory solutions including SPI NOR/NAND, RAM, and HyperRAM products for embedded and industrial markets.

The W955N8MBYA5I TR belongs to Winbond's HyperRAM family, designed specifically to replace parallel NOR/PSRAM in bandwidth-constrained, pin-limited applications such as automotive displays, smart home hubs, and portable medical devices.

FAQ

What is the maximum supported clock frequency for W955N8MBYA5I TR?

The W955N8MBYA5I TR supports a maximum clock frequency of 200MHz, enabling Double Data Rate transfers at up to 400 MT/s. This specification is validated across the full −40°C to +85°C operating temperature range and requires compliance with tACC ≤ 7.5ns and setup/hold timing per the official Winbond datasheet. The W955N8MBYA5I TR achieves this performance using either single-ended CK or differential CK/CK# signaling.

Does W955N8MBYA5I TR support true DDR operation with both rising and falling clock edges?

Yes, the W955N8MBYA5I TR implements true DDR operation: command/address bits are center-aligned with clock edges, and data transfers occur on both rising and falling edges of CK during read/write transactions. This is intrinsic to the HyperBus protocol and confirmed in the W955N8MBYA5I TR datasheet Figures 1–3 and Section 6.1. The RWDS signal remains edge-aligned with read data and center-aligned with write data.

How does RWDS function during write transactions in W955N8MBYA5I TR?

In W955N8MBYA5I TR write transactions, RWDS acts as a per-byte write mask: when driven High by the host, the corresponding DQ[7:0] byte is masked (not written); when Low, the byte is valid and written. This enables unaligned multi-byte writes without read-modify-write cycles. During zero-initial-latency writes, RWDS may be left Hi-Z by the slave, and full words are always written - a behavior explicitly defined in Section 7.4 of the W955N8MBYA5I TR datasheet.

Can W955N8MBYA5I TR operate with only a single-ended clock (CK only)?

Yes, the W955N8MBYA5I TR supports single-ended clocking using CK only, with CK# left unconnected or tied to a fixed voltage. The datasheet confirms CK# is "not used" in single-ended mode, and the internal receiver adapts accordingly. This simplifies routing in cost-sensitive designs, though differential mode is recommended for noise immunity above 100MHz. The W955N8MBYA5I TR's clock input structure is explicitly designed for this dual-mode flexibility.

What power-saving modes are implemented in W955N8MBYA5I TR?

The W955N8MBYA5I TR implements three hardware-controlled power-saving modes: Interface Standby (reduced I/O activity), Hybrid Sleep (partial array refresh + clock gating), and Deep Power Down (sub-10µA current, full array retention lost). Entry into each mode is controlled via Configuration Register 0/1 bits and requires specific command sequences. These modes are fully documented in Sections 10.2 and 9.4–9.5 of the W955N8MBYA5I TR datasheet and validated across industrial temperature.