Winbond Electronics Corporation W955K8MBYA5I TR

Overview

W955K8MBYA5I TR from Winbond Electronics is a 32Mb HyperRAM device implementing a high-speed, low-pin-count DDR interface for embedded memory expansion. It operates at 1.8V, supports up to 200MHz clock frequency (400 MT/s), and delivers sustained read throughput of 400 MB/s in linear burst mode. Its primary circuit role is as a high-bandwidth, low-latency external memory buffer for microcontrollers and application processors in graphics, firmware, and real-time data buffering applications.

For engineers reviewing the W955K8MBYA5I TR datasheet, W955K8MBYA5I TR pinout, W955K8MBYA5I TR application, or W955K8MBYA5I TR equivalent, key selection considerations include HyperBus interface compatibility, configurable burst modes (wrapped/linear/hybrid), deep power-down and hybrid sleep power states, drive strength tuning, and partial array refresh support for thermal and power-constrained designs.

Technical Context

The W955K8MBYA5I TR implements a DDR HyperBus interface with bidirectional RWDS acting as both latency indicator and source-synchronous read strobe/mask during writes. It uses command-address (CA) encoding over DQ[7:0] with differential (CK/CK#) or single-ended (CK) clocking, enabling precise timing control across variable initial latency conditions.

Internally, it features configurable configuration registers (CR0/CR1) governing wrapped/linear/hybrid burst lengths (16–128 bytes), initial/fixed latency settings, drive strength, deep power-down entry, hybrid sleep, and partial array refresh - all accessible via HyperBus register space without interrupting memory operations.

Key Specifications

Pinout & Package

24-ball TFBGA package (5 mm × 5 mm, 0.8 mm pitch), ball-down mounting. Compatible with standard reflow profiles and automated optical inspection (AOI).

Key Features

Applications

Equivalent & Alternatives

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

Compared with W955K8MBYA6I TR, the W955K8MBYA5I TR offers identical performance and feature set but is optimized for industrial-grade thermal operation; versus the IS66WV51216EBLL-100B1LI, it delivers 4× higher effective bandwidth with half the pin count and integrated power management-making it superior for new designs targeting scalability and energy efficiency.

Availability

W955K8MBYA5I TR is available at Aetrix Electronics and suitable for display frame buffering, firmware overlay storage, real-time data logging, and industrial PLC memory expansion requiring stable component supply, long-term lifecycle assurance, and full traceability.

Supply support for W955K8MBYA5I 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, HyperRAM, and mobile DRAM for embedded and automotive markets.

The W955K8MBYA5I TR belongs to Winbond's HyperRAM product line, designed specifically to replace parallel NOR/PSRAM in resource-constrained MCUs by delivering DDR bandwidth with minimal pin count and intelligent power management.

FAQ

What interface protocol does the W955K8MBYA5I TR use?

The W955K8MBYA5I TR uses the HyperBus interface-a low-pin-count, double-data-rate (DDR) protocol with 8-bit DQ, RWDS, differential/single-ended clock (CK/CK#), CS#, and RESET#. It transfers two 8-bit words per clock cycle, achieving up to 400 MT/s. Unlike traditional parallel interfaces, HyperBus embeds command/address and data on the same DQ lines using DDR timing and uses RWDS for latency signaling and write masking-enabling high bandwidth with only 11 signal pins.

Does the W955K8MBYA5I TR support both wrapped and linear burst modes?

Yes, the W955K8MBYA5I TR supports wrapped bursts (16/32/64/128 bytes), linear bursts, and hybrid bursts (one wrapped followed by linear) via Configuration Register 0. Wrapped bursts wrap within word-group-aligned boundaries and are ideal for cache-line fills; linear bursts increment sequentially and suit large contiguous transfers like display frames. The burst type is selected per-transaction via the CA0[45] bit, allowing dynamic mixing in real-time applications.

What power-saving modes are available on the W955K8MBYA5I TR?

The W955K8MBYA5I TR offers Hybrid Sleep Mode (reduced ICC with fast wake-up) and Deep Power Down (<10 µA ICC). Both are entered via HyperBus register writes to Configuration Register 0/1. Hybrid Sleep retains memory contents and configuration while disabling clocks and I/O drivers; Deep Power Down powers down most internal circuits except the reset detection logic. Neither mode requires hardware reset to exit-both resume operation after CS# assertion and clock restart.

How is the RWDS pin used during read and write operations on the W955K8MBYA5I TR?

During read operations, RWDS serves as a source-synchronous read data strobe-data is edge-aligned with RWDS transitions. During the Command/Address phase, RWDS output indicates whether additional initial latency (tRFH) is required (High = add latency). During writes, RWDS acts as a per-byte mask: High masks the corresponding DQ byte (prevents write), Low enables it-allowing unaligned multi-byte writes without read-modify-write cycles. RWDS is bidirectional and LV-CMOS compatible.

What is the package type and ball count of the W955K8MBYA5I TR?

The W955K8MBYA5I TR is packaged in a 24-ball Thin Fine-Pitch Ball Grid Array (TFBGA) with 5 mm × 5 mm footprint and 0.8 mm ball pitch. Ball assignment includes dedicated signals for CS#, RESET#, CK/CK#, DQ[7:0], RWDS, VCC, VCCQ, VSS, VSSQ, and RFU (Reserved for Future Use) positions. The package supports standard reflow soldering and is optimized for high-density PCB layouts in space-constrained embedded systems.