Winbond Electronics Corporation W958D8NBYA4I

Overview

W958D8NBYA4I from Winbond Electronics is a 256Mb (32MB) HyperRAM device implementing the HyperBus DDR interface for high-bandwidth, low-pin-count external memory expansion in resource-constrained embedded systems. It operates at 1.8V, supports up to 250MHz clock frequency, delivers up to 500 MB/s read/write throughput, and uses an 8-bit bidirectional data bus with RWDS strobe/mask signaling - deployed in graphics buffers, firmware code execution, and real-time DSP data storage.

For engineers reviewing the W958D8NBYA4I datasheet, W958D8NBYA4I pinout, W958D8NBYA4I application, or W958D8NBYA4I equivalent, key selection considerations include its 24-ball TFBGA package, configurable burst modes (wrapped/linear/hybrid), hybrid sleep and deep power-down power states, and HyperBus-specific timing requirements including initial latency negotiation via RWDS.

Technical Context

The W958D8NBYA4I implements a DDR HyperBus interface with differential (CK/CK#) or single-ended (CK) clocking, using DQ[7:0] for command/address/data multiplexing and RWDS as a bidirectional strobe/mask signal. Its internal architecture includes row/column decoders, data latches, and configurable refresh logic supporting full or partial array refresh.

It supports two distinct burst types per transaction - wrapped bursts for cache-line fills (16–128 byte lengths) and linear bursts for contiguous transfers - with hybrid burst enabling one wrapped segment followed by linear continuation. Latency is dynamically negotiated during Command/Address phase via RWDS output state, and drive strength is configurable via Configuration Register 0.

Key Specifications

Pinout & Package

W958D8NBYA4I is housed in a 24-ball Thin Fine-Pitch Ball Grid Array (TFBGA) package with 5×5 mm footprint and 0.5 mm ball pitch, optimized for space-constrained PCB layouts in portable and automotive modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with W958D8NBYA5I, the W958D8NBYA4I enables 25% higher bandwidth at same voltage and package; versus IS66WV51216EBLL-15BLI, it trades pin count and simplicity for DDR efficiency and power-aware refresh - making it optimal for new-generation MCU-based edge nodes.

Availability

W958D8NBYA4I is available at Aetrix Electronics and suitable for graphics frame buffer, firmware XIP execution, and real-time DSP data buffer applications requiring stable component supply, long-term industrial lifecycle support, and consistent parametric performance across production batches.

Supply support for W958D8NBYA4I 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, Serial Flash, and high-performance HyperRAM products for embedded and automotive markets.

The W958D8NBYA4I belongs to Winbond's HyperRAM family, designed specifically to replace parallel PSRAM and SRAM in bandwidth-constrained, pin-limited microcontroller and application processor platforms - emphasizing DDR efficiency, low-power states, and seamless integration with modern bus controllers.

FAQ

What interface standard does the W958D8NBYA4I implement?

The W958D8NBYA4I implements the HyperBus DDR interface, a low-pin-count, double-data-rate protocol defined by Cypress (now Infineon) and adopted by Winbond. It uses an 8-bit bidirectional DQ bus, RWDS strobe/mask, and differential or single-ended clock (CK/CK# or CK) - not SPI, QSPI, or standard parallel interfaces. This architecture enables 500 MB/s throughput with only 12 signal lines, making it ideal for MCU-based systems with limited I/O resources.

Does the W958D8NBYA4I support execute-in-place (XIP) operation?

Yes, the W958D8NBYA4I supports execute-in-place (XIP) operation when interfaced with a compatible HyperBus controller, such as those found in NXP i.MX RT series or STMicroelectronics STM32H7 microcontrollers. Its linear burst mode provides deterministic, low-latency instruction fetches, and its 256Mb capacity allows storage of substantial firmware images. The device retains data during hybrid sleep, enabling fast resume from low-power states without reloading code.

How does RWDS function during read versus write transactions in the W958D8NBYA4I?

In read transactions, RWDS acts as a source-synchronous read data strobe - data on DQ[7:0] is edge-aligned with RWDS transitions. In write transactions, RWDS functions as a byte mask: high indicates the corresponding byte is masked (not written), low enables writing. During the Command/Address phase of any transaction, RWDS output indicates whether additional initial latency (tRFH) is required before data transfer begins - a key mechanism for dynamic latency negotiation in the W958D8NBYA4I.

What power-saving modes are available on the W958D8NBYA4I?

The W958D8NBYA4I offers Hybrid Sleep and Deep Power Down modes. Hybrid Sleep reduces current to approximately 10 µA while retaining memory contents and enabling sub-µs wake-up; Deep Power Down lowers current to ~1 µA but requires longer initialization (~100 µs). Both modes are entered via HyperBus register writes and support automatic exit on CS# assertion. These features make the W958D8NBYA4I suitable for battery-powered edge devices requiring aggressive duty cycling without data loss.

Is the W958D8NBYA4I pin-compatible with other Winbond HyperRAM devices?

The W958D8NBYA4I uses a standardized 24-ball TFBGA package shared across Winbond's 256Mb HyperRAM family, including W958D8NBYA5I and W958D8NBYA3I. Pin assignments (CS#, CK/CK#, DQ[7:0], RWDS, RESET#, VCC/VCCQ, VSS/VSSQ) are identical per the official Winbond ball assignment diagram. However, timing parameters (e.g., max clock rate) and register defaults differ - so while PCB layout is reusable, firmware initialization sequences must be verified per specific speed grade.