Winbond Electronics Corporation W958D6DBCX7I TR

Overview

W958D6DBCX7I TR from Winbond is a 256Mb x16 asynchronous/burst/synchronous pseudo-static RAM (PSRAM) with address/data multiplexing, designed for low-power portable systems requiring DRAM density and SRAM-like interface simplicity. It features 70ns random access time, 133MHz burst clock support, and operates at 1.8V VCC/VCCQ across –40°C to +85°C. Its primary role is as a high-bandwidth, low-standby-current memory replacement for SRAM in mobile baseband, application processors, and cellular modem subsystems.

For engineers reviewing the W958D6DBCX7I TR datasheet, W958D6DBCX7I TR pinout, W958D6DBCX7I TR application, or W958D6DBCX7I TR equivalent, key selection considerations include its CellularRAM 1.5–compliant A/D MUX interface, dual-mode (async/burst) operation, temperature-compensated refresh (TCR), partial-array refresh (PAR), and deep power-down (DPD) capability - all critical for battery-constrained wireless SoC designs.

Technical Context

This PSRAM integrates a DRAM core with on-die logic enabling SRAM-compatible command protocols via a 16-bit multiplexed bus. It supports both asynchronous control (CE#, ADV#, OE#, WE#, LB#/UB#) and synchronous burst transfers synchronized to CLK, with mode selection controlled by the Bus Configuration Register (BCR[15]).

The device implements two user-configurable registers: BCR governs bus timing, burst length (4/8/16/32/continuous), latency (fixed/variable), and drive strength; RCR controls refresh behavior - including TCR (on-chip temperature sensing), PAR (refresh subset of array), and DPD entry/exit - all accessible via CRE-enabled register reads/writes.

Key Specifications

Pinout & Package

Package: 54-ball Very Thin Fine-Pitch Ball Grid Array (VFBGA), 8mm × 8mm × 0.6mm, 0.5mm ball pitch, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ISSI IS66WV12816EBLL-70NLI and APMemory AP256K16S133, W958D6DBCX7I TR uniquely combines CellularRAM 1.5 compliance, temperature-compensated refresh, and deep power-down - delivering verified <400μA standby and seamless integration into cellular modem reference designs without timing margin compromises.

Availability

W958D6DBCX7I TR is available at Aetrix Electronics and suitable for mobile baseband, wireless modem, GPS navigation, smartphone application processor, and cellular IoT module designs requiring stable component supply, long-term lifecycle assurance, and industrial-grade temperature performance.

Supply support for W958D6DBCX7I 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 global semiconductor manufacturer specializing in specialty memory solutions, including SPI NOR/NAND Flash, PSRAM, and audio codecs.

W958D6DBCX7I TR belongs to Winbond's CellularRAM-compliant ADMUX PSRAM product line, engineered specifically for low-power, high-density memory substitution in cellular and portable wireless platforms where SRAM cost and DRAM complexity must both be avoided.

FAQ

What is the maximum supported burst clock frequency for W958D6DBCX7I TR?

The W958D6DBCX7I TR supports a maximum burst clock frequency of 133MHz (tCLK = 7.5ns), as specified in its ordering information and AC timing tables. This allows sustained data transfer rates up to 2.1GB/s in continuous burst mode. The device maintains timing integrity across its full industrial temperature range (–40°C to +85°C) when operated at 1.8V VCC/VCCQ. Clock stability requirements mandate that CLK remain static during asynchronous operations when burst mode is enabled.

Does W958D6DBCX7I TR require an external refresh controller?

No, W958D6DBCX7I TR incorporates transparent self-refresh logic that operates autonomously without external intervention. The DRAM core refresh is managed internally using either full-array, partial-array (PAR), or temperature-compensated (TCR) methods - all configurable via the Refresh Configuration Register (RCR). System memory controllers need not issue refresh commands, and refresh activity has no measurable impact on READ/WRITE bandwidth or latency.

How is deep power-down (DPD) entered and exited on W958D6DBCX7I TR?

DPD is entered by writing RCR[4] = 1 (enable DPD) followed by driving CE# HIGH while all other control signals remain static. Exit occurs when CE# transitions from HIGH to LOW, initiating a 200μs recovery period before normal operation resumes. During DPD, current drops to sub-μA levels, and all I/Os enter high-impedance state. The W958D6DBCX7I TR retains data throughout DPD as long as VCC/VCCQ remain within specification.

What address lines are used for 256Mb addressing in W958D6DBCX7I TR?

The W958D6DBCX7I TR uses A[23:0] for full 256Mb (32MB) addressing, with A[23:16] physically routed to dedicated balls (A16–A23) and A[15:0] multiplexed onto the A/DQ[15:0] bus. Address latching occurs on the rising edge of ADV# in asynchronous mode or the first rising CLK edge after ADV# goes LOW in burst mode. The device's block diagram and pin assignment confirm A[max:16] corresponds to A23–A16 per datasheet section 4.1.

Is W958D6DBCX7I TR compatible with standard SRAM controllers?

W958D6DBCX7I TR is not a direct SRAM drop-in replacement due to its multiplexed A/DQ bus and mandatory register initialization. However, it emulates SRAM timing in asynchronous mode (70ns access, CE#/OE#/WE# control) and is fully compatible with CellularRAM 1.5–compliant memory controllers found in Qualcomm, MediaTek, and Broadcom baseband SoCs. Legacy SRAM controllers require interface logic or firmware adaptation to manage ADV#, CRE, and register configuration sequences.