Winbond Electronics Corporation W956D6KBKX7I TR

Overview

W956D6KBKX7I TR from Winbond is a 64Mb (4M × 16) pseudo-static RAM with asynchronous/burst/synchronous operation and address/data multiplexing. It features a DRAM core with transparent self-refresh, 70ns random access time, 133MHz max clock rate, and operates at 1.8V VCC/VCCQ. It serves as low-power memory in portable embedded systems requiring SRAM-like interface with DRAM density.

For engineers reviewing the W956D6KBKX7I TR datasheet, W956D6KBKX7I TR pinout, W956D6KBKX7I TR application, or W956D6KBKX7I TR equivalent, key selection considerations include burst length programmability (4/8/16/32/continuous), variable/fixed latency modes, WAIT-driven collision handling, and deep power-down (DPD) entry/exit timing compliance.

Technical Context

This ADMUX PSRAM implements a dual-mode bus interface controlled by the Bus Configuration Register (BCR): asynchronous mode (BCR[15]=1, default) uses ADV#/CE#/OE#/WE# timing similar to SRAM, while burst mode (BCR[15]=0) enables synchronous CLK-driven transfers with configurable latency (3–6 clocks) and wrap behavior. The device supports both CRAM 1.5 x16 A/D MUX compliance and a higher-speed second mode doubling data rate.

Refresh is fully hidden and managed via two user-accessible registers: BCR governs bus timing and drive strength (e.g., BCR[5:4] = half-drive default), while the Refresh Configuration Register (RCR) controls partial-array refresh (PAR), temperature-compensated refresh (TCR), and DPD activation (RCR[4]). Standby current is minimized through PAR, TCR, and DPD - all software-configurable without external controller intervention.

Key Specifications

Pinout & Package

Package: 49-ball WFBGA (5.0mm × 5.0mm × 0.6mm, 0.65mm ball pitch), RoHS-compliant, moisture sensitivity level 3.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar pseudo-static RAM applications.

Compared with IS66WV51216EBLL-70BLI, W956D6KBKX7I TR delivers 128× more density and 99% lower standby current but requires WAIT-aware controller logic; versus W958D6KBKX7I TR, it offers optimal cost-per-Mb for mid-tier applications where 64Mb suffices.

Availability

W956D6KBKX7I TR is available at Aetrix Electronics and suitable for mobile baseband processing, wireless IoT edge nodes, automotive infotainment display buffering, and industrial HMI graphics caching requiring stable component supply across extended product lifecycles.

Supply support for W956D6KBKX7I 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, PSRAM, and audio codecs, with global manufacturing and quality certifications.

The W956D6KBKX7I TR belongs to Winbond's ADMUX PSRAM product line, designed specifically to replace SRAM in portable and battery-operated systems where density, power efficiency, and industry-standard interface compatibility are critical.

FAQ

What is the difference between CRAM 1.5 mode and the second operation mode of W956D6KBKX7I TR?

The W956D6KBKX7I TR supports two programmable operation modes. In CRAM 1.5 mode, it complies fully with the CellularRAM 1.5 x16 A/D MUX standard - matching timing, signaling, and register definitions for drop-in replacement. In the second mode, the device doubles its effective data rate by optimizing internal pipeline and burst sequencing, enabling higher throughput in custom-designed systems where strict CRAM 1.5 compliance is not required. Both modes retain identical pinout and power characteristics.

How does the WAIT signal behave during burst READ operations in W956D6KBKX7I TR?

In W956D6KBKX7I TR, the WAIT signal asserts at the start of a burst READ to indicate pending data validity, de-asserts when the first data word is ready (after configured latency), and re-asserts at row boundaries unless burst wrapping is enabled. During refresh collisions in variable-latency mode, additional WAIT assertion cycles are inserted to delay data output until refresh completes. WAIT polarity (active-HIGH/active-LOW) is configurable via BCR[10], and the signal is Hi-Z when CE# is HIGH.

Can W956D6KBKX7I TR operate without a clock signal?

Yes, W956D6KBKX7I TR supports full asynchronous operation with no CLK requirement. In this mode (BCR[15]=1, default), all READ/WRITE cycles are controlled solely by CE#, ADV#, OE#, WE#, and LB#/UB#. The CLK pin may be tied to VSSQ or VCCQ. However, burst mode, synchronous timing, and certain low-power features like precise DPD exit timing require CLK to be active and stable - so clock-free operation excludes burst transfers and some advanced power management sequences.

What is the minimum CE# LOW pulse width required to avoid refresh-related failures in W956D6KBKX7I TR?

The W956D6KBKX7I TR specifies tCEM (maximum CE# LOW duration) as 100ms under typical conditions. Exceeding this limit risks refresh starvation and data retention failure. To sustain long transfers, the controller must break bursts into segments shorter than tCEM - for example, issuing CE# HIGH between 4-word bursts - or use DPD mode for extended idle periods. This constraint applies to both asynchronous and burst operations and is enforced by internal refresh watchdog logic.

How is partial-array refresh (PAR) configured and used in W956D6KBKX7I TR?

Partial-array refresh (PAR) in W956D6KBKX7I TR is enabled by writing RCR[2:0] to select 1/2/4/8 sub-arrays for refresh, while RCR[4] must be 0 (DPD disabled). PAR reduces refresh current proportionally - e.g., refreshing only one-eighth of the array cuts self-refresh current to ~12.5% of full-array value. It is most effective when application data is localized (e.g., firmware code in lower addresses, buffers in upper addresses), and requires software coordination to ensure refreshed sub-arrays contain live data.