Winbond Electronics Corporation W634GU8QB-11

Overview

W634GU8QB-11 from Winbond is a 4Gb (64M × 8) DDR3L SDRAM organized across 8 internal banks, operating at 1866 MT/s with CL-13 timing (13-13-13), 1.35V nominal supply, and VFBGA-78 package. It supports programmable CAS latency (CL = 5–13), CAS write latency (CWL = 5–9), ZQ calibration, on-die termination (ODT), and asynchronous RESET# for power-up initialization in embedded computing and industrial control memory subsystems.

For engineers reviewing the W634GU8QB-11 datasheet, W634GU8QB-11 pinout, W634GU8QB-11 application, or W634GU8QB-11 equivalent, key selection considerations include DDR3L-1866 speed bin compliance, industrial temperature support (0°C to 95°C), VDD/VDDQ voltage flexibility (1.283–1.45V), and compatibility with JEDEC-standard DDR3L command protocols and timing constraints.

Technical Context

This DDR3L SDRAM implements an 8-bit prefetch architecture synchronized to differential CK/CK# clocks, with bi-directional DQS/DQS# strobes edge-aligned on reads and center-aligned on writes. Its DLL aligns DQ and DQS transitions to clock edges, enabling stable high-speed data capture.

It supports posted CAS with additive latency (AL = 0, CL−1, CL−2), auto-precharge, burst lengths of 8 or 4 (OTF selectable), and multi-purpose register (MPR) readout for system-level timing calibration. Refresh modes include self-refresh, auto self-refresh (ASR), and partial array self-refresh (PASR).

Key Specifications

Pinout & Package

VFBGA-78 package with 8×10.5 mm² footprint, 1.0 mm profile, and ball pitch of 0.8 mm. Designed for surface-mount assembly with standard reflow profiles and thermal pad grounding.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DDR3L SDRAM applications.

Compared with MT41K256M8DA-125:A and IS43TR16256B-125KBL, the W634GU8QB-11 delivers higher bandwidth (1866 MT/s), native 4Gb density in 78-ball VFBGA, and full JEDEC DDR3L feature set including PASR, MPR, and dynamic ODT - making it optimal for space-constrained, thermally demanding industrial designs needing single-chip 4Gb solutions.

Availability

W634GU8QB-11 is available at Aetrix Electronics and suitable for industrial HMI controllers, network edge routers, medical imaging terminals, and automated test equipment requiring stable component supply, long-term lifecycle assurance, and JEDEC-compliant DDR3L performance.

Supply support for W634GU8QB-11 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 manufacturer specializing in specialty memory, flash, and logic ICs, with over 30 years of DRAM design heritage and ISO/TS 16949-certified manufacturing.

The W634GU8QB-11 belongs to Winbond's DDR3L SDRAM product line, engineered specifically for industrial and embedded applications demanding extended temperature operation, low-voltage efficiency, and robust signal integrity without sacrificing JEDEC compliance.

FAQ

What is the maximum supported CAS latency for W634GU8QB-11 at DDR3L-1866 speed?

The W634GU8QB-11 supports CAS latency (CL) settings of 5, 6, 7, 8, 9, 10, and 13 for DDR3L-1866 operation. CL = 13 is the highest validated setting for this speed bin, corresponding to the 13-13-13 timing specification. CL = 14 is not supported in the -11 speed grade per the datasheet's Sup_CL table. This ensures tRCD and tRP meet 13 ns minimums at 933 MHz.

Does W634GU8QB-11 support 1.5V operation like standard DDR3?

Yes, the W634GU8QB-11 is backward compatible with 1.5V DDR3 systems. It operates with VDD/VDDQ = 1.5V ± 0.075V per JEDEC JESD79-3F, allowing drop-in replacement in legacy DDR3 designs. However, its DDR3L-1866 timing specifications (e.g., CL13) are guaranteed only at 1.35V; 1.5V operation may require timing derating per AC characteristics table.

How does the RESET# pin function during power-up for W634GU8QB-11?

The RESET# pin on the W634GU8QB-11 initiates an asynchronous power-up initialization sequence. When asserted low after VDD/VDDQ stabilize, it resets internal registers, clears mode registers, and triggers DLL initialization. The device enters a known state before accepting commands, ensuring reliable startup without external controller intervention - critical for unattended industrial systems.

Can W634GU8QB-11 be used in systems requiring Partial Array Self-Refresh (PASR)?

Yes, the W634GU8QB-11 fully supports Partial Array Self-Refresh (PASR) as defined in MR2. PASR allows selective refresh of 1/2, 1/4, or 1/8 of the memory array, reducing self-refresh current (IDD6) proportionally. This feature is confirmed in Section 8.3.3.1 and Table 4, making W634GU8QB-11 suitable for battery-backed or thermally constrained applications where full-array refresh is unnecessary.

What ball configuration and package type does W634GU8QB-11 use?

The W634GU8QB-11 uses a VFBGA-78 package (8 mm × 10.5 mm, 1.0 mm height) with 0.8 mm ball pitch and RoHS-compliant lead-free construction. Ball mapping follows JEDEC-standard DDR3L layout, including dedicated VDD, VDDQ, VSS, and NC positions. Full pinout details are provided in Sections 5 and 6 of the datasheet, confirming 78 functional balls including address, data, control, and power terminals.