Winbond Electronics Corporation W634GU8QB11I

Overview

W634GU8QB11I from Winbond is a 4Gb (64M × 8) DDR3L SDRAM with 8 internal banks, 1.35V nominal supply, and industrial temperature support (−40°C to +95°C). It operates at DDR3L-1866 speed (13-13-13 CL-tRCD-tRP), delivers up to 1866 MT/s data rates, and implements ZQ calibration, programmable CWL/AL, and dynamic ODT for high-signal-integrity memory subsystems in embedded controllers and networking equipment.

For engineers reviewing the W634GU8QB11I datasheet, W634GU8QB11I pinout, W634GU8QB11I application, or W634GU8QB11I equivalent, key selection factors include its industrial-grade thermal range, DDR3L-1866 timing compliance, VFBGA78 package compatibility, and support for write leveling and MPR-based system calibration.

Technical Context

This DDR3L SDRAM uses an 8-bit prefetch architecture synchronized to differential CK/CK# inputs, with all commands latched on CK rising edge and data aligned via bi-directional DQS/DQS# strobes. Its DLL aligns DQ and DQS transitions to clock edges, enabling precise timing control across temperature and voltage variations.

The device supports asynchronous RESET#, programmable mode registers (MR0–MR3) for CAS latency, additive latency, CWL, PASR, and ASR, plus dynamic ODT (Rtt_WR) and ZQ calibration using an external 240Ω reference resistor - all critical for stable operation in thermally demanding industrial platforms.

Key Specifications

Pinout & Package

VFBGA78 package with 8×10.5 mm² footprint, 1.0 mm thickness, and ball pitch of 0.8 mm. Ball map conforms to JEDEC MO-270AC standard for DDR3L SDRAM.

Key Features

Applications

Equivalent & Alternatives

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

Compared with W634GU8QB11I, IS43TR16256B-125KBL offers higher density and bandwidth but demands x16 interface support, whereas MT41K256M8DA-125:A provides true pin- and timing-compatible redundancy without layout changes - making it ideal for supply chain risk mitigation in industrial designs.

Availability

W634GU8QB11I is available at Aetrix Electronics and suitable for industrial PLC controllers, network edge routers, medical imaging front-ends, and automated test equipment requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for W634GU8QB11I 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 NOR/NAND Flash, SRAM, and DRAM products for industrial, automotive, and communications markets.

The W634GU8QB11I belongs to Winbond's DDR3L SDRAM product line, engineered for robust operation in thermally demanding embedded systems where reliability, JEDEC compliance, and industrial temperature support are mandatory design requirements.

FAQ

What is the maximum supported CAS Latency for W634GU8QB11I at DDR3L-1866 speed?

The W634GU8QB11I supports CAS Latency (CL) values of 5, 6, 7, 8, 9, 10, and 11 at DDR3L-1866 speed. CL=13 and CL=14 are not supported in this speed bin per the datasheet's Sup_CL table for -11/11I/11J grades. Valid combinations require matching CWL (e.g., CL=11 pairs with CWL=8) and must satisfy tAA and tRCD timing constraints.

Does W634GU8QB11I support both DDR3L and standard DDR3 voltage levels?

Yes, W634GU8QB11I supports dual-voltage operation: 1.35V nominal (DDR3L) with VDD/VDDQ range 1.283V–1.45V, and backward compatibility to 1.5V ±0.075V (standard DDR3). Voltage switching is allowed only during power-down states and must follow the VDD/VDDQ transition procedure defined in Section 11.4 of the datasheet to avoid latch-up or data corruption.

What package type and ball count does W634GU8QB11I use?

W634GU8QB11I uses a VFBGA78 package: 78-ball Very-thin Fine-pitch Ball Grid Array with 8 mm × 10.5 mm body size, 1.0 mm maximum height, and 0.8 mm ball pitch. It complies with JEDEC MO-270AC and is RoHS-compliant with lead-free terminations.

How is write leveling implemented on W634GU8QB11I?

W634GU8QB11I implements write leveling via its dedicated DQS/DQS# strobe pair and internal leveling logic. The host controller issues a write leveling command, and the DRAM returns a phase-shifted DQS pulse; the controller adjusts DQS delay until edge alignment with CK is achieved. This process is defined in Section 8.9 and requires MPR mode entry for feedback pattern readout.

Is W634GU8QB11I qualified for industrial temperature operation?

Yes, W634GU8QB11I is explicitly rated for industrial temperature operation from −40°C to +95°C (TCASE), as confirmed in the Order Information table and Section 10.2. This rating applies to the "11I" suffix variant and is validated across full AC/DC specifications per JEDEC JESD209-3C.