Winbond Electronics Corporation W9751G8KB-25

Overview

W9751G8KB-25 from Winbond Electronics is a 512Mbit DDR2 SDRAM organized as 16M × 4 banks × 8 bits, operating at DDR2-800 speed (5-5-5 or 6-6-6 timing), with 1.8 V supply, CAS latency options of 3–7, and burst lengths of 4 or 8. It serves as main system memory in embedded controllers, industrial HMIs, and network edge devices requiring reliable synchronous DRAM with on-die termination.

For engineers reviewing the W9751G8KB-25 datasheet, W9751G8KB-25 pinout, W9751G8KB-25 application, or W9751G8KB-25 equivalent, key selection considerations include its -25 speed grade timing compliance, WBGA-60 package footprint, SSTL_18 interface compatibility, and support for OCD impedance calibration and differential DQS strobes in source-synchronous read/write operations.

Technical Context

This DDR2 SDRAM implements a double-data-rate architecture synchronized to differential CLK/CLK inputs, with all commands latched on the crossing of rising CLK and falling CLK. Its internal DLL aligns DQ and DQS transitions to clock edges, enabling stable data capture at up to 400 MHz clock frequency (800 MT/s).

It supports programmable additive latency (AL = 0–2), yielding read latency RL = AL + CL, and write latency WL = RL − 1. On-die termination (ODT) and off-chip driver (OCD) impedance adjustment are controlled via extended mode registers, allowing dynamic signal integrity tuning during operation without external components.

Key Specifications

Pinout & Package

W9751G8KB-25 is packaged in a 60-ball Wafer-Level Ball Grid Array (WBGA) measuring 8 mm × 12.5 mm with 0.8 mm ball pitch. The package uses lead-free materials and complies with RoHS directives.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DDR2 SDRAM applications.

Compared with MT47H128M8HQ-25E and IS42S16160F-25BLI, W9751G8KB-25 offers optimal fit for space-constrained x8 DDR2 interfaces where WBGA-60 footprint, RDQS capability, and proven industrial temperature stability are prioritized over raw density or bus width.

Availability

W9751G8KB-25 is available at Aetrix Electronics and suitable for industrial HMIs, network edge routers, embedded vision systems, and medical diagnostic devices requiring stable component supply across extended product lifecycles.

Supply support for W9751G8KB-25 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 DDR SDRAM for industrial, automotive, and communications markets.

The W9751G series targets cost-sensitive, space-constrained embedded systems needing JEDEC-compliant DDR2 memory with enhanced signal integrity features like OCD and ODT - designed specifically for controller integration in resource-limited SoC platforms.

FAQ

What DDR2 speed grade does W9751G8KB-25 support?

W9751G8KB-25 supports DDR2-800 operation with two timing bin options: 5-5-5 and 6-6-6 (tCK min = 2.5 ns at CL=5/6). It is not rated for DDR2-1066 or DDR2-667 speeds. The -25 suffix explicitly denotes this speed grade, and the device must be initialized and operated within the AC and DC specifications defined for this bin in the official Winbond datasheet revision A02.

Does W9751G8KB-25 support differential DQS operation?

Yes, W9751G8KB-25 supports differential DQS strobes (DQS/DQS) when enabled via Extended Mode Register 1 (EMR(1)) bit A10 = 0. In this mode, DQS functions as a true differential pair for both read and write operations, improving timing margin and noise immunity. The device also supports single-ended DQS mode (A10 = 1), where DQS operates alone and A2 becomes NU/RDQS.

What is the purpose of the VREF pin on W9751G8KB-25?

The VREF pin on W9751G8KB-25 provides the reference voltage for all SSTL_18 input receivers (address, command, clock). It must be externally supplied at VDDQ/2 ±300 mV and remain stable during power-up and operation. Incorrect VREF level causes setup/hold violations and command decoding errors - proper VREF decoupling and routing are mandatory per Winbond's layout guidelines in the W9751G8KB-25 datasheet.

Can W9751G8KB-25 operate with CL=3 at DDR2-800 speeds?

No, W9751G8KB-25 does not support CAS Latency 3 at DDR2-800 speeds. Per the datasheet's KEY PARAMETERS table, CL=3 is only specified for tCK ≥ 5 ns - corresponding to DDR2-400 or slower operation. At DDR2-800 (tCK = 2.5 ns), the minimum supported CL is 5. Attempting CL=3 at 400 MHz violates timing margins and will result in read data corruption.

How is on-die termination (ODT) controlled on W9751G8KB-25?

ODT on W9751G8KB-25 is controlled by the dedicated ODT pin (ball F9), which must be driven HIGH to enable internal termination resistors on DQ/DQS lines during reads/writes. ODT is registered, meaning its state is sampled on the CLK/CLK crossing and takes effect after tODT latency. Termination values are fixed per datasheet (typically ~150 Ω), and cannot be adjusted - unlike OCD, which tunes driver output impedance.