Winbond Electronics Corporation W971GG8NB25I

Overview

W971GG8NB25I from Winbond is a 1G-bit DDR2 SDRAM organized as 16M × 8 banks × 8 bits, supporting DDR2-800 (5-5-5 or 6-6-6) operation at 400 MHz clock frequency with CAS Latency 5 or 6. It features on-die termination (ODT), off-chip driver (OCD) impedance adjustment, and differential clock inputs (CLK/CLK), designed for industrial embedded systems requiring stable memory operation across –40°C to +95°C.

For engineers reviewing the W971GG8NB25I datasheet, W971GG8NB25I pinout, W971GG8NB25I application, or W971GG8NB25I equivalent, key selection considerations include its industrial temperature rating, SSTL_18 interface compliance, ODT programmability, burst length support (4/8), and compatibility with DDR2-800 timing constraints in memory subsystems.

Technical Context

This DDR2 SDRAM implements a double-data-rate architecture synchronized to differential CLK/CLK edges, with all address/control inputs latched at the crossing point. Its internal DLL aligns DQ and DQS transitions to the clock, enabling precise source-synchronous read/write timing.

It supports programmable additive latency (AL = 0–2), yielding read latency RL = AL + CL (e.g., CL=5 + AL=0 → RL=5), and write latency WL = RL − 1. Command decoding includes bank-select (BA0–BA2), row/column addressing (A0–A13), and mode register configuration via MRS/EMRS commands for ODT, OCD, and DLL control.

Key Specifications

Pinout & Package

Packaged in a lead-free, RoHS-compliant Window BGA (WBGA) with 60 balls (8 mm × 9.5 mm, 1.0 mm thickness). Ball pitch is 0.8 mm; package uses VSSQ/VDDQ isolation for improved DQ noise immunity.

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, the W971GG8NB25I offers optimal trade-offs for new 8-bit DDR2 designs: smaller 60-ball WBGA footprint reduces PCB area and layer count, lower operating current extends thermal headroom in sealed enclosures, and Winbond's industrial qualification provides documented reliability for medical and test equipment use cases.

Availability

W971GG8NB25I is available at Aetrix Electronics and suitable for industrial HMI panels, network router memory buffers, medical imaging edge devices, and automated test equipment controllers requiring stable component supply across extended temperature ranges.

Supply support for W971GG8NB25I 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 W971GG8NB series belongs to Winbond's industrial-grade DDR2 SDRAM product line, engineered specifically for long-lifecycle embedded applications demanding guaranteed performance from –40°C to +105°C and robust JEDEC compliance.

FAQ

What is the maximum supported clock frequency for W971GG8NB25I?

The W971GG8NB25I is rated for DDR2-800 operation, meaning it supports a 400 MHz differential clock frequency (800 MT/s data rate). This is validated across its full industrial temperature range (–40°C to +95°C) with CL=5 or CL=6 timing. The device does not support DDR2-1066 speeds; those require the -18/-18I/-18J variants.

Does W971GG8NB25I support differential DQS operation?

Yes, W971GG8NB25I supports differential DQS/DQS operation, enabled by setting EMR(1)[A10] = 0. When enabled, DQS functions as a true differential strobe aligned with read data and centered with write data. Ball A2 (NU/RDQS) becomes active as RDQS only when both differential strobe mode and RDQS enable (EMR(1)[A11] = 1) are configured.

How is on-die termination (ODT) controlled on W971GG8NB25I?

ODT on W971GG8NB25I is controlled via the dedicated ODT pin (ball F9), which must be registered HIGH to enable internal termination resistors on DQ/DQS lines. Termination values are set using Extended Mode Register 1 (EMR(1)) bits A0–A2. The ODT function is fully compliant with JEDEC DDR2 standards and operates independently of external resistor networks.

What is the purpose of the VDDL and VSSDL pins on W971GG8NB25I?

VDDL (ball E1) and VSSDL (ball E7) are dedicated power and ground supplies for the internal DLL circuitry. Separating DLL power from core (VDD/VSS) and I/O (VDDQ/VSSQ) domains prevents DLL jitter caused by switching noise, ensuring stable DQ–DQS alignment at 400 MHz - a critical requirement for reliable DDR2-800 operation in noisy industrial environments.

Can W971GG8NB25I operate in self-refresh mode at +95°C?

Yes, W971GG8NB25I supports self-refresh mode across its full industrial temperature range, including +95°C. At temperatures above +85°C, the device requires doubled refresh frequency (tREFI = 3.9 µS instead of 7.8 µS), achieved by setting A7 = 1 in EMR(2). Self-refresh current remains ≤ 8 mA, enabling low-power retention in thermally constrained applications like portable medical devices.