Winbond Electronics Corporation W971GG8NB-25

Overview

W971GG8NB-25 from Winbond is a 1G-bit DDR2 SDRAM organized as 16M × 8 banks × 8 bits, compliant with DDR2-800 (5-5-5 or 6-6-6) timing, operating at 1.8 V ± 0.1 V supply, and rated for 0°C ≤ TCASE ≤ 85°C. It delivers 800 Mbps data transfer rates in systems requiring high-bandwidth memory buffering for embedded controllers, industrial HMIs, and network edge devices.

For engineers reviewing the W971GG8NB-25 datasheet, W971GG8NB-25 pinout, W971GG8NB-25 application, or W971GG8NB-25 equivalent, key selection criteria include CAS latency support (CL=3–7), on-die termination (ODT), OCD impedance calibration, differential clock interface (CLK/CLK), and SSTL_18 I/O compatibility.

Technical Context

This DDR2 SDRAM implements a double-data-rate architecture synchronized to differential CLK/CLK inputs, 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 precise timing control across temperature and voltage variations.

The device supports programmable additive latency (AL=0–2), auto-precharge, burst lengths of 4 or 8, and multiple power management modes including precharged power down and self-refresh. ODT and OCD are controlled via extended mode registers (EMR1–EMR3), allowing dynamic impedance tuning without external components.

Key Specifications

Pinout & Package

Packaged in 60-ball Window BGA (8 mm × 9.5 mm, 1.0 mm height), RoHS-compliant and lead-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with W971GG8NB-25, MT47H128M8CB-25E offers identical performance but demands board-level changes, while IS42S16160F-25BLI trades density and feature depth for lower unit cost in narrower bus architectures.

Availability

W971GG8NB-25 is available at Aetrix Electronics and suitable for industrial HMIs, network edge routers, medical imaging gateways, and automated test equipment requiring stable component supply across long production lifecycles.

Supply support for W971GG8NB-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 and microcontrollers, with over 30 years of DRAM design heritage.

The W971GG8NB series belongs to Winbond's industrial-grade DDR2 SDRAM product line, engineered for reliability in extended-temperature embedded systems with stringent signal integrity and power management requirements.

FAQ

What is the maximum supported CAS latency for W971GG8NB-25?

W971GG8NB-25 supports programmable CAS latency values of CL=3, 4, 5, 6, and 7. At its rated DDR2-800 speed (tCK = 2.5 ns min), CL=5 corresponds to a 12.5 ns read access delay from column address assertion to first data output. CL=7 is usable at reduced frequencies or for timing margining in noisy environments, but not at full 400 MHz operation.

Does W971GG8NB-25 support differential DQS operation?

Yes, W971GG8NB-25 supports differential DQS/DQS operation when enabled via EMR(1) bit A10 = 0. In this mode, both DQS pins function as complementary strobes synchronized to read/write data. When disabled (A10 = 1), only single-ended DQS is active and DQS is unused. The W971GG8NB-25 datasheet specifies edge-alignment for reads and center-alignment for writes in either configuration.

How does ODT behavior differ between W971GG8NB-25 and earlier DDR2 generations?

W971GG8NB-25 implements JEDEC-compliant ODT with programmable termination resistance values (75 Ω, 150 Ω, or off) selected via EMR(1). Unlike first-generation DDR2, it supports dynamic ODT activation per-burst and maintains termination during precharge power-down mode. This allows precise control of stub reflections on multi-drop DQ buses without requiring external resistors - a capability confirmed in the W971GG8NB-25 AC characteristics table (Section 10.4).

Can W971GG8NB-25 operate with VDD and VDDQ supplied from separate regulators?

Yes, W971GG8NB-25 permits independent regulation of VDD (core) and VDDQ (I/O), provided both remain within 1.8 V ± 0.1 V and |VDD − VDDQ| ≤ 0.3 V at all times. The W971GG8NB-25 datasheet explicitly allows this in Section 8.1 Power-up Sequence Option B, noting that VDD/VDDL must ramp before or simultaneously with VDDQ to prevent latch-up. VREF must still track VDDQ/2 ± 300 mV regardless of regulator separation.

What is the minimum refresh interval required for W971GG8NB-25 at 85°C case temperature?

At 0°C ≤ TCASE ≤ 85°C, W971GG8NB-25 requires an average periodic refresh interval (tREFI) of ≤7.8 μs, per JEDEC DDR2 specification. This corresponds to issuing 8,192 refresh commands every 64 ms. The W971GG8NB-25 datasheet confirms this value applies to the -25 speed grade across its full rated temperature range, with no derating needed at 85°C.