Winbond Electronics Corporation W9725G6KB25I TR

Overview

W9725G6KB25I TR from Winbond is a 256M-bit DDR2 SDRAM organized as 4M × 4 banks × 16-bit, supporting DDR2-800 (5-5-5 or 6-6-6) operation at 1.8 V supply, with CAS latency options of 3–7 and burst lengths of 4/8, deployed in embedded industrial control and network interface memory subsystems.

For engineers reviewing the W9725G6KB25I TR datasheet, W9725G6KB25I TR pinout, W9725G6KB25I TR application, or W9725G6KB25I TR equivalent, key selection considerations include industrial temperature support (−40°C to +95°C), on-die termination (ODT), off-chip driver (OCD) impedance calibration, and SSTL_18 interface compliance for signal integrity in high-speed PCB layouts.

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 to read data and center-aligned to write data. It integrates a DLL for precise DQ–DQS–clock alignment and supports posted CAS (AL = 0–2) to decouple command and data bus timing.

Functional operation includes auto-precharge, self-refresh, and power-down modes (precharged and active), with ODT programmable per bank via EMR(1) and OCD calibration enabled through extended mode register commands. All control/address inputs are sampled on the crossing of CLK rising and CLK falling edges.

Key Specifications

Pinout & Package

Packaged in lead-free, RoHS-compliant WBGA-84 (8 mm × 12.5 mm, 0.8 mm pitch), with dedicated VDDQ/VSSQ planes for I/O power integrity and isolated VDDL/VSSDL for DLL circuitry.

Key Features

Applications

Equivalent & Alternatives

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

Compared with W9725G6KB25I TR, MT47H64M4HQ-25E IT:C offers identical speed and temperature but lacks OCD calibration, while IS42S16160F-25BLI matches the package and speed but omits programmable ODT - making W9725G6KB25I TR uniquely suited for high-signal-integrity DDR2 designs requiring both on-die termination and driver tuning.

Availability

W9725G6KB25I TR is available at Aetrix Electronics and suitable for industrial automation, network infrastructure, and medical imaging systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for W9725G6KB25I TR 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, flash, and trusted computing solutions, with over 30 years of DRAM design heritage.

The W97 series targets industrial and networking applications demanding extended temperature operation, low-power self-refresh, and advanced signal integrity features like OCD and programmable ODT - distinguishing it from consumer-grade DDR2 offerings.

FAQ

What is the maximum operating frequency supported by W9725G6KB25I TR?

W9725G6KB25I TR supports DDR2-800 operation, achieving up to 800 megatransfers per second (MT/s) with a minimum clock period (tCK) of 2.5 ns at CAS Latency 5. This speed grade is validated across the full industrial temperature range (−40°C to +95°C), and the device also supports slower DDR2-667 operation if system timing margins require relaxation.

Does W9725G6KB25I TR support on-die termination (ODT) and how is it configured?

Yes, W9725G6KB25I TR supports programmable on-die termination (ODT) via Extended Mode Register 1 (EMR1). ODT is enabled by driving the ODT pin HIGH and configuring resistance values (e.g., 75 Ω, 150 Ω, or 50 Ω) through EMR1 bits A9–A7. This eliminates the need for external parallel termination resistors on DQ/DQS lines, improving signal integrity in point-to-point and multi-drop DDR2 topologies.

How does the OCD (Off-Chip Driver) calibration function work in W9725G6KB25I TR?

OCD calibration in W9725G6KB25I TR adjusts the output driver impedance of DQ and DQS pins to match PCB trace impedance (typically 40 Ω or 60 Ω). It is initiated via EMR1 commands with specific A9–A7 bit patterns, followed by a calibration sequence that compares internal reference voltages. The calibrated value is retained until next reset or reprogramming, ensuring consistent drive strength across voltage and temperature.

What is the purpose of the VDDL and VSSDL pins on W9725G6KB25I TR?

VDDL (J1) and VSSDL (J7) are dedicated power and ground supplies for the internal DLL (Delay-Locked Loop) circuitry in W9725G6KB25I TR. Isolating DLL power from core (VDD) and I/O (VDDQ) domains minimizes noise coupling into the clock alignment path, preserving DQ–DQS–CLK timing accuracy and reducing jitter - critical for maintaining setup/hold margins at DDR2-800 speeds.

Can W9725G6KB25I TR be used in place of the -25 speed grade part?

W9725G6KB25I TR is functionally identical to W9725G6KB-25 in electrical and timing specifications (DDR2-800, 5-5-5 or 6-6-6), differing only in its extended industrial temperature qualification (−40°C to +95°C vs. 0°C to +85°C). Pinout, package, and initialization sequence are identical, allowing direct substitution where wider thermal operation is required - no layout or firmware changes are needed.