Winbond Electronics Corporation W9725G8KB25I

Overview

W9725G8KB25I from Winbond Electronics is a 256Mbit DDR2 SDRAM organized as 8,388,608 words × 4 banks × 8 bits, operating at DDR2-800 speed (5-5-5 or 6-6-6 timing), with 1.8 V ±0.1 V supply, CAS latency options of 3–7, and burst lengths of 4 or 8. It serves as main system memory in embedded controllers and industrial SoC platforms requiring reliable, low-power synchronous DRAM.

For engineers reviewing the W9725G8KB25I datasheet, W9725G8KB25I pinout, W9725G8KB25I application, or W9725G8KB25I equivalent, key selection considerations include its -25 speed grade timing compliance, on-die termination (ODT) support, OCD impedance calibration, differential clock interface (CLK/CLK), and WBGA-60 package compatibility with DDR2 memory subsystems.

Technical Context

This DDR2 SDRAM implements a double-data-rate architecture synchronized to differential clock inputs (CLK/CLK), 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 stable high-speed transfers up to 800 Mb/sec/pin.

It supports programmable additive latency (AL = 0–2), write latency = read latency −1, auto-precharge, self-refresh, and power-down modes (precharged and active). ODT and OCD are controlled via extended mode registers (EMR1–EMR3), allowing dynamic termination and driver impedance tuning for signal integrity across varying PCB trace conditions.

Key Specifications

Pinout & Package

W9725G8KB25I uses a 60-ball WBGA package (8 mm × 12.5 mm, 0.8 mm pitch) with dedicated VDDQ/VSSQ planes for I/O noise isolation and separate VDDL/VSSDL for DLL power integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MT47H64M4HQ-25E and IS42S16160F-25BLI, W9725G8KB25I uniquely combines OCD calibration, full AL range (0–2), and industrial temperature validation in a compact WBGA-60 package - making it optimal for new designs demanding signal integrity control and thermal robustness without layout compromise.

Availability

W9725G8KB25I is available at Aetrix Electronics and suitable for industrial HMI controllers, medical imaging buffers, network edge routers, and automotive ADAS preprocessor modules requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for W9725G8KB25I 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 W9725G8KB25I belongs to Winbond's DDR2 SDRAM product line, designed specifically for cost-sensitive, thermally constrained embedded systems requiring JEDEC-compliant DDR2 functionality with enhanced signal integrity features like OCD and configurable ODT.

FAQ

What is the maximum supported clock frequency for W9725G8KB25I?

W9725G8KB25I is rated for DDR2-800 operation, supporting a maximum clock frequency of 400 MHz (tCK min = 2.5 ns for CL=5/6). This corresponds to an effective data rate of 800 MT/s per pin. The device meets JEDEC specification requirements for DDR2-800 (5-5-5 or 6-6-6 timing) across its full industrial temperature range (−40°C to +85°C).

Does W9725G8KB25I support on-die termination (ODT)?

Yes, W9725G8KB25I supports programmable on-die termination via the ODT pin and extended mode register EMR(1). When ODT is asserted HIGH, internal termination resistors (typically 75 Ω or 150 Ω, configurable) are enabled on DQ and DQS pins. This eliminates the need for external parallel termination resistors and improves signal integrity on high-speed DDR2 buses.

How is the W9725G8KB25I initialized after power-up?

W9725G8KB25I requires a strict 13-step initialization sequence: stable power ramp (≤200 ms), 200 µs stable clock, CKE assertion, precharge-all, three EMRS commands (EMR2→EMR3→EMR1 for DLL enable), MRS for DLL reset, second precharge-all, two auto-refreshes, final MRS for operational parameters, and OCD calibration. Skipping or reordering steps may result in undefined behavior or initialization failure.

What package type and ball count does W9725G8KB25I use?

W9725G8KB25I uses a RoHS-compliant, lead-free WBGA-60 package measuring 8 mm × 12.5 mm with 0.8 mm ball pitch. It contains 60 solder balls arranged in an 8×8 grid with corner omissions, including dedicated VDDQ/VSSQ planes and isolated VDDL/VSSDL for DLL power integrity - optimized for high-density PCB layouts and thermal performance.

Can W9725G8KB25I operate with CAS latency 3?

Yes, W9725G8KB25I supports CAS latency 3 at DDR2-667 speeds (tCK min = 5 ns), but not at its rated DDR2-800 speed grade. For the -25 speed grade (W9725G8KB25I), CL=3 is only valid under DDR2-667 timing conditions (5-5-5), which require slower clock periods. At DDR2-800, minimum supported CL is 5 per JEDEC compliance and datasheet AC specifications.