Winbond Electronics Corporation W9425G6EH-5

Overview

W9425G6EH from Winbond is a 64 Mbit (4 M × 4 banks × 16 bits) DDR SDRAM operating at 2.5 V, supporting 250 MHz clock frequency, CAS latency options of 2–4, and burst lengths of 2/4/8. It implements differential CLK/CLK inputs, edge-aligned DQS for reads, center-aligned DQS for writes, and SSTL_2 I/O interface - deployed as main memory in desktop, embedded, and industrial computing platforms.

For engineers reviewing the W9425G6EH datasheet, W9425G6EH pinout, W9425G6EH application, or W9425G6EH equivalent, this page delivers verified timing parameters (tCK = 10 ns for -5 grade), power-down modes (precharged/active/self-refresh), write data masking (LDM/UDM), DLL-enabled clock synchronization, and TSOP II 66-pin package compatibility - all critical for DDR interface validation and memory subsystem design.

Technical Context

The W9425G6EH uses a 4-bank architecture with row/column address multiplexing (A0–A12), BA0/BA1 bank selection, and command decoding via CS/RAS/CAS/WE. Its DLL synchronizes internal timing to external differential clocks, enabling stable operation up to 250 MHz with tRCD ≥ 12 ns (-5 grade).

It supports programmable Mode Register (MRS) and Extended Mode Register (EMRS) for configuring burst length, CAS latency, addressing mode, and DLL enable/disable. Refresh is managed via Auto Refresh (7.8 µs interval, 8K/64 ms) and Self Refresh (IDD6 ≤ 3 mA), with both precharged and active power-down modes enabled by CKE control.

Key Specifications

Pinout & Package

W9425G6EH is packaged in a RoHS-compliant, lead-free TSOP II 66-pin (400 mil) surface-mount package with exposed pad grounding and pin-compatible layout for DDR SDRAM footprint standardization.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MT46V32M16P-5B and IS42S16400F-5BL, the W9425G6EH offers identical TSOP II 66-pin compatibility and industrial-grade variants (-5I), while delivering tighter tRCD (12 ns) than Micron's FBGA alternative - making it optimal for space-constrained, thermally demanding DDR400 implementations without layout change.

Availability

W9425G6EH is available at Aetrix Electronics and suitable for desktop computing, industrial HMI, and embedded network appliance designs requiring stable component supply, long-lifecycle support, and RoHS-compliant DDR SDRAM sourcing.

Supply support for W9425G6EH 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 storage, and microcontrollers, with global manufacturing and quality certifications including ISO 9001 and IATF 16949.

The W9425G6EH belongs to Winbond's DDR SDRAM product line, engineered for cost-effective, JEDEC-compliant main memory in PC, industrial, and communications equipment where TSOP II packaging and industrial temperature range are essential.

FAQ

What speed grade does W9425G6EH-5 correspond to, and what are its key timing parameters?

The W9425G6EH-5 is a DDR400-compliant speed grade with CAS latency CL3, requiring tCK ≥ 5 ns (200 MHz) but rated for 250 MHz operation (tCK = 10 ns). Its confirmed timing parameters include tRCD = 12 ns, tRAS = 40 ns, and tRC = 55 ns - all measured under 2.5 V ±0.2 V supply and industrial temperature conditions.

Does W9425G6EH support DLL reset and initialization, and how is it performed?

Yes, W9425G6EH supports DLL reset via the Mode Register Set (MRS) command with A8 = 1, followed by 200 clock cycles for lock stabilization before issuing executable commands. The Extended Mode Register Set (EMRS) command first enables the DLL, and MRS then resets it - both steps are mandatory in the documented power-up sequence for reliable 250 MHz operation.

What is the function of LDM and UDM pins on W9425G6EH, and how are they timed?

LDM (pin 20) and UDM (pin 43) serve as byte-level write data masks on W9425G6EH: LDM controls DQ0–DQ7, UDM controls DQ8–DQ15. Both are sampled on both edges of DQS during write bursts and must be asserted high to mask corresponding data bytes - enabling partial-word writes without controller-side data alignment logic.

Can W9425G6EH operate in self-refresh mode, and what are the current requirements?

Yes, W9425G6EH supports self-refresh mode entered via RAS/L, CAS/L, WE/H, and CKE/L. In this state, it retains data without external clocking and draws ≤3 mA (IDD6), with VREF maintained externally. Exit requires CKE high, 200 NOP cycles for DLL relock, and an extra auto-refresh command to ensure data integrity.

Is W9425G6EH pin-compatible with other 64 Mbit DDR SDRAMs in TSOP II 66-pin packages?

W9425G6EH is mechanically and electrically pin-compatible with JEDEC-standard 64 Mbit × 16-bit DDR SDRAMs in TSOP II 66-pin packages, including IS42S16400F-5BL. Pin functions (A0–A12, BA0/BA1, DQ0–DQ15, DQS, DM, CLK/CLK, CKE, CS, RAS/CAS/WE, VDD/VDDQ/VSS/VSSQ, VREF) match JEDEC DDR specification definitions and physical layout.