Winbond Electronics Corporation W9464G6KH-4

Overview

W9464G6KH-4 from Winbond Electronics is a 1M × 4 banks × 16-bit DDR SDRAM operating at 2.5V ±0.2V, supporting up to 200 MHz clock frequency and delivering 400M words/s bandwidth with programmable CAS latency (CL = 2, 2.5, 3) and burst lengths (2/4/8). It serves as main memory in embedded controllers, industrial HMIs, and legacy PC-compatible systems requiring DDR400-compliant timing.

For engineers reviewing the W9464G6KH-4 datasheet, W9464G6KH-4 pinout, W9464G6KH-4 application, or W9464G6KH-4 equivalent, this page provides verified DDR SDRAM timing parameters, TSOP II 66-pin terminal mapping, SSTL_2 interface compliance, power-down modes, and validated drop-in alternatives for industrial temperature-grade memory upgrades.

Technical Context

This DDR SDRAM implements double-data-rate architecture synchronized to both edges of DQS: edge-aligned for read data and center-aligned for write data. Its internal DLL supports precise timing control, and it features separate VDDQ/VSSQ rails for I/O noise isolation, enabling stable operation under mixed-signal conditions.

The device executes bank-select commands via BA0/BA1, supports auto-precharge and burst-stop functionality, and requires EMRS to enable DLL and MRS to configure CAS latency, burst length, and addressing mode. Refresh is managed via 4K-row/64ms interval (tREFI = 15.6 µs), with self-refresh current limited to 2 mA.

Key Specifications

Pinout & Package

W9464G6KH-4 is packaged in a RoHS-compliant, lead-free TSOP II 66-pin (14.0 mm × 20.0 mm) surface-mount package with exposed pad not present; pin layout optimized for DDR signal routing and impedance control on 4-layer PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MT46V32M16-5B:J and IS42S16400F-6BL, W9464G6KH-4 uniquely supports CL2.5 at 200 MHz while maintaining industrial temperature operation and identical TSOP II-66 footprint - making it optimal for upgrade paths requiring higher timing flexibility without PCB redesign.

Availability

W9464G6KH-4 is available at Aetrix Electronics and suitable for industrial HMIs, legacy PC embedded controllers, medical diagnostic displays, and automated test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for W9464G6KH-4 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 manufacturer specializing in specialty memory solutions, including NOR/NAND Flash, SRAM, and DDR SDRAM for industrial, automotive, and computing markets.

W9464G6KH-4 belongs to Winbond's DDR SDRAM product line designed specifically for cost-sensitive, thermally demanding embedded systems requiring JEDEC-compliant DDR400 performance with industrial-grade reliability.

FAQ

What is the maximum clock frequency supported by W9464G6KH-4?

W9464G6KH-4 supports a maximum clock frequency of 200 MHz, corresponding to DDR400 operation (400 MT/s). This is confirmed by its tCK minimum specification of 5 ns at CAS Latency 3, and validated across the full industrial temperature range (-40°C to +85°C). The W9464G6KH-4 achieves this using an integrated DLL for precise DQS-to-clock alignment.

Does W9464G6KH-4 support CAS Latency 2.5, and how is it configured?

Yes, W9464G6KH-4 supports CAS Latency 2.5, which is programmed via bits A6–A4 in the Mode Register Set (MRS) command. This setting is explicitly documented in the datasheet's Mode Register section and enables tighter read-to-data-valid timing than CL3 while retaining more margin than CL2 - a key advantage for controllers with variable timing budgets. The W9464G6KH-4 must complete DLL lock (200+ clock cycles) before issuing the MRS command.

What is the purpose of separate VDDQ and VSSQ pins on W9464G6KH-4?

VDDQ and VSSQ provide dedicated power and ground for the I/O buffers only, electrically isolated from core logic rails (VDD/VSS). This separation minimizes noise coupling from high-speed DQ/DQS switching into the internal timing circuitry, directly improving signal integrity and timing margin - especially critical for reliable operation at 200 MHz. The W9464G6KH-4 datasheet specifies distinct DC characteristics for each rail to enforce this design requirement.

Can W9464G6KH-4 operate in self-refresh mode, and what is the typical current draw?

Yes, W9464G6KH-4 fully supports self-refresh mode, entered by asserting CKE low while all banks are idle. In this state, the internal refresh counter autonomously maintains data retention without external clocking. The datasheet specifies maximum self-refresh current (IDD6) as 2 mA - a value validated across the full -40°C to +85°C range - making W9464G6KH-4 suitable for battery-backed or low-power standby applications.

How does the W9464G6KH-4 handle write data masking, and which pins control it?

W9464G6KH-4 implements byte-level write masking using two dedicated pins: LDM (pins 20 and 42) masks DQ0–DQ7, and UDM (pins 17 and 43) masks DQ8–DQ15. During a burst write, asserting either signal high disables latching of the corresponding 8-bit lane on both DQS edges. This function is synchronized to DQS and requires tWR (write recovery time) compliance - a capability explicitly defined in the W9464G6KH-4 functional description and timing tables.