Winbond Electronics Corporation W948D2FBJX5I

Overview

W948D2FBJX5I from Winbond is a 256Mb mobile LPDDR SDRAM with x16 data bus, 1.8V VDD/VDDQ supply, CAS latency of 2 or 3, and 60-ball VFBGA package. It delivers burst lengths of 2/4/8/16 in sequential or interleave mode and supports Partial Array Self Refresh (PASR) and Automatic Temperature Compensated Self Refresh (ATCSR) for ultra-low-power operation in portable devices.

For engineers reviewing the W948D2FBJX5I datasheet, W948D2FBJX5I pinout, W948D2FBJX5I application, or W948D2FBJX5I equivalent, key selection criteria include its LPDDR interface compliance, x16 VFBGA-60 footprint, 133–200MHz clock rate variants, industrial temperature range (–40°C to +85°C), and support for Deep Power Down and Clock Stop modes in battery-constrained systems.

Technical Context

The W948D2FBJX5I implements a four-bank architecture with independent row activation and column access, enabling bank interleaving to hide precharge latency. Its differential CK/CK̄ inputs synchronize all command, address, and data transfers, while bidirectional DQS strobes center-aligned on write and edge-aligned on read ensure timing robustness at high speeds.

Initialization requires strict sequencing: power ramp with CKE high, ≥200μs stable clocks, PRECHARGE ALL, two AUTO REFRESH commands, then Mode Register and Extended Mode Register programming. The device supports programmable output drive strength, data mask (UDM/LDM), and auto-precharge per burst-critical for low-latency memory subsystems in mobile SoCs.

Key Specifications

Pinout & Package

W948D2FBJX5I uses a 60-ball Very Thin Fine-Pitch Ball Grid Array (VFBGA) package with 0.5mm ball pitch and 5.0mm × 8.0mm body size. Pin assignments follow JEDEC-standard LPDDR x16 ballout, including dedicated VDD/VSS/VDDQ/VSSQ power and ground balls for noise isolation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MT46H32M16LFQ-6 IT:F and K4P2G324EC-BCF7, the W948D2FBJX5I offers direct LPDDR1 x16 compatibility, single 1.8V supply simplicity, and industrial temperature support - making it optimal for cost-sensitive, space-constrained LPDDR1 designs where voltage and footprint must remain unchanged.

Availability

W948D2FBJX5I is available at Aetrix Electronics and suitable for smartphone main memory, tablet GPU buffers, industrial handheld terminals, automotive display caches, and other applications requiring stable component supply with long-term industrial temperature support.

Supply support for W948D2FBJX5I 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 Flash, PSRAM, and low-power DRAM for mobile and embedded markets.

The W948D2FBJX5I belongs to Winbond's Mobile LPDDR SDRAM product line, designed specifically for power-constrained portable devices requiring JEDEC-compliant LPDDR1 performance with industrial-grade reliability and compact packaging.

FAQ

What is the correct power-up sequence for W948D2FBJX5I?

The W948D2FBJX5I requires simultaneous ramp-up of VDD and VDDQ to 1.8V while holding CKE high. After power stabilization, ≥200μs of stable CK/CK̄ must be applied before issuing PRECHARGE ALL. Two AUTO REFRESH commands must follow, each separated by ≥tRFC, before Mode Register programming. This sequence prevents undefined behavior and ensures reliable initialization of the W948D2FBJX5I.

Does W948D2FBJX5I support both sequential and interleave burst types?

Yes, the W948D2FBJX5I supports both sequential and interleave burst types, selectable via bit A3 in the Mode Register. Sequential mode accesses addresses in linear order (e.g., A0, A1, A2…), while interleave mode uses XOR-based addressing for improved cache line alignment. This flexibility allows system designers to optimize W948D2FBJX5I performance for specific processor memory access patterns.

What is the purpose of UDM and LDM pins on W948D2FBJX5I?

UDM (Upper Data Mask) and LDM (Lower Data Mask) are input-only signals that selectively mask write data on DQ8–DQ15 and DQ0–DQ7, respectively. When sampled HIGH on either edge of DQS, they inhibit corresponding byte writes - enabling precise byte-level updates without full-word overwrites. This functionality is essential for efficient memory management in the W948D2FBJX5I's LPDDR1 interface.

How does Partial Array Self Refresh (PASR) reduce power in W948D2FBJX5I?

PASR in the W948D2FBJX5I allows the memory controller to specify which banks or subarrays remain active during self-refresh, while inactive portions enter ultra-low-power retention. By refreshing only required segments - e.g., keeping only the OS kernel region active while suspending user app pages - W948D2FBJX5I cuts self-refresh current by up to 50% versus full-array refresh, extending battery life in always-on mobile devices.

Is W948D2FBJX5I pin-compatible with other Winbond LPDDR parts like W948D6FB?

No, W948D2FBJX5I is not pin-compatible with W948D6FB. While both are 256Mb LPDDR SDRAMs, W948D2FBJX5I uses a 60-ball VFBGA for x16 operation, whereas W948D6FB uses a 90-ball VFBGA for x32 operation. Their ball maps differ significantly - especially in DQ, DM, and DQS pin counts and placement - making them mechanically and electrically incompatible without PCB redesign.