Renesas SSTUAF32866CHLF

Overview

SSTUAF32866CHLF from Renesas (formerly IDT) is a 25-bit configurable registered buffer IC designed for DDR2 memory module applications, supporting both 25-bit 1:1 and 14-bit 1:2 pinout configurations with integrated parity checking. It operates at 1.7–1.9 V, accepts SSTL_18 inputs, delivers 1.8-V CMOS outputs, and features differential clocking (CLK/CLK) with asynchronous RESET. Used in DDR2 RDIMMs for signal integrity and error detection.

For engineers reviewing the SSTUAF32866CHLF datasheet, SSTUAF32866CHLF pinout, SSTUAF32866CHLF application, or SSTUAF32866CHLF equivalent, key selection criteria include its dual-mode configurability (C0/C1-controlled), 410 MHz max clock frequency, QERR open-drain error reporting, PPO parity output, and 96-ball LFBGA package compatibility with DDR2 400/533/667 systems.

Technical Context

The SSTUAF32866CHLF implements a dual-stage registered architecture with independent control of data flow via C0 and C1 inputs to select between 25-bit 1:1, 14-bit 1:2 A-configuration, or 14-bit 1:2 B-configuration modes. Its differential clock receiver supports JEDEC SSTL_18 timing, with data registered on the crossing of CLK rising and CLK falling edges.

It integrates parity logic that validates D1–D25 (1:1) or D1–D14 (1:2) against PAR_IN, generating PPO and latching QERR on error. RESET disables differential receivers, resets registers, forces outputs low, and must be held low during power-up to prevent glitches - critical for DDR2 RDIMM initialization where RESET is fully asynchronous to CLK.

Key Specifications

Pinout & Package

Package: 96-ball Low-Profile Fine-Pitch Ball Grid Array (LFBGA), MO-205CC footprint, lead-free (HLF suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SSTUA32866CHLF, SSTUA32864CHLF offers backward compatibility but no 1:2 flexibility, while PI74FCT162374AHLEX lacks DDR2-specific electrical and timing features entirely - making SSTUAF32866CHLF the only option supporting JEDEC-compliant dual-rank RDIMM designs with integrated parity.

Availability

SSTUAF32866CHLF is available at Aetrix Electronics and suitable for DDR2 memory modules, server DIMM manufacturing, and embedded computing platforms requiring stable component supply with long-term lifecycle support.

Supply support for SSTUAF32866CHLF 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

Renesas Electronics Corporation acquired Integrated Device Technology (IDT) in 2019 and now manufactures high-performance timing, memory interface, and RF products for datacenter, networking, and automotive markets.

The SSTUAF32866CHLF belongs to IDT's DDR2 registered buffer product line, engineered specifically to meet JEDEC DDR2 RDIMM signal integrity, timing, and reliability requirements in high-density memory subsystems.

FAQ

What is the primary function of the SSTUAF32866CHLF in a DDR2 memory system?

The SSTUAF32866CHLF serves as a configurable registered buffer for DDR2 RDIMMs, retiming and driving address, command, and control signals while providing real-time parity checking. Its dual-mode capability (25-bit 1:1 or 14-bit 1:2) allows flexible use across single- and dual-rank modules. The SSTUAF32866CHLF integrates PPO and QERR outputs to support system-level error detection without external logic.

How does the C0 and C1 pin configuration affect the SSTUAF32866CHLF pinout and functionality?

C0 and C1 are LVCMOS control inputs that configure the SSTUAF32866CHLF into three distinct operating modes: C0=0/C1=0 enables 25-bit 1:1 buffering; C0=0/C1=1 selects 14-bit 1:2 A-configuration; C0=1/C1=1 activates 14-bit 1:2 B-configuration. These settings determine which data inputs (D1–D25 vs. D1–D14) and outputs (Q1–Q25 vs. Q1A/Q1B pairs) are active, directly mapping to DDR2 RDIMM rank topology requirements.

What is the role of the QERR output in the SSTUAF32866CHLF, and how is it timed?

The QERR output of the SSTUAF32866CHLF is an open-drain error flag that latches low for at least two clock cycles upon detecting a parity mismatch between data inputs and PAR_IN. In 1:1 mode, QERR becomes valid two cycles after the erroneous data is clocked in; in 1:2 A-configuration, it is valid one cycle later. The SSTUAF32866CHLF ensures deterministic timing so system controllers can synchronize error response without additional latency estimation.

Why must the RESET pin be held low during power-up of the SSTUAF32866CHLF?

The SSTUAF32866CHLF requires RESET to be held low during power-up to prevent undefined output states and potential glitches on Qn outputs before clocks and VREF stabilize. This ensures differential receivers remain disabled until valid reference and timing signals are present. The SSTUAF32866CHLF specification mandates this sequence to guarantee glitch-free initialization - especially critical in DDR2 RDIMMs where asynchronous RESET relative to CLK is permitted but timing-critical.

Does the SSTUAF32866CHLF support both DDR2-400 and DDR2-667 data rates?

Yes, the SSTUAF32866CHLF supports DDR2-400 (200 MHz clock), DDR2-533 (266 MHz), and DDR2-667 (333 MHz) data rates, with a maximum clock frequency of 410 MHz - exceeding DDR2-800 (400 MHz) requirements. Its propagation delay (1.3–1.9 ns) and setup/hold timing margins (0.5–0.7 ns) are validated across the full 1.7–1.9 V VDD range, ensuring robust operation at all standard DDR2 speeds.