Diodes Incorporated PI74SSTU32864NBE

Overview

PI74SSTU32864NBE from Pericom Semiconductor is a 25-bit 1:1 or 14-bit 1:2 configurable registered buffer for DDR-II RDIMM applications, operating at 1.8V VDD, supporting SSTL_18 inputs (except LVCMOS RST/C0/C1), optimized 1.8V CMOS outputs for DIMM loads, and differential clock (CK/CK) registration with asynchronous RST. It enables reliable memory subsystem buffering in server and workstation memory modules.

For engineers reviewing the PI74SSTU32864NBE datasheet, PI74SSTU32864NBE pinout, PI74SSTU32864NBE application, or PI74SSTU32864NBE equivalent, key selection criteria include 270 MHz max clock frequency, 1.41–2.15 ns propagation delay, 1.8V SSTL_18 compatibility, low-power standby mode, and 96-ball LFBGA package with dual configuration modes (C0/C1 controlled).

Technical Context

The PI74SSTU32864NBE uses advanced CMOS to implement dual-mode register logic: 25-bit 1:1 forwarding or 14-bit 1:2 fanout, with data latched on CK↑/CK↓ crossing. Its differential input receivers support JEDEC SSTL_18 (VIH/VIL = VREF ±250 mV), while LVCMOS RST/C0/C1 enable mode selection and asynchronous reset.

It features hierarchical output control: QCS, QODT, QCKE outputs are immune to DCS/CSR gating, whereas Q1–Q25 outputs are suspended when both DCS and CSR are high. RST has priority-forcing all outputs low and disabling differential receivers regardless of DCS/CSR state.

Key Specifications

Pinout & Package

Package: 96-ball LFBGA (NB), Pb-free & Green compliant, 10 mm × 10 mm footprint, 0.8 mm ball pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DDR-II registered buffer applications.

Compared with IDT74SSTU32864BKG and NB3N551DR2G, the PI74SSTU32864NBE uniquely supports dual-mode operation with true SSTL_18 I/O, lower standby current, and guaranteed 270 MHz timing-making it the only validated choice for JEDEC-compliant DDR-II RDIMM designs requiring configurability and power efficiency.

Availability

PI74SSTU32864NBE is available at Aetrix Electronics and suitable for server RDIMM manufacturing, workstation memory module assembly, and industrial DDR-II memory interface design requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle assurance.

Supply support for PI74SSTU32864NBE 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

Pericom Semiconductor was a fabless provider of high-speed interface and timing solutions, acquired by Diodes Incorporated in 2016; its legacy products remain widely deployed in memory and computing infrastructure.

The PI74SSTU32864NBE belongs to Pericom's SSTU-series registered buffer family, engineered specifically for DDR-II RDIMM signal integrity, low-voltage operation, and dual-mode configurability in memory subsystems.

FAQ

What is the function of the ZOH and ZOL pins on PI74SSTU32864NBE?

ZOH and ZOL are reserved terminals with no internal connection. They must be left unconnected or tied to VDD/GND per PCB layout guidelines-neither serves as an output enable, test port, nor voltage reference. Their presence accommodates future feature expansion but imposes no functional requirement in current silicon revision.

Can PI74SSTU32864NBE operate with VREF externally supplied at 0.85V instead of nominal 0.9V?

Yes, but only within JEDEC SSTL_18 tolerance: VREF must stay within 0.49×VDD to 0.51×VDD (0.833–0.969 V at VDD = 1.7–1.9 V). At 0.85 V, VIH = 1.10 V and VIL = 0.60 V remain valid, provided VREF stability is ≤±10 mV peak-to-peak to avoid input threshold jitter.

How does the RST pin interact with DCS and CSR during power-up sequencing?

RST has absolute priority: when asserted low, it forces all outputs low and disables differential receivers-regardless of DCS/CSR state. During power-up, RST must be held low until VDD and VREF stabilize, then released only after clocks and data meet valid logic levels to prevent output glitches.

Is PI74SSTU32864NBE compatible with DDR3 memory interfaces?

No. It is designed exclusively for DDR-II (SSTL_18, 1.8V) signaling. DDR3 requires SSTL_15 (1.5V) I/O, different timing parameters (e.g., tIS/tIH), and lacks support for DDR3-specific commands like ZQ calibration. Using it in DDR3 systems violates JEDEC specifications and risks timing failure.