74SSTUB32868 - 28-Bit to 56-Bit Registered Buffer | TI
MPN: 74SSTUB32868 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.5 | $4.50 |
| 10 | $4.05 | $40.50 |
| 100 | $3.6 | $360.00 |
| 500 | $3.24 | $1,620.00 |
| 1,000 | $2.88 | $2,880.00 |
74SSTUB32868 Overview
A registered buffer is a type of logic device that latches address and control signals to reduce the electrical loading on the memory controller, enabling higher-speed and higher-capacity memory systems. In the hierarchy of memory interface components, the registered buffer sits between the memory controller and the DRAM devices, providing signal buffering and timing alignment. This function is critical in DDR2 and DDR3 modules where signal integrity and timing margins are paramount.
Key features include a 1:2 configurable registered buffer topology, which allows one input to drive two outputs, effectively doubling the fan-out for address and control signals. The device also includes address-parity test functionality, which detects parity errors on the address bus, enhancing system reliability. The 176-ball NFBGA package provides excellent thermal and electrical performance, with a compact footprint suitable for space-constrained memory module designs.
From a technical perspective, the 74SSTUB32868 uses SSTL_18 I/O standards, compatible with 1.8V memory interfaces. It supports differential clock inputs (CK and CK#) for precise timing, and includes a reset function for initialization. The device is designed to meet JEDEC standards for DDR2 registered DIMMs, ensuring interoperability with standard memory modules. Its low-voltage operation reduces power consumption, making it ideal for power-sensitive applications.
Typical applications include DDR2 registered DIMMs, servers, workstations, and networking equipment where high memory capacity and reliability are required. The device is also used in embedded systems that demand robust memory interfaces. Its address-parity test feature is particularly valuable in mission-critical systems where data integrity is paramount.
When designing with this device, ensure proper decoupling of the VCC and VDDQ supplies, and follow the layout guidelines in the datasheet to minimize signal skew. The differential clock inputs should be routed with controlled impedance to maintain timing accuracy.
Drop-in alternatives for 74SSTUB32868 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
74SSTUB32868ZRHR
✅ Drop-In📋 Reference alternative (not in catalog)
74SSTUB32866
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
74SSTUB32868ZRHR
✅ Drop-In📋 Reference alternative (not in catalog)
74SSTUB32868ZRHR
✅ Drop-In📋 Reference alternative (not in catalog)
74SSTUB32868ZRHR
✅ Drop-In📋 Reference alternative (not in catalog)
74SSTUB32868 Maximum Ratings & Electrical Characteristics
| Function | 28-bit to 56-bit registered buffer with address-parity test |
| VCC Supply Voltage | 1.7 V to 1.9 V |
| VDDQ Supply Voltage | 1.7 V to 1.9 V |
| I/O Standard | SSTL_18 |
| Configuration | 1:2 configurable registered buffer |
| Parity Test | Address-parity test |
| Differential Clock | CK and CK# inputs |
| Reset Function | Yes |
| Package | 176-ball NFBGA (6x15 mm) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| Number of Pins | 176 |
74SSTUB32868 Pin Configuration
| Pin A1 | VCC — Core supply voltage |
| Pin A2 | GND — Ground |
| Pin B1 | CK — Differential clock input (positive) |
| Pin B2 | CK# — Differential clock input (negative) |
| Pin C1 | RESET# — Active-low reset input |
| Pin D1 | A0 — Address input 0 |
| Pin E1 | A1 — Address input 1 |
| Pin F1 | A2 — Address input 2 |
| Pin G1 | A3 — Address input 3 |
| Pin H1 | A4 — Address input 4 |
| Pin J1 | A5 — Address input 5 |
| Pin K1 | A6 — Address input 6 |
Typical Applications
74SSTUB32868 is suitable for 6 applications: DDR2 Registered DIMM, Server Memory Subsystem, Networking Equipment, Embedded Systems, Workstation Memory, Telecommunications Infrastructure.
DDR2 Registered DIMM
The 74SSTUB32868 is designed for DDR2 registered DIMMs, providing buffering for address and control signals. Its 1:2 configurable registered buffer topology allows one input to drive two outputs, reducing loading on the memory controller. Operating at 1.7V to 1.9V, it matches DDR2 I/O levels, ensuring signal integrity. The address-parity test feature enhances reliability by detecting parity errors on the address bus, which is critical for server and workstation memory modules.
Recommended
Server Memory Subsystem
In server memory subsystems, the 74SSTUB32868 buffers address and control signals between the memory controller and DRAM devices. Its low-voltage operation (1.7V to 1.9V) reduces power consumption, while the 176-ball NFBGA package saves board space. The address-parity test feature is essential for detecting data corruption in mission-critical server applications. The device supports high-speed DDR2 interfaces, ensuring reliable operation in demanding environments.
Recommended
Networking Equipment
Networking equipment such as routers and switches often require high-capacity memory modules. The 74SSTUB32868 provides reliable buffering for DDR2 memory, ensuring signal integrity at high speeds. Its 1:2 configurable registered buffer allows flexible fan-out, accommodating various memory configurations. The address-parity test feature helps maintain data integrity in network processing, where errors can lead to packet loss or corruption. The compact NFBGA package is ideal for space-constrained line cards.
Recommended
Embedded Systems
Embedded systems that require high memory bandwidth and reliability can benefit from the 74SSTUB32868. Its low-voltage operation (1.7V to 1.9V) is suitable for battery-powered or power-sensitive applications. The address-parity test feature provides an extra layer of data integrity, which is valuable in industrial control and medical devices. The 176-ball NFBGA package allows for compact PCB layouts, enabling smaller form factors in embedded designs.
Recommended
Workstation Memory
Workstations used for demanding applications like 3D rendering and scientific computing require high-capacity, reliable memory. The 74SSTUB32868 buffers address and control signals in DDR2 registered DIMMs, ensuring stable operation at high speeds. Its address-parity test feature detects errors that could corrupt computation results. The device's low-voltage operation reduces power consumption, contributing to overall system efficiency.
Recommended
Telecommunications Infrastructure
Telecommunications infrastructure, such as base stations and switches, relies on high-reliability memory subsystems. The 74SSTUB32868 provides robust buffering for DDR2 memory, with address-parity test to ensure data integrity in critical signaling paths. Its 1:2 configurable registered buffer supports flexible memory topologies, while the 176-ball NFBGA package offers a compact solution for dense line cards. The device operates at 1.7V to 1.9V, aligning with low-voltage memory standards.
Recommended
Recommended Products Summary
Engineering reference data for 74SSTUB32868 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | 74SSTUB32868ZRHR | 74SSTUB32866 |
|---|---|---|---|
| Package | 176-NFBGA (6x15) | 176-NFBGA (6x15) | 176-NFBGA (6x15) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Function | 28-bit to 56-bit registered buffer with parity test | Same | 28-bit to 56-bit registered buffer (no parity test) |
| VCC Range | 1.7V to 1.9V | 1.7V to 1.9V | 1.7V to 1.9V |
| I/O Standard | SSTL_18 | SSTL_18 | SSTL_18 |
| Configuration | 1:2 configurable | 1:2 configurable | 1:2 configurable |
| Parity Test | Yes | Yes | No |
| Differential Clock | Yes (CK, CK#) | Yes (CK, CK#) | Yes (CK, CK#) |
Key Differentiators
- Integrated address-parity test (vs 74SSTUB32866)
- 1:2 configurable registered buffer (vs 74SSTUB32866)
- Low-voltage operation (1.7V to 1.9V) (vs 74SSTUB32866)
Design Notes
Ensure proper decoupling of VCC and VDDQ supplies. Place 0.1uF ceramic capacitors close to each power pin, and a 10uF bulk capacitor near the device. The low-voltage operation (1.7V to 1.9V) requires stable supplies to maintain signal integrity.
Route differential clock inputs (CK and CK#) with controlled impedance (typically 50 ohms single-ended, 100 ohms differential) and matched lengths to minimize skew. Keep address and control traces as short as possible to reduce propagation delay and signal degradation.
Do not exceed the maximum VCC of 1.9V, as this can damage the device. Ensure the RESET# pin is properly pulled up during normal operation. Verify that the address-parity test feature is correctly configured to avoid false error detection.
Compliance Information
RoHS compliant per TI product page. Lead-free per TI datasheet. AEC-Q100 not applicable for this logic device.
