DDRx Data Buffer (DB) for LRDIMM

JEDEC-Compatible DQ/DQS Buffering for High-Capacity Load-Reduced DIMMs

The Deep-I DDRx Data Buffer (DB) is a JEDEC DDR5DB-compliant bidirectional data buffer designed for DDR5 and DDR4 LRDIMM applications. The DB isolates the DQ/DQS data path so the host memory controller does not directly see the large aggregate capacitive load of multiple DRAM devices and ranks. A DDR5 LRDIMM is equipped with one RCD and 10 DBs (5 per subchannel), each featuring a dual 4-bit host bus interface and a dual 4-bit DRAM interface connecting to two x4 DRAMs, enabling higher memory capacity, robust signal integrity, and maximized channel eye opening through capacitive load reduction, data alignment, and signal recovery.

>9600 MT/sMax Transfer Rate
DDR5DBJEDEC Compatible
10 DBsPer LRDIMM (5/Ch)
Dual 4-bitHost & DRAM I/F
DFESignal Recovery
BCOMRCD Sideband Control
Si-ProvenVerified Design
2× Capacityvs RDIMM
>9600 MT/sMax Transfer Rate
DDR5DBJEDEC Compatible
10 DBsPer LRDIMM (5/Ch)
Dual 4-bitHost & DRAM I/F
DFESignal Recovery
BCOMRCD Sideband Control
Si-ProvenVerified Design
2× Capacityvs RDIMM

Deep-I DDRx Data Buffer Architecture

Bidirectional DQ/DQS data buffer isolating host IMC from DRAM loading,
controlled by RCD via BCOM sideband bus for coordinated LRDIMM operation.

Host-Side DQ/DQS Interface

Dual 4-bit bidirectional host bus with DQS strobes. VDD-terminated drivers present controlled impedance to host IMC.

Host Interface

DRAM-Side DQ/DQS Interface

Dual 4-bit interface to two x4 DRAMs per DB. DQS regeneration and capacitive load reduction for max speed.

DRAM Interface

Signal Recovery & DFE

Data alignment and DFE on both host and DRAM interfaces maximize eye opening at high data rates.

Equalization

BCOM Control & ZQ Cal

BCOM sideband from RCD for coordinated control. Dedicated ZQ calibration and parity error alert.

Sideband Control

DB System Architecture on LRDIMM

10 Data Buffers isolate DQ/DQS between host IMC and DRAM ranks for maximum capacity and signal integrity

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Key Benefits

Si-proven data buffer chip enabling 2× capacity over RDIMM with maximum speed

📈

2× Memory Capacity

Enables 2× memory capacity vs RDIMM by isolating DRAM loading for higher density without signal degradation.

👁️

Maximized Eye Opening

Load reduction, data alignment, and signal recovery maximize eye opening at full speed.

Si-Proven & JEDEC-Compatible

JEDEC DDR5DB01 compliant. Real Silicon verified. Optimized RCD/PMIC/SPD interoperability.

Key Features

Advanced bidirectional buffering with coordinated RCD sideband control

🔬

DQS Regeneration & DFE

Differential DQS strobes sample DQ inputs and are regenerated for driving the opposite side. DFE on both host and DRAM interfaces enables data rates beyond 9600 MT/s.

📡

BCOM Sideband from RCD

BCK/BCS_n/BCOM[3:0] sideband bus from RCD coordinates DB operating modes: normal, training, power-down, and loopback. BCKE and BODT pins for clock enable and on-die termination control.

🔧

ZQ Cal & Parity Alert

Dedicated ZQ calibration pins for impedance matching. Parity error alert support for data-path reliability. Internal control word registers for flexible device configuration.

Product Comparison

DDR5 Data Buffer chip portfolio at a glance

DDRx Data Buffer Comparison

Speed grade evolution from DB01 to MDB

Specification
DB01
DB02
DB03
MDB (MRDIMM)
Transfer Rate
≤ 6400 MT/s
≤ 8800 MT/s
≤ 9600 MT/s
12800+ MT/s
Interface
Dual 4-bit bidir
Dual 4-bit bidir
Dual 4-bit bidir
Multiplexed
DFE
Host side
Host + DRAM
Host + DRAM
Advanced
DBs / LRDIMM
10 (5/sub-ch)
10 (5/sub-ch)
10 (5/sub-ch)
10 (MDB)
Bandwidth
Baseline
+35% vs DDR4
+35% vs DDR4
2× native DRAM
Si-Proven
✔ Yes
✔ Yes
◐ Sampling
◐ In Dev

From Specification to Si-Proven DB

Deep-I DB is designed, verified, and characterized for first-time-right LRDIMM integration.

Phase 1

JEDEC DDR5DB Specification Analysis

DDR5DB01 standard analysis. DQ/DQS interface, BCOM protocol, ZQ calibration, RCD coordination.

Phase 2

TX/RX & DFE Circuit Design

VDD-terminated drivers, DQS regeneration, DFE equalization, ZQ impedance calibration.

Phase 3

BCOM Integration & Layout

BCOM receiver integration, control registers, optimized 10-DB LRDIMM layout with SI/PI.

Phase 4

Silicon Verification & LRDIMM Qualification

Real-Si fabrication. RCD+DB chipset validation, LRDIMM characterization, multi-vendor DRAM compatibility.

Visualize Your Idea

From JEDEC specification to Si-proven Data Buffer — see Deep-I's DB in action.

Ready to Integrate Data Buffer?

Contact our technical team to discuss your LRDIMM requirements and discover how Deep-I's JEDEC-compatible DB can accelerate your high-capacity server memory development.