GX76476 - 4x64GBd Linear Differential I/O Driver | Renesas
MPN： GX76476 ✓ 啟用中GX76476 概覽
A linear differential driver (LDD) is a specialized analog amplifier that conditions high-speed electrical data before it reaches an optical modulator, where it converts voltage swings into optical intensity modulation. Linear drivers sit in the signal chain between the DSP/SerDes and the optical subassembly; in the broader IC taxonomy they belong to the high-speed amplifier family, which is itself a branch of amplifier ICs and interface ICs. The GX76476's architecture is tailored for the demanding linearity, gain, and power budget of 400G/600G pluggable modules rather than for general-purpose amplification.
Key features include four independent 64 GBaud driver channels, integrated per-channel bias-T and amplitude control via SPI, single-die integration that minimizes channel-to-channel skew, and a low-power architecture compatible with QSFP-DD and OSFP thermal envelopes. Each lane supports AC-coupled differential signaling, and the integrated SPI allows per-lane DC settings such as swing, de-emphasis, and bias without external DACs.
The architecture uses matched differential pairs with on-chip 60 ohm terminations and adjustable gain stages. The single-die integration keeps channel-to-channel skew below the values achieved with four discrete drivers, which is critical for coherent optical modules that depend on tightly-matched analog paths across all four lanes.
Typical applications include 400G/600G coherent QSFP-DD and OSFP transceivers, metro and long-haul DWDM line-side pluggable modules, integrated transmitter sub-assemblies combining driver + MZM/EML, and OIF-compliant CFP2-DCO analog front ends. The 64 GBaud per-lane capability also supports emerging 1.6T architectures built from 4x100G or 8x100G channel groupings.
When designing with the GX76476, plan input AC-coupling, output bias-T networks, and a clean SPI isolator. The driver dissipates significant power at full per-lane swing; thermal management of the QSFP-DD housing must be considered from the start of the PCB layout.
This page synthesizes Renesas product information, distributor pricing, and application context to support engineers evaluating the GX76476 for 400G/600G optical transmitter designs.
直接替換替代品，適用於 GX76476 — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： GX76476 （相同外形與佔位） — 差異在於 Control Interface, Application Domain, Driver Type, Integration, Product Type.
GX76476-DNT
✅ 直接替換聯絡詢價
查看資料表 →GX76476-DNT-EVB
✅ 直接替換聯絡詢價
查看資料表 →GX76476 最大額定值與電氣特性
| Product Type | Quad-channel linear differential I/O driver |
| Number of Channels | 4 |
| Data Rate per Lane | 64 GBaud |
| Input Interface | 100 ohm differential, AC-coupled |
| Output Termination | 60 ohm differential |
| Control Interface | SPI (per-channel DC controls) |
| Integration | Single-die (all 4 lanes + SPI on one die) |
| Target Application | 400G/600G optical transmitter SFF modules |
| Network Reach | Metro and long-haul |
| Form Factor Compatibility | QSFP-DD / OSFP coherent pluggable modules |
| Power Profile | Low-power architecture |
| Differential Signaling | AC-coupled differential input, differential output |
| Document Type | Short-form datasheet |
| Document Release | 2023-09-28 (Mouser hosting) |
GX76476 standard 腳位配置指南
GX76476（standard 封裝）的腳位配置。 此類比元件具有輸入、輸出與電源腳位。偏移歸零、補償與致能腳位配置請參閱製造商資料表。適用於訊號調理與放大器電路。
無詳細腳位定義資料： GX76476.
請參閱 資料表 以查看完整腳位配置。
典型應用
GX76476 適用於 7 應用s: 400G QSFP-DD Coherent Transmitter, 600G Integrated Transmitter Sub-Assembly, Metro DWDM Line-Side Pluggable, Long-Haul High-Power Transmitter Modules, 1.6T Plug-In Architecture Prototyping, OIF 400ZR/800ZR Line-Side Test Bed, Datacenter Edge Aggregation Interfaces.
400G QSFP-DD Coherent Transmitter
The GX76476 is purpose-built for 400G QSFP-DD coherent pluggable modules where four lanes of 64 GBaud signaling must be tightly matched. Its single-die integration keeps inter-lane skew to a minimum, which is essential for coherent modulation formats that depend on phase alignment across lanes. Each lane's 100 ohm AC-coupled input matches standard SERDES outputs, while the 60 ohm differential output directly drives an EML or MZM optical subassembly through a bias-T network. The integrated SPI block exposes per-lane swing, de-emphasis, and bias control without external DACs, trimming the QSFP-DD BOM and host-software overhead.
推薦
600G Integrated Transmitter Sub-Assembly
At 600G aggregate rates, the GX76476's four 64 GBaud lanes deliver the bandwidth headroom for 4x150G-class PAM4 or 4x150G coherent channelization within a single driver IC. Integrated SPI control enables per-lane optimization of swing and de-emphasis required to hit tight TDECQ masks on heavily-equalized optical links. The low-power architecture simplifies thermal management at the 600G OSFP envelope compared with discrete four-channel driver stacks, while single-die integration removes the lane-to-lane mismatch that plagues discrete builds.
推薦
Metro DWDM Line-Side Pluggable
For metro DWDM line-side pluggable optics, the GX76476's 64 GBaud per-lane capability supports 100G and 200G wavelength channels that aggregate into 400G and 800G coherent carriers. The 100 ohm AC-coupled input preserves isolation between the SERDES reference and the driver's bias network, while the 60 ohm differential output couples cleanly into lithium-niobate or silicon-photonics IQ modulators. SPI bias control delivers the fine-tuning needed to keep transceiver TDECQ and OSNR metrics compliant with MSAs such as OpenZR+.
推薦
Long-Haul High-Power Transmitter Modules
Long-haul pluggables depend on driving optical sub-assemblies with maximum linearity and minimum added jitter, which is precisely the design point of the GX76476. Four integrated lanes operating at 64 GBaud into a 60 ohm differential load enable high OSNR modulation when paired with external drivers; SPI per-lane gain shaping balances dynamic range against output swing for both high-bias and low-bias optical setups. Single-die integration keeps the channel-response deviation below what is achievable with four discrete drivers, preserving the modulation accuracy needed for thousands of kilometres of fiber.
推薦
1.6T Plug-In Architecture Prototyping
Although 1.6T shipping modules will use 200G/lane class devices, the GX76476 serves as a proven 4-lane building block for prototypes exploring new AECs and CRX topologies. Its SPI-driven per-lane control lets designers sweep both swing and de-emphasis in software, enabling rapid OEO/converter characterization. QSFP-DD and OSFP reference designs based on the GX76476-DNT-EVB accelerate the roadmap from 400G/600G production today to 1.6T pilot deployments in the same thermal and mechanical envelopes.
推薦
OIF 400ZR/800ZR Line-Side Test Bed
The GX76476 supports OIF 400ZR and 800ZR implementation agreements, which spec 60 Gbaud and 64 Gbaud coherent signaling on four lanes. Engineers building test beds can use the GX76476-DNT-EVB as a hardware baseline to characterize SERDES-driver-analog performance with OIF-defined test patterns and masks. On-board SPI tuning enables iterative optimization for analog impairments common in coherent pilots, including skew compensation and per-lane amplitude correction.
推薦
Datacenter Edge Aggregation Interfaces
Aggregation switches at the datacenter edge increasingly deploy 400G uplinks via QSFP-DD coherent pluggables, where the GX76476 drives the linear optical interface. Quad-channel single-die integration lowers host-switch BOM, and SPI-driven per-lane control enables remote calibration through CMIS. Low-power architecture keeps the QSFP-DD case temperature within MSA-mandated limits, while the 100 ohm differential inputs ease board layout with standard high-speed SERDES channels on the host switch ASIC.
推薦
推薦產品摘要
工程參考資料，適用於 GX76476 — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | GX76476-DNT | GX76476-DNT-EVB |
|---|---|---|---|
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics |
| Channels | 4 lanes | 4 lanes | 4 lanes |
| Data Rate per Lane | 64 GBaud | 64 GBaud | 64 GBaud |
| Input Interface | 100 ohm differential, AC-coupled | 100 ohm differential, AC-coupled | 100 ohm differential, AC-coupled |
| Output Termination | 60 ohm differential | 60 ohm differential | 60 ohm differential |
| Control Interface | SPI | SPI | SPI |
| Integration | Single die (4 lanes + SPI) | Single die | Single die on EVB |
主要差異化特點
- Quad-channel integration on a single die (對比Discrete 4-driver design)
- Integrated SPI for per-lane DC control (對比External DAC control)
- 100 ohm AC-coupled input directly matched to SERDES (對比Non-standard input impedance)
設計說明
Place AC-coupling capacitors directly at the GX76476 differential input pins and at the SERDES-side to maintain impedance continuity through the coupling. Use a 50 ohm grounded coplanar waveguide (GCPW) or stripline structure with 100 ohm differential impedance on the input side, and a 60 ohm differential output network terminated through the bias-T into the optical sub-assembly. The Renesas short-form datasheet does not specify the package outline; contact Renesas for the mechanical drawing before final layout. Estimated: target 0.18 dB/in loss budget on the output side to preserve 64 GBaud eye margins.
Although Renesas markets the GX76476 as low-power, dissipating four lanes of 64 GBaud linear driver into QSFP-DD or OSFP thermal envelopes still demands strong copper thermal relief below the die. Per the chip's single-die integration, expect the entire device's dissipation to concentrate in one package heat-spreader footprint; use thermal vias to spread heat into the host PCB inner planes. Estimated: total power budget in the 4W-6W range at 64 GBaud full swing, justifying careful 3D thermal simulation before release.
Do not bypass the SPI DC-control block on production modules. Although static resistor-divider trimming may appear simpler, the SPI serves both production calibration and in-field compensation for aging optical sub-assemblies, especially in long-haul coherent links. Also verify that the AC-coupled input common-mode voltage is within the datasheet's allowed range before enabling the serializer; out-of-range CM bias is a frequent cause of dropped links at the pluggable module's host switch.
合規資訊
The Renesas GX76476 short-form datasheet released 2023-09-28 does not include explicit compliance statements. Engineers should request the full datasheet from Renesas or review the RoHS/REACH certificates at https://www.renesas.com for definitive declarations.
