GX76476 - 4x64GBd Linear Differential I/O Driver | Renesas
MPN: GX76476 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $171.12 | $171.12 |
| 10 | $162.5 | $1,625.00 |
| 100 | $148.75 | $14,875.00 |
| 500 | $132.4 | $66,200.00 |
| 1,000 | $119.9 | $119,900.00 |
GX76476 Overview
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.
Drop-in alternatives for GX76476 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with GX76476 (same form factor and footprint) — differing in Control Interface, Application Domain, Driver Type, Integration, Product Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
GX76476-DNT
✅ Drop-In✓ In Stock
$265.55 / Unit
View Datasheet →GX76476-DNT-EVB
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →GX76476 Maximum Ratings & Electrical Characteristics
| 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 Pin Configuration Guide
Pin configuration for GX76476 (standard package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for GX76476.
Refer to the datasheet for full pin configuration.
Typical Applications
GX76476 is suitable for 7 applications: 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.
Recommended
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.
Recommended
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+.
Recommended
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.
Recommended
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.
Recommended
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.
Recommended
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.
Recommended
Recommended Products Summary
Engineering reference data for GX76476 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | 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 |
Key Differentiators
- Quad-channel integration on a single die (vs Discrete 4-driver design)
- Integrated SPI for per-lane DC control (vs External DAC control)
- 100 ohm AC-coupled input directly matched to SERDES (vs Non-standard input impedance)
Design Notes
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.
Compliance Information
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.
