Why Semtech is reserving SiGe capacity for faster interconnects
Illustrative image: Maxence Pira on Unsplash
Semtech’s expanded agreement with Tower Semiconductor concerns the analogue devices that sit between digital processing and the physical communication link.
Semtech is investing in dedicated silicon-germanium capacity across Tower’s fabs in the United States, Israel and Japan. The arrangement covers a portfolio that includes transimpedance amplifiers, laser and modulator drivers, and linear equalizers for optical and copper interconnects.
These functions have different jobs. A transimpedance amplifier converts the photodetector’s current into a usable voltage signal at the receiver. Drivers provide the electrical signal required by the optical transmitter. Equalizers compensate for frequency-dependent losses in electrical channels.
The process requirements consequently differ from those of a large digital processor. High-frequency analogue performance, noise and linearity matter alongside integration density.
Tower’s SiGe BiCMOS platform combines high-speed bipolar devices with CMOS circuitry and passive components. Its published offering includes silicon-germanium heterojunction bipolar transistors with transition and maximum oscillation frequencies of 340/450 GHz and beyond. Those transistor figures are process characteristics, not the data rate of a finished transceiver. Tower identifies its SBC18H5 volume-production process with optical and copper transceiver functions and networks reaching 1.6 Tb/s and beyond.
The agreement links that technology roadmap to manufacturing capacity. Tower and Semtech describe support for today’s 800G and 1.6T products and progression towards 3.2T interconnects. Their collaboration also produced Semtech’s 224 Gb/s-per-lane transimpedance-amplifier family for linear pluggable optics.
Geographic distribution provides more than one manufacturing location, but it remains a relationship with one foundry partner. The arrangement should therefore be understood as multi-region capacity planning rather than an announcement of interchangeable second-source suppliers.
Its significance lies in connecting future product programmes to reserved analogue manufacturing capacity. Faster optical modules require those specialised front-end devices as well as the digital silicon that supplies their data.
