What this transimpedance amplifier does
The MAX40658ETA+T from Maxim Integrated is a single-channel transimpedance amplifier designed to convert photodiode current into a differential voltage output. Its 520 MHz gain-bandwidth product supports high-speed optical receivers, LIDAR front-ends, and fiber-optic links where bandwidth and low noise are critical. The differential output drives ADCs or subsequent stages with common-mode rejection, reducing susceptibility to ground bounce and coupled noise on the board.
520 MHz GBW — what it means for the link budget
A 520 MHz gain-bandwidth product sets the usable transimpedance gain before the closed-loop bandwidth rolls off. For a typical photodiode capacitance of 1 pF, this part maintains a flat gain up to several hundred MHz, which is the difference between a clean eye diagram and a closed one in 1 Gbps optical links. The single 3.3 V supply simplifies rail design in systems that already run 3.3 V logic and FPGAs.
Package and mounting
The 8-TDFN (3x3) footprint keeps the signal path short — critical for preserving bandwidth and minimizing parasitic inductance from the photodiode to the input. Surface-mount assembly is standard for reflow processes. The exposed pad must be soldered to a ground plane for thermal and electrical performance; a via array under the pad helps pull heat into the inner layers.
Temperature range and environment
Rated for -40°C to 85°C, this amplifier suits industrial optical sensors, outdoor fiber-to-the-antenna equipment, and automotive LIDAR modules that see under-hood or cabin temperature swings. The 21 mA supply current is typical for a wideband TIA — budget for it in the power tree alongside the photodiode bias and ADC supply.
Lifecycle and sourcing
Maxim lists the MAX40658ETA+T as Active and ROHS3 compliant.