LTC6563 Amplifier

ADI's LTC6563 is a low-noise four-channel TIA with 600 MHz bandwidth. The LTC6563 TIA’s low noise, wide linear range, and low power dissipation are ideal for LIDAR receivers using avalanche photodiodes (APDs) and photodiodes (PDs). The amplifier features selectable 22.2 kΩ/16.7 kΩ/11.1 kΩ/5.55 kΩ transimpedance gain (RT) and 90 μA linear input current range. Using an APD with a total input capacitance of 0.5 pF, the input current noise density is 1.8 pA/√Hz at 100 MHz and 3.7 pA/√Hz at 600 MHz. The LTC6563 consumes between 194 mW and 325 mW on a 3.3 V supply depending on output mode. An internal 4-to-1 MUX simplifies the system design. In addition, external multiplexing capability allows channel expansion up to 64 channels, saving space and power. Fast overload recovery and fast channel switchover make the LTC6563 well suited for LIDAR receivers with multiple APDs. The built-in high-speed differential ADC driver can swing as much as 2 V_P-P while driving into 100 Ω external differential load.

Demonstration circuit EVAL-LTC6563-TQFN features the LTC6563 four-channel TIA with output multiplexing. This demo kit, EVAL-LTC6563TQFN-EZKIT shipped along with the SDP-K1 controller board, has four installed single APDs, allowing optical testing of the TIA functionality. Electrical testing using an external lab pulse generator as the input current pulse is also possible with small board modifications.

Features

• 600 MHz bandwidth and low noise enable narrower LIDAR pulse widths down to 2 ns
• Integrated DC cancellation and TILT function extend the linear input range to accommodate photosensors
• Integrated high-speed ADC driver reduces signal path complexity