Hi Team,
We are using OPT3101 for TOF based 40m ranger module. We are referring to the document "Extending the Range of OPT3101 Systems".
In order to meet our requirement of a 40-meter range, we are using two VCSEL (MFG PN: VD-0850C-200M-3A-2A0 ) sources having 2.4V Forward Voltage.
But we have some concerns about the series connection of the VCSEL. Please refer to the attached snapshot from the mentioned doc.
As per the OPT3101 datasheet, the TX0 pin needs to have a Voltage swing of 0.7V to 3.6V.
We are planning to connect both VCSELs to 6V serially so that during on time TX0 pin of OPT3101 will get a 1.2V and the circuit will work.
But at the time of off condition, I hope the DC bias current will flow to the TX0 pin. DC bias current is programmable from 0.5mA to 7.5mA .
But To make at least 3.6V at TX0 pin near 20 mA need to flow through the VCSEL and the TX0 Pin. So that 1.2V drop will come across one VCSEL (This is according to the V-I graph of the VCSEL) and 3.6V on the TX0 pin. Unfortunately, DC bias current of 20mA is not programmable.
Could you please share your thoughts on this and also recommend possible solutions for the same.
