at the moment were busy designing a OTDR application. Because of the high trans impedance gain we thought of LTC6560 which is suitable for LIDAR application.
Datasheet on page 14 states:
So we decided to use a positive biased ADP which anode is connected in direction of TIA input in combination with a capacitor. But up to now there is no chance to get it work. It doesn't matter if we use ac decoupling capacitor or not the resulst stays the same.
When using LTSPICE I recognized the same effect. When changing input current into positive dircetion there is no chance to get the output of LTC6560 below 0,9V.
This leads to the follwing questions:
- Did misunderstand the information in the datasheet quoted above?
- Is there a contradiction within datasheet because later on datasheet explains something about limited ability of sinkung current or is 0,9V the lowest possible voltage at the output?
Is there any hint how to get setup work without changing APD power supply to negative?
Thanks in advance