Other Parts Discussed in Thread: THS4541, , OPA857, TINA-TI, ADC32J45, THS4551
I have a question about THS4541 of ADC32J45EVM.
My customers are going to implement OTDR using the ADC32J45EVM.
What they refer to is TI Designs Optical Front-End System Reference Design.
Therefore, ADC32J45EVM input (Bch) was remodeled to the path using THS4541.
Assuming that it is input from OPA857, the constant was referred to p30 Figure 35.
We also performed simulation using TINA-TI.
However, VIN/P which could be confirmed on actual machine was different from simulation.
VIN = 1.83V
sim: VIN/P = 1.69 V
test: VIN/P = 1 V
Next, we compared the result of THS4541EVM with the simulation result of TINA-TI.
The result of the THS4541EVM test is the same as the simulation result.
Therefore, the THS4541EVM and TINA-TI determined that the simulation result was correct.
Subsequently, the input (Bch) of the ADC32J45EVM was modified to be the same as the THS4541EVM.
The results obtained are as follows.
(1) VIN = 1.83V
VIP/N = 1.89V
VIP/N = 2V
(2)VIN = Open
INN/P = 197mV
VIN/P = 771mV
INN/P = 500mV
VIN/P = 1.94V
Therefore, THS4541 of Bch thought that it is not working properly.
Next, I confirmed the THS4541 of ADC32J45EVM C ch.
Cch is an input that has never been remodeled, inputting a signal.
The input was Open, we confirmed the voltage of the THS4541 at the time of power-on.
INN = 36.92mV
INP = 70.8mV
VIN/P = 316mV
VOP = 993mV
VON = 910.56mV
INN = 110mV
INP = 211mV
VIN/P = 0.94V
VOP = 0.97V
VON = 0.97V
Could you tell me why the THS 4541is like this?
Why is the THS4541 EVM operating properly, but the THS4541 of the ADC32J45EVM does not work properly?
Why does not it work properly even on THS4541 that neither remodel nor input?
There are two ADC32J45EVM, but the same phenomenon is occurring in both.
Thank you for your cooperation.