Part Number: DS15BR401
Other Parts Discussed in Thread: SN65LVDS250, DS92LV040A, DS92001
Hi support-team,
We used two of these devices in a circuit to become bi-directional. We have signals that are AC-coupled and another circuit with DC-coupling (like in the picture).
The problems only occur with DC-coupling.
Two inputs with an identical signal are fed in (2x Differential Signals DS) and the device outputs two different DS levels. Once as LVDS with ~700mV Vpp (signals B_7_IO_B2B) and once with
~200mV Vpp (signals B_10_IO_B2B).
Small list of facts:
-Signal generator sends 800mV Vpp to the inputs (signals B_7_IO_Buff and B_10_IO_Buff)
-The DS15BR401TSQ/NOPB are powered by 3V3 and are mutually locked (Output_Enable_2_Class_B_LVTTL ≠ INV_Output_Enable_2_Class_B_LVTTL)
-The 100R are terminating resistors
-A conversion to AC-coupling (100nF capacitors in series at the outputs) solves the problem but is not desired.
The oscilloscope image (see appendix) shows the two signal pairs (B_7_IO and B_10_IO respectively) that were measured on the left side of the circuit diagram at the respective terminating resistor. The amount of the voltage level at B_10_IO is only about 100mV (corresponds to EyeHeight 200mV), which according to the data sheet should have at least 250mV (corresponds to EyeHeight 500mV).
What could be the cause of the lower voltage swing in the B_7_IO_B2B signal pair?
n?
