Other Parts Discussed in Thread: LMH0340
We are using the LMH1983 the generate SDI timing for an FPGA driving a camera sensor and outputting SDI signal through an LMH0340.
All clock sources (1 to 3) are fed to the FPGA through the crosspoint and ClkOut2. And all the TOF (1 to 3) are fed to the FPGA.
Application configures the clock generator to output the appropriate clock source and TOF signal corresponding to the wanted output format.
However, in freerun, we have observed that the LMH1983 randomly skips some beats on TOF2 (or TOF3) when the component is "hot". By hot I mean package temperature above 60-65°C according to a thermocouple epoxy bonded to it. There is no NO_LOCK pulse though, and TOF1 (always on) is still pulsing regularly.
This cause our camera to stop streaming until the next TOF pulse (FPGA does not trigger the sensor to produce a new image, and SDI output stage does not output an image).
On the image below, running in PAL (625i50) :
- in green : TOF2 (25Hz, for every other image)
- in blue : NO_LOCK
- in purple : FPGA TOF output (50Hz, for every image)
There is a pulse missing on the TOF2 signal resulting (with some latency) to a long pulse in the FPGA generated TOF signal
