I am having trouble with the 7107 IC. I have 5 of them on my PCB: 3 being used as current measurement and the other 2 are being used as a voltage measurement.
Only one of the 5 are displaying readings on the 7-segment display (may not be calibrated correctly but is showing something). The other 4 are the 7-segments are all blank. I have attached the circuit diagram below.
I have check the all 7-segments are working with the test feature on pin 37. The clock is oscillating at 40-43KHz (check with oscilloscope). The difference I am seeing with respects to the one working versus the others is that 100nF connected to cref+ and cref- on the working unit is pulsing about 1.3V, the others have no pulse or very low (mV) pulses.
I really starting to believe I have a bad batch of IC's. Please provide any tips or recommendations. Thanks in advance.