Hello,
I am using the TI MPY634 in a standard multiplier/squarer configuration. I have included photos of my schematic and breadboard:
At low frequencies (<100 kHz), it behaves as expected. However, at higher frequencies, there is a significant growth of a DC offset in the output.
Here are some sample shots of the reading I am getting on the scope for demonstration:
Channel 1 is the output of the multiplier/squarer, channel 3 is the input straight from the function generator for reference.
Driven at 100 kHz (Normal)
Driven at 1 MHz (small DC offset)
Driven at 2 MHz (larger DC offset, notice the increase in Ch1 mean, the signal is barely visible at the top of the screen)
In general the DC offset seems to grow with frequency above 100 kHz.
Is there something that I am missing? from what I understand this multiplier should operate well at these frequencies as it has 10 MHz bandwidth and I am not using a feedback attenuator. The DC offset is greater than the specification says the input offset voltage should max out at 100 mV when being used at 2 MHz so I do not think that this is the cause. Also, my application is not well suited for trimming as I need to read out the proper DC level of the multiplied signal at various frequencies.
