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AMC1336-Q1: output is abnormal

Part Number: AMC1336-Q1
Other Parts Discussed in Thread: AMC1336,

Dear team,

When the AMC1336QDWVRQ1 is used for voltage sampling, the output should only flip after the rising edge (clock 20MHz), that is, the narrowest output pulse should be 50ns, but we found the following abnormal flip during testing, the value read by the MCU will be varied from 0V to a few hundred volts of negative voltage, please help to analyze, thank you~
The dark blue channel 1 is the clock signal, and the sky blue channel 2 is the AMC1336 output signal

This fault occurs occasionally at low temperatures of -20 degrees. When we change the resistor marked in green from 46.4ohm to 11ohm, we can reoccur this fault at room temp.

When we change below 22uF marked in red to 47uF and keep the resistor marked in green at 46.4ohm, the fault will disappear.

Thanks & Best Regards,


  • Hi Sherry,

    The most likely cause is that the clocking signal is outside of spec for either the AMC1336-Q1 or the digital filter that the clock and data are being fed to over temperature. The AMC1336-Q1 requires a minimum clock duty cycle of 40% with a high level of 0.7xDVDD, which would be 3.5V for DVDD=5V. From the picture I cannot tell if these specs are being violated or not, but the clock signal is certainly not ideal. The resistor R2412 should be placed close to the clock output and the capacitor C2406 should be placed close to the clock input of the AMC1336-Q1. We typically recommend RC values 50ohm and 10pF for digital data lines. 

    What does the clock signal look like with the 11ohm resistor?  

    Do you mean 22pF to 47pF? 

    Can the test be re-created using a clocking signal from a signal generator?