Hi, I am using ADA4528-2ACPZ in a design where The exposed pad has been connected to ground. Data sheet suggest connecting the pad to V- or to leave it opened. The circuit is simply used as a buffer (non inverting gain 1). However the input voltage is attenuated at its output to +/- 40mV peak. In put is +1V peak sinewave with frequencies swept from 1 to 1000Hz.
I have got the ground connecting vias disconnected (by pcb manufacturer using back-drilling technique used on high speed pcb designs). The results is the same. The power rails are +/- 2.5V.
Could the cip be damaged?
With thanks and regards, Vic
Have you tried isolating the ADA4528-2 on its own to see whether you get the same response? Let me know how this works out.
Hi Donnie, It happens that the output is run through :Coaxial Connectors Micro Switch PCB Strt Jack Surf Mnt 50 ohm (Amphenol 902-9235), thus the measurement has been done without a load or in situ with 8k resistor connected to ADA4528 amplifier as part of LPF. Checked out the resistivity path to ground and is about 40K. Kind regards, Vic
Could you try probing the outputs of the ADA4528 directly? The attenuation could be a result of an impedance mismatch between the PCB coaxial jack and the scope/measuring equipment that you're using.
If you could provide a sample schematic or connection diagram between the ADA4528 and the measuring equipment you're using then that would greatly help.