Follow these instructions to improve the
performance and noise immunity of the LOG300:
- Provide a star connection
style supply for Freq_supply and VCC. This connection enables better noise
immunity and decoupling.
- Design Log_Inp, Log_Inm and
LNA_In traces with guard traces to improve immunity against noise pickup.
Use shielding when possible to improve radiated noise immunity.
- Place small capacitors on the
AFE and LNA enable pins to allow high-frequency noise to be grounded before
entering into the device.
- As per Section 7.3.2 the impedance seen
from Log_Inp and Log_Inm to the external circuit must be the same. The trace
length to Log_Inp and Log_Inm must be kept similar to keep impedance
matched.
- Keep minimal capacitance at
the Freq_Out pin either by placing the load circuit close to the pin or by
removing the analog ground plane under the output trace or both.
- Dedicate one layer of the PCB
for a solid analog ground pour to terminate all the capacitors used across
the pins using sufficient vias.