Texas Instruments recommends a layout that minimizes parasitic capacitance and inductance, with a solid ground plane and short traces. A 4-layer PCB with a dedicated analog ground plane is recommended. See the TI application note 'AN-1187: PCB Layout for Switching Regulators' for more details.
The gain resistors (Rf and Rg) should be chosen based on the desired gain and bandwidth of the amplifier. A higher gain requires smaller resistors, but may also increase noise and reduce stability. TI provides a gain resistor calculator tool to help with this selection.
The maximum power dissipation of OPA342NA/3KG4 is 1.4W, which is limited by the package thermal resistance (θJA) of 125°C/W. The actual power dissipation should be calculated based on the operating conditions, including supply voltage, output current, and ambient temperature.
Yes, OPA342NA/3KG4 can be used as a unity-gain buffer by connecting the output directly to the inverting input (i.e., Rf = 0Ω and Rg = ∞Ω). However, this configuration may reduce the stability and bandwidth of the amplifier, and may require additional compensation capacitors.
To protect OPA342NA/3KG4 from EMI, use a shielded enclosure, keep the amplifier away from high-frequency sources, and use bypass capacitors (e.g., 10nF to 100nF) between the power supply pins and ground. Additionally, use twisted-pair wiring and keep the input and output traces separated to minimize radiation.
OPA342NA/3KG4 datasheet
by Texas Instruments
