Part Details for LM4940TSX/NOPB by Texas Instruments

A good PCB layout for the LM4940TSX/NOPB involves separating the analog and digital grounds, using a star-ground configuration, and placing the device close to the power supply. Additionally, it's recommended to use a 4-layer PCB with a dedicated ground plane to reduce noise and EMI.

To ensure proper biasing, make sure to follow the recommended voltage supply and biasing scheme outlined in the datasheet. This typically involves connecting the VCC pin to a stable voltage source, and the BIAS pin to a voltage divider network that sets the desired output voltage.

The LM4940TSX/NOPB has a maximum junction temperature of 150°C. To ensure reliable operation, it's essential to provide adequate heat sinking, such as a thermal pad or heat sink, and to follow proper PCB design guidelines to minimize thermal resistance. Additionally, consider using thermal interface materials to improve heat transfer.

To filter out noise and ripple, you can use a combination of capacitors and resistors to create a low-pass filter. A common approach is to use a 10uF capacitor in parallel with a 10Ω resistor, followed by a 100nF capacitor in parallel with a 100Ω resistor. This helps to attenuate high-frequency noise and ripple.

To ensure EMI and EMC compliance, follow proper PCB design guidelines, such as using a shielded enclosure, minimizing trace lengths, and using EMI filters or common-mode chokes. Additionally, consider using a metal shield or screen to enclose the device, and ensure that the device is properly grounded to prevent radiation.