11.1 Layout Guidelines
To achieve the levels of high performance of the TLV246x-Q1, follow proper printed-circuit board design techniques. A general set of guidelines is shown in the following list.
- TI recommends using a ground plane on the board to provide all components with a low inductive ground connection. However, in the areas of the amplifier inputs and output, the ground plane is removed to minimize the stray capacitance.
- Use a 6.8-μF tantalum capacitor in parallel with a 0.1-μF ceramic capacitor on each supply terminal. It may be possible to share the tantalum among several amplifiers depending on the application, but a 0.1-μF ceramic capacitor must always be used on the supply terminal of every amplifier. In addition, the 0.1-μF capacitor must be placed as close as possible to the supply terminal. As this distance increases, the inductance in the connecting trace makes the capacitor less effective. The designer must strive for distances of less than 0.1 inches between the device power terminals and the ceramic capacitors.
- TI does not recommend using sockets. The additional lead inductance in the socket pins often leads to stability problems. For best implementation, solder surface-mount packages directly to the printed circuit board.
- Optimum high performance is achieved when stray series inductance is minimized. The circuit layout must be made as compact as possible, which minimizes the length of all trace runs. Take care to pay attention to the inverting input of the amplifier; keep the length as short as possible. This minimizes stray capacitance at the input of the amplifier.
- TI recommends using surface mount passive components for high performance amplifier circuits. Stray series inductance is reduced because of the low lead inductance of surface mount components.. The small size of surface-mount components leads to a compact layout, which minimizes stray inductance and capacitance. TI recommends that lead lengths be kept as short as possible if leaded components are used.