Printed circuit board layout considerations

TS616

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Printed circuit board layout considerations

In the ADSL frequency range, printed circuit board parasites can affect the closed-loop

performance.

The use of a proper ground plane on both sides of the PCB is necessary to provide low

inductance and a low resistance common return. The most important factors affecting gain

flatness and bandwidth are stray capacitance at the output and inverting input. To minimize

capacitance, the space between signal lines and ground plane should be maximized.

Feedback component connections must be as short as possible in order to decrease the

associated inductance which affects high-frequency gain errors. It is very important to

choose the smallest possible external components—for example, surface mounted devices

(SMD)—in order to minimize the size of all DC and AC connections.

6.1

Thermal information

The TS616 is housed in an exposed-pad plastic package. As described in Figure 55, this

package has a lead frame upon which the dice is mounted. This lead frame is exposed as a

thermal pad on the underside of the package. The thermal contact is direct with the dice.

This thermal path provides an excellent thermal performance.

The thermal pad is electrically isolated from all pins in the package. It must be soldered to a

copper area of the PCB underneath the package. Through these thermal paths within this

copper area, heat can be conducted away from the package. The copper area

must be

Figure 55.

Exposed-pad package

Figure 56.

Evaluation board

Cross Section View

Bottom View

Side View

DICE

1

Cross Section View

Bottom View

Side View

DICE

1