ADRF6820ACPZ-R7 datasheet(29/45 Pages) AD

29 / 45 page

Data Sheet

ADRF6820

Rev. C | Page 29 of 45

LAYOUT

Careful layout of the ADRF6820 is necessary to optimize

performance and minimize stray parasitics. The ADRF6820

supports two RF inputs; therefore, the layout of the RF section

is critical in achieving isolation between each channel. Figure 58

shows the recommended layout for the RF inputs. Each RF input,

RFIN0 and RFIN1, is isolated between ground pins, and the

best layout approach is to keep the traces short and direct. To

achieve this, connect the pins directly to the center ground pad

of the exposed pad of the ADRF6820. This approach minimizes

the trace inductance and promotes better isolation between the

channels. In addition, for improved isolation, do not route the

RFIN0 and RFIN1 traces in parallel to each other; split the

traces immediately after each one leaves the pins. Keep the

traces as far away from each other as possible to prevent cross

coupling.

The input impedance of the RF inputs is 50 Ω, and the traces

leading to the pin must also have a 50 Ω characteristic impedance.

For unused RF inputs, terminate the pins with a dc blocking

capacitor to ground.

GND

RFIN1

RFIN0

GND

Figure 58. Recommended RF Input Layout

ADRF6820ACPZ-R7 Datasheet(PDF) 29 Page - Analog Devices