BOARD LAYOUT CONSIDERATIONS

If you are at all familiar with RF devices you may be concerned about

specialized layout requirements. Fortunately, because of the care taken in

design, integrating an RM receiver into your design is very straightforward.By

adhering carefully to a few basic design and layout rules, you can enjoy a

trouble-free path to RF success.

Figure 7 shows the suggested PCB footprint for the RM receiver.

1)

A ground-plane (as large as possible) should be placed directly under the

RM receiver. This ground-plane can also be critical to the performance of your

antenna.

2)

The RM receiver should, as much as reasonably

possible, be isolated from all other components on your PCB. Specifically, high-

frequency circuitry such as crystal oscillators should be kept as far away as

possible from the receiver.

3)

The module may be mounted vertically or bent horizontal to the product’s

PCB. If the receiver is to be mounted parallel to the board, it should be bent over

so that the side without components is closest to the PC board and the

component side is facing away from the PC board.

4)

No conductive items should be placed within .25 in. of the module’s

component side to prevent detuning.

5)

The trace from the receiver to the antenna should be kept as short as

possible. A simple trace is suitable for runs up to 1/4 inch for antennas with wide

bandwidth characteristics. For longer runs or to avoid detuning a high-Q narrow

bandwidth antenna such as a helical, use a 50-ohm coax or 50-ohm microstrip

transmission line as shown in the adjoining diagram.

Page 6

POWER SUPPLY REQUIREMENTS

The receiver module requires a clean, well-

regulated voltage. While it is preferable to power

the unit from a battery, the unit can also be

powered from a power supply as long as noise

and ‘hash’ is less than 20mV. A 10µF capacitor

to ground on pin 5 (Vcc) and a 10

Ω series

resistor will help in cases where the quality of

supply power is poor.

Figure 6: Suggested supply filter

Figure 7: Recommended pad layout