Layout Considerations

Although the pinout of the LM1863 has been chosen to min-

imize layout problems some care is required to insure prop-

er performance If the LM1863 is used with a loopstick an-

tenna care in the placement of C3 must be observed in

order to minimize tweet radiation Orient C3 parallel to the

axis of the loopstick and as far away as possible Keep C3

close to the IC The ground on C6 should be located near

the ground terminal of the 450 kHz ceramic filter C11

should be located near Q2 and C12 should be located near

the IC Also the resonator on Pin 7 and resistor R2 should

be located near the IC in order to minimize tweet radiation

The mixer output Pin 10 and the IF input Pin 11 traces

should be as short as possible to prevent stray pick up from

the resonator

Applications Information

(See typical application and LM1863 schematic diagram)

STOP DETECTOR

There are two criteria that determine when an electronically

tuned radio is tuned to a valid station The first criterion is

that the incoming signal be of sufficient strength to be listen-

able The second criterion requires that the radio be tuned

PC Layout (Component Side)

TLH5185 – 22

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