TH72002

315MHz

ASK Transmitter

3901072002

Page 6 of 20

Data Sheet

Rev. 007

June/07

2.7

Mode Control Logic

The mode control logic allows two different

modes of operation as listed in the following

table. The mode control pin ENTX is pulled-

down internally. This guarantees that the whole

circuit is shut down if this pin is left floating.

ENTX

Mode

Description

0

TX standby

TX disabled

1

TX active

TX enable

2.8

Timing Diagrams

transmitter start-up time. The crystal oscillator starts oscillation and the PLL locks to the desired output fre-

and then the RF carrier can be ASK modulated.

Fig. 4:

Timing diagram for ASK modulation

low

low

high

high

LOCK

ASKDTA

RF carrier

t

low

high

ENTX