TH72002 datasheet(6/20 Pages) MELEXIS

Numer części	TH72002

Szczegółowy opis	ASK Transmitter

PDF	20 Pages

Scroll/Zoom	100%

Producent	MELEXIS [Melexis Microelectronic Systems]

Strona internetowa	http://www.melexis.com

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6 / 20 page

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

TX standby

TX disabled

TX active

TX enable

2.8

Timing Diagrams

After enabling the transmitter by the ENTX signal, the power amplifier remains inactive for the time ton, the

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

quency within the time duration ton. After successful PLL lock, the LOCK signal turns on the power amplifier,

and then the RF carrier can be ASK modulated.

Fig. 4:

Timing diagram for ASK modulation

low

high

LOCK

ASKDTA

RF carrier

low

high

ENTX

t on

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