ISM 433/315 MHz FSK/ASK Transmitter – Data Sheet

AS3901

Rev. 6, August 2000

Page 6 of 18

AS3901

STDBY

DATA

TX/ASK

RESET

NRES

TX/ASK

uC

10k

Transmit

switch

SW

STDBY

I

O

O

I

DATA

I

CLK

CLK

I

I

O

O

O

Figure 2:

Interconnection of the AS3901 with a typical µC.

Note:

At room temperature, resistor values of

≈10 kΩ are suggested for the µC interface.

For other temperatures to be calculated from figure 5.

TX/ASK

CLK

NRES

STDBY

standby

XTon

TX on

transmitting

3 clocks

standby

reset

uC

init PLLon

Figure 3:

µC interface timing for a transmission cycle.

Note:

Activating the transmit switch results in a „weak L state“ at TX/ASK. It can be overridden by the

microcontroller so that the transmission cycle remains unaffected by the duration the switch is pressed. The STDBY and

TX/ASK inputs have internal pullup resistors of ~100k

Ω