ata5756-6dqy ATMEL Corporation, ata5756-6dqy Datasheet - Page 6

• Manufacturer Part Number: ata5756-6dqy
• Description: Ata5756 Uhf Ask/fsk Transmitter
• Manufacturer: ATMEL Corporation

4.1
4.1.1
4.1.2
6
Transmission with ENABLE = open
ATA5756/ATA5757
ASK Mode
FSK Mode
The ATA5756/ATA5757 is activated by ENABLE = open, FSK = High, ASK = Low. The microcon-
troller is then switched to external clocking. After typically 0.6 ms, the CLK driver is activated
automatically (i.e., the microcontroller waits until the XTO and CLK are ready). After another
time period of 250 µs, the PLL is locked and ready to transmit. The output power can then be
modulated by means of pin ASK. After transmission, ASK is switched to Low and the microcon-
troller returns back to internal clocking. Then, the ATA5756/ATA5757 is switched to power-down
mode with FSK = Low.
Figure 4-1.
The ATA5756/ATA5757 is activated by FSK = High, ASK = Low. The microcontroller is then
switched to external clocking. After typically 0.6 ms, the CLK driver is activated automatically
(i.e., the microcontroller waits until the XTO and CLK are ready. After another time period of
ASK = H. The ATA5756/ATA5757 is then ready for FSK modulation. The microcontroller starts to
switch on and off the capacitor between the crystal load capacitor and GND by means of pin
FSK, thus, changing the reference frequency of the PLL. IF FSK = L the output frequency is
lower, if FSK = H output frequency is higher. After transmission, FSK stays High and ASK is
switched to Low and the microcontroller returns back to internal clocking. Then, the
ATA5756/ATA5757 is switched to power-down mode with FSK = Low.
Figure 4-2.
250 µs, the PLL is locked and ready to transmit. The power amplifier is switched on with
ASK
FSK
CLK
FSK
ASK
CLK
Timing ASK Mode with ENABLE not Connected to the Microcontroller
Timing FSK Mode with ENABLE not Connected to the Microcontroller
Power-down
Power-down
T
T
XTO
Power-up,
XTO
Power-up,
PA off
PA off
> 250 µs
> 250 µs
(f
Power-up,
Power-up,
RF
PA on
PA on
(High)
= High)
(f
Power-up,
Power-up,
RF
PA off
PA off
(Low)
= Low)
Power-down
Power-down
4702I–RKE–11/05