ata5756-6dqy ATMEL Corporation, ata5756-6dqy Datasheet - Page 7

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

4.2
4.2.1
4.2.2
4702I–RKE–11/05
Transmission with ENABLE = High
FSK Mode
ASK Mode
The ATA5756/ATA5757 is activated by ENABLE = High, FSK = High and ASK = Low. The micro-
controller 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 power amplifier is switched
on with 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, ASK is switched to Low and
the microcontroller returns back to internal clocking. Then, the ATA5756/ATA5757 is switched to
power-down mode with ENABLE = Low and FSK = Low.
Figure 4-3.
The ATA5756/ATA5757 is activated by ENABLE = High, FSK = High and ASK = Low. After acti-
vation the microcontroller is switched to external clocking. After typically 0.6 ms, the CLK driver
is activated automatically (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
microcontroller returns back to internal clocking. Then, the ATA5756/ATA5757 is switched to
power-down mode with ENABLE = Low and FSK = Low.
ENABLE
ASK
FSK
CLK
Timing FSK Mode with ENABLE Connected to the Microcontroller
Power-down
T
XTO
Power-up,
PA off
> 250 µs
(f
Power-up,
RF
PA on
= High)
ATA5756/ATA5757
(f
Power-up,
RF
PA off
= Low)
Power-down
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