Rainbow Electronics ATA6286 User Manual
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4958AS–AUTO–09/06
ATA6285/ATA6286 [Preliminary]
With ASK = High the power amplifier is switched on. This is used to perform the ASK modula-
tion. During ASK modulation the IC is enabled with the FSK or the ENABLE pin.
With FSK = Low the switch at pin XTO2 is closed, with FSK = High the switch is open. To
achieve a faster start-up of the crystal oscillator, the FSK pin should be High during start-up of
the XTO because the series resistance of the resonator seen from pin XTO1 is lower if the
switch is off.
The different modes of the ATA6285/ATA6286 are listed in
4.5.1
Transmission with ENABLE = Open
4.5.1.1
ASK Mode
The ATA6285/ATA6286 is activated by ENABLE = open, FSK = High, 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 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 ATA6285/ATA6286 is switched to power-down
mode with FSK = Low.
Figure 4-2.
Timing ASK Mode with ENABLE Open
Table 4-1.
Transmitter Part
ASK Pin
FSK Pin
ENABLE Pin
Mode
Low
Low
Low/open
Power-down mode, FSK switch High Z
Low
Low
High
Power-up, PA off, FSK switch Low Z
Low
High
High/open
Power-up, PA off, FSK switch High Z
High
Low
High/open
Power-up, PA on, FSK switch Low Z
High
High
High/open
Power-up, PA on, FSK switch High Z
Low/High
High
Low
Idle mode, FSK switch High Z
High
Low/High
Low
Idle mode, FSK switch High Z
Power-down
Power-down
Power-up,
PA off
Power-up,
PA on
(High)
Power-up,
PA off
(Low)
FSK
ASK
CLK
∆
T
XTO
> 250 µs