
PLL Tuned UHF Transmitter Module
Data Sheet
MC68HC908QF4 — Rev. 1.0
106
PLL Tuned UHF Transmitter Module
MOTOROLA
State 1
The circuit is in standby mode and draws only a leakage current from the power
supply.
State 2
In this state, the PLL is enabled but out of the lock-in range. Therefore the RF
output stage is switched off preventing any data transmission. Data clock is
available on pin DATACLK. In normal operation, this state is transitional.
State 3
In this state, the PLL is within the lock-in range.
If t < tPLL_Lock_In, then the PLL can still be in acquisition mode.
If t
≥ t
PLL_Lock_In, then the PLL is locked.
The circuit is ready to transmit in band and is waiting for the first data (see
State 4
A rising edge on pin DATA starts the transmission. Data entered on pin DATA
are output on pin RFOUT. The modulation is the one selected through the level
applied on pin MODE.
State 5
An out-of-lock condition has been detected. The RF output stage is switched off
preventing any data transmission. Data clock is available on pin DATACLK.
State 6
When the supply voltage falls below the shutdown voltage threshold (VSDWN)
the whole circuit is switched off. Applying a low level on pin ENABLE is the only
condition to get out of this state.
Figure 12-4 shows the waveforms of the main signals for a typical application cycle
Figure 12-4. Signals, Waveforms, and Timing Definitions
ENABLE
DATACLK
DATA
RFOUT
STATE 1
STATE 2
STATE 4
STATE 3
MODE = 0,
OOK MODULATION
MODE = 1,
FSK MODULATION
STATE 1
fCarrier
fCarrier2
fCarrier1
fCarrier2
fCarrier1
tPLL_Lock_In
tDATACLK_Settling
SEE NOTE
Note: PLL locked, circuit ready to tramsmit in band.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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