MC33493 Motorola, MC33493 Datasheet - Page 5

• Manufacturer Part Number: MC33493
• Description: PLL tuned UHF Transmitter for Data Transfer Applications
• Manufacturer: 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 out of the lock-in range. Therefore the RF output stage is switched off preventing RF
transmission. Data clock is available on pin DATACLK. Each time the device is enabled, the state machine
passes through this state.
State 3:
In this state, the PLL is within the lock-in range. If t<t
t≥t
Data entered on pin DATA are output on pin RFOUT according to the modulation selected by the level applied on
pin MODE.
State 4:
When the supply voltage falls below the shutdown voltage threshold (V
Applying a low level on pin ENABLE is the only condition to get out of this state.
Figure 4 shows the waveforms of the main signals for a typical application cycle.
PLL_lock_in
MOTOROLA
, then the PLL is locked.
ENABLE=0
lock-in range
PLL out of lock-in range
PLL in
Transmission mode
AND ENABLE=0
Freescale Semiconductor, Inc.
Standby mode
No RF output
ENABLE=1
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Power ON
State 1
State 2
State 3
lock-in range
Figure 3: State machine
PLL out of
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MC33493 Technical Data
PLL_lock_in
then the PLL can still be in acquisition mode. If
Shutdown mode
V
battery
SDWN
ENABLE=0
State 4
) the whole circuit is switched off.
< V
shutdown
STATE MACHINE
5