RF65 Datasheet, PDF (30/72 Pages) List of Unclassifed Manufacturers – Low Power Integrated UHF Receiver With -120dBm High Sensitivity

ADVANCED COMMUNICATIONS & SENSING
RF65
DATASHEET
4. Operating Modes
4.1. Basic Modes
The circuit can be set in 4 different basic modes which are described in Table 12.
By default, when switching from a mode to another one, the sub-blocks are woken up according to a pre-defined and
optimized sequence. Alternatively, these operating modes can be selected directly by disabling the automatic sequencer
(SequencerOff in RegOpMode = 1).
Table 12 Basic Receiver Modes
ListenOn
in RegOpMode
0
0
0
0
1
Mode
in RegOpMode
000
001
010
100
x
Selected mode
Sleep Mode
Stand-by Mode
FS Mode
Receive Mode
Listen Mode
Enabled blocks
None
Top regulator and crystal oscillator
Frequency synthesizer
Frequency synthesizer and receiver
See Listen Mode, section 4.3
4.2. Automatic Sequencer and Wake-Up Times
By default, when switching from one operating mode to another, the circuit takes care of the sequence of events in such a
way that the transition timing is optimized. For example, when switching from Sleep mode to Receive mode, the RF65
goes first to Standby mode (XO started), then to frequency synthesizer mode, and finally, when the PLL has locked, to
Receive mode.
 The crystal oscillator wake-up time, TS_OSC, is directly related to the time for the crystal oscillator to reach its steady
state. It depends notably on the crystal characteristics.
 The frequency synthesizer wake-up time, TS_FS, is directly related to the time needed by the PLL to reach its steady
state. The signal PLL_LOCK, provided on an external pin, gives an indication of the lock status. It goes high when the
PLL reaches its locking range.
Three specific cases can be highlighted:
Receiver Wake Up time from Sleep mode
Receiver Wake Up time from Sleep mode, AGC enabled
Receiver Wake Up time from Sleep mode, AGC and AFC enabled
= TS_OSC + TS_FS + TS_RE
= TS_OSC + TS_FS + TS_RE_AGC
= TS_OSC + TS_FS + TS_RE_AGC&AFC
These timings are detailed in section 4.2.1.
In applications where the target average power consumption, or the target startup time, do not require setting the RF65 in
the lowest power modes (Sleep or Standby), the respective timings TS_OSC and TS_FS in the former equations can be
omitted.
4.2.1. Receiver Startup Time
It is highly recommended to use the built-in sequencer of the RF65, to optimize the delays when setting the chip in
receive mode. It guarantees the shortest startup times, hence the lowest possible energy usage, for battery operated
systems.
The startup times of the receiver can be calculated from the following:
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