SX1239IMLTRT Semtech, SX1239IMLTRT Datasheet - Page 30

• Manufacturer Part Number: SX1239IMLTRT
• Description: IC, RF RECEIVER, 1.02GHz, QFN-24
• Manufacturer: Semtech

Specifications of SX1239IMLTRT

• Applications: Wireless Sensor Networks, Automated Meter Reading, Home And Building Automation
• Receiving Current: 16mA
• Data Rate: 300Kbps
• Modulation Type: FSK, OOK
• Sensitivity Dbm: -120dBm
• Rohs Compliant: Yes
• Rf Ic Case Style: QFN
• No. Of Pins: 24
• Sensitivity (dbm): -120dBm
• Supply Voltage Range: 1.8V To 3.6V
• Operating Temperature Range: -40°C To +85°C
• Lead Free Status / Rohs Status: Supplier Unconfirmed

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
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 SX1239
goes first to Standby mode (XO started), then to frequency synthesizer mode, and finally, when the PLL has locked, to
Receive mode.
Three specific cases can be highlighted:
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 SX1239
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 SX1239, 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:
Rev 3 - Jan 2011
ADVANCED COMMUNICATIONS & SENSING
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.
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
in RegOpMode
ListenOn
0
0
0
0
1
in RegOpMode
Mode
0 0 0
0 0 1
0 1 0
1 0 0
x
Selected mode
Stand-by Mode
Receive Mode
Listen Mode
Sleep Mode
FS Mode
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Frequency synthesizer and receiver
= TS_OSC + TS_FS + TS_RE_AGC
= TS_OSC + TS_FS + TS_RE_AGC&AFC
= TS_OSC + TS_FS + TS_RE
Top regulator and crystal oscillator
See Listen Mode, section 4.3
Frequency synthesizer
Enabled blocks
None
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SX1239