SX1276 View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SX1276' PDF : 132 Pages View PDF
SX1276/77/78/79
WIRELESS, SENSING & TIMING
DATASHEET
4.2.5. Startup Times
The startup time of the transmitter or the receiver is Dependant upon which mode the transceiver was in at the beginning.
For a complete description, Figure 17 below shows a complete startup process, from the lower power mode “Sleep”.
Current
Drain
IDDR (Rx) or IDDT (Tx)
IDDSL
0
IDDST
TS_OSC
IDDFS
TS_OSC
+TS_FS
Sleep
mode
Stdby
mode
FSTx
FSRx
TS_OSC
+TS_FS
+TS_TR
TS_OSC
+TS_FS
+TS_RE
Transmit
Timeline
Receive
Figure 17. Startup Process
TS_OSC is the startup time of the crystal oscillator which depends on the electrical characteristics of the crystal. TS_FS is
the startup time of the PLL including systematic calibration of the VCO.
Typical values of TS_OSC and TS_FS are given in Section 2.5.2.
4.2.5.1. Transmitter Startup Time
The transmitter startup time, TS_TR, is calculated as follows in FSK mode:
TS
_
TR
=
5μs
+
1.25 ×
PaRamp
+
1
2
× Tbit
,
where PaRamp is the ramp-up time programmed in RegPaRamp and Tbit is the bit time.
In OOK mode, this equation can be simplified to the following:
TS
_
TR
=
5μs
+
1
2
× Tbit
4.2.5.2. Receiver Startup Time
The receiver startup time, TS_RE, only depends upon the receiver bandwidth effective at the time of startup. When AFC is
enabled (AfcAutoOn=1), AfcBw should be used instead of RxBw to extract the receiver startup time:
Rev. 4 - March 2015
©2015 Semtech Corporation
Page 56
www.semtech.com
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