SX1231 SEMTECH [Semtech Corporation], SX1231 Datasheet - Page 35

• Manufacturer Part Number: SX1231
• Description: Low Power Integrated UHF Transceiver
• Manufacturer: SEMTECH [Semtech Corporation]

The different timings shown above are as follows:
Rev 2 - Nov 2009
(sequencer or user)
ADVANCED COMMUNICATIONS & SENSING
Rx startup request
XO Started and
RxReady
PLL is locked
ModeReady
Group delay of the analog front end:
Channel filter’s group delay in FSK mode:
Channel filter’s group delay in OOK mode:
DC Cutoff’s group delay:
PLL lock time after AFC adjustment:
AFC sample time:
RSSI sample time:
ModeReady
RxReady
XO Started and PLL is locked
Analog FE’s
group delay
Tana
(sequencer or user)
Rx startup request
Channel Filter’s
RxReady
ModeReady
XO Started and PLL is locked
group delay
Tcf
Analog FE’s
group delay
(sequencer or user)
Rx startup request
Tana
group delay
DC Cutoff’s
Tdcc
Channel Filter’s
sampling
Figure 15. Rx Startup - No AGC, no AFC
group delay
RSSI
Trssi
Figure 17. Rx Startup - AGC and AFC
Figure 16. Rx Startup - AGC, no AFC
Tcf
Analog FE’s
group delay
Tana
sampling
RSSI
Trssi
group delay
TS_RE_AGC&AFC
Tpllafc = 5 / PLLBW (PLLBW = 300 kHz)
Tafc = 4 x Tbit
DC Cutoff’s
Trssi = 2 x int(4.RxBw.Tbit)/(4.RxBw)
Tdcc = max(8 , 2^(round(log2(8.RxBw.Tbit)+1)) / (4.RxBw)
Tcf = 21 / (4.RxBw)
Tcf = 34 / (4.RxBw)
Tana = 10 us
Channel Filter’s
Channel Filter’s
Tdcc
group delay
group delay
Tcf
Tcf
TS_RE_AGC
sampling
Page 35
TS_RE
RSSI
Trssi
DC Cutoff’s
group delay
Tdcc
DC Cutoff’s
group delay
sampling
Tdcc
RSSI
Trssi
sampling
RSSI
Trssi
(also denoted TS_AFC in the general specification)
sampling
Channel Filter’s
RSSI
Trssi
group delay
The LNA gain is adjusted by
the AGC, according to the
Tcf
AFC
Tafc
sampling
RSSI result
RSSI
Trssi
Tpllafc
PLL
lock
group delay
DC Cutoff’s
Channel Filter’s
group delay
Tdcc
Tcf
Reception of Packet
sampling
(aka TS_RSSI)
RSSI
Trssi
group delay
DC Cutoff’s
Tdcc
The LNA gain is adjusted by
Reception of Packet
the AGC, according to the
Reception of Packet
Carrier Frequency is adjusted
DATASHEET
RSSI result
www.semtech.com
SX1231
by the AFC