TDA5240 Datasheet, PDF (114/284 Pages) Infineon Technologies AG – Enhanced Sensitivity Multi-Channel Quad-Configuration Receiver

TDA5240
Functional Description
Single Channel, Single Config
run mode
RX polling
A
1
sleep mode
TAON
TOFF
TMasterPeriod
Channels = 1
TMasterPeriod = TAON + TOFF
Multi Channel, Single Config
run mode
RX polling
A
1
A
2
A
3
sleep mode
TAON TAON TAON
TOFF
TMasterPeriod
Channels = m
TMasterPeriod = m*TAON + TOFF
Multi Channel, Multi Config
run mode
RX polling
A
1
A
2
A
3
sleep mode
TAON TAON TAON
B
1
TBON
B
2
TBON
TMasterPeriod
TOFF
Channels Config A = m
Channels Config B = n
TMasterPeriod = m*TAON + n*T BON+ TOFF
Figure 80 Constant On-Off Time
Calculation of the On time:
The On time for each channel must be long enough to ensure proper detection of a
specified wake-up criterion. Therefore the On time depends on the wake-up pattern, and
the wake-up criterion. It has to include transmitter data rate tolerances.
A widely used wake-up pattern is a sequence of equal Bi-phase encoded bits or a certain
Bi-phase encoded bit pattern.
T_ON also must include the relevant start-up times. In case of the first channel after T_OFF,
this is the Receiver Start-Up Time. In case of following channels (RF Receiver is already
on, there is only a change of the channel or the configuration), e.g. if Configuration B is
used, this is the Channel Hop Latency Time. In addition, it has to be considered that
some data bits are required for synchronization and internal latency, see
Chapter 2.4.8.8 RUNIN, Synchronization Search Time and Inter-Frame Time.
There are other wake-up patterns in use as well, which have several (up to 10 and more)
short wake-up sequences (a few byte each) that are separated by a certain pause (again
a few byte each). In this case the On time has to be set, so that a possible wake-up can
be found within two wake-up sequences including the pause in-between.
Calculation of the Off time:
The longer the Off time, the lower the average power consumption in Self Polling Mode.
On the other hand, the Off time has to be short enough that no transmitted wake-up
Data Sheet
114
V4.0, 2010-02-19