tda5235 Infineon Technologies Corporation, tda5235 Datasheet - Page 117

• Manufacturer Part Number: tda5235
• Description: Enhanced Sensitivity Double-configuration Receiver With Digital Baseband Processing
• Manufacturer: Infineon Technologies Corporation

2.6.2.3
This mode is used to switch off the receiver, if there is no RF signal, as quickly as
possible to reduce power consumption.
During the search for wake-up data, there is a check for a bit stream, to which the system
can be synchronized. If there is no synchronization to a bit stream within the so-called
Sync Search Time Out (SYSRCTO), the wake-up search for this channel is stopped. If
synchronization to a bit stream is possible (and not lost again), the TDA5235 waits if the
wake-up criterion is fulfilled. If the wake-up criterion is not fulfilled (in worst case, if the
last bit of an expected wake-up data pattern is wrong), the wake-up procedure for this
configuration is stopped, and the TDA5235 tries to synchronize on the next
configuration, or falls back to sleep. That means that the effective search time and,
consequently, the receiver active time is significantly shorter, and power consumption is
reduced, when no input signal is present. Calculation of Sync Search Time Out can be
found in
Time.
The needed time for detecting that no relevant transmission took place can be further
reduced by using Ultrafast Fall Back to SLEEP (UFFB). When there was no Wake-up on
Level criterion fulfilled in UFFB Mode during the Observation Time (T
Chapter
further reduce the receiver active time, when no data is available. When Wake-up on
Level criterion was fulfilled, then the system proceeds with normal FFB functionality
(SYSRCTO, optional Wake-up data criterion).
Note: UFFB and FFB start working at the same time!
Ultrafast Fall Back to SLEEP is working, when a Wake-up on Data criterion is selected,
the UFFBLCOO bit is enabled and FFB or PWUS mode is selected. The UFFB level
criterion can be selected in the x_WUC register.
Figure 82
Data Sheet
RF signal
RX ON
SLEEP
2.4.8.5), then the system goes back to SLEEP (or to next config). This can
Chapter 2.4.8.8 RUNIN, Synchronization Search Time and Inter-Frame
Fast Fall Back to SLEEP (FFB)
e.g. ASK
Ultrafast Fall Back to SLEEP
t
Startup
t
WULOT
UFFB
t
SYSRCTO
117
t
ON
FFB
t
WU-data-pattern
Functional Description
V1.0, 2010-02-19
WULOT
TDA5235
FFB
, see
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