MLX71121 Datasheet, PDF (9/28 Pages) Melexis Microelectronic Systems – 300 to 930MHz FSK/FM/ASK Receiver

MLX71121
300 to 930MHz
FSK/FM/ASK Receiver
1.13 Baseband Data Path
The baseband data path can be divided into a data filter section and a data slicer section.
MODSEL
DF1 DF2
ASK
FSK _SW1
data filter
100k
100k
OA1
DF0
SLCSEL
PKDET+ ^{data slicer}
PDP
S4
S1
100k
S2
switches S3 _VCC
SLC
PKDET_
S5
PDN
S6
OA2
Control
logic
DTAO
CINT
Fig. 5: Block diagram of the data path
The data filter input is either connected to the ASK or to the FSK demodulation output. Pin MODSEL can be
used to set the internal switch SW1 accordingly.
MODSEL
0
1
Description
ASK demodulation
FSK demodulation
For ASK demodulation, the RSSI signal of the IFA is used. During FSK demodulation, SW1 is connected to
the FSK demodulator output.
The SLCSEL pin is used to control the internal switches depending on operating and slicer mode.
Pins DF1, DF2, DFO, SLC and DTAO are left floating during shutdown mode. So they are in a high-Z state.
39010 71121
Rev. 007
Page 9 of 28
Data Sheet
Feb/08