MLX71121KLQ Melexis Inc, MLX71121KLQ Datasheet - Page 12

• Manufacturer Part Number: MLX71121KLQ
• Description: RCVR FSK/FM/ASK 32-QFN
• Manufacturer: Melexis Inc

Specifications of MLX71121KLQ

• Frequency: 300MHz ~ 930MHz
• Sensitivity: -108dBm
• Data Rate - Maximum: 100 kbps
• Modulation Or Protocol: ASK, FM, FSK
• Applications: General Remote Control, Garage Opener, RKE
• Current - Receiving: 8.1mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Features: RSSI Equipped
• Voltage - Supply: 2.1 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 32-QFN
• Data Rate: 100Kbps
• Frequency Range: 300MHz To 930MHz
• Modulation Type: AM, FM, FSK
• Rf Ic Case Style: QFN
• No. Of Pins: 32
• Supply Voltage Range: 2.1V To 5.5V
• Operating Temperature Range: -40°C To
• Sensitivity Dbm: -112dBm
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: MLX71121A

1.15 Noise Cancellation Filter and Data Output
The data output pin DTAO delivers the demodulated data signal which can be further processed by a noise
cancellation filter (NCF). The NCF can be disabled if pin CINT is connected to ground. In this case the
multiplexer (MUX) connects the receiver output DTAO directly to the data slicer output.
Fig. 9:
The noise cancellation filter can suppress random pulses in the data output which are shorter than t
The NCF can also operate as a muting circuit. So if the RF input signal is below sensitivity level (or if no
RF signal is applied) then the data output will go to a constant DC level (either HIGH or LOW). This can be
achieved by setting the bandwidth of the preceding data filter (sec 1.13) about 10 times higher than the
bandwidth of the NCF.
Having the NCF activated is a good means for reducing the computing power of the microcontroller that fol-
lows the receiver IC for further data processing.
In contrast to a conventional muting (or squelch) circuit, this topology does not need the RSSI signal for level
indication. The filtering process is done by means of an analogue integrator. The cut-off frequency of the
NCF is set by the external capacitor connected to pin CINT. This capacitor C
the maximum data rate. Below table provides some recommendations..
During receiver start-up a sequencer checks if pin CINT is connected to a capacitor or to ground. The maxi-
mum value of C
noise cancellation filter is activated.
In shutdown mode pin DTAO is set to Hi-Z state.
39010 71121
Rev. 009
CF3
=
15
Data output and noise filter
⋅
10
R
6 -
RZ
data slicer
⋅
F3
output
[kbit/s]
0.6
1.2
1.6
2.4
3.3
4.8
6.0
t
min
should not exceed 12nF. This defines the lowest data rate that can be processed if the
=
15
noise cancellation filter
R
⋅
NRZ
10
NCF
−
6
=
MUX
7
5 .
R
⋅
RZ
10
−
6
DTAO
CINT
Page 12 of 28
R
CF3
NRZ
1.2
2.4
3.2
4.8
6.6
9.6
12
[kbit/s]
FSK/FM/ASK Receiver
F3
should be set according to
MLX71121
C
300 to 930MHz
F3
6.8
4.7
3.3
2.2
1.5
1.2
12
[nF]
Data Sheet
min
.
Oct/10