U3741BM-M2FLG3 TEMIC [TEMIC Semiconductors], U3741BM-M2FLG3 Datasheet - Page 5

• Manufacturer Part Number: U3741BM-M2FLG3
• Description: UHF ASK/FSK Receiver
• Manufacturer: TEMIC [TEMIC Semiconductors]

Rev. A1, 15-Oct-98
Please notify that for all coupling conditions (see
figures 5 and 6), the bond wire inductivity of the LNA
ground is compensated. C3 forms a series resonance
circuit together with the bond wire. L = 25 nH is a feed
inductor to establish a DC path. Its value is not critical but
must be large enough not to detune the series resonance
circuit. For cost reduction this inductor can be easily
printed on the PCB. This configuration improves the
sensitivity of the receiver by about 1 dB to 2 dB.
Analog Signal Processing
IF Amplifier
The signals coming from the RF front end are filtered by
the fully integrated 4th-order IF filter. The IF center
frequency is f
f
RF
f
RF
RF
RF
IN
IN
= 433.92 MHz
= 433.92 MHz
8.2p
C2
15p
22p
C3
3.3p
TOKO LL2012
F33NJ
22n
33n
L2
IF
= 1 MHz for applications where
TOKO LL2012
25n
25n
L
100p
F22NJ
2
1
IN
IN_GND
C16
8
9
100p
8
9
CASE_GND
LNAGND
U3741BM
LNA_N
LNAGND
LNA_N
U3741BM
Figure 6. Input matching network without SAW filter
B3555
3,4 7,8
Figure 5. Input matching network with SAW filter
Preliminary Information
27n
L3
OUT_GND
TOKO LL2012
F27NJ
C17
8.2p
OUT
14107
5
6
14105
f
RF input frequencies refer to table 1 to determine the
center frequency.
The U3741BM is available with 2 different IF
bandwidths.
B
TEMIC PLL transmitter U2741B is used. The receiver
U3741BM - M3
f
U2741B in FSK and ASK mode. If used in ASK
applications, it allows higher tolerances for the receiver
and PLL transmitter crystals. SAW transmitters exhibit
much higher transmit frequency tolerances compared to
PLL transmitters. Generally, it is necessary to use
B
f
RF
RF
IF
f
RF
RF
IF
IF
RF
IN
= 600 kHz. This version can be used together with the
IN
= 315 MHz or f
= 300 kHz, is well suited for ASK systems where the
= 600 kHz together with such transmitters.
= 315 MHz
= 315 MHz
10p
C2
33p
47p
C3
3.3p
TOKO LL2012
F82NJ
U3741BM-M2,
39n
L2
82n
employs
RF
TOKO LL2012
25n
25n
L
100p
F39NJ
= 433.92 MHz is used. For other
2
1
IN
IN_GND
U3741BM
an
C16
8
9
100p
8
9
CASE_GND
LNAGND
U3741BM
LNA_N
LNAGND
LNA_N
U3741BM
B3551
3,4 7,8
the
IF
47n
L3
OUT_GND
bandwidth
TOKO LL2012
version
F47NJ
C17
22p
OUT
5 (25)
14108
5
6
with
14106
of