U3742BM Datasheet, PDF (6/32 Pages) ATMEL Corporation – UHF ASK/FSK RECEIVER

Table 1. Calculation of LO and IF Frequency
Local Oscillator
Conditions
Frequency
f_RF = 315 MHz, MODE = 0
f_RF = 433.92 MHz, MODE = 1
f_LO = 314 MHz
f_LO = 432.92 MHz
300 MHz < f_RF < 365 MHz, MODE = 0
f_LO
=
-------f-^R----^F-------
1 + ----1-----
314
365 MHz < f_RF < 450 MHz, MODE = 1
f_LO
=
-----------f--^R---^F-----------
1 + --------1---------
432.92
Intermediate Frequency
f_IF = 1 MHz
f_IF = 1 MHz
f_IF
=
-f--^L---^O---
314
f_IF
=
------f--^L--^O-------
432.92
Figure 5. Input Matching Network with SAW Filter
8 _LNAGND
U3742BM
C₃
L
9 _{LNA_IN}
22p
25n
8 _LNAGND
U3742BM
C₃
L
9
LNA_IN
47p
25n
f_RF = 433.92 MHz
C₁₆
C₁₇
100p
L₃
27n
8.2p
TOKO LL2012
F27NJ
f_RF = 315 MHz
C₁₆
C₁₇
100p
L₃
47n
22p
TOKO LL2012
F47NJ
L₂
RF_IN
TOKO LL2012
F33NJ
1 _IN
B3555
5
OUT
C₂
33n
2 _{IN_GND}
OUT_GND ⁶
CASE_GND
8.2p
3, 4 7, 8
RF_IN
L₂
TOKO LL2012
F82NJ
1 _IN
B3551
5
OUT
C₂
82n
2 _{IN_GND}
OUT_GND ⁶
CASE_GND
10p
3, 4 7, 8
Figure 6. Input Matching Network without SAW Filter
f_RF = 433.92 MHz
15p
25n
8 _LNAGND
U3742BM
9 _{LNA_IN}
f_RF = 315 MHz
33p
25n
8 _LNAGND
U3742BM
9 _{LNA_IN}
RF_IN
3.3p
22n
100p
TOKO LL2012
F22NJ
RF_IN
3.3p
39n
100p
TOKO LL2012
F39NJ
6 U3742BM
4735A–RKE–11/03