U4065B Datasheet, PDF (21/34 Pages) TEMIC Semiconductors – FM Receiver

First IF Preamplifier
Figure 31. First IF Preamplifier Principle Application
U4065B
50
f_IF
2VI_IF
1:2
VI_IF21
21
I_L1 ^RG21 ^{= 200}
12
56
7
IF
4
T_amb
V (pin 4)
VO_IF7
2:1
R_L7 = 200
I_L2
21
65
I₄
Power gain G_IF = 20 log (VO_IF/VI_IF) + I_L1 (dB) + I_L2 (dB)
I_L1, I_L2 = insertion loss of the RF transformers
VO_IF
50
Figure 32. Power Gain of the First IF Amplifier versus I₄
25
20
T = 90°C
15
T = -30°C
10
5
0
T = 30 °C
-5
0
20
40
60
80
100
120
140
I₄ (µA)
21
4807A–AUDR–05/04