LA1781M_09 Datasheet, PDF (41/48 Pages) Sanyo Semicon Device – For Car Radios Single-Chip Tuner IC

LA1781M
Gain Distribution (FM)
This section investigates the gain in each block in the LA1781M when the Sanyo recommended circuits are used.
(Test conditions)
Ambient temperature : 26°C
Antenna and mixer input frequency : 98.1MHz
First and second IF input frequency : 10.7MHz
The input levels when VSM = 2V will be as follows.
ANT IN : 19dBμ
MIX IN : 30dBμ
1st IF IN : 42dBμ
2nd IF IN : 60dBμ
When the gains for each block are determined according to the above, the results are as follows.
RF GAIN : 11dB
MIX GAIN : 12dB
1st IF GAIN : 18dB
FM
1st IF IN 56 pin
MIX IN 64 pin
RF
ANT IN
2nd IF IN 51 pin
11dB
12dB
Fig. 54
18dB
(AM)
This section investigates the gain in each block in the LA1781M when the Sanyo recommended circuits are used.
(Test conditions)
Ambient temperature : 26°C
Antenna and mixer input frequency : 1MHz
First and second mixer input frequency : 10.7MHz
Second IF input frequency : 450kHz
The gains at each stage will be as follows.
RF Gain (ANT IN-pin62) : 17dB
1st MIX Gain (pin62-pin56) : 8dB
1st IF Gain (pin55-pin53) : 15dB
AM
1st MIX
1st IF
2nd MIX
2nd IF
AM DET
RF
RF
Gain
1st MIX
Gain
1st IF
Gain
2nd MIX
Gain
Fig. 55
2nd IF
Gain
No.6038-41/48