UPC2533GS-01 NEC [NEC], UPC2533GS-01 Datasheet - Page 15

• Manufacturer Part Number: UPC2533GS-01
• Description: AM TUNER FOR ELECTRONIC TUNING CAR RADIOS
• Manufacturer: NEC [NEC]

2.5 IF Amplifier Block and Detection Block
from pin 18, an output pin. The DC electric potential of pin 18 is designed to be fixed approximately equal to the (+)
side input of the IF amplifier. The value of R19 is the input impedance, so impedance matching to 450 kHz ceramic
filter is possible.
the detection circuit after frequency selection.
In the IF amplifier block, DC feedback is carried to pin 19 via an external low pass filter (composed of T
The output signal current of the IF amplifier is converted to signal voltage by being resonated by T3 and input to
Emitter follower detection by Q302 is adopted for the detection circuit block.
From 450kHz BPF
19
R19
Fig. 2-5 IF Amplifier and Detection Block
–
+
From IF AGC circuit
(Fig. 2-6)
+
C19
IF amp
R301
18
R302
T3
R303
Q301
To IF AGC circuit
(Fig. 2-6)
Q302
To SD circuit
R304
17
15
V
CC
PC2533
3
and C
Audio
output
15
19
)