UPC2533GS-01 NEC [NEC], UPC2533GS-01 Datasheet - Page 16

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

2.6 IF AGC Block
of pin 20, and its DC voltage controls the IF AGC.
then controls the gain of MIX2.
to voltage by the external resistor of pin 7 or 9. Therefore, output voltage value and gain can be set by the value of
the external resistor.
16
V
CC
To SD circuit
(Fig. 2-7)
From SD circuit
(Fig. 2-7)
IF AGC block configuration is shown in Fig. 2-6. The signal detected from pin 15 is smoothed by the capacitor
The IF AGC controls the IF amplifier and MIX2. In the operation sequence, it first controls the gain of the IF amplifier,
The signal meter circuit output (current output) is in proportion to the DC voltage smoothed by pin 20, and converted
Note For relation between the external resistor and the signal meter, refer to Signal meter output voltage
(adjustment by resistor between pin 9 and GND) in section 4. Characteristic Curves.
Signal meter circuit
Note
7
R501
5 k
9
R502
5 k
Note
To MIX2 (Fig. 2-3)
Fig. 2-6 IF AGC Block (for PC2533GS-01)
Q503
Q501
D501
Q502
To IF amp. (Fig. 2-5)
D502
Q504
20
+
Time
constant
switchover
From detection circuit
Note In the case of
(Fig. 2-5)
the part enclosed by the
dotted line is illustrated as
shown below.
R501
5 k
R502
5 k
PC2533GS-02,
Voltage
limiter
PC2533