CXA3225N 데이터 시트보기 (PDF) - Sony Semiconductor
부품명
상세내역
일치하는 목록
CXA3225N Datasheet PDF : 16 Pages
| |||
CXA3225N
Description of Operation
(See the Electrical Characteristics Measurement Circuit.)
VHF oscillator circuit
This circuit is a differential amplifier-type oscillator circuit. Pin 13 is the output, Pin 11 is the input and Pin 12
is the GND.
Oscillation is performed by connecting an LC resonance circuit including a variable capacitance diode, to Pin
13 via coupled capacitance, inputting to Pin 11 with feedback capacitance, and applying positive feedback.
Note that if the capacitance across Pins 11 and 13 is too large, positive feedback may be applied via a
parasitic capacitance causing undesired stray oscillation. The resistor connected Pin 11 prevents the
parasitic oscillation.
VHF mixer circuit
The mixer circuit employs a double balanced mixer with little local oscillation signal leakage. The input
format is the base input type. Pin 7 is grounded and the RF signal is input to Pin 8. The RF signal is
converted to IF frequency by the signal supplied from the oscillator and then output to Pins 4 and 5. Pins 4
and 5 are open collectors, so the power must be supplied externally. The electric potential of Pins 4 and 5 at
this time must be DC 4.0 V or more.
UHF oscillator circuit
This oscillator circuit is designed so that two collector ground type Colpitts oscillators perform the differential
oscillation operation via an LC resonance circuit including a variable capacitance diode. The resonance
capacitors which configure the Colppits oscillator are connected between Pins 14 and 15, 15 and 16, 16 and 17.
The LC resonance circuit including the variable capacitance diode Di is connected between Pins 14 and 17.
UHF mixer circuit
This circuit employs a double balanced mixer like the VHF mixer circuit. The RF signal is input to Pins 9 and
10. There are two input methods; one is the symmetrical input where the signal is input to Pins 9 and 10
differentially and the other is the asymmetrical input where Pin 9 is grounded via a capacitor and the signal is
input to Pin 10.
Pins 4 and 5 are the mixer outputs. Pins 4 and 5 are open collectors, so the power must be supplied
externally. The electric potential of Pins 4 and 5 at this time must be DC 4.0 V or more.
IF amplifier circuit
The signals frequency converted by the mixer are output from Pins 4 and 5, and then they are input to the IF
input Pins 1 and 2 via the external tuned circuit. As the IF tuned circuit, the single-tuned circuit shown in the
Electrical Characteristics Measurement Circuit or double-tuned circuits can be connected. When used as the
single-tuned filter, be sure to connect it via the capacitor so that the DC voltage may not be applied to Pins 1
and 2.
The signal amplified by the IF amplifier is output with symmetrical or asymmetrical output format. Selecting
symmetrical or asymmetrical is performed at Pin 7. Asymmetrical output when Pin 7 is grounded via the
capacitor; symmetrical output when it is directly grounded. During symmetrical output, SAW filter direct
connection is possible and during asymmetrical output. During asymmetrical output, output is performed
from Pin 20, and during symmetrical output, output is performed from Pins 19 and 20. The output impedance
is approximately 30 Ω.
U/V switch circuit
UHF operation is chosen by applying voltage of 3 V or more to Pin 18, VHF operation for 0 V or open.
—8—
Share Link: 