CXA1999 SONY [Sony Corporation], CXA1999 Datasheet - Page 10

• Manufacturer Part Number: CXA1999
• Description: IF Amplifier for M-ary FSK Pagers
• Manufacturer: SONY [Sony Corporation]

Application Note
1) Power Supply
2) Oscillator Input
Oscillator input method
3) Mixer
4) IF Filter
5) IF Limiter Amplifier
The CXA1999N, with built-in regulator, is designed to permit stable operation at wide range of supply
voltage from 1.1 to 4.0 V. Decouple the wiring to V
a) Using Pins 1 and 2, input self-excited oscillation signal through the composition of a Colpitts type crystal
b) Directly input a local oscillation signal to Pin 1.
The mixer is of double-balance type. Pin 20 is the input pin. Input though a suitable matching circuit. The
input impedance is 2.0 kΩ.
Pin 3 serves as the output pin for the mixer, and a load resistance of 1.5 kΩ is incorporated.
The filter to be connected between this mixer output and the IF limiter amplifier input should have the
following specifications.
The gain of this IF limiter amplifier is approximately 100 dB. Take notice of the following points in making
connection to the IF limiter amplifier input pin (Pin 5).
a) Be sure to wire to the IF limiter amplifier input (Pin 5) is as short as possible.
b) As the IF limiter amplifier output appears at QUAD (Pin 8), be sure to wire to the ceramic discriminator
oscillator circuit.
connected to QUAD is as short as possible and reduce the interference with the mixer output and IF
limiter amplifier input.
I/O impedance : 1.5 kΩ ±10 %
Band width
V
CC
1
V
CC
2
: Changes according to applications.
3
Shortest possible wirings which
must be apart as far as possible
3
4
Ceramic
filter
5
—10—
Fig. 1
Fig. 2
CC
6
(Pin 4) as close to the pin as possible.
As short as possible
7
From local signal
8
1
9
2
Ceramic
filter
3
CXA1999N