|
|
PDF BA1442A Data sheet ( Hoja de datos )
| Número de pieza | BA1442A | |
| Descripción | AM radio / FM IF stereo system IC | |
| Fabricantes | ROHM Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de BA1442A (archivo pdf) en la parte inferior de esta página. Total 17 Páginas | ||
|
No Preview Available !
Audio ICs
AM radio / FM IF stereo system IC
BA1442A
The BA1442A is an AM radio and FM IF stereo system IC developed for radio cassette players. The FM circuit is com-
prised of a differential IF amplifier, a double-balance type quadrature detector, and a PLL-type stereo MPX circuit. The
AM circuit is comprised of a local oscillator, a double-balanced mixer, an IF amplifier, a detector, and an AGC circuit.
FApplications
Radio cassette players
FFeatures
1) The “S” curve characteristic of the FM detector can
be used for upper heterodyne (“N” curve) operation.
2) Audio high cut and low cut can be used to improve the
AM fidelity.
3) A reference voltage supply is provided to ensure
good frequency stability in the shortwave bands.
4) Good FM stability.
5) Built-in damping resistor (3.3kΩ) for the quadrature
coil.
6) The FM MPX uses a Laser Locked Loop, making
adjustment of the VCO and addition of external
components unnecessary.
7) Built-in forced monaural function for the MPX (VCO
stops, LED off).
8) VCO of the MPX is switched off during AM opera-
tion.
9) The stereo indicator pin has a constant drive cur-
rent, and a current limiting resistor is not required.
10) Few external components required.
FAbsolute maximum ratings (Ta = 25_C)
FRecommended operating conditions (Ta = 25_C)
337
1 page  
Audio ICs
BA1442A
FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 5V, FM IF MPX: fin = 10.7MHz,
400Hz modulation, 22.5kHz dev (30%), 19kHz 7.5kHz dev (10%)
AM: fin = 1000kHz, fm = 400Hz 30%)
FMeasurement circuit
341
5 Page 
Audio ICs
Pin 9: Forced monaural (SW1)
If the voltage on pin 9 goes to 2.2V or higher in FM mode,
forced monaural operation starts (VCO stops, the stereo
indicator goes off, and audio output goes monaural). Do
not apply a voltage to pin 9 that is higher than the voltage
on pin 3 (VCC). Also, when in AM mode, the AM detector
output is output on pin 9, so use a switch to switch pin 9
open circuit in AM mode, as shown in the application cir-
cuit example. If you change the voltage on pin 9 during
AM operation, the AGC characteristics will be disturbed.
Pin 10: Stereo indicator
The pin 10 current is fixed at 10mA, so an external cur-
rent-limiting resistor is not required. If you wish to reduce
the brightness of the LED, connect a resistor in parallel
to reduce the current. If you do not wish to use stereo in-
dication, connect pin 10 directly to the power supply,
however, the current consumption is that same as that
when stereo indication is used. The withstanding voltage
of pin 10 is 9V, so use caution when connecting it to pow-
er sources other than the IC power supply.
BA1442A
Pin 14: PLL filter (C15, C16, and R4)
PLL loop filter for the MPX. Varying the values of these
components changes the capture range of the PLL, but
can also result in PLL beat, or the PLL going out of lock
due to temperature changes, so do not change these
component values.
Pin 15: Pilot filter and AGC filter (C17)
Pin 15 is used by both the MPX pilot filter and the AM
AGC filter. Lower values for C17 will result in increased
THD for bass-region AM audio, and larger values will in-
crease the time required to switch between monaural
and stereo for FM. Characteristic curves for various val-
ues of C17 are given in Figs. 7 to 9.
Pins 11 and 12
De-emphasis capacitors (C13 and C14)
The output impedance of pins 11 and 12 (5kΩ), and C13
and C14 set the de-emphasis time constant (50µsec. for
0.01µF, and 75µsec. for 0.015µF). Do not connect C13
and C14 if composite (voice multiplex etc.) signal proces-
sing will be performed at the following stage.
Pin 13: AM / FM switching noise reduction filter
Pin 13 is the AM power supply pin. When power is ap-
plied, the circuit is in AM mode. By setting a CR time
constant, it is possible to reduce the audible switching
noise that occurs when switching between AM and FM.
Choose the resistor so that the voltage drop across the
resistor is 0.5V max. with respect to the pin 3 (VCC). Do
not apply a voltage higher than the voltage on pin 3 (VCC)
to pin 13.
347
11 Page | ||
| Páginas | Total 17 Páginas | |
| PDF Descargar | [ Datasheet BA1442A.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| BA1442A | AM radio / FM IF stereo system IC | ROHM Semiconductor |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |