MC13028AP View Datasheet(PDF) - Motorola => Freescale
Part Name
Description
Manufacturer
MC13028AP Datasheet PDF : 20 Pages
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MC13028A
Figure 9 presents more detailed information with respect
to the value of resistor R1 at Pin 1 versus the desired
incoming signal level for stereo threshold.
Figures 10 and 11, discussed briefly in the Pin Function
Description Section, show the importance of using a quality
component at Pin 14 to ground. It can be seen that an
electrolytic capacitor leakage current of 600 nA can
unbalance the PLL to the point where stereo performance
may degrade to only 25 dB of separation with a
corresponding 2.0% distortion at 50% modulation levels.
The value of the capacitor connected to Pin 14 (47 µF) is
also a factor in the determination of the low frequency corner
of the PLL circuit response. Three traces of PLL response
appear in Figure 12 where they have been plotted for three
different values of loop filter capacitor. The recommended
value of 47 µF provides the best response shape in this
particular circuit set–up where a Murata Products
CSA3.60MGF108 part is used.
Figure 13 presents the response of the AGC voltage
versus decoder input signal level. This is a typical response
when the IC is used as shown in the application schematic of
Figure 1. The trace begins approximately at the point of
decoder sensitivity, and rises rapidly until reaching the area
of stereo sensitivity, approximately 50 dBµV. Thereafter, the
circuit responds in a linear fashion for the next 30 dB of input
signal increase.
Figures 14 through 17 inclusively depict the VCC ripple
rejection performance for the MC13028A under mono and
stereo conditions for nominal and for low values of VCC. It
should be noted that this data was collected without any VCC
filtering. As one might expect, the ripple rejection is better in
mono than in stereo. When the decoder operates in stereo,
the VCO is functional, thus the decoder becomes more
susceptible to audio ripple on the VCC line. Under normal
operating conditions, with the recommended value of 47 µF
at Pin 12 and 10 µF at Pin 7, a VCC ripple reading will be
virtually the same as measuring the noise floor of the IC.
AM STEREO TUNER / FM STEREO IF
Description of Application
This application combines a Sanyo LA1832M with the
Motorola MC13028A AM Stereo decoder IC. The LA1832
provides an FM IF, FM multiplex detection, AM tuning, and
the AM IF functions. The MC13028A provides the AM Stereo
detection as well as Left and Right audio outputs. An
MC145151 synthesizer provides the frequency control of the
local oscillator contained within the LA1832. Frequency
selection is by means of a switch array attached to the
synthesizer. The application circuit is shown in Figure 18.
Circuit Board Description
The copper side layout and the component locations are
shown in Figure 19. The view is from the plating side of the
board, with the components shown in hidden view. Several
jumper wires are placed on the component side of the board
to complete the circuit. Posts are provided for electrical
connections to the circuit. The circuit board has been scaled
to fit the page, however, the dimensions provide the true size.
Circuit Description
The Sanyo data sheet for the LA1832 should be
consulted for an understanding of the FM detection and
multiplex decoding.
Special Parts
The following information provides circuit function, part
number, and the manufacturer’s name for special parts
identified by their schematic symbol. Where the part is not
limited to a single source, a description sufficient to select a
part is given.
U1 IC – AM Stereo Decoder
MC13028AD by Motorola
U2 IC – AM/FM IF and Multiplex Tuner
LA1832M by Sanyo
U3 IC – Frequency Synthesizer
MC145151DW2 by Motorola
T1 AM IF Coil
A7NRES–11148N by TOKO
F1 AM IF Ceramic Filter
SFG450F by Murata
F2 FM IF Detector Resonator
CDA10.7MG46A by Murata
F3 FM Multiplex Decoder Resonator
CSB456F15 by Murata
F4 AM Tuner Block
BL–70 by Korin Giken
X1 10.24 MHz Crystal, Fundamental Mode,
AT Cut, 18 pF Load Cap, 35 Ω maximum series R.
HC–18/U Holder
X2 3.6 MHz AM Stereo Decoder Resonator
CSA3.60MGF108 by Murata
S5 8 SPST DIP Switch
12
MOTOROLA ANALOG IC DEVICE DATA
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