MC13028A
Figure 1. Typical Circuit for E.T.R. Applications
NRSC Roll–Off Filter
V
CC
R
O
0.22 µF
+
10 µF
0.47 µF
(Note 2)
47 µF
R
O
(Note 4)
+
+
+
Right Output
Left Output
47 µF
(Note 1)
43 pF
(Note 3)
Pilot
Input
Pilot Q
Input
Pilot I
Input
47
14
16
15
13
12
11
10
9
VCO
8
Optional
Force to
Mono
Pilot Tone
Detector
AM Stereo
Decoder
IF
Amp
Signal Quality
Detector
AGC
Reg
RF AGC’d IF Signal from
Mixer (450 kHz from
Tuner IC Section)
1
2
3
IF
4
IF
5
Gnd
6
7
8
Stereo
AGC
Bypass
Stereo
Ref
Blend
Threshold Adjust
Bypass Input
Indicator
+
+
+
+
Scan
Mute
R1
(Note 6)
10 µF 0.47 µF 0.01 µF
10 µF
10 µF
(Note 5)
NOTES: 1. The 47 µF capacitor is recommended to be a low leakage type capacitor. Leakage current due to this capacitor causes
increase in stereo distortion and decreased separation performance.
2. The recommended source for this part is Murata Products. CSA3.60MGF108. The location of this part should be carefully
considered during the layout of the decoder circuit. This part should not be near the audio signal paths, the 25 Hz pilot filter
lines, or the V high current lines, and the ceramic element ground line should be direct to the chassis ground lead in order
CC
to avoid any oscillator inter–modulation.
3. The 43 pF capacitor is recommended to be a NPO type ceramic part. Changing the value of this capacitor alters the lock
range of the decoder PLL.
4. The tolerance on the value of the 0.22 µF capacitor should be within ±20% for the full design temperature range of operation.
Any reduction in the value of this capacitor due to temperature excursions will reduce the pilot tone circuit sensitivity.
5. The 0.47 µF capacitor is recommended to be a low ESR type capacitor, (less than 1.5 Ω) in order to avoid increased audio
output distortions under weak input signal conditions with higher modulation levels.
6. The scan/mute function is located on the Blend pin at Pin 8. To provide this function, Pin 8 should be pulled down below 0.3 V
until the decoder and the synthesizer have both locked to a new station.
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MOTOROLA ANALOG IC DEVICE DATA