MC13028A
7
MOTOROLA ANALOG IC DEVICE DATA
IF
Input
Figure 1. Typical Circuit for E.T.R. Applications
NOTES:
1.The 47
μ
F 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 VCC high current lines, and the ceramic element ground line should be direct to the chassis ground lead in order
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
μ
F 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
μ
F capacitor is recommended to be a low ESR type capacitor, (less than 1.5
) 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.
RF AGC’d IF Signal from
Mixer (450 kHz from
Tuner IC Section)
10
μ
F
0.01
μ
F
R1
Stereo
Threshold Adjust
AGC
Bypass
IF
Bypass
Gnd
Stereo
Indicator
(Note 6)
Blend
Scan
Mute
Reg
Signal Quality
Detector
AGC
IF
Amp
AM Stereo
Decoder
VCO
8
Pilot Tone
Detector
Optional
Force to
Mono
1
2
3
4
5
6
7
Ref
8
16
15
14
13
12
11
10
9
Pilot I
Input
Pilot Q
Input
Pilot
Input
10
μ
F
0.47
μ
F
+
(Note 4)
0.22
μ
F
VCC
43 pF
(Note 3)
(Note 2)
47
47
μ
F
(Note 1)
RO
Left Output
Right Output
NRSC Roll–Off Filter
RO
0.47
μ
F
(Note 5)
10
μ
F
10
μ
F
+
+
+
+
+
+
47
μ
F
+