MC13028A

7

MOTOROLA ANALOG IC DEVICE DATA

IF

Input

Figure 1. Typical Circuit for E.T.R. Applications

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 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

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.

RF AGC’d IF Signal from

Mixer (450 kHz from

Tuner IC Section)

10

µF

0.01

µF

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

B8

Pilot Tone

Detector

Optional

Force to

Mono

12

34

5

6

7

8

16

15

14

13

12

11

10

9

Pilot I

Input

Pilot Q

Input

Pilot

Input

10

µF

0.47

µF

(Note 4)

0.22

µF

VCC

43 pF

(Note 3)

(Note 2)

47

47

µF

(Note 1)

RO

Left Output

Right Output

NRSC Roll–Off Filter

RO

0.47

µF

(Note 5)

10

µF

Ref

10

µF

+

+

++

++

+

47

µF

+